Clinical Pearls for Imaging: Ge3ng the Most Bang for Your

Radiology Buck

Cost Considera?ons

• Hospital/HospitalAffiliatedvsStand-alone•  Facili5esUseFees•  SeparatevsGlobalBilling/KnownvsUnknown•  Medicareallowed

Totalcost• Deduc5ble• Price-Shopping• NUMBEROFEXAMS

Impact of Number of Exams

• Cost•  TimeTimetoreceivingusefulinforma5onPhysician5meandstaff5metoorder/schedule/preauthorize

Your Armamentarium

• Ultrasound• X-Ray• CT• MRI

Ultrasound

•  Soundwavegenerated• Wavestrikesanobjectandcomesbackasanecho•  Timeforechotoreturntomachinemeasured• Distancetoobjectcalculated=howdeep• Beamofsoundwavessentoutandbouncebackonlyifstrikeanobject,otherskeepgoing.Thewidthofthereturningbeamofwaves=thewidthoftheobject

What is it?

• Numberofreturningechoes=density=whitedots•  Simpleliquidisuniform,nothingsolidtobounceoff=nowhitedots=blackonanultrasoundimage

Bladder “Increasedthroughtransmission”

Polycys?c Ovaries

Complex Fluid

•  Solidpar5clesinsimplefluid=whitedotsfloa5ngindarksimplefluid

Hemorrhagic Ovarian Cyst

Solid

• Moresolid=morewhitedots•  SoZTissue=shadesofgray• Bone=wallofwhitedots

Kidney

Renal Stone “Shadowing”

UltrasoundNOTsensi5veforkidneystones

Verysensi5veforkidneyblockage

Uterus Curvedteardropshape

Myometrium

Leiomyoma

Adenomyosis

Endometrium

EndometrialHyperplasia/Atrophy,EndometrialPolyp,SubmucosalFibroid,EndometrialCancer,IUDplacement

Uterine Leiomyoma Verycommon

Usuallynotaproblemunless:

Toolarge

Intheuterinecavity

Bleeding

Interferencewithpregnancy

Submucosal Fibroid

Adenomyosis Abnormallyplaceddepositsofendometrial5ssue

Endometrial Hyperplasia

Endometrial Polyp

Endometrial Cancer

Ultrasound and Blood Flow

• Dopplereffect•  Seeandmeasurebloodflow

Ovarian Blood Flow

Corpus Luteum Cyst “Ringoffire”

Ovarian Neoplasm

Ultrasound Quirks

• UltrasoundwavesandInterfaces•  Fat:lotsofinterfaces=bright

Renal Hilum

Renal Angiomyolipoma

Ovarian Dermoid Dermoidplug

Ultrasound Quirks

•  Interfaces• Air:tooabruptatransi5onbetweensubstances,toodrama5caninterfaceblockstheultrasoundbeam,sendsallthewavesbackatoncesononegetthrough

When do you use ultrasound?

•  FriendsofUltrasound•  Fluid

•  Ascites,freepelvicfluid•  Bladder,renalpelvis•  Ovariancysts,ovariancys5ctumors,uterinecavity,obstetrics

•  Solid•  Solidorgans:kidneys,ovaries,uterusincludingendometrium

•  Bloodvessels•  Increasedvascularity•  Decreasedvascularity

Ascites

Free Pelvic Fluid

Hydronephrosis

Ectopic Pregnancy Tubalringsign

NoIUP

Ovarian Tumor Cystadenoma

Tuboovarian Abscess

Ovarian Torsion Enlargedovary

Peripheralcysts

Li_leornovenousflow

Decreasedarterialflow

Freefluid

TendertoUSprobe

Enemies of Ultrasound

• Gas•  Bowel:stomach,smallbowel,largebowel,appendixinanadultsizedpa5ent

• Bone•  Ribs

•  Fat:some5mesfriend,some5mesfoe•  Brightbecausemanyinterfaces•  Toothick=Weakultrasoundbeam

X-Ray

• X-raygenerated• Beampassesthroughandisvariablyblockedby5ssuesofdifferentdensi5es• Remainingbeamstrikeseitheraphotographicordigitalplateinunequaldistribu5on•  Theunequaldistribu5onisrecordedasthex-rayimage• Morebeampassage=lessdense5ssue=black•  Lessbeampassage=moredense5ssue=white• Anx-rayimageshowsdifferencesindensity

Friends of X-Ray

• Materialsattheextremesofdensityinthebody•  Bone•  Metal•  Air

Uterine Leiomyoma “Popcorn”calcifica5on

Kidney stone

Bowel Obstruc?on

Bowel Ileus

Enemies of X-Ray

•  Largebodyhabitus(bodyfatorSeahawk)•  Limitedabilitytomove

CT Scan

• X-raygenerated• Bandsofdetectors• Measureamountofx-raypassingthroughapar5cularblockof5ssue• Assigndensitytothatblockof5ssue•  Likex-raybutnowknowtheloca5onofthesmallblockof5ssuein3D• Computergeneratesimagewithdensitylikex-rayso• Denser5ssueiswhite•  LessDense5ssueisblack

CT of Kidneys ExcellentsoZ5ssueresolu5onofdensity

Orienta5on

Anatomicposi5on:ptfacingyou

Renal stone Excellentresolu5onofdensitydifferences

CTKUB

nocontrast

veryquickexamsocaneasilybe

“addedon”toaCTappointment

list

Ureteral stone Excellentresolu5onofdensitydifferences:

calcifica5on

Ovarian Dermoid Excellentresolu5onofdensitydifferences:

fat

Anatomicorienta5on:ptinanatomicposi5onlyingdownasiffellawayfromyou

CT and Blood Flow

•  Intravenouslydeliveredcontrast•  Timedscanningtocapturepar5cularphaseofblood/contrastinfusionintothevessels/organs• Usethepa_ernofbloodflowintheorgantodifferen5atediseaseen55es

Renal Cyst Nephrographicphase

Orienta5on:AXIAL:anatomicposi5onasifpa5entthenfellbackwards

Complex Renal Cyst Orienta5on

CORONAL,soptinanatomicposi5on

Renal Carcinoma Orienta5on?AxialorCoronal?

Moredelayedphase

Renal Angiomyolipoma Bloodflow(enhancement)andfat

Pyelonephri?s

Inguinal Hernia

Friends of CT

•  Fat• Uncoopera5vepa5ents

•  Fast:currentgenera5onscannersareupto1.5Billionwitha“B”percentfasterthanthefirstscanner(1974)

Diver?culi?s Fatseparatestheorgans

Appendici?s CTvsUS

Enemies of CT

• Poorkidneyfunc5on,ac5veCHF/pulmonaryedema• AllergytotheCTcontrast

•  Premedicate•  Hospitalsejng•  NoncontrastCT•  Useothermodality:ultrasound,MRI,nuclearmedicine,PET

• Metal•  Hipprosthesis•  Prostateseedimplants

Radia?on Dose

• Diagnos5cDose• Dosecon5nuestodecrease• ALARA• BackgroundDose(Effec5vedose):3milliSieverts/year• CTAbdomenandPelvis=backgrounddosefor2-3yrs•  LivinginColoradoorNewMexico=backgrounddose4.5mSv/yr

How much dose?

• Manywaystomeasuredose:Absorbeddose,Equivalentdose,Effec5vedose,dosetocenterofbody,dosetoreproduc5veorgans,skindosesoCOMPLICATEDques5on•  Thinkabout:

•  Pregnancy:avoidedunlesslifeendangered•  Ageofpa5ent:child,child-bearingage,elderly•  Mul5pleCT’sinfuture•  Pa5entajtude•  RISKOFNOTDOINGTHETEST:RELATIVERISK•  Unfortunately,cost

Magne?c Resonance Imaging(MRI)

• Pa5entplacedinamagne5cfield• Protonsinwaterandfatalignwiththemagne5cfield• RadiowavesimilarinfrequencytoFMradioisgenerated• Protons5ltthenreturntoalignmentwiththemagne5cfield•  Speedwithwhichtheyreleaseenergyastheyrealignisdependentontheirsurroundings,differentforwaterandsolid:T1,T2• Addi5onalradiowavestodetermineloca5onorspecialeffects• Computergeneratedimages

Friends of MRI

• Bone•  Solidorgans•  Fluidfilledstructures• Vessels

Renal Angiomyolipoma Fatdifferen5a5on

Uterine Leiomyoma LowsignalmassonT2weightedimages

Sagi_alplaneimage

Endometrial Cancer

Enemies of MRI

• Claustrophobicpa5ents•  Tubelikestructure•  Therefore:Wide-bore,Short-bore,Bagel-likeopendesignwithnosides,Uprightwithnotopmachinedesigns.Alsoanxiolysis/seda5on.

• Mo5on:takesmuchlongerthanaCTscan•  GItractmo5on:swallowinginneck,peristalsisinabdomenandpelvis•  Respira5onandcardiacmo5oninchestandupperabdomen

• Allergyifgivecontrast:differentfromCTcontrast,lessallergenic• PoorRenalFunc5on(ifgivingintravenouscontrast)• Medicaldeviceswithmetalpartsesp.pacemakers,cochlearimplants

Summary: Which test to order?

• Ultrasound•  Goodfirstline.Noradia5on.Goodforlookingforfluidorfluid-filledstructures•  Notforstructureswithairsuchaslungs,bowel,notforbones•  Lessusefuliflargepa5ent

• X-Ray•  Goodforextremedensi5es,notsomuchforsolids•  Goodforgas-filledstructuressuchaslungs,bowel•  Goodforboneorstones•  Inexpensive

Summary: Which test to order?

• CT•  Good/fastforsolidstructures,notasgoodasultrasoundforfluid-filledstructuresorpelvicorgans•  Goodforbonesandstones•  Goodforair-filledstructures•  Limita5ons:Poorrenalfunc5on,allergytoIVCTcontrast,pregnancy,CHF

• MRI•  Excellentforalmosteverything(CTbe_erforlungs)andnoradia5on,butmoreexpensive•  Claustrophobiacanbeaddressedwithopendesignmagnets,anxiolysis/seda5on•  Contraindica5onsformagne5cmetaldevices,espthosewithmovingparts

How to Get the Most Bang for Your Radiology Buck • Non-HospitalAffiliatedImagingCentersmuchcheaperthanHospital/HospitalAffiliatedImaging•  Save5meandmoneyforyouandyourpa5entsbyorderingtheimagingtestmostlikelytogiveyoutheanswertoyourques5on•  Tapyourexperienceandresourceslikethislecture•  UseanImagingGuidelinesSheet•  CallyourRadiologistanddiscussthepar5cularsofthecaseifyouhaveconcernsaboutapar5cularpa5ent(e.g.large,immobile,renalorpulmonaryimpairment,movementdisorder,young,pregnant,allergies,cost)