2002 magnetom flash 2

No.2 . 2002s

An Applicat ions Reference for Siemens MAGNETOM Users

M A G N E T O MFlashFlashFlash

2

The information presented in MAGNETOMFlash is for illustration only and is notintended to be relied upon by the reader forinstruction as to the practice of medicine. Any health care practitioner reading thisinformation is reminded that they must usetheir own learning, training and expertise indealing with their individual patients. This material does not substitute for that dutyand is not intended by Siemens MedicalSolutions, Inc. to be used for any purpose inthat regard.

Topic Page

Ultra High-Field 6

Gastrointestinal Imaging 10

MR Colonography Workshop 12

Dark Lumen MR Colonography 14

Paste the motion with PACE & HASTE 16

Vascular Imaging 18

New with syngo MR 2002A – Large FOV Adapter 18

Cardiac Imaging 20

MAGNETOM World Site Visit Pictorial Essay – MAGNETOM Sonata in Monaco 20

New with syngo MR 2002A / Cardiac 22

Fast Black Blood Cardiovascular Imaging 24

TrueFISP Imaging 28

Two News for Viability Imaging 31

Women’s Health 34

Breast MRI: Improved Bilateral 3D Imaging 34

MR Guided Breast Biopsy 36

Diagnosis of Invasive Ductal Carcinoma only with MR 37

Breast MRI: Importance of Dynamic 3D 38

Pediatric Imaging 40

Spin-Echo Acquisition Protocols: Considerations in the Pediatric Brain 40

TrueFISP Thickslice Lung MRI at Low Field Strength 44

Spectroscopy 46

syngo MR Spectroscopy (MRS) in Clinical Practice 46

Upgrades & Options 48

Upgrade your MAGNETOM Impact / Expert to Harmony Maestro Class 48

Neuro Imaging 52

New with syngo MR 2002A / Restore 52

Open Class 54

New with syngo MR 2002A / MAGNETOM Concerto 54

Coil Concept for MAGNETOM Concerto 56

iPAT 60

SENSE and SMASH, Physical Principle, Advantages 62

iPAT: The Siemens Solution 65

iPAT Coils 66

Liver Imaging with VIBE iPAT 68

Super Technologists 70

:Content:

:Editorial:

MAGNETOM World Flash New communications for the MAGNETOM WorldThe MR Marketing team has venturedupon a very extensive project involvingall our MAGNETOM users, to create acommunity made up of different interestgroups – including clinical applicationsand system interests. The project issupported by Siemens’ MR Group. Thecommunications medium for this globalcommunity will be the Internet site:www.siemensmedical.com/MAGNETOM-World

Parallel to this Internet site, we willpublish the magazine “Flash”, appearingquarterly, with news on what is hap-pening in this world wide community.The content will cover MR physics,clinical case reports, clinical methods,application tips, clinical protocols fromreference sites, new product informationand MAGNETOM-World site visits.

We hope you enjoy being part of theMAGNETOM World and find the Flashhelpful and interesting.

A. Nejat Bengi, M.D.Editor in Chief

3

M A G N E T O MFlashFlashFlashTony Enright, Ph.D.

Asia PacificCollaboration,Australia

Marion Hellinger,MTRA

MR Marketing-Application Training,Erlangen

Milind Dhamankar,M.D.

MR Marketing-Applications,Erlangen

Dagmar Thomsik-Schröpfer, Ph.D.

MR Marketing-Products, Erlangen

Peter Kreisler, Ph.D.

Collaborations &Applications,Erlangen

Charlie Collins,B.S.R.T.

Market Manager(USA), Erlangen

Antje Hellwich

Design Editor,Erlangen

Laurie Fisher,B.S.R.T., R, MR

US Installed BaseManager, Iselin, NJ

Daniel Grosu, M.D.

US R&DCollaborations, Iselin,NJ

Michael Wendt,Ph.D.

US R&D Collaborati-ons, Iselin NJ

Helmuth Schultze-Haakh, Ph.D.

Technical Editor,Iselin NJ

Judy Behrens, R.T.(MR) (CT)

Adv. ClinicalApplicationsSpecialist

Raya Dubner

Design Editor, Iselin,NJ

Achim Riedl

Technical Support,Erlangen

Editorial Team

4

:Let’s work together to build the MAGNETOM World…:

We believe that the future success ofMAGNETOM products in the world ofMR will exceed even its recent glories. In the next few years we will be able toseize the tremendous opportunitieswaiting for us.

MR imaging is becoming the ultimateimaging technique in radiology.MAGNETOM systems are steadilydiversifying and advancing into newapplication areas. Advanced gradientsand novel parallel imaging techniqueswill allow greater imaging speed withoutsacrificing spatial resolution and willreplace established modalities in theimaging world. 3D Volume imaging isbecoming routine. Cardiovascularimaging techniques are opening up newhorizons, providing simple solutionswith important information: this has notbeen possible until recently. Viability*imaging to see infarct zones, evaluationof silent infarction, real time cine imagingof the heart – these are only a few of the revolutionary changes that MR isbringing to the medical world.

*This information concerns a use of contrast media that has not been approvedby the Food and Drug Administration. (21 CFR 99.103 (a) (1) (i).

MR Cholangiopancreatography and MR Colonography have the potential tobecome clinical examinations that will greatly reduce the invasiveness,morbidity and cost associated withinvasive procedures. MR imaging alsopromises to become an essential part ofan operating room. MR spectroscopicimaging with syngo is showing goodresults in helping the physicians toassess prostate cancer. Spectroscopyhas already been an important tool inevaluating recurrent brain tumors andmany other neurological diseases.Conventional angiography is being usedmore and more only for guiding interven-tions, as each new development comingfrom MR angiography replaces thediagnostic aspects.

There are many more MAGNETOMdevelopments creating challenges interms of providing continuous updatednews to existing customers and respon-ding to their technical and applicationssupport needs and even, on occasions,their related clinical information needs.The remarkable increase in the numberof MAGNETOM systems is also creatingchallenges in quickly reaching all thoseMAGNETOM users who would like tomaintain their positions as state-of-the-artMR users.

We at Siemens MR see challenges asground for new opportunities and newideas. The challenge has brought us theconcept of “hi5”. We trust this willcreate a network amongst our custo-mers which will solve the questions ofever-expanding number of MAGNETOMusers and encourage close contactbetween other MAGNETOM users, aswell as developing contacts betweenSiemens MR in Erlangen and the userswhom we call the “MAGNETOMWorld”.

MAGNETOM World specials

MAGNETOM World “specials” arespecially priced options offered to our“installed base” members. MAGNETOMWorld “specials” will help maintain theMAGNETOM World members as “state-of-the-art” users, staying at all times onestep ahead of the competition.

We offer specially priced options and up-grades to our “installed base” memberssuitable to their needs. That means thateach customer can make giant leapsforward, or advance by small, steadysteps, exactly as they wish.

No MAGNETOM World member isexpected to “buy a pig in a poke”: all ofour hardware and software can be triedand tested before any commitment tobuy is made.

The message is clear: Our community has the technologyto lead from the front, and to staythere.

What are the “hi5” points for theMAGNETOM World?

MAGNETOM World working groups

MAGNETOM World will be made up ofdifferent working groups led by SiemensCollaboration partners who are there tohelp us develop MR solutions. The pilotprojects will include the “CMR Ambas-sadors” for cardiovascular MR, “Gastro-intestinal Imaging” for Abdominal MR,“Ultra High-Field Club” for users of 3 Tesla and “Super Technologists” as a platform for exchange of informationbetween the technologists, led by well-known professionals in this area. Futureadditional working groups, such as“Pediatric Imaging”, “Women's Health”,“Open Class”, “Head & Neck Imaging”and “Orthopedic Imaging”, will completethe MAGNETOM World, making it aplatform where every user will find thefriendly working atmosphere in whichtheir personal and professional interestsare nurtured.

MAGNETOM World communications

We see the Internet as the most suitable platform for fast, reliable andinteractive information exchange. In thenear future this will be achieved with a community Internet address at: www.siemensmedical.com/MAGNETOM-World, which will be thesource for the different working groups’homepages. Each group homepage willalso be the source for different hospitalsor imaging centres from around theworld. MAGNETOM World members willprovide case reports, clinical methods,MR protocols, application tips, an imagegallery and web-casts of advanced androutine applications. This will be an im-portant, up-to-date common clinical database for the MAGNETOM World. The discussion board of this platform willallow interaction amongst customerswhen they need answers to questions.The e-training portion, in cooperationwith Siemens Med Academy, will providecredits for continuing education to users

5


who don’t have the time to attendmeetings to collect this information. MAGNETOM World Flash magazine willbe the print medium for communica-tions and will have the same contentstructure as the internet.

MAGNETOM World training

We believe that after standard systemtraining, the real training necessary forthe customers is information exchangeat the clinical level where ‘state-of-the-art’ applications are being performed.We are planning to act as a mediatorbetween the “collaboration sites” andthe other MAGNETOM World members,so that “fellowships” and “workshops”can be organized in these places withemphasis on hands-on training. When a MAGNETOM World member goes to a hospital or imaging center for either a fellowship or a workshop, they shouldbe able to use the scanner and also beable to watch the routine use of thesystem, and not just obtain high-leveltheoretical information. The first step for us is to create a training program, inwhich we will list the sites providing“workshops” and “short-term fellow-ships”.

MAGNETOM World meetings

We envisage three different types ofmeetings:

1. The various working groups will havetheir own meetings for information

exchange and product planning.

2.Once a year, all working groups with members from around the

world will meet together in a friendlyatmosphere where they will be provideda platform to show their results andexchange information.

3.Regional meetings will be under the flag of MAGNETOM World and will

be supported centrally from Erlangen,particularly with regard to the scientificcontent perspective.

6

Ultra High-Field

FDA Clearance of MAGNTOM Trio:The 3T whole body system

In January 2002, the MR Division in Iselin,NJ received official notice from the FDAthat the 3T Trio MR System was clearedas a commercial MR product and forclinical use in the US. This was a majormilestone for the new 3T whole bodyMR system from Siemens, because itincluded a broad range of features thatother 3T vendors have not achieved in a single FDA review.

Like the Sonata, which stands head andshoulders above its 1.5T competitors,the Trio distinguishes itself from the 3Tpack with many advanced, cutting-edgefeatures, in both its hardware and soft-ware. Features such as the remarkablegradient system, capable of industry-leading slew rates of 200, and the RFsystem, with 8 fully independent EPIcapable channels, are included in thestandard MAGNETOM Trio configuration.The Trio includes a standard whole bodyRF coil in addition to its head coil system.The high level of attention that the Triohas attracted so quickly, is surely anindication that it has a very bright futureas the newest member of theMAGNETOM family.

First Trio installed at MGH in recordsix days

From the time that the riggers deliveredthe MAGNETOM Trio magnet into the facility at the MGH on 6 November2001, it took a well-rehearsed SiemensMR installation team a record time ofjust six days to obtain the first images on12 November. To fully appreciate thisunprecedented event, just rememberhow early competitive 3T installationsused to require several months!

Equally competitive, the MGH teamwasted no time obtaining very impressiveclinical images throughout the body. Infact, many 3T enthusiasts who visitedRSNA 2001 remarked on viewing theSiemens MR exhibit that these first Trioimages were the highlight of their visitand were clear evidence that Siemenswas the leading player in the new “UltraHigh-Field MR” market.

New Trio installations have quickly follo-wed in Germany, the Netherlands andDenmark as well as continuing in the US,with Emory University Medical Center in Atlanta, and at other sites around theworld. The very high interest in the Trioand its success in the market has, inturn, given the Siemens experts in Erlan-gen the challenge of rapidly increasingthe Trio manufacturing capabilities inMR. Siemens MR is now well-poised toaddress the high demand for this new,exciting MR system.

MAGNETOM Trio Sites:

MGH Boston

FC Donders, Nijmegen, Netherlands

Emory University, Atlanta, GA

UKE Hamburg, Germany

NYU Medical Center, New York

Hyidovre Hospital. Denmark

Shapiro Medical Clinic, Orlando, FL

Max Planck Institute, Gottingen, Germany

Northwestern University, Chicago, US

Yale University, New Haven, CT

Kyoto Univeristy, Japan

Health South Hospital, Birmingham, AC

Uni. Of Miami Medical, Center, FL

The MAGNETOM Allegra continues its unique 100% market share in brain mapping centres since its introduction !

Since its FDA review in October 2000, the dedicated 3T Neuro MR system –MAGNETOM Allegra – has been installedat an ever-growing number of sites thatuse the MR exclusively to performhighly sensitive functional MRI studieson healthy human subjects. Their soleuse for the 3T MR is to perform brainmapping studies with the goal of under-standing how the brain is organized andhow it works. This is a significantcontrast to the more common use forthe MR, namely the diagnostic study ofdisease in clinical patients.

The first such Allegra installation at anon-medical facility is at PrincetonUniversity in NJ, where the system isused exclusively by the Department ofPsychology research faculty to unravelthe mysteries of the human brain. This

Figure 1: MAGNETOM Trio (3 Tesla whole-body MR)

Figure 2: BOLD imaging

:Siemens Captures Exploding MRMarket with Two 3T MR Products:Yuri Wedmid, Ph.D., Siemens Medical Solutions USA, Iselin, NJ

profession) rather than lagging behindthe field. Your teeth are important toyou, and that’s why you need the righttoothpaste and the right dentist! Cer-tainly, such advertising claims carry realweight in the oral hygiene market.Imagine, then, the huge impact the follo-wing statement creates amongst the 3T MR community: “ALL of the leaders in the human brain mapping world use -MAGNETOM Allegra 3T MR systems intheir own brain mapping research!”What else could you safely buy?

It all started with Dr. Seiji Ogawa. Duringhis time at Bell Labs in NJ, Dr. Ogawawas the first to discover a new biophysi-cal phenomenon that the MR communitynow knows as the “BOLD (Blood Oxy-genation Level Dependence) effect”.Using animal models and various physicalstimuli – including tactile stimulation oftheir paws (tickling), he was able to detectminor contrast changes in the brainimages when comparing stimulated andcontrol images. It was these exact areasof the brain that he determined weredirectly affected by the tactile stimulation.He then proposed that such “susceptibi-lity-based” effects could be used tofollow other brain events.

There are now several large internationalscientific societies which attract thou-sands of scientists to meetings exclusi-vely devoted to the discussion of brainmapping studies. The basis for this wholeacademic field goes back to the earlydiscovery of this unusual phenomenonwe now call “BOLD”. Today, Dr. Ogawais the proud owner of a MAGNETOMAllegra 3T MR system at his new facilityin Tokyo, Japan, where he continuesresearch into this growing area, an areawhich has rewarded him so muchrecognition.

Similarly, a research team at the MGHNMR Center in Boston was the first todiscover that the human brain could bemapped by stimulating different brainstructures via visual stimuli. In theirseminal paper, published in Science, the

team was the first to describe the BOLDeffect in humans. MGH continues to be a very important site in the brain map-ping community, which also uses theMAGNETOM Allegra to pursue itspioneering work in this research area.

Many other leaders involved in brain mapping throughout the world also have, or are in line to obtain, a 3T MAGNETOM Allegra MR system –the “ultimate fMRI machine”. These 3T Allegra sites include:

Mallincrodt Institute, Washington Univ Med Ctr,St Louis, MO;

Univ Med & Dent of NJ partnered with RutgersUniv Psychology in Newark, NJ;

Univ North Carolina Med Ctr, Chapel, Hil, NC;

Cleveland Clinic, Cleveland, OH;

Univ Indiana Med Ctr, Indianapolis, IN;

Carnegie Mellon Univ Psychology, Pittsburgh, PA;

Univ of Oregon Psychology , Eugene, OR;

Mt Sinai Med Ctr, NY, NY;

Univ Florida Brain Ctr, Gainesville, FL;

Univ Kansas Med Ctr, KC, KS;

New York Univ Psychology, NY, NY;

Univ of Illinois Brain Ctr, Urbana, IL

Baylor Univ Med Ctr, Houston, TX (2 Allegras );

National Institute of Drug Abuse, Baltimore, MD;

International Neuroscience Institute, Hannover,Germany;

Univ Lund Med Ctr, Lund, Sweden,

Prof. S Ogawa, Tokyo, Japan;

Prof. Sadato, Tokyo, Japan;

Univ Liege, Liege, Belgium

Singapore Gal Hospital, Cognitive NeuroscienceLab, Singapore

Hacettepe Univ. Ankara, Turkey

Functional Imaging Laboratory, London, UK

… and the list grows by the day …. !!

7


Figure 3: MAGNETOM Allegra, 3T dedicated headscanner

site – the Center of Brain, Mind &Behavior (www.csbmb.princeton.edu) –is now a recognized leader in this area.Its research reports, incorporating theAllegra results, have appeared in majorscientific publications such as Natureand specialized neuroscience journals.The NY Times has highlighted its workon several occasions for its many noveland seminal discoveries in the basicneuro-sciences. Of course, the Allegra,as the centrepiece technology of theCSBMB, has also attracted similar highlevels of attention in this specialized,non-medical MR community. In fact, theAllegra is becoming ubiquitous in thissophisticated community of brain map-ping neuroscience sites. There are nowMAGNETOM Allegra installations inEurope and Japan as well as in the US.

“BOLD” leaders favor the Allegra –“the ultimate fMRI machine” – fortheir own brain mapping research

When you hear the claim that “tooth-paste X is recommended by 4 out of 5 Dentists”, you probably feel comfor-table buying that brand of toothpaste.You probably also secretly hope thatyour dentist is in the mainstream of con-temporary dentistry (one in four of the

8

Ultra High-Field

Spectra from a double oblique CSI slice in healthy volunteer brain.Courtesy of MGH-NMR Center

TSE-T2-weighted, spine body coilTR 3500 ms, TE 139 ms slice thickness 4 mmFOV 380x380 mm

TSE-T2, TR/TE 5000 / 51 ms,slice thickness 3 mm, FOV 179x220 mm

Turbo-Inversion-Recovery,TI / TR / TE 2400 / 9000 / 99 msslice thickness 3 mmFOV 201x230 mm

T1-weighted, 3D Turbo-FLASH (MP-RAGE), TI / TR / TE 1100 / 300 / 5 ms 1mm,FOV 192x256 mm

TOF 3D; FOV 150x200 mm; 72 slices in 4:50 min; TR / TE 40 / 7.2 ms; SL 0.8 mm, 512-Matrix

Tx / Rx body coilTR / TE 5.6 ms / 2.8 ms,slice thickness 5 mm, FOV 212x340 mm2D TrueFISP sequence

Heart, short axis view, body coilTR 47 ms, TE 1.6 ms, slice thickness 7 mm, FOV 292x360 mm2D TrueFISP sequence

Tx / Rx body coilTR / TE 24.6 / 2.5 ms,slice thickness 3 mm, FOV 360x360 mm2D TrueFISP sequence

3 Tesla Image Gallery

9


TSE 2D with fatsat, FOV 150x200 mm, 19 slices in 2:06 min, TR / TE 4500 / 35 ms, SL 2 mm, 512 matrix

Wrist imaging512x512 FLASH 3D water excitation

TSE, 22x16 FOV, 5 mm skip 1 mm, 28 slices, 256x192x4 NEX, Acquisition time: 4:08 min.

3.0T Siemens MAGNETOM Allegra, TSE, 22x22 FOV, 4 mm skip 0.8 mm, 25 slices,512x255, Acquisition time: 5:11 min.

14 year old male with single seizure 1.5T Images interpreted as showing ventricular dilation, otherwise normal

3T provides improved resolution and diagnostic capability:Heterotopic gray matter now clearly evident

1.5 Tesla3 Tesla

More for abdominal imaging…

Improved protocols for abdominalimaging can be found under the 2002Aprotocol tree, / / Upper abdomen.

You will find new fat-sat TrueFISPprotocols as well as new respiratorytriggering sequences (Fig. 2).

Ti p

New with syngo MR 2002A: Normalize Improvements

For abdominal imaging there is an impro-ved algorithm with our normalize filter.This algorithm replaces the old algorithmused in previous software versionswhen using the body array coil and thespine array coil, the body extender plusthe spine array coil, or the endo-rectalcoil and spine array coil. It reduces thesignal drop in the center of the imageand reduces the intensity of the sub-cutaneous fat (Fig. 1).

In your protocol, when you select

the resolution card, you can select

which normalize algorithm to use.

When the new one is selected, there

are no other options within the

normalize filter. If you are using a

coil other than the above mentioned

coils, the normalize filter will still

have the options for intensity,

width, and cut-off as before the

upgrade.

10

Gastrointestinal Imaging

TrueFISP fatsat TrueFISP

New Algorithm Old Algorithm

Figure 1: New image normalize algorithm

Figure 2: TrueFISP fat-sat for abdominal imaging

With “respiratory triggering”, therespiratory signal rises during inspirationand falls during expiration. It is used togenerate the trigger signal depending onthe selected respiratory phase. Tominimize motion artifacts, the acquisi-tion window is typically selected duringexpiration.

This technique is useful to reduceartefacts caused by respiratory motion.These new respiratory- triggeredsequences can be found in the syngoMR 2002A protocol tree under upperabdomen / respiratory triggered. Theyare listed as T1 FLASH 2D, T1 FLASH inand out of phase for the segmented

Ti p

Ti p

Under threshold you select at which

point in the respiratory cycle

scanning is to be triggered. When

the respiratory curve reaches this

threshold value, the signal is

triggered. Acquisition is set by using

the tool tip. Select which phase you

want to use – expiration or inspiration.

The TR is going to depend on

whether you use a gradient echo,

TSE, or TIR sequence and the

coil. Be sure to check that the

airflow in the belt is not be restricted

in any way.

VIBE not only for abdomen…

There are three new 3D VIBE fat-satsequences in the syngo MR 2002Aupgrade. One for arthrography of theshoulder, hip and knee.

11

M A G N E T O MFlashFlashFlashgradient echo sequences. For the TSEsequences they are listed as T2TSE2D27, and a T2 TIR2D23 where the23 & 27 represent the echo train for thesequence. The improvement with therespiratory-triggered gradient echo isthat with the FLASH you can now havesegmented sequences with constantRF that will improve T1 contrast withless scan time. These are labelled FL2D3 and FL2D5, where 3 and 5 representthe number of segments. Due to respi-ratory triggering and the variation in thepatient’s breathing, the T1 from onedata line to another could vary. With thenew sequences and the constant RF, all data points have the same relaxationtime, and therefore all have the sametissue characteristics (Fig. 3).

On the physio card, when you

are setting up segmented FLASH,

your TR is set to the minimum TR

for each segment. Put the mouse

cursor next to the acquisition

window and you get a tool tip that

tells you the recommended acquisi-

tion window for the segmented

sequences. The acquisition window

should be set according to the

number of segments if using seg-

mented gradient echo. For the

TSE and TIR the TR should be equal

to, or less than, the acquisition

window.

With T2 respiratory-triggering, use

multiple concatenations and

interleaved slice order, since this

will eliminate the bright slices of

the data set and reduce cross-talk

between the slices.

Figure 3: Improved T1 weighted gradient echo imagingwith constant RF

Figure 4: Reduced crosstalk between slices in T2weighted imaging

Figure 5: MR Arthrography with VIBE

:MR Colonography Workshop 24-25 January, Erlangen:

12

Figure 1: Scene from the meeting

Colon cancer is the second mostcommon malignant tumor in the UnitedStates. The incidence of colorectalcancer can be reduced with early polypdetection.

Conventional colonoscopy, an accuratemethod in detection of colorectal lesions,offers the advantage of simultaneousbiopsy or polyp removal. Patientacceptance for this procedure has beenpoor due to many reasons ranging from procedural discomfort to risk ofperforation.

Virtual colonography with either 3D CTor MR has been shown to be accurate indetection of polyps exceeding 10 mm indiameter.

To evaluate present and potential futureof MAGNETOM MR systems in this area,a workshop was organized in Erlangen.Participants were: Dr. Diego Martin fromUniversity of West Virginia, Dr. A. ThomasLauenstein from University of Essen, Dr. Nina So from Prince of Wales HospitalHong Kong, Dr. David Szapiro fromUniversity of Liege, and Professor Dr. J. F. Riemann and Priv-Doz. Dr. H. E.Adamek of the Department of Gastro-enterology and Priv-Doz. Dr. GuenterLayer of the Department of Radiology,of the Academic Teaching Hospital,Ludwigshafen, Germany.

Dr. Diego Martin shared his experiencein TrueFISP colon imaging with theMAGNETOM World members. The re-sults were impressive due to intrinsichigh S/N ratio of this sequence. In True-FISP colonography, water is used as theintraluminal contrast and no additional IVcontrast material administered. Virtualendoscopic views were easily obtainedand of good quality due to high S/N andintensity difference between lumen andcolon wall. The problem with TrueFISPcolonography is air bubbles. They havethe same intensity as the colon wall anda polyp can be hidden in such an airbubble. The air bubbles also can causeconfusion in diagnosis as they mayimitate a polyp (Fig. 2).

Dr. David Szapiro mentioned his animalexperiments with MR VIBE imaging andthe comparison with CT. The resultswere surprisingly in favor of MR. Theintraluminal contrast he used in his expe-riments was air.

Another interesting concept in ourworkshop was that we could possiblywin over gastroenterologists participati-on in this non-invasive method of colonexamination. Professor Dr. Riemanngave a very interesting lecture about thestatus of prevention of colon cancer andendoscopy. So we could learn abouttheir perspectives in this techniquewhich is regarded by some gastroente-rologists as a threat to conventionalendoscopy. Prof. Riemann pointed outthat new comfortable screening methodsare needed in order to increase scree-ning acceptance among the population.Virtual Colonoscopy could fill this gapbetween occult blood tests and invasiveendoscopy procedures. Their contributi-on to our product planning was invalua-ble. One of the important contributionswas that the clinicians see this techni-que more in the direction of whole abdo-men information possibility rather thanreplacement of endoscopy. Everybodyagreed on the fact that MR had more toprovide than just the virtual endoscopicresults from the 3D VIBE technique.Many diseases in the abdomen,including ulcerative colitis and Crohn’sdisease could benefit from bowel walland vessel information coming from raw 3D VIBE images.

Dr. Lauenstein from Essen Universityshowed his results with the new emer-ging MR colonography technique called“Dark Lumen Colonography”(Fig. 3, 5).In this approach, water is used as rectalenema and IV paramagnetic contrastmaterial is administered, which helpsthe diagnosis of polyps due to theirenhancement characteristics. The


Figure 2: TrueFISP colonography Images

Dr. Nina So showed examples from thePrince of Wales Hospital, Hong Kongand brought a new perspective to colonimaging by the presentation of HASTEColonography approach. She stressedthat HASTE images with intraluminal airwere very useful in diagnosis of colonrelated pathologies bigger than 8 mm.This feedback was very important to usin support of our plans of new HASTEtechniques with thinner slices. Parallelacquisition techniques might also beused in the future as the early results haveshown the efficacy of this technique insingle shot imaging by providing higherspatial resolution than today in the sameor shorter acquisition time. Of course,PACE techniques might also be helpfulfor patients having difficulty with breath-holding.

results were extremely encouraging for various reasons. Residual stool caneasily be differentiated from a polyp due to lack of enhancement. With darklumen imaging you need to examine thepatient only in supine or prone position,you do not need both positions as in CT examinations or conventional MRColonography. Evaluation of otherorgans due to IV paramagnetic contrastis far better than other techniques. This dark lumen imaging with IV contrastis also useful in patients with Crohn´sdisease.

Dr. Bernard Geiger from PrincetonSiemens Corporate Research showedMR Virtual Colonoscopy results fromdifferent MR imaging techniques. Hissignificant conclusion on behalf of EssenUniversity “Dark Lumen Colonography”was, “I was amazed at the quality ofvirtual endoscopic views from VIBEimages”. Dark Lumen imaging withVIBE also has the advantage that air andwater have the same intensity so thatyou do not have the problem of air bub-bles causing confusion. This problemwas seen with conventional MR Colono-graphy (lumen bright, air dark, polypdark) and TrueFISP MR Colonography.(lumen bright, air dark, polyp dark). Shortnotes from Dr. Geiger's presentation are as follows:

VRT uses an opacity mapping functionthat maps data values to 100% transpa-rent (e.g. the lumen) and other values to100% opaque (e.g. the wall). Values inbetween are mapped to a percentage ofopacity between 0% and 100% (Fig. 4).

The intensity values should not overlap.An overlap means that some voxelsfrom the lumen have the same value assome voxels from the wall. If this is thecase, any opacity mapping will eitherproduce images that show opaquelumen voxels floating in the lumen, orproduce holes in the wall.

IV contrast-enhanced VIBE colonoscopyimages provide the contrast needed to successfully separate wall and lumen and create a high-quality surfacerendering (Fig. 5).

TrueFISP images have an even betterspectrum of values and allow a betterseparation of lumen and wall if water isused as intraluminal contrast. Unfort-unately, however, the presence of airbubbles creates a problem for the rende-ring, since air and wall have overlappingvalues. In IV contrast enhanced VIBE,both air and water show as dark

contrast. VIBE images without IVcontrast enhancement were not suitablefor 3D rendering, since there was notenough dynamic range to successfullyseparate the values of wall and lumen.

13


Figure 3: Showing dark lumen polyp detection

Figure 4: Volume-rendering diagramFigure 5: Showing snapshot from “VIBE Colonography”

:Dark Lumen MR Colonography:

14

■ Change of MR Colonography trendfrom Bright Lumen to Dark LumenImaging

■ VIBE for MR Colonography

■ Fecal tagging

In conventional “Bright Lumen MRColonography” water mixed with Gado-linium is administered via the rectaltube. The result is that the colon wall isdark and the colon lumen bright (Fig. 1).This creates quite homogenous endos-copic views of the colon. Bright LumenMR Colonography has provided resultsin which diagnosis of 5-6 mm polypswere possible. Nevertheless, brightlumen colonography was associatedwith high costs due to the quantity ofGadolinium, which could be more than60 cc (Fig. 1).

In “Dark Lumen Colonography”, thecolon is filled with normal water. Thisfilling process is monitored by usingTrueFISP sequence TR: 3.2 msec; TE: 1.6 msec ; flip angle 70°; matrix256x256; FoV 400 mm; section thick-ness: 4 mm. After complete filling andadequate distension of the colon, thefirst imaging series is obtained. After intravenous paramagnetic contrastadministration, the post-contrast seriesare obtained after a delay of 75 seconds.(VIBE, TR: 1.64 ms , TE: 0.6 ms , FOV 45cm, effective section thickness 1.57mm and a matrix 460x512, acquisitiontime 22 seconds).

The FOV coverage includes the liver.The ability to evaluate the extracolonicorgans of the entire abdomen and pelvis,in addition to assessing the colon, is animportant benefit inherent to MR colono-graphy. The possibility of detecting life-threatening lesions in organs outside thecolon in the course of colon screening is an important potential benefit (Fig. 3, 4, 5).


Figure 1: Conventional Bright Lumen MR Colonography

Figure 3: Dark lumen colon image showing polyp and liver metastasis (left). Virtual endoscopic view showing polyp (right).

Pre-contrast 75 sec post contrast Virtual endoscopic view

Figure 2: Dark lumen colonography and virtual endoscopic view

15


The results with this technique haveshown that colorectal lesions enhancestronger than the colon wall and polypsranging in size from 7 mm to 12 mm canbe detected (Fig. 2, 3).

Will fecal tagging be the preferredmethod in the future ?

Most patients going through bowel pre-paration for colonoscopy complain aboutthe procedure and patient acceptance is rather low. Essen University doctorsare trying a new tagging technique byadding contrast-modifying substancesto regular meals. To achieve this fecaltagging, barium sulphate is being usedand proved to be an ideal tagging tooldue to its low cost. Patient preparation is as follows:

■ A highly concentrated barium sulphatecontaining contrast agent is administe-red in a dose of 200 ml with each of fourprincipal meals, beginning 36 hoursbefore MR Colonography. Patients areinstructed to avoid intake of all fiber-richfood and nourishment with a highconcentration of manganese, such aschocolate or fruit during this period.

■ The rest of the examination is done asexplained before for dark lumen imagingtechnique.

The Essen experience has shown highdiagnostic accuracy regarding detectionof clinically relevant lesions with fecaltagging MR Colonography.

Figure 4: Crohn´s disease with Dark Lumen MR imaging. Thickened bowel wall and increased contrast enhancement in descending / sigmoid colon.

Figure 5: MIP reconstruction Dark Lumen Colonography data set demonstrates aorticaneurysm in patient with colorectal carcinoma

Figure 6: Effect of fecaltagging in DarkLumen MRColonography

Without fecal tagging With fecal tagging

Acknowledgements:

Special thanks go to Dr. Lauenstein from University of Essen for his clinical input andvaluable image data.

Ti p

:Paste the motion with PACE & HASTE:

16

Major advances in abdominal MRimaging in recent years have been dueto development of ultra fast breath-holdsequences like VIBE, TrueFISP and newdeveloping techniques like iPAT. Never-theless, there is still interest in the areaof non-breath-hold imaging due to pati-ents who cannot hold their breath evenin the range of 15 to 20 seconds. syngoMR 2002A provides the MAGNETOMusers a unique technique called PACE(Prospective Acquisition Correction).This integrates navigators into differentabdominal MR scanning methods. Oneof the most important application ofPACE has been with HASTE sequenceswhich practically allows the patient tobreath freely. The navigator informationobtained from the diaphragmatic motion,allows the sequence to run automaticallyat the appropriate phases of thebreathing cycle. Image quality of HASTEwith PACE is equal to, or even excels,breath-hold HASTE imaging.

How does HASTE & PACE work ?

syngo tells you in detail…

■ When the scan is commenced, it does180 scans to look at the patient’sbreathing, before the actual scanningbegins.

■ The system automatically determinesthe central position of the acceptancewindow during the initial learning phase.

■ The turquoise window shows thenavigator position during the phase ofthe gating algorithm. After the learningphase, a slice is generated if thedetected position (green curve) falls intothe yellow acceptance window. Duringdata acquisition, the respiratory curve isnot continued. However, the greencurve is replaced by a red section thatidentifies the acquisition phase.

Terminate the measurement if

the position is not correct. Guide the

navigator asymmetrically to the

edge of the diaphragm. This may

be required, for example, when the

localizer was scanned during full

inspiration or expiration.


Figure 1: HASTE & PACE whole abdomen image

What is the navigator in PACE ?

■ The navigator of the abdominal 2DPACE is a low-resolution gradient echoimage.

■ The excitation volume is a disk thatextends in 2 directions across the entiremeasurement volume and intersectswith the tissue to be examined.

■ The navigator pulse produces an echo as it tracks the movement of thediaphragm.

■ You can see the result of this tracewithin the “online display”.

Figure 2: Pancreas imaging with HASTE & PACE

Figure 3: Online display showing the breathing cycles

Figure 4: syngo

syngo will raise a lot of questions

Why is the waiting room called a waiting room?

Why are the patient data available at the click of a mouse?

How come the technologists work so relaxed?

What explains the administrator’s good mood?

A9

11

00

-M-Z

66

2-0

4-7

60

0

www.SiemensMedical.com

syngo, the revolutionary software for medical imaging,

improves workflow and enhances efficiency. With an

intuitive user interface, syngo creates a new, wide-reaching

standard. syngo is more than just a process improvement

tool. It can improve attitudes as well. syngo makes the

technologist’s routine easier, saves the administrator a lot

of headaches, and patients a lot of waiting. That‘s what we

call Best Practice Integration.

Siemens Medical Solutions that help

18

:New with syngo MR 2002A –Large FOV Adapter:

Vascular Imaging

Figure 2:Additional possibility of connecting CP BodyArray Extender

Figure 3:Examples of peripheral run-off studies withthe Large FOV Adapter

The routine evaluation of renal arteries inperipheral run-off studies is a favoredmethod by the vascular radiologists. The normal coverage of the MAGNETOMSystems with “CP Body Array + CP SpineArray + Peripheral CP Angio Array Coil”has sometimes created shortcomings inevaluation of renal arteries of tall patients.One solution for this would be the use ofthe Body Coil to image the renal arteries,although this will not provide the highspatial resolution needed for the gradingof renal artery stenosis. Another solutionwould be to increase the length of cover-age of CP Array Coils. The large FOVAdapter was developed for this purpose,being placed immediately below thespace for the head coil. This allows youto move the CP Spine Array Coil down

the table away from the magnet. Thisincreased coverage is useful for tallpatients when doing renals and peri-pheral runoffs. Another advantage of thelarge FOV adapter is that the CP BodyArray Extender can be connected to it,allowing additional signal and coveragefrom this CP Array Coil. Typical for thiscombination, (Peripheral CP Angio ArrayCoil + CP Body Array + CP Body ArrayExtender + CP Spine Array), the cover-age extends from the diaphragmaticlevel to the pedal arteries.

Extended FOV Peripheral MR Angiography

Atherosclerotic occlusive diseasecauses a spectrum of ailments with sub-stantial morbidity, including claudication,rest pain, tissue loss and gangrene.When planning a revascularization proce-dure, information about the number,length and severity of vascular lesions isessential. Magnetic Resonance angio-graphy has recently emerged as a non-invasive alternative to conventionalangiography.

Figure 1:Large FOV Adapter shifts the CP-Spine Arraycoil by 35 cm. CP Body Array Extender can be connected to the plugs of the adapter.

:New with syngo MR 2002A –3D ToF with Water Excitation:

19


A 3D water excitation time-of-flight sequence has beenadded for angio of the brain. This sequence providesimproved contrast to noise. The advantage of using a waterexcitation pulse for fat suppression, is that water outsidethe shim volume cannot be inadvertently pre-saturated andyou can use a lower TR.

This sequence can be found under angio-head / ToF arteries.

Figure 4:Head angiography 3D ToF with we

20

:MAGNETOM World Site Visit Pictorial Essay – MAGNETOM Sonata in Monaco:

Cardiac Imaging

Cardio Thoracic Centre in Monaco (50 beds private clinic with state-of-the-art equipment).

MR scanning room with windows facing the harbor of Monaco.

Exquisite noise reduction system:Specially designed floating panelsinside the scanning room, each panel is freely movable to attenuatevibrations.

21


Dr. Civaia (the cardiologist in charge of Cardiac MR) standing next to a verypatient-friendly device:

Imitation window which shows the outsideworld in real-time in the new ICU (IntensiveCare Unit) located in the interior of thebuilding. Live video of the harbor taken withcamera from the top of the building.

Private cable TVviewing for eachbed in the ICU

“If you have to be in the intensivecare unit, this is the best it can get.”

They were not picky, they only wantedthe best…

MAGNETOM Sonata gradients

■ 40 mT/m @ 200 T/m/s (per axis)

■ 69 mT/m @ 369 T/m/s (effective)

■ 200 µs rise time

Ti p

Ti p

:New with syngo MR 2002A / Cardiac:

22

With syngo MR 2002A, it will be possibleto use gradient echo sequences andTrueFISP with retrogated gating allowingscanning of a complete cardiac cycle.

ECG/Retro or Pulse/Retro options

can be selected as the Signal / Mode

on the Physio card. The acquisition

window should be set to approxi-

mately 125% of the average RR

interval – longer in case of a highly

variable heart rate. The parameter

“Calculated Phases” determines

the number of reconstructed

images. This can be arbitrarily set by

the user. The resulting images are

evenly distributed across the entire

cardiac cycle.

The parameter “Phases” is auto-

matically set by the sequence to the

maximum (Acquisition Window /

TR). This is the number of repetiti-

ons of each line which occurs over

the Acquisition Window. The sam-

pling interval is indicated by “TR”.

If “Calculated Phases” is lower than

“Phases”, averaging of the data

occurs. If “Calculated Phases” is

higher than “Phases”, interpolation

of the data occurs.

New TrueFISP sequences with echo-sharing help to improve the temporalresolution in cardiac cine examinations.

Echo-shared cine sequences are set

up and run the same way as existing

unshared sequences. The TR reflects

the effective temporal resolution

after echo-sharing. The number of

segments does not reflect the echo-

sharing. Thus, a typical protocol may

acquire 32 segments per heartbeat

with a temporal resolution of

50 ms. The number of phases is

automatically set to the maximum

allowed by the acquisition window.

Cardiac Imaging

The acquisition speed possible withecho sharing makes multi-slice cine ima-ging feasible. For example, it is possibleto acquire 32 segments with under 50 mstemporal resolution. Thus, including a single heartbeat for magnetization pre-paration, a single slice cine series can be acquired in 5 heartbeats (128 x 256matrix), and 3 slices can be acquired in arelatively short 15 heartbeat breath-hold.This not only speeds up the entire cardiacstudy, but also reduces the number ofbreath-holds that a patient is required toendure (Fig. 2).

Figure 1: Images acquired in a volunteer using 24 segments and 35 msec effective temporalresolution

Slice 1

Slice 2

Slice 3

Figure 2: Three slice levels acquired during a single breath-hold of less than15 seconds. Three time frames are shown for each of the slices

Ti p

23


Figure 3: Images are examples of real-time cine in ahealthy volunteer acquired in multi-slice mo-de using an R-wave trigger to start the scan of each slice level. Cines at 7 short-axis levelswere obtained in a single breath-hold of 14 heartbeats. Matrix was 70x128.

Figure 4: IR prepared TrueFISP single breath-hold of 13 heart beats using IR TrueFISP with 65 segments

Figure 5: Single-shot Black-Blood TrueFISP imagesare shown

Single-shot Black-Blood Imaging withTrueFISP: Single-shot 2D TrueFISP com-bined with the Dark Blood double inver-sion preparation may provide higherresolution and less sensitivity to cardiacmotion than HASTE for static anatomicalimaging of the thoracic vasculature (Fig. 5).

Coronary Imaging with PACE: Thenew PACE technique with navigators isespecially useful where 3D TrueFISPsequences can be used for coronaryimaging without IV contrast material (Fig. 6).

Figure 6: Coronary Imaging with TrueFISP with navigators compared to breath-hold 3D MRA

3D breath-holdfree breathing 3D navigatorgating + slice following

Realtime TrueFISP sequence is nowavailable for cine cardiac imaging ofpatients who are otherwise difficult to scan due to many reasons, such assevere arrhythmia and difficulty inbreath-holding (Fig. 3).

Cine series of multiple slice levels

can be acquired in a single acquisi-

tion. Breath-holding is helpful to

maintain slice position registration,

but breathing motion will not affect

image quality in a real-time acquisi-

tion.

In multi-slice acquisitions, the begin-

ning of each slice acquisition can be

synchronized to the R-wave by

selecting ECG triggering. Following

the R-wave, images are acquired in

rapid succession for the period

of time specified as the acquisition

window.

A cine series can be obtained with-

out any synchronization to an ECG

or other physiological signal by

turning off triggering. The number

of phases is used to define how

long the acquisition will run without

triggering.

IR prepared TrueFISP: Segmented 2DInversion Recovery Imaging post-contrast(late enhancement viability imaging fornon-cooperative patients, patients withsevere arrhythmia). IR-prepared True-FISP can be substituted for segmentedturboFLASH in applications requiring IR contrast. The short TR and high SNRof TrueFISP makes it possible to acquiremore lines per cardiac cycle, and therebyacquire multiple slices in a single breath-hold. Short TR also makes it feasible to acquire an entire 3D volume coveringthe heart in a single breath-hold usingsegmented TrueFISP.

:Fast BLACK BLOOD Cardiovascular Imaging:Orlando P. Simonetti, Ph.D., Niels Oesingmann, Ph.D.Siemens Medical Solutions, Chicago, IL and Erlangen, Germany

With the introduction of multi-echo spinecho techniques, known as turbo spinecho (TSE), the possibility of acquiringhigh resolution BLACK BLOOD images of the heart and blood vessels within abreath-hold, or even in a single heartbeat,became a reality. These rapid multi-echotechniques have generally replacedstandard spin echo sequences for anato-mical cardiovascular imaging.

Technical Details

Spin echo imaging of the heart andvascular system relies on the washoutof blood signal to generate contrastbetween the blood and vessel or heartwall. Blood flowing rapidly through theimaging plane does not experience the90º excitation pulse and 180º refocusingpulse and therefore exhibits little or nosignal. Spin echo imaging has proven tobe relatively successful in generatingblack blood images of the heart andblood vessels. However, it does sufferfrom several drawbacks. Firstly, bloodmust flow completely through the slicein the time between the 90º and 180ºpulses. The time is typically on the orderof 5 ms to 10 ms and may not besufficient, particularly if the primarydirection of flow is not perpendicular tothe image plane. Secondly, this samewashout effect can cause signal dropoutand motion artifact within the heart itself if data is acquired during phases of rapid cardiac motion. Thirdly, at an acquisition rate of only one line percardiac cycle, ECG gated spin echosequences must run for a period ofseveral minutes and respiratory motionartifact can be problematic.

To address these problems TSE sequen-ces designed specifically for cardio-vascular imaging were introduced. Oneof the primary benefits of TSE overstandard spin echo is that the acquisitiontime is reduced to the point that imagescan be obtained in a short breath-hold.This is accomplished by applying multi-ple refocusing 180º pulses after eachexcitation. Typically from 8 to 32 echoes

are acquired following each excitationreducing the acquisition of a 128 x 256image down to from 4 to 16 heartbeats.While reducing the acquisition to a breath-hold successfully eliminatesrespiratory motion artifacts, the washouteffect can still be insufficient to elimina-te blood signal and provide high contrastbetween blood and vessel or heart wall.A double inversion blood nulling prepara-tion pulse has been used successfully to suppress blood signal in both Turbo-FLASH and TSE pulse sequences. Thecombination of a spatially non-selective180º pulse followed immediately by asection selective 180º pulse is appliedwhen the R wave trigger is detected(Fig. 1).

null point in 500 - 600 ms, depending inthe time allowed for recovery betweeninversion pulses. The shorter the timebetween successive inversion pulses,the shorter the TI required to null theblood signal. This fact enables the tech-nique to work over a wide range of heartrates. At shorter heart rates, the timeavailable within the cardiac cycle forinversion recovery delay is shorter, butfortuitously the repetition time andinversion time to null blood are alsoshorter. Acquiring the image data duringmid to late diastole also avoids rapidcardiac motion which can occur duringsystolic contraction and the early fillingphase of diastole.

24

Cardiac Imaging

Figure 1:Timing diagram for black blood turbo spinecho. The double inversion pulse is applied atthe R wave trigger, effectively inverting allspins outside of imaged slice. During TI,inverted blood replaces blood within the sliceplane. The 90º excitation pulse is applied nearthe time that inverted blood recovers to itsnull point. A third inversion pulse can beoptionally applied to generate STIR contrastfor fat suppression and greater sensitivity to tissue fluid.

The result of this combination is that allspins outside the selected slice areinverted, while the magnetization withinthe slice experiences both 180º pulsesand therefore undergoes zero net rota-tion. The inversion recovery time extendsover systole, allowing the uninvertedblood within the slice plane to be replacedby inverted blood. The 90º excitationpulse of the TSE readout is then appliedin diastole after the heart has returned toapproximately the same shape andposition that it was at the R-wave whenthe blood nulling preparation pulse wasapplied. Blood, which has a relativelylong T1 relaxation time, approaches its

Several variations of the basic blood TSEscheme are possible and are currently in widespread clinical use. T1 weightedimaging can be performed by using ashort echo train (7-15 echoes) to keepthe effective TE short and triggeringevery cardiac cycle to keep the effectiveTR as short a possible. T2 weighted ima-ging is achieved by triggering every twoor three cardiac cycles and using a relati-vely long echo train (15 to 35 echoes)and long effective echo time.

STIR imaging for fat suppression and enhanced sensitivity to tissue fluid is attained through the use of a third inversion pulse (Fig. 2).

BLACK BLOOD HASTE (Fig. 3) is a single-shot variation of TSE for BLACKBLOOD imaging in a single heartbeat.HASTE employs partial-Fourier dataacquisition and very short echo-echospacing to reduce the scan time for anentire image to less than 300 ms. Singleheart-beat imaging is also possible bythe combination of the BLACK BLOODpulse preparation with TurboFLASH and TrueFISP acquisitions.

Clinical Applications

BLACK BLOOD TSE is currently in wide-spread use in clinical cardiac MRI prac-tice. Its primary application is for mor-phological imaging of the myocardium,valves and thoracic blood vessels. T2 weighted and STIR variants of thetechnique are sensitive to tissue edemaand have been used for evaluation andcharacterization of cardiac and mediasti-nal masses as well as acute myocardialinfarction. More recently, high resolutionvariations of BLACK BLOOD TSE havebeen applied to imaging of vessel wallsand atherosclerotic plaque in the aortaand coronary arteries.

Cardiovascular Morphology

■ Congenital and acquired aorticdisease

■ Congenital Heart Disease

■ Valve Disease

25

M A G N E T O MFlashFlashFlashFigure 2: STIR sequencediagram. A third inversion pulse is applied to generate STIRcontrast for fat suppression and greater sensitivity to tissue fluid.

Figure 3: BLACK BLOODHASTE sequencediagram

Figure 4: High resolution anatomical imaging of heartand great vessels with BLACK BLOOD TSE .Courtesy of Dr. Marchal, Leuven Belgium.

26

Cardiac Imaging

Cardiac TissueCharacterization

■ Right Ventricular Dysplasia

■ Cardiac Masses

■ Myocardial Infarction

■ Myocarditis

BLACK BLOOD HASTE 1 slice per heartbeat

Turbo Spin Echo BLACK BLOODSingle Breath-hold per slice

Turbo STIR BLACK BLOOD imagingSingle Breath-hold per slice

Figure 5: Transposition of great vessels (Mustard repair).Courtesy of Washington Univ. St. Louis, Dr. Pam. Woodard

Figure 6: Left pulmonary artery stenosismeasured on BLACK BLOODimages. Courtesy of Children’s HospitalPhiladelphia.

Figure 7: Acute myocardial infarction: BLACK BLOOD imaging with STIR shows edema.Courtesy of Dr. Bis, William Beaumont.

STIR Focal edema caused by septal infarct

First-pass Gd Focal perfusiondeficit*

*This information concerns a use of contrast media thathas not been approved by theFood and Drug Administration.(21 CFR 99.103 (a) (1) (i).

Vascular Tissue Characterization

■ Arteritis

■ Intramural hematoma

■ Atheroma

References

1. Afidi RJ, Haaga JR et al. Preliminary Experimental Results Humans and Animals with a Super-conducting, Whole-Body, Nuclear Magnetic Resonance ScannerRadiology 1982; 143:175-181

2. Simonetti OP, Finn JP et al. “BLACK-BLOOD” T2 weightedInversion Recovery MR Imaging of theHeart. Radiology 1996; 199:49-57

3. Laub G, Simonetti OP, Nitz W .Single-Shot Imaging of the Heart withHASTE (abstr.) 1995,246

4. Stemerman DH, Krinsky GA, et al.Thoracic Aorta: Rapid BLACK-BLOODMR Imaging with Half-Fourier RapidAcquisition with Relaxation Enhance-ment with or without ECG triggering.Radiology 1999; 213:185-191

5. Axel L. Blood Flow Effects inMagnetic Resonance Imaging AJR1984; 143:1157-1166

6. Edelman RR,Chien D, Kim D. FastSelective BLACK-BLOOD MR Imaging.Radiology 1991; 181:655-660

7. Arai AE, Epstein FH, Bove KE, Woff SD. Visualization of the Aortic Valve Leaflets using BLACK BLOODMRI. J. Magn. Reson. Imaging 1999; 10:771-777

8. Fayad ZA, Nahar T, et al. In Vivo Magnetic Resonance Evaluationof Atherosclerotic Plaques in theHuman Thoracic Aorta. Circulation 2000; 101:2503

9. Fayad ZA, Fuster V,et al. Noninvasive In Vivo Coronary ArteryLumen and Wall Imaging Using BLACKBLOOD Magnetic Resonance Imaging.Circulation 2000; 102:506

27


Figure 8: Pericardial metastasis sarcoma. Courtesy of Cleveland Clinic

Figure 10: BLACK BLOOD Image of atheroma (left) and contrast enhanced FLASH 3D. Courtesy of Cleveland Clinic.

Figure 9: BLACK BLOOD Imaging. Diagnosis arteritis. Courtesy of Cleveland Clinic.

T2 weighted BLACK BLOOD imaging T1 weighted with Gadolinium

:TrueFISP Imaging:Gerhard Laub, Ph.D.Siemens Medical Solutions, MR Research and Development, Chicago, Ilinois, US

Recent developments in gradient tech-nology have made it possible to performeven faster acquisitions by reducing therepetition time (TR). A shortening of theTR, however, leads to less signal due to spin saturation that occurs in conven-tional gradient echo imaging. The signalto noise ratio (SNR) is further reduceddue to higher bandwidth typically used inshort TR sequences. Possible solutionsto this problem include using fewer RF pulses while covering k-space (e.g.echoplanar imaging), or spiral imagingtechniques. Alternatively, one couldpreserve the transverse magnetizationand acquire the signal in a steady statefree precession mode with a significantboost in SNR. In MAGNETOM systemsthis sequence is referred to as TrueFISP.

Gradient Echo Sequences:The magnetization is typically reducedfrom the equilibrium magnetization Moin conventional gradient echo imaging(Fig.1). The steady state magnetizationMs may be quite small (depending onthe tissue T1 relaxation time, the TR and the flip angle).The steady statemagnetization is particularly small forsequences with short TRs. As a result theintrinsic signal is low and such gradientecho sequences (with ultrashort TR)have primarily been used together withT1 shortening contrast agents (eg. 3Dcontrast enhanced MRA and 3D VIBE) tohighlight specific anatomic structures.

TrueFISP: In contrast to the gradientecho sequences where the transversemagnetization is spoiled immediatelyafter the signal has been received onecan also try to maintain both the trans-verse and longitudinal magnetizationwhile exposing the magnetization to atrain of equally spaced rf pulses (Fig. 2).After a certain period which depends on the spins T1 and T2 relaxation timesthe spin system reaches a dynamicequilibrium which can be very large evenfor extremely short TR times of just a few milliseconds (Fig. 2).

Imaging with steady state free precessionsequences has been demonstrated inthe early days of MRI but withoutimaging gradients the practical use ofthese techniques was very limited.More recently with the improvements ingradient hardware technology it becamepossible to use these SSFP (Steadystate free precession) sequences forslice selective imaging purposes. A typical sequence which is used forTrueFISP imaging is shown in Figure 3.

28

Cardiac Imaging

Figure 1: A series of RF pulsesis applied. A spoilergradient schemetogether with an RFspoiler is used todephase the trans-verse magnetization.The magnetizationdecreases from the equilibriummagnetization Mo to a very smallsteady state valueMs.

Figure 2: A series ofequidistant RFpulses creates a steady state oflongitudinal andtransversemagnetization. A phase alternatingRF series is shownhere.

It is important to note that the symmetricgradient structure helps minimizing the sensitivity to flow effects. The firstmoments along the read and slicegradient axis is zero over each TR cycle.Along the phase encoding axis the firstmoment is non-zero but scales with the phase encode amplitude andaccordingly is minimal in the center of k-space.

Steady state preparation

During the period of transition into steadystate the magnetization is highly oscilla-tory which would result in significantimage artifacts when used for dataacquisition. One way is to simply waitand use multiple RF pulses until themagnetization finally reaches a steadystate. This transition period may take inthe order of a second or longer depen-ding on the T1 and T2 times of the tissueto be imaged. This effect is very prohi-bitive for ultrafast imaging techniques.Alternatively, a special preparation pulsescheme can be used to bring themagnetization very close to the steady

state value and avoid the multiple rfpulses. An example of this steady statepreparation is shown in Figure 4. A preceding RF pulse �/2 and TR/2 beforethe first � pulse brings the magnetizationright into the steady state and data acquisition can be started from thebeginning of the � pulses (Fig. 4).

Off Resonance Effects

A steady state with high signal intensityrequires a homogenous magnetic fieldwith a frequency such that the phaseshift over one TR period corresponds toa multiple of π. If this is not the case acomplete signal cancellation may occur.In practice these banding artifacts willoccur in areas of inhomogenities particu-larly at tissue interfaces. A shimmingprocedure is required before using True-FISP sequences. As the phase shift isdetermined by the product of TR and thefrequency offset one can try to useshorter TR times to minimize the offresonance effects in practical clinicalsituations. Due to the intrinsic high signalto noise ratio which is available with theTrueFISP sequences a very high readoutbandwidth can be used to further reducethe TR times in these applications. Still it is important to have a good magneticfield homogeneity and correct frequencysetting to obtain good image quality. Ingeneral the TrueFISP sequences shouldbe applied with the shortest possible TRtimes which are available on a scanner.

New Applications

TrueFISP sequences with the �/2 preppulse allow subsecond imaging in allareas of the body. The intrinsic contrastof TrueFISP is determined by the T1/T2ratio of the tissues. In general fluidsproduce the maximum signal. Therefore,TrueFISP sequences are advantageouslyused for imaging of fluids in the bodysuch as blood. In a specific implemen-tation the TrueFISP sequence is usedwith an ECG gated acquisition loop to create a series of images of the beatingheart. In contrast to a gradient echo

29


Figure 3: TrueFISP imagingsequence. A highlysymmetric gradientscheme is used to maintain a steadystate of both thelongitudinal andtransverse magne-tization. A linearphase encoding trajectory is appliedwith a rewinder after the echoreadout.

Figure 4:Steady state preparation with an �/2 RF pulse

sequence where contrast predominantlydepends on the inflow of fresh spins the TrueFISP sequence offers a higherintrinsic contrast between blood andmyocardium even in patients with com-promised flow. Furthermore, the flowcompensated gradient structure of theTrueFISP sequence helps to minimizeflow artifacts.

More recently other applications forTrueFISP sequences have been presen-ted including first pass myocardial per-fusion*, myocardial tagging and coronaryMRA. These applications make use ofan additional magnetization preparationperiod to create image contrast otherthan T1/T2. For example when using aninversion pulse and start the data acqui-sition after a certain wait period to createT1 contrast. These techniques are verypromising for the assessment of myo-cardial perfusion with high spatial andtemporal resolution due to the intrinsicsignal to noise advantage that comeswith the TrueFISP sequence. In anotherimplementation the TrueFISP sequenceis preceded by a fatsat pulse to suppresssignal from fat while maintaining thesignal from fluids. A centric phaseencode reordering scheme is used withthis technique for best fat suppression.This implementation of TrueFISP allowsimaging of the coronary arteries in asingle breath hold.

30

Cardiac Imaging

Figure 5: Flash Segmented TrueFISP

Figure 6:Cine imaging of the heart, segmentedTrueFISP

Figure 7: Enhancing myocardium showsinfarct tissue.Single shot IR-TrueFISP,112 lines, BW / pixel = 975HzTE = 1.2 ms (asym echo)TI = 360 msCourtesy of NWU Hospital

Figure 8: Coronary imaging with TrueFISPfatsatCourtesy of Dr.Li, NWU Hospital

*This information concerns a use of contrastmedia that has not been approved by theFood and Drug Administration. (21 CFR99.103 (a) (1) (i).

:Two News for Viability Imaging*:

Viability

Contrast-enhanced MRI is emerging as a new clinical modality for the assess-ment of myocardial viability. In cardiacischemia, percutaneous interventionwith the goal of revascularization is often performed with the expectationthat regions of contractile dysfunction are viable and will therefore recover. Viable tissue is defined as living myocytesirrespective of their functionality.Traditional techniques to assess myo-cardial viability are dobutamine echocardiography and radionuclidescintigraphy.

Viability MR Solution = Late enhancement with Viabilitytechnique (Patented by Siemens andNorthwestern University)

The technique is to visualize the heartafter IV contrast administration, using aninversion recovery TurboFLASH sequencewhich nulls the signal from the normalmyocardium. Delayed hyper-enhance-ment is defined for myocardial regions in which post-contrast image intensitiesare significantly greater than those innormal myocardial regions for imagesacquired more than 10 min after contrastadministration (Fig. 2).

Recent studies have shown that delayedhyper-enhancement is exclusivelyrelated to irreversible injury. Basically itcan be said that hyper-enhanced regionsare not viable and regions without hyper-enhancement are viable (Fig. 2, 3).

31


Figure 1:Sequence diagramfor segmented IR TurboFLASH forviability imaging

Figure 2:Myocardial Viabilitydiagram showing -delayed enhance-ment of infarctedmyocardium

Figure 3:Enhancingmyocardium showsinfarct tissueCourtesy of NWUHospital

*This information concerns a use of contrastmedia that has not been approved by theFood and Drug Administration. (21 CFR99.103 (a) (1) (i).

Two New Solutions from MAGNETOM

NEW: Single shot TrueFISP for non-breathhold Viability MR imaging

The image quality of IR TurboFLASHmay suffer due to irregular ECG (arrhyth-mia patients) or due to the fact thatsome critical patients cannot hold theirbreath for 20 seconds and, of course,due to the general problem of uncoope-rative patients. For such patients, wherebreathing artifacts or inadequate nullingof the myocardium is seen, diagnosismay be difficult (Fig. 4).

The ideal solution for the above mentio-ned problems would be a single shotsequence in the timeframe of one heart-beat. The advantage would be that the sequence would not be dependent on the heart-rate variation due toarrhythmia, patient motion or breathing.

The challenge in such a sequence is thatit has to be fast within the acquisitiontimeframe in the range of 200-250 ms.

The ideal solution would seem to be a single shot TrueFISP sequence withinversion pulse. This sequence, single-shot 2D Inversion Recovery Imaging, is a product of syngo MR 2002A. The shortTR and high SNR of IR TrueFISP makesingle-shot imaging feasible on patientswho cannot hold their breath for a seg-mented acquisition. Single-shot imagingis insensitive to respiratory motion andcardiac arrhythmia. Although there is a compromise in spatial resolution whencompared to a segmented acquisition,this sequence has to be seen as a solutionfor the patient group who cannot be scanned with normal IR segmentedTurboFLASH sequences (Fig. 5, 6).

NEW: IR Scout for optimalmyocardial signal suppression

The inversion time is very important with TurboFLASH sequences in viability imaging to be able to suppressthe myocardium signal optimally. Themyocardium signal intensity varies withdifferent patients. The solution withMAGNETOM (syngo MR 2002B**) is aquick scout sequence which usesdifferent inversion pulses so that thebest inversion time for myocardialsuppression can be decided and usedfor late enhancement studies.

32

Cardiac Imaging

IR-TFL, 25 segments,124 lines(10 beats), BW / pixel = 140 HzTE = 4.4 ms, TI = 280 ms

Single shot IR-TrueFISP, 100 lines, BW / pixel = 975 HzTE = 1.2 ms (asym echo)TI = 350 ms

Figure 4:In patients with arrhythmia, segmented IR TurboFLASH may sometimes not producediagnostic images (image left). In these cases, it might be beneficial to use “Single shot TrueFISP” (image right). Courtesy of NWU Hospital

Figure 5:Sequence diagramfor Single ShotTrueFISP with IR

IR-TFL, 25 seg, 135 lines (12 beats),BW / pixel = 140 HzTE = 4.3 ms, TI = 300 ms

Single shot IR-TrueFISP,112 lines, BW / pixel = 975 HzTE = 1.2 ms (asym echo)TI = 360 ms

Figure 6:Non-cooperative patient, segmented IR TurboFLASH vs. Single shot TrueFISP.Courtesy of NWU Hospital

**The information about syngo MR 2002B isbeing provided for planning purposes. Thesyngo MR 2002B packages is pending 510 (k)review, and is not commercially available inthe U.S.

6:00 a.m. Admission to the ER 6:02 a.m. ECG, blood samples

6:04 a.m. Check of data from cardiac network

Two hearts saved in less than one hour

6:12 a.m. Interventional procedures start

6:06 a.m. Suspicion confirmed: myocardial infarct

A9

11

00

-M-Z

66

1-0

4-7

60

0

www.SiemensMedical.com

Integrated cardiac care solutions from Siemens speed up

processes and provide the cardiologist with the tools for

making the best-possible informed decision. Intelligent data

management ensures that all patient data – from ECG to

lab findings, from hemodynamics to prior clinical images –

are immediately available at all points of the cardiac care

continuum. That’s what we call Best Practice Integration.


Introduction

Some types of breast cancers have a high incidence of contra-lateral occur-rence. To provide the best service to thepatient, every breast evaluation for can-cer should include not only the affectedbut also the contra-lateral breast. Sincecontrast agents (Gd DTPA) can only beadministered once for the dynamic eva-luation of contrast uptake, both breastsneed to be scanned at the same time.The best orientation is transverse.

For breast MR imaging, the debate inrecent years has been whether to usehigh spatial resolution post-contrastacquisitions where the morphologicalstructure of a lesion can be well circum-scribed or good temporal dynamicinformation for improved specificity oflesions. In their 1989 publication,Werner Kaiser et al. [1] demonstratedthat using fast 2D gradient echo sequen-ces (2D FLASH) in a bilateral dynamicmanner with multiple measurements ofabout 1 minute each over a time periodof 5 to 10 minutes after contrast injec-tion, to visualize the contrast uptake of a breast lesion and its wash-outbehavior, could be strongly correlatedwith whether a lesion was malignant or benign.

In contrast to this dynamic approachSteve Harms et al. [2] introducedRODEO (rotating delivery of excitationoff resonance) in 1994. This 3D techniqueuses a non-selective water rf-excitation(1-3-3-1 binomial) with a specializedtransmit and receive coil to minimize fatsignal. Due to the design of the coil it isnot possible to acquire bilateral studies.Relatively high spatial resolution wasobtained in a sagittal slice orientation.RODEO is a highly sensitive techniquewhich led to the improved understandingof lesion structures. And yet, its speci-ficity remained low. Figure 1 showsa unilateral acquisition in the sagittalorientation with water excitationobtained on a MAGNETOM Sonata. ThisSiemens protocol optimized for spatialresolution shows good structural detailin the breast and good fat suppression.

34

:Breast MRI: Improved Bilateral 3D Imaging:Helmuth Schultze-Haakh, Ph.D.Siemens Medical Solutions USA, Inc., Iselin, NJ

Women’s Health

Figure 1:Unilateral VIEWS (Sonata): 1.0 mm thick,256x256 interpolated to 512, TA ca 5 minutes. Note the even fat suppressionthroughout the image (normal volunteer)

Figure 2:3D dynamic bilateral fat-saturated breast MRI (Harmony with Turbo gradient system):1 pre-contrast followed by 5 post-contrast acquisitions at 1 minute increments. Note the good bilateral fat-saturation. The infiltrating ductal cancer enhances quickly (1 min) with a wash-out (signal decrease over time).

Methods

Recently, breast MR images were ob-tained on various Siemens MR systems(1.0 T MAGNETOM Harmony, 1.5 TMAGNETOM Symphony and Sonata).Our primarily bilateral techniques avail-able in the standard system configura-tion running syngo MR not only utilizethe important temporal information forgreater lesion specificity but provideadditionally high spatial detail for lesiondifferentiation according to their structu-ral differences. These techniques alsouse fat-suppression either with a spec-tral selective fat-saturation RF pulse (3Ddynamic: Fig. 2) or a water-excitationbinomial RF pulse scheme (Fig. 1, 3, 5).Fat could obscure contrast-enhancedbright lesions if not suppressed. Theadvantage of fat-saturation in our 3DFLASH sequences for the dynamic con-trast-enhance acquisition (fl3d_ce) is,

that only one fat-saturation pulse isapplied for each pass through the parti-tions loop, keeping the TR and thus theacquisition time short. This is importantin order to maintain good temporalresolution (1 minute) while optimizingthe spatial resolution within this timeconstraint. However, if many partitionsare being acquired some fat relaxationmight occur. In contrast, water-excitationonly stimulates the water spins and thusshows improved fat suppression effectssince every rf-pulse uses a spatial-spectral selectivity by incorporating asinc envelope into a 1:2:1 binomialexcitation scheme [3]. Each binomial rf-excitation requires more time than asimple alpha sinc pulse extending theTR and the acquisition time. This in turnwould limit the spatial resolution in a dynamic acquisition or prevent thissequence to be used as a dynamic onealtogether.

Results

The 3D dynamic contrast-enhancetechnique was described elsewhere (Breast MRI: Importance of Dynamic 3D).Volume Interpolated Examinations withWater-Stimulation (VIEWS), a 3D gradientecho sequence can produce voxel sizesdown to 0.7 x 0.7 x 0.7 mm3. This can be applied unilaterally in a sagittal plane(Figure 1), the aesthetically preferredorientation or even bilaterally in a trans-verse (fl3d_vibe) or a double slab sagittalorientation (gre) as seen in Figure 3 andFigure 5.

Multi-planar reconstruction (MPR) of this often close to isotropic voxel seriescan assist in viewing the images in otherplanes (Fig. 4).

For good fat-suppression, shimming is important. The air-tissue interface in a peculiar geometry as is the case inbreast imaging becomes a challenge.However, syngo MR with its shim phaseplot has solved this problem. Goodbilateral fat-suppressed images havebecome commonplace on syngo MRsystems (Fig. 2).

35


Figure 3: Bilateral water-excitation 3D (VIEWS) sagittalacquisition (2 slabs). Same case as in Figure2. Note: dark area in left breast lesion is froma previous needle biopsy. Approximately 8 minutes post-contrast injection (Harmony).

Figure 4: Coronal reconstruction of the left breast fromsagittal acquisition data seen in Figure 3.Some image aliasing due to under-samplingin the partitions direction is present.

If combined with a 3D dynamic contrast-enhanced bilateral examination, a com-plete breast evaluation can be achieved.The delayed contrast-enhanced VIEWStechnique, with its high resolution andgood fat-suppression, can show lesionswhich otherwise might not becomeapparent, such as ductal carcinoma insitu (DCIS).

Both the 3D dynamic fat-saturated andthe 3D high resolution water-excitationtechniques are standard on all syngo MRbased systems with the Advanced 3D option. A bilateral circularly polarizedarray breast coil is essential for highsignal-to-noise and contrast-to-noisepresentation.

Acknowledgements

Special thanks go to Dr. Bruce Porterand Michael Middleton for their educa-tional and clinical input as well as valuableimage data; to Dr. Cynthia Sherry andTodd Frederick for their comparison dataand feedback; and to Dr. David Thomas-son for his constant advice.

References

1. Kaiser, WA, et al. MR imaging of the breast: fast imagingsequences with and without Gd-DTPA. Preliminary observations, Radiology1989; 170: 681-686.

2. Harms, SE, et al. MR imaging of the breast with rotatingdelivery of excitation off resonance: clinical experience with pathologic correlation, Radiology 1994; 187:493-501.

3. Pooley, RA, et al. Fat-suppressed multi-slab FLASH 3Dimaging, to be published, 2002.

Conclusion

Our new VIEWS technique not onlyimproves the fat-saturation effect butcan also be applied bilaterally with evenbetter spatial resolution (Figure 3, 5). In a double slab approach, the extended TRcan improve signal-to-noise andcontrast-to-noise in these T1-weightedpost-contrast series (Fig. 5) without anincrease in time, compared to a singleslab technique with the same spatialresolution.

Figure 5: Bilateral VIEWS (Symphony). The sequencewith an acquisition time of 5:50 minutes was run after the 3D dynamic scans (about 8 minutes post-contrast), voxel size: 0.7 x 0.7 x 0.8.

:MR Guided Breast Biopsy:

The MR imaging guided localization and biopsy system is needed to obtain ahistological diagnosis of lesions detec-ted on MR images that are mammo-graphically, sonographically and clinicallyoccult. For this reason, an MR BreastBiopsy device was developed forMAGNETOM systems. This device canbe used for lesion localization by wire,regular biopsy, vacuum biopsy or fineneedle aspiration. This device will be available for MAGNETOM Harmony /Symphony with syngo MR 2002B*.

The biopsy device has undergoneextensive optimization and testing in aEuropean multi-center study across five centers on > 200 MR guided wirelocalization and > 400 MR guided vacu-um biopsies. The study was supportedby the European Commission in the Biomed 2 project BMH4-CT-374.

Publications:

1. Heywang-Köbrunner SH, Heinig A,Schaumlöffel-Schulze U, Viehweg P,Buchmann J, Lampe D, Spielmann RP.MR-guided percutaneous excisionaland incisional biopsy (PEIB) of breastlesions. Europ Radiology 1999; 9:1656-1665

2. Prat X, Sittek H, Grosse A, Baath L,Perlet C, Alberich T, Lamarque JM,Andersson I, Reiser M, Fischer H,Heywang-Köbrunner SH. EuropeanQuadricentric evaluation of a breastMR biopsy and localisation device:technical improvements based onphase I evaluation. Europ Radiology2001, preliminary accepted

3. Perlet C, Heinig A, Prat X, Baath L,Sittek H, Stets C, Lamarque JM,Andersson I, Schneider P, Taourel P,Reiser M, Heywang-Köbrunner SH.Multicenter study for the evaluation of a dedicated localisation and biopsydevice for MR-guided intervention:preliminary results after 18 months,Europ Radiology preliminary accepted

4. Perlet C, Schneider P, Amaya B,Grosse A, Sittek H, Reiser M,Heywang-Köbrunner SH. MR-geführteVakuumbiopsie bei kontrastmittel-anreichernden Läsionen der Mammaan 228 Patientinnen: Ergebnissezweier Zentren.

Customer Testimonial from Prof. Dr. Sylvia H. Heywang-Köbrunner

Martin-Luther University, Halle-Wittenberg, Halle, Germany

The MR breast biopsy device offeredby Siemens Medical Solutions, is until now the only approved devicewhich offers the following features:

■ Approach to the breast laterally and medially.

This feature is highly appreciated bysurgeons. Wire localization with the shortest possible access supportsthe surgeon's choice of an optimalcosmetic approach. Both, wirelocalization and percutaneous biopsyusing such an access, allow unproble-matic oncosurgical planning andexcision of the needle path in case ofmalignancy.

■ Optimized approach to practicallyall areas of the breast

■ by the use of compression plateswith flexible bars.

■ by allowing software supportedaccess to the lesion at variousangles.

■ Possibility of adapting andsupporting any needle type or biopsygun, including the unique possibilityof vacuum biopsy.

Vacuum biopsy offers the followingimportant advantages over coreneedle biopsy or FNA:

■ Compensation for tissue shift dueto needle insertion, local anaestheticor bleeding, by use of vacuum suctionand acquisition of sufficient tissue(approx. 10 g).

■ Avoidance of sampling errors.

36

Women’s Health

Image 1:Breast Biopsy Device

*The information about syngo MR 2002B is being provided for planning purposes. The syngo MR 2002B packages is not commercially available in the U.S.

:Diagnosis of Invasive Ductal Carcinoma only with MR:Prof. Dr. Sylvia H. Heywang-Köbrunner, Martin-Luther University, Halle-Wittenberg, Halle, Germany

History

57 year old patient with family history(both mother and sister ) of post-meno-pausal breast cancer. Clinical examinationwas normal. Mammography revealeddense breast without suspicious findings.Ultrasound examination was defined aswithin normal range.

After correct needle placement has beenconfirmed, the patient is moved out ofthe bore. The transverse slice containingthe lesion is aligned with the aimingdevice; the substitute needle is exchan-ged again with the vacuum biopsy needle(which is mounted in the correspondinggun on the aiming device) and thevacuum biopsy is performed.

37


Figure 1:Bilateral mammogram Craniocaudal & Lateraloblique views showing dense breasts.

Figure 2:A nodular enhancing lesion is seen in breastMR images. Since the lesion was not visiblewith any other method, even in retrospect,the patient was referred for MR-guided biopsy.

Figure 3:For the biopsy the patient is positioned prone.The breast in question is moderately com-pressed and thus fixed in the biopsy device.

Figure 4:Pre-contrast, post-contrast and subtraction image of theslice in question, imaged while the breastwas fixed in the biopsy device.

Figure 5:By clicking a zero marker and the centre ofthe lesion, the coordinates for needleinsertion are calculated for various angles (0, 15, 30). In this case a 15° angle was chosenand an MR compatible substitute needle wasintroduced outside the bore (Fig. 6).

Figure 6:This image shows correct placement of the substitute needle. (The lesion is pierced by the needle and the needle exceeds thecentre of the lesion by another 18 mm).

Figure 7:Pre-contrast, post-contrast and subtractionimages confirm removal of the enhancinglesion ( the cavity collapsed ), which proved to be a 1cm invasive ductal carcinoma.

Correct excision can be checked imme-diately after vacuum biopsy. Anotherpossibility is to test the next day, orseveral days later, by acquiring 3D dataset of images before and after injectionof MR contrast agent (0.15 mmol Gd-DTPA/kg bw) (Fig. 7).

Results and discussion

Histological evaluation of the excisedtissue proved to be a 1cm invasiveductal carcinoma.

:Breast MRI: Importance of Dynamic 3D:Helmuth Schultze-Haakh, Ph.D.Siemens Medical Solutions USA, Inc., Iselin, NJ

Most malignant lesions develop a denseproliferative network of small, low-resi-stance vessels with abnormally porousendothelium. This neo-vascularity showsa very rapid enhancement after Gd-DT-PA injection, compared to normal breasttissue or benign lesions. Evaluating thetime-dependent enhancement characte-ristics over the course of at least 5 minu-tes (in 1 minute increments) can provideadditional information for determininglesion type. Infiltrating lobular cancersare often difficult to detect with traditio-nal x-ray mammography and palpation,but can readily be seen using theindicated technique (Fig. 1). Furthermo-re, such cancers often show a decreasein signal after the initial peak. This wash-out behavior has been closely linked tomalignant cancers (Fig. 2).

All current 1 and 1.5 Tesla Siemens MR systems are capable of performingthe dynamic 3D contrast-enhancedbreast examination technique. Theimages in Figure 1 were acquired on aMAGNETOM Harmony with Turbogradients, whereas the image in Figure 3was obtained on a MAGNETOMSymphony with Quantum gradientsystem. It is desirable to keep the

acquisition time to less than (or equal to)one minute: the shorter the repetition(TR) and echo time (TE), the higher theresolution within a given scan time. TR’sof about 4 ms and TE’s of less than 2 mshave given excellent results even withfat-saturation (Fig. 3). Some post-processing can be easily done on themain operator’s console. These includesubtractions (subtract pre-contrast fromthe post-contrast series) for improvedlesion conspicuity (Fig. 4), dynamic cur-ve evaluations (Fig. 2) and MIP (Fig. 5).

The Siemens bilateral circularly polarized(CP) Breast Array Coil (Fig. 6) is not onlyhighly sensitive to the individual breast,but also allows for penetration well intothe body to visualize structures withinthe thorax. Despite the difficult geo-metry of the air-tissue interface, good shim for homogeneous fat-saturation isobserved (Fig. 3) particularly on syngoMR based systems.

38

Women’s Health

Figure 2:“Malignant curve”: high peak followed by washout

Figure 1:3D dynamic contrast-enhanced FLASH:TR = 7 ms. TE = 2.7 ms. 302x512. 64 partitions. Measurement time: 60 seconds. Harmony with Turbo gradientssystem (Numaris 3.5).

Breast cancer has reached epidemicproportions, according to a report spon-sored by the U.S. Public Health ServicesOffice on Women’s Health (PHS OWH).1 in 8 women in the United States willdevelop breast cancer during their lifetime(JMRI 10:980, 1999). An InternationalWorking Group on Breast MRI has beenestablished, which has determined theincreased need for a diagnostic tool thatcan provide a high degree of sensitivityand specificity. Magnetic ResonanceImaging (MRI) has been shown to be verysensitive in breast cancer diagnosis.Improved imaging techniques based onfaster and more powerful gradient and computer systems, and a betterunderstanding of the pathological andmorphological behavior of breast lesionsseen on MR images, have lead to anincrease in interest in breast MRI. Thedebate over high spatial vs. high tempo-ral resolution contrast-enhanced 3Dimaging has lessened, since rather highspatial resolutions can be obtained insufficiently short acquisition times (1 minute or less). Dynamic 3D bilateralbreast examinations provide goodspatial resolution on both breasts simul-taneously. There is no need for a repeatvisit or a second injection.

pre

1 min

2 min

3 min

4 min

5 min

39


Figure 3:MAGNETOM Symphony with Quantumgradients (syngo MR): TR = 4.5 ms. TE = 1.6 ms. 80 partitions.338x512. TA = 60 sec, with fat-sat.

Figure 4:1 minute subtraction: post- minus pre-contrast (MAGNETOM Harmony with Turbogradients). Only the contrast-enhanced tissuesare seen. This is the same as in Figure 1. The inhomogeneous fat signal disappears.

Figure 5 :Bilateral MIP of subtracted 3D data set (post-contrast minus pre-contrast, MAGNETOM Harmony with Turbo gradients).Before (top) and after (bottom) chemo-therapy.

Figure 6:Bilateral circularly polarized (CP) Breast ArrayCoil with compression control knobs

With a Siemens MAGNETOM system,now operating on the syngo interface,breast MR examinations will quicklybecome a daily routine.

Acknowledgements

Special thanks go to Dr. Bruce Porter at First Hill Diagnostic Imaging in Seattle(MAGNETOM Harmony with Turbogradients), and to Dr. Michael Middletonat the University of California, San Diego(UCSD) (MAGNETOM Symphony withQuantum gradients) for data and imagecontributions and for their continuousand constructive collaboration.

Introduction

Magnetic Resonance Imaging of thepediatric brain is more complicated thanthe adult brain because the standardgrey-white matter contrast changes sig-nificantly during normal brain develop-ment. This is due to the rapidly decrea-sing water content of the brain in thefirst few months of life, with white matterloss significantly greater than grey matterloss. In addition, there is a simultaneousincrease in protein and lipid content asmyelin is developed in the white mattertracts (1). These developments signifi-cantly alter the tissue T1 relaxation andtherefore require judicious choices inoptimal measurement acquisition para-meters. Also, the use of Gadoliniummust be considered when choosingoptimal parameters for a spin echosequence. Gadolinium is a T1 relaxation-altering contrast agent that significantlyshortens the T1 and T2 of the tissuesinto which it has infiltrated.

There are two basic imaging parametersone has to adjust to obtain optimumpediatric neuro spin echo (SE) imaging:TE, which affects overall signal to noise,and contrast, and TR, which mostlyaffects the T1 weighting. These para-meters should be considered in the con-text of the tissue relaxation parametersT1 and T2. As a general rule, the minimumTE available for a given MR system willproduce the optimal imaging results.

However, repetition times (TRs) com-monly used to obtain optimal imagequality in adult brain imaging would notprovide the best contrast for imaging the brain of children less than one year old due to the significantly different T1values in these two populations. In addition optimal TRs for studies usingGadolinium where there would be a marked T1 shortening relative to non-contrast brain tissues requires signifi-cantly different TR values for optimallesion-brain contrast.

Higher performance systems such asthe MAGNETOM Sonata (with 40 mT/mgradients) and Symphony Quantum(with 30 mT/m gradients), in conjunctionwith flexible protocol parameters (fullyflexible bandwidth; asymmetric echo;flexible RF pulse and gradient parame-ters; half Fourier; concatenations), provideample opportunities for optimisingimaging protocols. With these systemsit is possible to achieve the smaller fields of view necessary for pediatricimaging, while still being able to optimizefundamental imaging parameters suchas TR and TE.

In this work, we present some initialsimulations, phantom images, andvolunteer studies, as well as some initialclinical data that suggest ways toconsider optimal protocol parameterselection, with the goal of optimizing thequality of clinical imaging. These wouldbe different for pediatric versus adultbrain studies, due to fundamentallydifferent brain tissue relaxationproperties.

Theory

The signal intensity for a simple spinecho (SE) sequence with a 90-degreeexcitation pulse has been described ingeneral terms by (2):

S(I) = Mo * (1-exp(-TR/T1)) * exp (-TE/T2)

We have used an Excel spreadsheet toprogram this equation to provide a simplesimulation for providing the direction forparameter optimizations. We usedpublished values for normal adult brainT1 and T2 in these simulations: for greymatter T1=870, T2=74, and for whitematter T1=650, T2=68) (3). Contrast isdefined as the signal differencebetween these two signal intensities.

Optimal TE

In simulations, it can be shown that TE has a role in optimizing both signal tonoise and contrast. Figures 1a and 1bshow the signal intensity for TE’s from 5 to 35 for Grey Matter (GM) and WhiteMatter (WM). It is clear that for both greyand white matter, the signal is increasedat lower TE’s. Figure 1c shows the“contrast” or signal difference betweenthese two tissues as the TE is increased.Here too it is clear that simulationspredict optimum contrast at minimumTE. It is important to note that no matterwhat tissue T1 or T2 one uses forcomparison, the best SNR and contrastwill be obtained at the minimum TE.

40

:Spin-Echo Acquisition Protocols*:Considerations in the Pediatric Brain:David Thomasson, Ph.D.1, Abraham Padua, RT1, Christine Harris, RT2

Pediatric Imaging

1 Siemens Medical Solutions USA, Inc., Iselin, NJ, USA

2 The Children's Hospital of Philadelphia, Philadelphia, PA, USA

*The safety of imaging [fetuses, infants] has not been established.

Figure 1:a) Signal intensity as a function of TE for GreyMatter (GM)

b) Signal intensity as a function of TE forWhite Matter (WM)

c) Signal difference between GM and WMplotted as a function of TE

To validate these findings, Figure 2shows phantom results at two differentTE values (10 and 16). Here too we show that contrast and signal areoptimized at the shorter TE.

Here we show that signal intensity atTE=10 (SI=775) is higher than at TE=16(SI=601). In addition, contrast (measuredas the signal difference between thetwo dissimilar T2 compartments) is alsogreater (TE10 contrast = 775-323 = 452,versus TE16 contrast = 601-319 = 282).

Clinical exams also demonstrate thisimproved contrast. Figure 3 showssimple SE brain exams at a) TE=10 andb) TE=14. The protocols were optimizedby taking advantage of the highergradient strength on the MAGNETOMSonata, and optimization of the receiverbandwidth as well as allowing a smallecho asymmetry in the readout.

41

M A G N E T O MFlashFlashFlashFigure 1a

Figure 1b

Figure 1c

Fig. 2a

Fig.2b

Figure 3:a) SE at TE=10 and b) SE at TE=14, showing improved contrast at the shorter TE

Figure 3a Figure 3b

Figure 2: a) at TE=10 and b) at TE=16 that showsimproved contrast at the shorter TE

Optimal TR

While it is easy to optimize TE (becausefor whatever tissues of interest, the op-timum TE is the minimum available on agiven system), the situation is a bit morecomplicated for TR. A simple simulationillustrates this phenomenon. (Fig. 4a-c)

While from Figure 4a and 4b it appearsthat the optimum might be a long TR(because the signal is always highest atthe longest TR), this is not in fact the ca-se. Figure 4c shows that the maximumcontrast (signal difference) is achievedat a specific maximum on the TR curvefor the given T1 and T2 of the adult brain.

Under 1 Year

In the case of the pediatric brain at anearly stage of development, where thewater content of the tissues is high, theT1 of the tissues are quite high. In thesesimulations, we show that the optimalcontrast is at a TR much higher than theprevious simulations (based on adultbrain studies) would suggest. In this case,the TE is not as important as the TR,which is consistent with the increasedT2 of these tissues as well. If we choosevalues of Grey T1 = 1300 and White T1 =900, then the contrast curve is quitedifferent. Figure 5 shows this behaviour.

Figure 6 shows how this is important inclinical studies. These images wereobtained with TR = 1000 and TR = 650.It is clear that the longer TR for this less-than-1-year-old shows a better contrast.

T1 Shortening with Gd Contrast

A particular consideration is the protocolparameters to choose with childrenunder 1 year when using gadolinium as a contrast agent. On the one hand, it isbetter to use a long TR to best visualizegray-white matter contrast, but unlike inthe adult brain, the long TR will decreasethe conspicuity of gadolinium-containingtissues. Here, simulations suggest that the best TR is approximately 550 ifwe estimate that the T1 shortening willreduce tissue T1 from 1300 to 700 for white matter and from 900 to 500 forwhite matter.

Figure 7 is a simulation showing thatcontrast is actually worse with the longerTR that one might expect to use withprotocols for the pediatric brain underone year. Improved contrast is obtainedby using the shorter TR with gadolinium-based T1 shortening. Therefore theoptimum TR for pre-contrast studies isnot necessarily the best for post-contrast42

Pediatric Imaging

Figure 4a

Figure 4b

Figure 4c

Figure 4:Signal intensity as a function of a) White Matter and b) Grey Matter as a function of TR c) the signal difference of these two tissues as a functionof TR demonstrating an optimum TR less that maximum TR for overallsignal intensity.

Figure 5:Optimal contrast for pediatric neuro exam for children less than 1 year old,with T1 = 1300 for Grey Matter (GM) and T1 = 900 for White Matter (WM)

43

M A G N E T O MFlashFlashFlashstudies. This is particularly important forprotocols optimised for use withimmature pediatric brain studies.

Figure 8 shows two images obtainedpost Gadolinium injection with TR’s of800 and 560. The signal from both aregion of the brain and a vascular regionof high gadolinium concentrations aredecreased with the lower TR values,however the signal decrease from brainis 39% while the signal decrease fromthe high gadolinium concentrationregion is reduced by only 21%. There-fore a net increase in overall conspicuitywould be expected by using the shorterTR values.

Conclusion

In conclusion, pediatric protocols should be technically arranged in a for-mat differentiating each set of sequencesby age group. At birth, the T1 for WM islonger than for GM. Most areas of thebrain at birth have a longer T1 than forthe adult brain. With this understanding,and the ability to create flexible protocoltrees, an efficient workflow paradigmcould be devised that would includeoptimized imaging parameters dividedinto age appropriate protocols.

Siemens has produced preliminaryprotocols that can be obtained bycustomers who are involved in pediatricimaging. They can be used as a startingpoint of reference for your practice. You, as the customer, can then evaluatethe usefulness and worth of suchtechniques.

Suggested Protocol Tree:

Figure 6:Grey-White matter contrast for two TR’s: a) 1000, and b) 650. The improvement in contrast is due to a better matching of TR to the tissuerelaxation parameters T1, which for children less than 1 year old are significantly higher.

Figure 6a Figure 6b

Figure 8a Figure 8b

Figure 7:Optimum TR for Gadolinium-containing tissues, assuming T1 and T2 are reduced to estimatedvalues of 700/64 and 500/58 for Gray matter and White matter.

Figure 8: a) TR=800, b) TR=560 showing reduced overall signal intensity but increased contrastwith TR matched to optimize tissues of interest.

References

1. MR and gadolinium define pediatricbrain pathology, Rosalind B. Dietrich,M.D. Diagnostic Imaging, pp. 96-103,February 1989

2. Pulse Sequences for MagneticResonance Imaging, by Dr PeterJoseph, in AAPM Monograph No. 14,NMR in Medicine, August 1985

3. Signal to Noise and Contrast inMagnetic Resonance Imaging, by Dr Felix Wherli, in AAPM monographNo.14, NMR in Medicine, August 1985

S t e p 2

:TrueFISP Thickslice Lung MRI at Low Field Strength:Prof. Dr. Thomas Rupprecht, radiologist and pediatrician, Department of Pediatric Radiology; Dr. Maren Wagner, research fellow for pediatrics and MRI, University Hospital for Children and Adolescent Medicine, Erlangen, Germany

Localizer with the positioning of

3 coronal slices (boxes) across the

entire thorax. Slice thickness will

usually be 30-60 mm.

Results of the coronal 3-slice True-

FISP MRI. In the posterior slice the

spine and the posterior part of the

lung is imaged, in the middle slice a

clear image of the lung is acquired

without major superposition of the

heart. The hilum is seen clearly.

The middle slice resembles mostly

44

Pediatric Imaging

Investigation has to be performed in a low-field MR scanner like SiemensMAGNETOM Open or Concerto.

Sequence:

TrueFISP TR = 5,94 msTE = 2,97 msFA = 90°Slices = 3Slice thickness = 20-400 mmExcitation order = interleavedDistance factor = 0,00Matrix = 200x256Phase over-sampling = 0Field of view 450-500 mm Number of acquisitions = 1Number of measurements = 1

S t e p 1

Positioning of the patient

Supine position, arms placed behind

the head or, as in the image on the

stomach. The thorax should be

covered by a conventional body coil.

Images are acquired during a short

breath hold of about 5 seconds.

No intravenous access or cardiac or

respiratory triggering is necessary.

For the investigation of children,

parents can stay with the child. First

of all, a routine localizer should be

acquired.

S t e pb y S t e p

S t e p 3

S t e p 4

a conventional chest x-ray.

The frontal slice gives a clear image

of the cardiac silhouette as well

as pathology in the frontal part of

the lung or the frontal mediastinum.

If better imaging of the lung paren-

chyma is needed, additional thinner

slices i.e. 20 mm slices can be

acquired.

20 mm coronal slice in a

16 year-old with interstitial lung

disease, especially in the lower

fields.

Following the coronal scan,

a sagittal 3-slice scan should be

performed for each lung. The

positioning is done in the localizer

or, as shown here, in the coronal

scans. Slice thickness should

be between 20 and 30 mm.

Routine imaging is finished with

the coronal and sagittal scans.

However, if a pathology is noted,

axial scans may be acquired,

additionally. Again, positioning of

the scans is done using the coronal

images, or the image where

pathology was seen best.

Positioning of the axial 3 slices

and result of the middle slice

in a boy with lung metastasis.

Reference :

Wagner M, Böwing B, Kuth R,Deimling M, Rascher W, Rupprecht T. Low Field Thoracic MRI –A Fast and Radiation Free RoutineImaging Modality in Children. Magnetic Resonance Imaging2001;19:975-983.

45


TrueFISP Lung Imaging in the German Press...Good news for worried parents: child-ren with lung disorders no longer ha-ve to be examined with dangerous x-rays. Now for the first time, magneticresonance tomographs (MRT) can beused to obtain meaningful images ofthe lung, without any health risk.

Prof. Thomas Rupprecht (43), chiefphysician at the Pediatric Hospital ofErlangen University, Germany, ex-plains: “Previously, x-ray was the onlyway we could diagnose disorders ofthe respiratory system, such as asth-ma and pneumonia. The downsidewas frequent exposure to x-rays,which could eventually damage thegenetic code in the cells, and lead tocancer.”

Prof. Rupprecht continues: “The newmethod works with magnetic fieldsand is completely harmless. The ex-aminations can be repeated withoutadverse effects. Children sufferingfrom mucoviscidosis will benefitgreatly from this advancement as wehave to examine their lungs frequently.”

The new MRT technique is now inuse in Erlangen and at the UniversityHospitals of Frankfurt / Main,Würzburg, and Mainz.

Sagittal 3-slice MRI of the left lung in a little girl suffering from cystic fibrosis

Positioning of the sagittal 3-slice scans of

the right and the left lung, independently.

The new automated syngo MR Spec-troscopy software for the MAGNETOMFamily makes MRS examinations as easyas imaging examinations. This has allowedMRS exams to be performed more routi-nely at clinical MR center with reliableand reproducible results. syngo protonMRS for brain applications consists ofSingle Voxel Spectroscopy (SVS) andChemical Shift Imaging (CSI). CSI is amultivoxel technique, also referred to asMRSI (MR Spectroscopic Imaging) orsimply SI (Spectroscopic Imaging). BothSVS and CSI use volume selection tech-niques based on double spin echo (SE)or Stimulated Echo Acquisition Mode(STEAM). SE uses a string of 90-180-180degree RF pulses whereas STEAM usesa string of 90-90-90 degree pulses. BothSVS and CSI can be used with echotimes as short as 20 ms. Long TE spectradisplay the major brain metabolitepeaks: NAA, creatine (Cr), and choline(Cho), as well as lactate when present indetectable quantities. Short TE spectrainclude additional peaks representingshort T2 metabolites. Those includeinositols (In), glutamine and glutamates(Glx), and glucose. Lipid signals aremore prominent on short TE spectra.

A short TE SVS spectrum from the fron-tal lobe of a normal volunteer, acquiredon the MAGNETOM Symphony(TR=1500 ms, TE=30 ms). Voxel size is20 mm x 20 mm x 20 mm. The labelledmajor metabolite peaks are: NAA at 2.02ppm, Cr at 3.02 ppm, Cho at 3.2 ppm,and myo-inositol (In) at 3.56 ppm. The Glx signals (not labelled) are smallpeaks between 2 and 2.5 ppm andbetween 3.6 and 3.8 ppm.

MRS Clinical Case

The following clinical case illustrates thecontribution of chemical shift imaging inthe management of a 34-year-old femalepatient with a diagnosis of an infiltratinganaplastic astrocytoma that was resec-ted 12 months prior to this MRS exami-nation. The patient is being followedwith conventional MRI, perfusion MRI,and MRS. MRI demonstrates a diffuseinfiltrating area of signal abnormalityinvolving the right medial frontal lobe,without evidence of contrast enhance-ment.

CSI measurements are performed atthree TE values (30 ms, 144 ms and 288ms) and a TR of 1500ms. Using weigh-ted k-space sampling, each CSI measu-rement takes 4 min 39 sec, with a spatialin-plane resolution of 1mm x 1mm and a slice thickness of 15 mm. The totalexamination time for the three CSI mea-surements is less than 15 minutes.

46

:syngo MR Spectroscopy (MRS) in Clinical Practice:N. Salibi, Ph.D.1, E.A. Knopp, M.D.2, M. Law, M.D.2

Spectroscopy

1 Siemens Medical Solutions USA, Inc., Iselin, NJ, USA

2 New York University School of Medicine,New York, NY, USA

Positioning of the Volume of Interest(VOI).

MRS data courtesy of Dr. E. Knopp andDr. M. Law, NYU School of Medicine,NY, NY, USA.

Results & Discussion

Spectral map* generated from the short TE (30 ms) CSI data set. Regionalvariations of the metabolite peaks areclearly seen. The brain tissue within the lesion has lower NAA peaks, withincreased choline and myo-Inositolcompared to brain tissue surroundingthe lesion. (See following figure for moredetails).

*This feature will be available on syngo MR2002B.

47


In this diagram, the first column of eachrow contains the voxel position corres-ponding to the spectra displayed on thesame row. Short TE (30 ms) spectra aredisplayed in the second column, inter-mediate TE (144 ms) spectra in the thirdcolumn, and long TE (288 ms) spectra inthe fourth column. The first row repre-sents spectra from a voxel containingpresumably healthy brain tissue; thebottom two rows represent spectrafrom within the lesion. Overall spectrafrom the lesion have reduced NAA/Crand elevated Cho/Cr. This, along withthe mild increase in cerebral blood flowseen on perfusion MRI, suggest presenceof residual tumor. The short TE spectrafrom the lesion have elevated myo-inositol, which may indicate an elementof gliosis/astrocytosis and may relate to the patient receiving post surgicaltherapy.

MRS data courtesy of Dr. E. Knopp andDr. M. Law, NYU School of Medicine,New York, NY, USA.

*The information about syngo MR 2002B isbeing provided for planning purposes. Thesyngo MR 2002B packages is pending 510 (k)review, and is not commercially available inthe U.S.

■ With state-of-the-art technology

• Quantum Gradient performance

• Advanced High Order Shim

• Highly Efficient Harmony Body Transceiver

• Computer Power

■ With new coil concept: IPA™ and IPP™

• 4 coils or 8 CP Array coil elementscan be used simultaneously

■ With intelligent syngo user inter-face and innovative applications

With state-of-the-art technology

The improvement in resolution andspeed is mostly possible as a result ofthe improvement in gradient hardware.The MAGNETOM Harmony Quantumgradients, 30 mT/m Gmax. and 125 T/m/sSlew Rate per axis (52 mT/m Gmax. and216 T/m/s Slew Rate effective), allowmost demanding applications to beperformed easily. The major benefits arein cardiovascular applications and inneuro imaging, where EPI is used (Fig. 1,2, 3, 4).

Advanced high order shim contains 5non-linear electronics channels of the 2nd

order for additional fine adjustment ofthe magnet field homogeneity. This im-proves the shimming capability especial-ly in fields like off-centre fat saturation,single shot EPI and spectroscopy (Fig. 5,6).

Integrated whole body resonator withsuperb S/N and performance. Themaximum FOV is 50 cm, which enablesexcellent coverage of the whole spineand also allows whole abdomen appli-cations like MR Colonography. This is a transmit/receive coil with fast digitaltuning and matching, in an efficient

design that requires low RF power.

Computer Power: The upgrade comeswith a Dual Pentium IV processor and a panoramic Recon Image Processorproviding ultimate reconstruction speedof up to 872 images / sec (2562 FFT,

48

:Upgrade your MAGNETOM Impact / Expert to Harmony Maestro Class:

Upgrades & Options

Figure 1:Single shot EPI diffusion imaging of the head showing an acute ischemic lesion. B value: 1000 sec/mm2, TA: 17 seconds

Figure 2:High resolution (176x512 matrix) pulmonaryangiography in only 17 seconds

Figure 3:Segmented TrueFISP cine cardiac imaging is possible with MAGNETOM Impact / Expertto Harmony upgrades

Figure 4:Abdominal angiography in 24 secs. Matrix:256x512, TR: 3.9 msec, TE: 1.4 msec

25% rec. FOV). The result is real-timeimage calculation while scanning.

With new coil concept: IPA and IPP

The Integrated Panoramic Array IPATM

system is a modular CP array conceptthat greatly accelerates coil set-up timeand significantly enhances throughputand productivity. IPA enables the CPSpine Array coil to remain on the tablefor most studies.

With IPA and Advanced Array interface,up to 4 independent coils can beconnected simultaneously and up to 8CP elements can simultaneously receivesignal.

IPPTM allows the active coil elements tobe selected remotely through user inter-face which can also be combined withremote patient table motion, allowingapplications like “Peripheral MR Angio-graphy run-off studies” and whole abdo-men examinations, combining upperabdomen and pelvis (Fig. 9).

With intelligent syngo user interfaceand innovative applications

syngo – the new Siemens Medicalsoftware standard optimizes clinicalworkflow.

syngo ensures that users feel at homeacross different modalities and work-stations, due to syngo functionalitiessuch as viewing, filming, or networking.

syngo combines the advantages ofstandardized software with customer-oriented flexible solutions.

49


Figure 6:Knee image with fat saturation showingposterior cruciate ligament and increasedsynovial fluid. Homogenous fat saturation isimportant in orthopedic imaging

Figure 5:Single voxel spectroscopy with 1 TeslaMAGNETOM Impact / Expert to Harmonyupgrade

Figure 8:Head and neck angiography with the combi-nation of CP Head Array coil and CP Neck coilwith IPA. The increased coverage with coil combinations has allowed high resolutionimaging of the head and neck vessels in onestudy.

Figure 7:Peripheral run-off angiography in three conti-nuous steps (each step ~30 seconds) whichallows the visualization of the lower extremityincluding the iliac arteries without venousenhancement. (Control of bypass graft fromright external iliac artery to left femoral artery)

Figure 9:CP Body Array coil allows high resolutionwhole abdomen studies. TrueFISP image ofthe abdomen. Diagnosis: Polycystic KidneyDisease.

An integral Part of your Workflow

Image stamps allow simple drag & dropmethods to load entire series of planningimages.

The task card concept enables structuredworkflow with multiple patients by easyimage exchange between tasks.

The scan program for the whole exami-nation is already programmed using theMaestro User Interface with its multilevel scouts, automatic table travel andpre and post contrast scanning. Eachparameter can be individually adjustedto the patient’s anatomy.

Images can be used from all tasks at thesame time.

Customized Scan Programs –Optimize once, use daily

This Scan Program concept supportsefficiency.

Customized Scan Programs means thatyou prepare programs once to fit theclinical requirement and then use theseoptimized programs in your daily routine.

Inline Technology

The complete exam is finished as soonas the image acquisition is finished.Inline technology uses an intelligent on-the-fly feedback loop to control scanningreconstruction and processing. Themotion is detected and corrected beforeimages are acquired and unwantedinformation is no longer filling up yourhard disk.

Customer Testimonial

Radiology Clinic Lothar Haas, M.D.Stuttgart, Germany

Dr. Haas: “Better image quality andpatient comfort result in better images. Working with syngo is a huge improve-ment. We increased the number ofpatients by 7.5%, which means we areable to treat two additional patients perday. More flexibility and higher bufferperiods mean a shorter waiting time forthe patient. The overall examinationtime dropped by 15%. The added appli-cations provided for faster examinationsand more accurate measurements,including higher resolution.”


Howard County General Hospital –Donnie Bracley, Cross Sectional ImagingSupervisor and John Austraw, RT Columbia, MD, USA

John added that patient satisfaction had improved as the magnet aperture islarger making it “easier to get largepatients into the magnet.” Additionally,“the stepping table is great for peri-pheral angio run offs” and the IntegratedPanoramic Array coils result in, “less coilchanges making it easier to manage thepatient schedule.”


Stevens Hospital – Kathy Dunham,CT/MR Supervisor, Mike Gomez, RT andElizabeth Nordlund, RT. Edmonds, WA, USA

Kathy: “It’s great we can upgrade amagnet (10+ years old) and make it ascapable as the new ones!!! We wereable to take an older magnet and installnew gradients, new coils, new softwareand give us an MR system that cancompete with the best of them!!!” The task card design with syngo trulyoptimizes workflow. “It is nice to switchbetween cards without stopping otherfunctions.”

50

Upgrades & Options

Figure 10:MAGNETOM Impact / Expert to Harmony Maestro Class

Fig 11:Technologists, Elizabeth and Mike, appear atease while Application Specialist, CatherineLeyen, provides instruction.

Mike: “Our image quality has vastlyimproved. We now have many newapplication features such as cardiac andCARE bolus, not to mention, the Quan-tum gradients”.

The lighting inside the magnet can beadjusted for each patient, “providing theperception of a much larger area insidethe scanner so patients tend to be lessclaustrophobic.”

Don: “It was a very good decision madeby our organization to upgrade. Theprocess was smooth as Siemens stayedon schedule and kept us updatedthroughout the process.”

Dr. Sungkee Ahn is the Chief MRI Radiologistat the MRI Center of Howard Countyand was eager to learn the new features andapplications that were offered with theupgrade.

“I need an MR systemthat provides

perfect all-around support”MAGNETOM Maestro Class –a new degree of perfection

MAGNETOM® Maestro Class – an MR system that offers you

everything you need for a fast and comfortable workflow:

intelligence – MAGNETOM Maestro Class thinks with you!

It automates processes, making them faster and simpler.

increased speed – MAGNETOM Maestro Class saves time!

Experience new dimensions in acquisition speed and

resolution.

SiemensMedical.com

innovative applications – MAGNETOM Maestro Class is

setting the standard! You’ll be able to expand your appli-

cation spectrum from cardiology, oncology and neurology

all the way to surgery. From the clinical routine up to

research applications.

Maestro Class

is inintelligence

increased speed

innovative applications

A9

11

00

-M-Z

71

6-1

5-7

60

0

Ti p

New with syngo MR 2002A / Restore

Restore is a modified Turbo Spin Echofor T2 weighted images with increasedsignal for those tissues which have along relaxation time. CSF is one example.Restore is helpful in spine imagingbecause it can give you better T2 con-trast in less time. With this sequence a90 degree pulse is added at the end ofthe echo train to flip the transversemagnetization back into the longitudinalplane, which will shorten the spinrelaxation time. This will allow shorterTR times. In 3D applications, scan timewill also be reduced with the addition of this pulse.

New with syngo MR 2002A /Segmented EPI

Segmented EPI gives you less suscepti-bility artifacts and better signal to noisecompared to single shot. It is part of theEPI package or the Advanced Turbopackage. Segmented EPI can be used inbrain imaging for high-resolution 3Dimaging with increased signal to noiseand decreased susceptibility. 3D EPIFLAIR also utilizes this technique.Segmented EPI can also be used in bodyimaging.

These protocols can be found in theSiemens protocol tree under head, EPIsegmented. Here you will find twoprotocols, T1 3D segmented EPI gradientecho with fat-sat and T2 segmented EPIwith fat sat.

■ With EPI, you will have minimum

susceptibility artifacts with the

shortest echo spacing. Echo

spacing generally is shortest for

high bandwidth, but maximum

bandwidth does not always give

the minimum echo spacing.

On the SEQUENCE card of your EPI

protocol you will find a check box

for free echo spacing.

52

:New with syngo MR 2002A / Restore:

Neuro Imaging

Ti p

Figure 1

■ Flow compensation is

recommended with this sequence.

■ For 3D Restore sequences use

a TR of 500 to 600 millisecond.

■ Restore protocols are found

under the / C-Spine / Restore.

There are two T2 Turbo Spin Echo

sequences with Restore.

■ On the SEQUENCE card for the

protocol you can find the RESTORE

Magnetization check box.

■ This sequence is useful for neuro

imaging to obtain myelographic

contrast.

■ This sequence can be used for

orthopedic applications (increased

synovial fluid signal) and abdominal

applications.

Figure 2:Cervical spine with (left) and without (right)restore pulse

Figure 3:High resolution 3D EPI imaging with reduceddistortions. 11 segments, TE: 12 msec, 3 mm, TA: 2:15 min

New with syngo MR 2002A / Diffusion with 3 scan trace

This new sequence allows you to dobrain diffusion imaging by adding a 3 scan trace weighted mode which usesa lower TE. Examples of this would bethe Symphony with Quantum gradientswith a minimum TE 83 and the Sonatawith a minimum TE 70. Also you cannow select b-values up to 10,000 sec/mm2 .

The sequences can be found in theSiemens protocol tree under / Stroke.There is an EPI 2D diffusion 3 scan trace.

In diffusion imaging, three base imagesare acquired for each b-value with diffu-sion weighting in three fixed orthogonaldirections. Trace-weighted images may becalculated from the three base images.In the previous software only one scanwas performed per image, which isfaster, but requires a longer TE and haslower signal to noise. With the 3 scantrace, three scans are performed perimage. This gives higher signal to noiseand allows lower TE’s. The advantagesof 3 scan trace weighting is that imagesare weighted by the average diffusion in all directions. So with 3 scan trace youhave optimum use of your gradientsystem, a lower TE, and higher signal tonoise than the one scan trace image.

New with syngo MR 2002A / BOLD imaging:

For those customers who have theBOLD imaging package.

BOLD imaging provides a non-invasivetechnique for localization of neuro activi-ties in the brain. Sufficient experiencewith BOLD imaging is really indispens-able for precise localization of the regionof interest and to obtain reliable results.New to the BOLD imaging package are mosaic image format, inline motioncorrection (3D PACE), inline spatialfiltering, and the ability to specify a thres-hold. These sequences can be found inthe Siemens protocol tree under /BOLD.

There are two sequences EP2D_mosaic_mc for motion correction.EP2D_mosaic_mc_filter 3D for motioncorrection and the 3D_filter.

With the mosaic image format, imagesfrom all slices are saved in a singleformat, one mosaic format image permeasurement. Image size will automati-cally adjust to the number of slices. Themore slices you have, the more images,the smaller the images will be. The be-nefits of the mosaic image format areimage database limitations are circum-vented, the maximum image acquisitionrate is increased, there is no compulsorypause between measurements, (youcan now select zero (0) pause betweenmeasurements), a very large number of measurements is possible and it’s aneasy overview of multi-slice datasets.

Another change with the BOLD Mosaicsis that the threshold can be changed andmotion correction is available.

53


Figure 5:Mosaic image format for BOLD imaging

Figure 4:Diffusion with 3 scan trace

Restore

Incorporates an additional 90° pulse atthe end of a typical Turbo Spin Echosequence. This additional pulse rebuildsthe longitudinal magnetization for thesubsequent TR. The result is that youcan use a shorter TR to obtain adequatecontrast – and therefore shorten yourmeasurement time, typically by 10%.

For instance, if you currently use a TR of5000 for an axial head study, you wouldbe able to reduce it to 4500 without areduction in contrast. This will help yousave time during each TSE scan, whichcan add up over the course of a workingday.

Restore Protocols can be found under “head, c-spine and l-spine” in theSiemens protocol tree.

54

:New with syngo MR 2002A / MAGNETOM Concerto:

Open Class

3D MP RAGE

Siemens Exclusive

RAGE (Rapid Acquisition Gradient Echo)inserts MP (Magnetization Preparation)pulses before a routine 3D gradient echosequence to manipulate image contrast.In this case a 180° pulse has beeninserted to provide high T1 contrast withthin, contiguous slices.

MP RAGE: High T1 contrast with thin,contiguous slices.

TR 450 ms, TE 4.4 ms, SL 5 mm, 2562, 40 contiguous slices in 6 minutes. Youcan find the protocol in the Siemensprotocol tree under: Head, T1, T1_mprage_sag.

New Protocols

The following new protocols can befound under the following areas:

3D MEDIC (prerequisite Core Plus Package)

Protocols for Shoulder, Knee and Cervical, Thoracic and Lumbar Spine

Siemens Exclusive

3D TrueFISP (prerequisite AdvancedTurbo Package)

Protocols for Brain, Cervical Spineand Lumbar Spine

Siemens Exclusive

55


Exam Program Protocol Time SL FOV # Part Matrix

c-spine T2 T2_med3D_tra 6:59 3 mm 250 40 218 x 256

t-spine T2 T2_med3D_tra 7:05 3 mm 250 40 204 x 256

l-spine T2 T2_med3D_tra 6:18 3 mm 250 40 204 x 256

shoulder T2 T2_med3D_tra 6:35 3 mm 192 40 190 x 256

shoulder T2 T2_med3D_cor 6:23 3 mm 192 26 190 x 256

knee T2 T2_med3D_tra 7:48 4 mm 200 32 225x 256

Exam Program Protocol Time SL FOV # Part Matrix

head trufi t2_trufi3d_tra 3:22 2 230 64 213_256

c-spine trufi t2_trufi3d_sag 6:14 2 250 64 224_256

c-spine trufi t2_trufi3d_tra 5:23 2 250 64 192_256

l-spine trufi t2_trufi3d_sag 5:00 1.5 280 64 256_256

3D TrueFISP provides high resolution,myelographic studies of the brain andspine.

Left: 2 mm slice. One of 64 partitionsacquired in 6 minutes.

Right: MPR reconstruction through thelumbar spine. Very thin (1.5 mm) sliceswere obtained in the sagittal plane and processed with the MPR softwareto create 2 mm coronal slices.

CARE Bolus (Option, Prerequisites:Advanced Angio Package, ImageProcessor Reconstruction Extension)Siemens Exclusive

The CARE Bolus software option offerson-line, real-time visualization of thearrival of a contrast medium bolus. Theuser can switch immediately from 2D to3D MRA acquisition with a single mouseclick, providing precise timing for efficientContrast Enhanced MRA studies.

CARE Bolus is another example of howthe syngo user platform enablesSiemens to bring high field applicationsto your patient-friendly open MR system.

Courtesy Hospital St. Gallen, Switzerland

:Coil Concept for MAGNETOM Concerto:

■ CP Array coils for head, body andspine

■ Concerto Integrated PanoramicArray™ (C-IPA)

■ Dual Phase Array receive coils fororthopedics

■ Multi Purpose (MP) coils for specialapplications like intervention

Open MRI is one of the most significanttrends in magnetic resonance imaging.The advantages of Open technology arebetter patient acceptance, less claustro-phobia and better patient access.

There have been numerous technologicadvances in RF coil design inMAGNETOM Concerto systems and aproliferation in the number of specializedcoils available to the imaging professio-nal. These developments have helpedincrease the use of MAGNETOMConcerto due to increased S/N ratio andimage quality reaching high-fieldsystems.

Intricately associated with SNR andspatial resolution, appropriate RF coilselection is a critical aspect of theprescription for successful MR imagingtechniques in Open Systems. The newMAGNETOM Concerto coils demonstratea wide range of functional characteristics

with coil selection of CP Array Coils forhead, body and spine, as well as dualPhase Array Receive coils for orthope-dics, Multi Purpose (MP) coils for specialapplications like intervention and the revolutionary Concerto IntegratedPanoramic Array (C-IPA).

MAGNETOM Concerto CP Head & Neck Array

■ Circular polarized array coil with highsignal-to-noise ratio for high-resolutionimaging of the head including the C-spine.

■ Completely removable top.

■ A neck loop can be plugged in for neckstudies. Two different diameters areavailable for high signal-to-noise ratio.

■ Part of MAGNETOM Concerto Coil Kit.

Examination with CP Head Array Coil: Only head top positioned.

Head examination results:

56

Open Class

TR 354, TE 9.0, SL 5 mm, 23 cm FOV, 192 x 256, 6:47Courtesy Medica Forsyth, US

TR 5000, TE 120, SL 5 mm, 17 x 23 cm FOV,172 x 230, 6:20 Courtesy Medica Forsyth, US

Examination with CP Head & Neck Array Coil :Recommended for head and neck studies.

Head top and neck coil (M or L)positioned. For cervical spine : HE2 and Neck are active.

Results with CP Head & Neck Array Coil:

Examination with neck coil only. Just NM (Neck medium) or NL (Neck large) is plugged

Results with only CP Neck Array Coil:

Circular polarized 2 channel array coilwith high signal-to-noise ratio forhigh-resolution imaging of the entirebody region including the spine.

Four sizes:

■ S (small) option■ M (medium) standard■ L (large) standard■ XL (extra large) option

57


TR 300, TE 25, 4 mm, 18 x 25 FOV, 7 min (left)TR 4500, TE 138, 4 mm, 256 2 matrix, 7 min (right)

3D CISS provides contiguous slices, excellent T2* contrast, 3 mm, 22 cm FOV,256 2 matrix, 48 slices acquired in 6 min

L Spine Position T Spine Position

Examination:

One lower part for all sizesS and M fits in the inner contact rowL and XL fits in the outer contact rowAlways connect both plugs

Results with CP Body & Spine ArrayCoils:

T1 imaging, TR 470,TE 19, 4 mm, 6 min

TR 470, TE 19, 4 mm, 6 min

TR 4500, TE 134, 4 mm, 6 min

T2 TSE tra respiratory triggeredTR 5141, TE 95, 8 mm, 28 FoV, 8 min

2 sec HASTE sequence (MR cholangio-graphy) TR 2800, TE 889, 40 mm, 2 sec

T2 contrast, TR 5000, TE 134, 5 mm, 8 min

MAGNETOM ConcertoCP Body / Spine Array Coils

Head & Neck

Body

■ Head and neck exams in one patientpositioning

■ Lower head part can remain on thetable for body exams

■ Body imaging with minimal patientpositioning

58

Open Class

MAGNETOM ConcertoConcerto Integrated Panoramic Arraycoil system

■ Dual Phased Array receive coils with high signal-to-noise ratio for high-resolution imaging.Left-right switch with shoulder arraycoil. Position doesn’t matter on theConcerto (due to array combination).The patient’s head is always positionedoutside the magnet.

Results with shoulder array coil:

MAGNETOM ConcertoDual Phased Array Coils

■ Dual Phased Array receive coil,anatomically adapted to the shape of thewrist for imaging of the hand andregions around the wrist

Results with Wrist Array Coil:

Wrist Array Coil

PD wt TSE cor

TR 2000TE 224 mm18 cm6 1/2 min

T2 wt Turbo SpinEcho cor

TR 3500TE 1194 mm18 cm6 min

3D DESS provides contiguous slices 2 mm8 x 10 cm FoV

Multipurpose Coils for Intervention

Primarily for interventionSmall: diameter 16 cm and 21 cmLarge: diameter 35 cm and 45 cm

59


Dual Phased Array receive coil for body and spine imagingLargest coil which takes a waist-size ofup to 69 inches (175 cm)

XXL Coil

■ Dual Phased Array receive coil with high signal-to-noise ratio for high-resolution imaging of the lowerextremities

■ Two diameters provided

Results with Extremity Array Coil:

Extremity Array Coil for knee and ankle imaging

3D DESS sag, contiguous slices, 2 mm, 18 cm, 47 slices, in 5 min., Patellar cartilage defects

2 x 6-channel bodyarray (anterior andposterior)**TA: 19 sec.Resolution:1.3 x 0.8 x 1.8 mmFOV: 400 mmBase Resolution:512 24 ml Magnevist,flow 2ml/s iPAT x 2 (GRAPPA)MAGNETOM Sonata (Univ. Essen)

60

:The combination of GRAPPA &mSENSE for a complete solution:

iPAT*M a e s t r o C l a s s

is in creased speed

* The informationabout syngo MR2002 B is beingprovided forplanning purposes.The syngo MR 2002 B packages ispending 510 (k)review, and is notcommerciallyavailable in the U.S.

61


Dynamic MRA ofthe pulmonaryvessels, thoracicand abdominal aortaand renal vessels.Only 2.19 sec foreach 3D data set.TR: 1.7 msTE: 0.7 ms145x2562x 6-channel bodyarray (anterior andposterior)**MAGNETOMSonataImage courtesy of NorthwesternUniversity, Illinois.

:SENSE and SMASHPhysical Principle, Advantages:Matthias Blasche, Siemens AG, Medical Solutions, MR Marketing, Erlangen

Introduction

The need for shorter measurementtimes in magnetic resonance imaging isas old as the procedure itself. Shorteroverall examination times increaseproductivity and patient comfort. Breath-hold times can be reduced. Dynamicprocesses, such as the beating heart,can be scanned with higher temporalresolution.

In traditional imaging, spatial resolutionis attained by switching the gradientfields. Each echo is individually encoded.Thus, the speed of a measurement is the result of how quickly the spatialencoding of an individual echo can beperformed sequentially.

One possibility of reducing measurementtime without compromising resolution is to reduce the number of echoesmeasured. This results in a rectangularfield of view (RecFOV). If, however, thefield of view is selected to be smallerthan the size of the object, so-calledaliasing is the result. Thus, with traditionaltechniques, the possibility of reducingmeasurement times with a rectangularfield of view is limited by the patient’sanatomy.

Shared Characteristics of SENSE and SMASH

In contrast to traditional sequentialmeasurement techniques, SENSE andSMASH are parallel imaging techniques.The spatial resolution of the image is no longer determined solely by theacquired, gradient-encoded echoes.With SENSE and SMASH, additionalspatial information is obtained from thespatial variation in the coil intensityprofiles during measurement with arraycoils. Thus, fewer echoes are measuredwith SENSE and SMASH than would beneeded to obtain the desired resolutionwith a traditional technique.

In simple terms, this is nothing morethan a measurement with a rectangularfield of view (RecFOV). The only “trick”with SENSE and SMASH is the eliminationof the aliasing that occurs with traditionaltechniques. This is the result of theadditional information that one can gainfrom the intensity profiles of the individualcoils during measurement with arraycoils. SENSE and SMASH use differentmethods to obtain this information.

The Physical Principle of SENSE

During a measurement with a single coil,the signal intensity of a pixel located at(x,y) is given as:

P(x,y) = S(x,y) . C(x,y) +

S(x+FoVPhase,y) . C(x+FoVPhase,y)

S(x,y) is the (coil-independent) signalintensity, indicated by the tissue andsequence parameters, of the measure-ment object at location (x,y). C(x,y) de-scribes the coil sensitivity (=coil profile)at location (x,y).

The second addend describes thealiasing. The aliasing appears in the imageif the anatomical structure extends tothe location (x+FoVPhase,y) and at the sametime the coil demonstrates a significantsensitivity at this location, that is to say,if both S(x+FoVPhase,y) and C(x+FoVPhase,y)are greater than zero. (For purposes ofclarity, the formula above considers onlyaliasing of the first magnitude.)

The actual signal intensity and the unde-sired aliasing cannot be distinguishedwhen measuring with only one coil. It isdifferent, however, when measurementis performed with array coils. Additionalinformation can be obtained as a result of the different coil profiles of theindividual coil elements.

The principle of the SENSE technique is explained in the following simpleexample with 2 coil elements (Fig. 1):

Figure 1:Coil profiles of individual coils in a simple 2-coil array

In the case of a measurement with a 2-coil array, the signal intensity of a pixel atthe location is the result of both portionsmeasured with the single elements:

P1(x,y) = S(x,y) . C1(x,y) +

S(x+FoVPhase,y) . C1(x+FoVPhase,y)

P2(x,y) = S(x,y) . C2(x,y) +

S(x+FoVPhase,y) . C2(x+FoVPhase,y)

If the coil profiles C1 and C2 are knownat all locations (e.g., as the result of asuitable reference measurement), theactual signal intensities can be separatedfrom the undesirable aliasing using thissystem of equations.

Thus, if the coil profiles are known, thecorrect image can be calculated usingthe individual images measured by the array-coil elements. The SENSEtechnique is a modified image recon-struction in the image space. Themaximum reduction in measurementtime is determined by the number of coil elements.

62

iPAT

Figure 2:How does SENSE work?

The Physical Principle of SMASH

Unlike SENSE, SMASH is based on a modified image reconstruction in the k-space. Compared to traditional techni-ques, measured (gradient-encoded)echoes are replaced by “artificial”echoes. Spatial information is imprintedonto these artificial echoes by anencoding using the coil sensitivities.

First, linear superpositions are formedfor the signals of the individual coils. Fig. 3 illustrates this with the simpleexample of a 2-coil array.

Figure 3:Linear superposition (dotted line) of theindividual coil sensitivity profiles

These superpositions of the coil profilesare quite similar to traditional gradientencodings. Thus, these superpositionscan be used to increase the number of(gradient-encoded) echoes measured.To a certain extent, the “gaps” in theraw data matrix that occur duringmeasurement with a reduced number ofmeasured echoes (RecFOV) can be clo-sed. The raw data matrix is completed inthis way, and no more aliasing occurs .As with SENSE, the maximum reductionin measurement time is equal to thenumber of coil elements.

63


Fig. 4:How does SMASH work ?

Advantages of SENSE and SMASHCase study

The patient was a 68 year old male withnumbness of his fingers and impairedbalance. An MR study was conducted toevaluate for cervical spondylotic myelo-pathy. The patient was unable to holdstill in the scanner because of severepain. Scanning at conventional speed(and even at an PAT factor of 2) yieldedimages with excessive motion artifacts.By using an PAT factor of 4, scan timewas shortened sufficiently to acquireartifact-free images, allowing accuratediagnosis (Fig. 5).

1. Reduced acquisition times

With SENSE and SMASH, imagescan be produced in a shorter time(though with a lower signal to noiseratio). The maximum reduction inacquisition time is determined bythe number of array coil elements.

Moving organs (for example, theheart) can be more clearly imaged,and dynamic processes (for example,transit of contrast agent) can bemeasured with higher temporalresolution.

Shorter scan times (and shorterbreath-hold times) lead to improvedpatient compliance, with impli-cations for image quality (e.g. lesspatient movement in the scanner,hence fewer motion artifacts).Patient comfort is also enhanced.(Figure 5)

2. Shorter echo trains for single-shot methods

A second advantage is that echotrains can be shortened for single-shot methods (single-shot EPI,single-shot TSE, HASTE) whilemaintaining the same resolution.

Shorter echo trains for single-shotprocedures result in lower “T2 filtering” (or “T2* filtering”) ofthe raw data. As a result, the imagesare more sharply focused, withfewer susceptibility artifacts anddistortions.

Literature:

1. Weiger M, Pruessmann KP,Boesiger P. Cardiac Real-Time ImagingUsing SENSE.

Magnetic Resonance in Medicine 43,177-184 (2000)

64

iPAT

T1, iPAT 4xAcquisition time: 37 sec

T2, iPAT 4xAcquisition time: 41 sec

Figure 5:Time-Critical MR Imaging of the Cervical Spine (Clinical case and images, courtesy of Edmond,A. Knopp, M.D., New York University School of Medicine)

T1, conventional speed. Acquisition time: 3:06 min

T2, conventional speed. Acquisition time: 3:48 min

2. Sodickson DK, Griswold MA, Jakob PM. SMASH Imaging.

MRI Clinics of North America, Vol. 7,No. 2, 237-254 (May 1999)

3. Internet page of Beth IsraelDeaconess Medical Center, Boston:

http://www.bidmc.harvard.edu/cmr/smash.html

Ti p

:iPAT: The Siemens Solution:

Siemens’ iPAT (integrated ParallelAcquisition Techniques) solution is theonly PAT product on the market thatoffers both reconstruction algorithmsimage-based (mSENSE, an enhancedversion of SENSE) and k-space-based(GRAPPA, GeneRalized AutocalibratingPartially Parallel Acquisition), Allowingfor a 2x enhancement in speed1. Siemens’iPATplus2 is an add-on allowing for speedenhancements of up to 4x – the fastestimplementation commercially available.iPAT works with most array coils current-ly offered by Siemens. In addition, iPAT-optimised head (8-channel) and body (6-channel) array coils are available asoptions, for maximum performance inparallel imaging scans3.

■ mSENSE has the following advantagesover the conventional SENSE:

• No threshold has to be used todetermine if the reference imageintensity is sufficient enough for coilmaps calculation. mSENSE calculatesautomatically.

• The technique is more robust forbreath-hold sequences and flexiblearray coils.

• Improved Signal to Noiseperformance.

■ Instead of a pre-scan for coil calibration,an autocalibration technique is usedwith Siemens’ iPAT sequences.Autocalibration has two advantages 1. You do not have to spend an additionaltime before scanning. 2. If there is any motion between scansyou do not have to pre-scan before eachseries to have optimal image quality.

■ iPAT is integrated into our revolutio-nary Integrated Panoramic Array (IPA)technology.

Figure 6:Image showing the combination of CP head - neck & spine array coils with iPAT technique

■ mSENSE should be preferred for axial body imaging (phase encoding A->P),

GRAPPA is more suitable for EPI, cardiac imaging

65


Conventional (TA: 70 sec) iPAT x3 (TA: 30 sec)

Figure 8:GRAPPA results in good image quality fordouble oblique slices (as used in cardiac imaging) and allows forsmall (folded) FOV

Figure 7:mSENSE shows betterimage quality thanGRAPPA for axial bodyimaging

GRAPPA x 2 SENSE x 2

Ti p :iPAT coils:

iPAT-optimized head (8-channel) andbody (6-channel) array coils are availableas options, for maximum performance inparallel imaging scans

6-Channel Body Array Coil**

■ Use pads to keep the coils approx.

10 mm away from the patient

■ mSENSE tolerates no folded FOV!

The mSENSE reconstruction is very

sensitive to a folded FOV. In axial

abdomen imaging without iPAT the

FOV is chosen very narrow as some

folding of subcutaneous fat can be

tolerated. With mSENSE the folding

will result in strong artifacts right in

the centre of the image. It is advised

that 10 mm space in phase encoding

direction is added on each side

of the FOV in such examinations.

■ Successful image reconstruction

in parallel imaging strictly requires

that the sensitivity profile of the

receiving coil array varies along the

phase encoding direction. For

example, in spine imaging, parallel

acquisition with the phase encoding

direction Head-Feet will work fine,

as the elements (up to 6) of the

spine coil are aligned in this direction.

Phase encoding A-P will, however,

not work, because regarding the AP

direction, the spine coil effectively

can be counted as one coil only

(Fig. 9).

■ For the 8-channel head coil (with

and without iPAT), a dedicated

normalize filter is recommended

which is included in the iPAT

sequences.

■ Adding a small amount of

over-sampling can considerably

increase image quality:

• effectively reduces the

acceleration factor

• makes PAT-reconstruction more

robust (more SNR, artifacts less

likely)

• helps to retain SNR

■ Use sagittal localizer for

abdominal imaging (to ensure, that

all slices have sufficiently large FOV)

66

iPAT

Figure 9:Phase encoding direction Head-Feet forsagittal spine imaging

Figure 10.T2 weighted TSE spine imaging results with iPAT

Conventional

TA : 84seciPATx2

TA : 44seciPATx3

TA : 32sec

iPATx4

TA : 24sec

8-Channel Head Coil

Prerequisite: Whole body array interface

Current CP array coils more or less limitthe encoding direction to anterior-posterior. 6-channel Body array was de-signed for parallel imaging with arbitraryphase encoding directions. This coil alsoallows an acceleration factor up to 3.This coil can be used integrated with thespine array coil. (Anterior 6-channelBody Array Coil + Posterior CP SpineArray coil) The other possibility is to usethe 6-channel body array coil anteriorlyand posteriorly. (Double -6- pack )

Prerequisite: Whole body array interface

1 Standard on the syngo 2002B software,available summer 2002

2 Available summer 2002 as an option for thesyngo 2002B software

3 Available summer 2002** The information about the 6 channel body array (anterior and posterior) is being provided for planning purposes. The product requires 510 (k) review and is not commercially available in the U.S.

67

M A G N E T O MFlashFlashFlashiPAT neuro imaging with 8 channel head coil:Post-traumatic epiduralhematoma withventicular drain. T2weighted high resolutionimages (334x512). 19 slices in 90 sec

Dark fluid contrast(192x256), 19 slices in 90 sec. PAT factor 2

iPAT abdominal imaging with 6 channelbody array coil**

T1 Flash coronal imaging without iPAT: 14 slices in 22 sec (left)

T1 Flash coronal imaging with iPAT: 14 slices in 12 sec (right)

Cholangiography withsingle shot turbo spinecho:

With IPA coils (Body andspine array coils), lessblurring with PAT factor 2(right) due to shorterecho train length (LessT2 decay)

:Liver Imaging with VIBE iPAT:Wolfgang Römer, M.D., Evelyn Wenkel, M.D., Franz Fellner, M.D., Insitut für Diagnostische Radiologie, Universität Erlangen-Nürnberg, Germany

In this case study, mSENSE an improvedSENSE related, autocalibrated, parallelacquisition technique, was used withVIBE.

Patient History

The patient was a 59 year old male withalcoholic liver cirrhosis of several years’duration. In October 2000, one lesionsuspicious for hepatocellular carcinoma(HCC) was detected in segment 4a in aliver MR examination, and HCC washistologically confirmed. The level ofalpha-feto-protein (AFP) was elevated.In December 2000, this lesion wassuccessfully treated by high-frequencythermo therapy (HFTT) outside MR Unitthat resulted in a decrease in AFPvalues. Follow-up MR examinations inMarch and July 2001 showed no recur-rence. In September 2001, the AFP levelrose again and control MR examinationwas performed.

The MR examination showed thefollowing:

Results and Discussion

The recent development of a 3Dgradient-echo dynamic T1 weightedsequence called VIBE (Volume Inter-polated Breath-hold Examination) withiPAT, offers the chance to performperfusion studies of the liver with hightemporal and spatial resolution. Thissequence offers the opportunity toexamine the whole liver volume with a3D data set and scanning intervals ofonly 14 seconds. The study is performedas a breath-hold technique. Gadolinium-containing contrast medium (0.2 ml / kgbody weight) is applied by an automaticpower injector using a flow of 1 ml / sec,and the first post-contrast sequence isstarted with a delay of 14 seconds.Using this sequence, hypervasculartumors such as HCC can be visualizedwith excellent signal-to-noise ratio incomparison to conventional dynamicstudies using FLASH sequences. This isimportant for lesions that may be seenonly on dynamic contrast-enhancedstudies, such as liver adenoma, focalnodular hyperplasia (FNH) or, as withthis case, hepatocellular carcinoma.

System: MAGNETOM Symphony with Quantumgradient system.

68

Figure 1:T2 weighted TSE showed no evidence offocal liver lesion suspicious for HCC

Figure 2:Arterial phase T1 weighted dynamic sequence(VIBE iPAT) showed a focal, early contrast-enhancing lesion in Segment 7, with adiameter of 1 cm, suspicious for HCC. iPATVIBE parameters: Acquisition time 14 seconds, 44 slices, 4 mm slice thickness,FOV: 400 mm x 300 mm, TR 6.2 msec, TE 3.2 msec, flip angle 12 degrees. CP Body Array – CP Spine Array combinationIPA was used.

Figure 3:Contrast-enhanced T1 weighted FLASH 2D showed no corresponding lesion (Acquisition time 25 seconds)

Figure 4:Corresponding three-phase spiral-CT(SOMATOM Plus 4) shows slight focalenhancement in the arterial and portal-venous phase in segment 7

A9

11

00

-M-Z

73

0-1

-76

00

Siemens Ultra High-Field

Programwww.SiemensMedical.com

The Siemens commitment to 3 Tesla can easily be seen in

our leading product line in the Ultra High-Field segment.

MAGNETOM® Allegra – See the Mind. Dedicated to brain

imaging, this most compact 3T scanner is equipped with

the strongest gradients in the market. MAGNETOM Trio –

See the Body. The Trio is your system for whole body

applications in the 3T Ultra High-Field sector. It offers a

full 40 cm Field of View and is the shortest 3T scanner

allowing clinical whole-body imaging at 3 Tesla.


smedical

Female Pelvis

70

:Saturation Band Effectiveness:Margaret King, RT (R) (MR), Manager, MRI Services, Wake Radiology Services / Raleigh MRI Center, Raleigh, NC

Super Technologists

How often does this happen to you?

Bright fat in the anterior abdomen cancause ghosting if the plane of fat isperpendicular to the phase direction.Respiration simply magnifies the effect.Careful placement of an anterior satura-tion band can significantly improve theimage quality. All anterior fat (two layers)must be within the saturation region for the saturation band to be effective.

Phase A-P Phase A-P Phase R-L

Saturation band is only effective if the ghosting occurs in the phase direction.

Saturation band effectively removedphase ghosting.

No Saturation Band With Saturation Band

One must suppress both subcutaneous fat as well as peritonealfat to effectively eliminate phase ghosting.

Sat Band

71

M A G N E T O MFlashFlashFlashHips

A saturation band that is too narrow to cover all of the subcutaneous fat will still lead to phase ghosting.

Note the ghosting of the non-suppressed bright fat within the saturation band.

No Saturation Band With Saturation Band

Again, severe ghosting due to respiratory and abdominal motion.Effective placement of a saturation band will eliminate ghostingcaused by respiration.

Sat Band

Saturation Band Width

The width of saturation bands can beused to your advantage. Varyingsaturation bandwidth can help you inyour day to day imaging. You can varythe width of the saturation bands to“see through” selective tissue, yet stilleffectively suppress the majority oftissue.

Saturation band effectively removed phase ghosting.

72

Super Technologists

As a general rule, the narrower thesaturation band is, the more effective itproves to be. The edges of narrowersaturation bands are more well defined,whereas the edges of the wider satura-tion bands are “blurrier” and in a sensenot as effective. You can use this“blurriness” to your advantage. If theinner layer or peritoneal layer of fat isvery close to the anatomy of interest, awider saturation band may be indicated.You will be able to “see through” theedge of the saturation band to seeanatomy, yet the abdominal fat will stillbe suppressed thus reducing any phaseghosting.

Defined Edge of Suppression Diffuse Edge of Suppression

Both saturation bandseffectively suppressedphase ghosting.

Sagittal Pelvis

Saturation Bands inBreath-hold Imaging

Axial T2 liver with phaseghosting from bright fat. Eventhough image was breath-hold,abdominal wall rarely remainsperfectly still.

The addition of a saturation bandto suppress phase ghosting is recommended. Widen the saturation band to“see through” anatomy.

Sat Band

T2 Axial Liver

Axial T2 liver with anterior saturationband. Substantially reduced phaseghosting. You can “see through” the edge of the saturation band allowingvisualization of all anatomy. Imageswere still obtained within a breath-hold.

Edge of saturation band is barely visibleas indicated by the arrows.

73


Summary

1. Bright fat will cause phase ghostingif the plane of the fat is perpendicularto the phase direction.

2. Respiration magnifies the phaseghosting effect.

3. Careful placement can significantlyreduce phase ghosting.

4. The saturation band must saturate both the subcutaneous and the peritoneal fat to be effective.

5. The narrower the saturation band,the better defined the edge of thesaturation band and the better thesaturation band is at suppressing thebright signal.

6. Conversely, the wider the saturationband, the more diffuse the edge of the saturation band, and therefore youmay be able to “see through” the anatomy, but the fat signal will still besuppressed.

7. Use the width of the saturation bandto your advantage. Use narrowersaturation bands when the desire is tocompletely suppress the signal fromtissue. Use a wider saturation bandwhen the desire is to suppress tissue,but at the same time “see through”the edge of the saturation band and notobscure any pertinent anatomy.

8. Two narrower saturation bands are more effective than one widesaturation band.

Margaret King, RT (R) (MR)

Manager, MRI ServicesWake Radiology Services /Raleigh MRI CenterRaleigh, NC

No Sat One 150 mm Sat Two 75 mm Sats(overlapped slightly)

No Sat One 150 mm Sat Two 75 mm Sats(overlapped slightly)

No Sat, one Sat or two Saturation Bands

Obviously the two narrower 75 mm sa-turation bands were more effective thanthe one 150 mm sat band. Use this toyour advantage when deciding whetherto use a sat band or not as well as deci-ding which width to choose from.

:Cholangiography with Blueberry juice:Bart Schraa, Chief Technologist, Dept. of Radiology, Dr. Daniel Den Hoed clinic, Academic Hospital RotterdamRotterdam, The Netherlands

74

Super Technologists

Introduction

It is known that the quality of the chol-angiography can be greatly impaired bythe abundance of water in the stomachand small intestine. One of the solutionsis to let the patient drink Lumirem (Guer-bet, France). The iron particles reducethe signal of the existing water. Another,much cheaper, solution is to use blue-berry juice (which can be bought in anysupermarket) for that purpose. Due tothe high manganese content (which hasa rather short T2 relaxation) of blueberryjuice, the high signal of the water in thestomach and small intestine on T2weighted images is greatly reduced. Thelonger the TE that is being used, themore prominent the signal is reduced.Apart from the T2 shortening, the T1 isalso shortened by manganese. Thiscould be utilized for imaging the gastro-intestinal (GI) tract as well.

Preparation and examination

For best results, the patient should havenothing further to eat 2 hours prior to the examination. The fuller the stomach,and thus the more dilution, the less theeffect is of the blueberry juice. Justbefore the patient is being put on to thetable, he should drink two glasses ofblueberry juice. Positioning is just likeany other liver examination. The standardprotocols for cholangiography (as storedunder the Siemens tree) can be used for the examination, although increasingthe TE is always helpful.

Discussion

Below is an example “phantom study”showing the characteristics of blueberryjuice using a T2 weighted scan, and using

the standard Siemens protocols for chol-angiography on the syngo MR 2002Asoftware on a MAGNETOM Sonata. Fordemonstration purposes, a small tubefilled with saline solution has beeninserted into the blueberry juice, actingas the common bile duct. To demon-strate the signal behaviour when usingdifferent TE’s, the sample has beenmeasured with 5 different TE’s.

The signal measured and the contrastbetween the saline solution and theblueberry juice is set out in table 1. Thistable shows clearly that there is highercontrast between saline solution andblueberry juice achieved at longer TE’s.Examples of the images obtained areshown in Figure 1. Figure 1a-e showsthe effect of TE with a TE thin slice and1f is an example of a thick slab HASTE at a TE of 1100 ms.

The benefit of blueberry juice in a volun-teer can be seen in Figure 2. Figure 2ashows the result of the examinationwithout using blueberry juice, whereasfigure 2b shows the result after drinkingblueberry juice. In figure 2a, the stomachand small intestine projects over the bileducts, whereas in figure 2b, the signal in both the small intestine and thestomach has been eliminated by theblueberry juice.

Figure 3 demonstrates the high signal ofthe blueberry juice in the stomach, thiscould be used for imaging the gastro-intestinal tract.

Sequence Water Blueberry juice Contrast ratio

T1 308 819 0.376068

T2 TE=105 1874 594 3.154882

T2 TE=142 1863 388 4.801546

T2 TE=2196 1652 230 7.182609

T2 TE=303 1520 100 15.2

T2 TE=596 1252 37 33.83784

Figure 3:T1 weighted FLASH with blueberry juice

Figure 2:Thick slab HASTE, TE 1100 ms: A without, B with blueberry juice

Figure 1:Blueberry juice at different TE's: A 105 ms, B 142 ms, C 196 ms, D 303 ms, E 596 ms,F 1100 ms (projection)

75

M A G N E T O MFlashFlashFlash:Tips in MRCP:Mark Lourensz, Deputy Chief MIT at St. Vincent’s Hospital, Melburne, Australia

■ Position coil so diaphragm is includedat the top of the FOV.

■ Patients must be well-coached inbreath holding technique. Use oxygen ifneeded, adjust scan time to suitedyspnoeic patients. Inspiration is easierto explain in a multi-lingual referral base.

■ Fast for 4 hours prior to examination.

■ Transverse T1 screen of liver –fl2d_4b260.ykc. 8 mm/0.3, FOV to suitepatient (Magnetom Vision).

Transverse HASTE screen of liver fromdiaphragm to below ampulla – haste_ 95b260.ykc. (fatsat), 4 mm/0,contiguous slices (Magnetom Vision).

■ Identify the ductal anatomy on thetransverse images and prescribe para-coronal HASTE slices to demonstrateanatomy and pathology.

Perform other projections as needed toshow any anomalous anatomy.

The above protocol provides us with allthe information we need for a compre-hensive study in a short period of time(<15 min).

Pitfalls to be aware of

Small stones <3 mm can be hard to detect.

Flow of bile can mimic stones.

Pneumobilia may mimic stones.

Surgical clips can cause artifact, whichmay hide or mimic pathology.

Normal vascular compression may mimic stenosis.

Peristaltic activity may mimic stenosis /pathology.

Incorrect windowing can hide pathology,review imaging on MRI monitor ifindicated.

Knowledge of these pitfalls prior toscanning can often preclude them frombeing a problem.

The use of Buscopan, or rescanningpatients after a suitable time period canhelp differentiate artifact from pathologyin many cases.

Fig 1a / 2a:4 mm slices in line with the CBD, 13 slices, 20 sec breath-hold

Fig 1b / 2b:15 or 20 mm single or multi slice sequence to show CBD, 2 – 13 sec breath-hold

Fig 1c / 2c:Lower end of CBD and PD

Fig 1d / 2d:Confluence of right and left hepatic ducts

Fig 1a Fig 1b

Fig 1c Fig 1dFig 2c

Fig 2a

Fig 2d

Fig 2b

MAGNETOM Flash – Reader ServiceLetters to the Editor – We welcome your com-ments about the content of MAGNETOM Flash.Please send comments to the Editor. Include yourname, address, and phone number or e-mail.

World Wide Web – Visit us at www.siemensmedical.com. This site provides information about all Siemens medical products.

Publish articles? – You are invited to publish articles in the newsletter to share your experiencewith MAGNETOM MR users all over the world. To submit an article please contact the Editor.

Subscription – You have seen the newsletter and want to get it on a regular basis? In the US, please contact the Applications Helpline (phone 800-888-SIEM) and give us your name andbusiness address (no home addresses, please). Outside the US, MAGNETOM Flash is distributedthrough the local Siemens offices. Please contactthe Editor and we will make sure that you areincluded on your local support office’s distributionlist.

Editor

Ali Nejat Bengi, [email protected]

Published by

Siemens AG Medical SolutionsP.O.Box 3260D-91052 Erlangen

Correspondence and International Distribution

Ali Nejat Bengi, M.D., Editor in ChiefMAGNETOM FLASHSiemens AG Medical Solutions, MR MarketingAllee im Röthelheimpark 3D-91052 ErlangenPhone: 49 - 91 31 - 84 - 75 99Fax: 49 - 91 31 - 84 - 21 86

US Distribution

MR APPLICATIONS HELPLINESiemens Uptime Service Center110 MacAlyson CourtCary, NC 27511Phone: 800 - 888 - SIEMFax: 919 - 319 - 28 64

Internet: www.siemensmedical.comAll articles represent the techniques and opinions of the authors and may not represent specific recommendations or endorsements from SiemensMedical Solutions. Contact the authors directly for further information about their techniques andopinion.

Siemens reserves the right to modify the design and

specifications contained herein without prior notice.

Please contact your local Siemens Sales representative

for the most current information.

Note:

Original images always lose a certain amount of detail

when reproduced.

Siemens AG, Medical SolutionsHenkestr. 127, D-91052 ErlangenGermanyTelefon: ++49 9131 84-0www.SiemensMedical.com

Order No. A91100-M2220-F691-3-7600

Printed in Germany

CCA 62691 WS 060220.

Please contact inthe U.S.A.:

Siemens Medical Systems, Inc.186 Wood Avenue SouthIselin, NJ 08830-2770(+1) 732 321-4500

Or your local Siemens Representative

Please contact in Japan:

Siemens-Asahi Medical Technologies Ltd.Takanawa Park Tower 14 F20–14, Higashi-Gotanda 3-chomeShinagawa-kuTokyo 141-8641(+81) 354 234 001

Please contact in Asia:

Siemens Medical SolutionsAsia Pacific Headquartersc/o Siemens Advanced Engineering Pte Ltd.Block 28 Ayer Rajah Crescent No.06-08Singapore 139959(+65)8715888

The information in this document contains general de-

scriptions of the technical options available, which do

not always have to be present in individual cases.

The required features should therefore be specified in

each individual case at the time of closing the contract.

2002 magnetom flash 2

Documents

ultimate fmri machine

intensive care unit

virtual endoscopic views

acute myocardial infarction

mosaic image format

chemical shift imaging

thick slab haste

syngo mr 2002b