angiography. outlines introduction x-ray aniography ct angiography ultrasound angiography mr...

Angiography

Outlines Introduction X-ray aniography CT angiography Ultrasound angiography MR angiography Neuclear angiography

Introduction:what is angiography?

An imaging technique used to visualize the blood vessels

When to be used?One of the reasons is to detect atherosclerotic

(plaque) disease in a blood vessel

Angiography imaging system Contrast agent Catheter Cathetarization lab

X-ray angiography

How does it work?

Injecting contrast agent to blood stream

Acquiring high contrast images .

Excellent resolution (100 µm).

visualize blood vessels and organs of the body

X-ray angiography image

Why is x-ray angiography done

Why x-ray angiography is done?

X-ray angiography is performed to specifically image and diagnose diseases of the blood vessels of the body, including the brain and heart.

Therapeutic Angiographic Procedures.


Therapeutic Angiographic Procedures.

Contrast Agent

Maximum contrast for minimum administrated dose.

iodine Based contrast agent :

Iodine based contrast media are usually classified as ionic or non-ionic.

X-ray parameters

Diagnostic X-ray.

15 150 kV, rectified AC∼

50 400mA anode current∼

tungsten wire (200 µm) cathode, heated to 2200◦C∼

anode rotates at 3000 rpm

Techniques

For all structures except the heart, the images are usually taken using a technique called digital subtraction angiography (DSA).

Digital subtraction angiography

Complications

Major complications :

Cardiac arrhythmias , kidney damage, hypotension and pericardial effusion.

Minor complications :

Bleeding , blood vessel damage and allergic reaction to the contrast.

Intravascular Ultrasound angiography(IVUS)

Ultrasound basics

Ultrasound is based mainly on pulse echo technique

To get the source of echo--->d =c(dt)/2 , c=1540m/s

IVUS : introducing the problemWhat's problem with typical angiography ?

IVUS Basic idea IVUS is a tomographic imaging technique

IVUS imageWhat is expected to be seen?

1-the adventitia

2-the media

3-the intima

4-the lumen

System's hardware Catheter :

sizes range between 2.6-3.5 French (0.87-1.17 mm) compatible with a 6F guiding catheter

Pullback device console

how image is acquired?

IVUS image,cont.Image modes: Typical 2-D image

Image modes:

L-Mode image

IVUS image,cont.

Image artifacts calcium shadow

Image artifacts ,cont. Coronary pulsation (motion artifact)

Benefits and limitations Benefits: Cross sectional view non ionizing radiation No contrast agent is needed

Limitations: invasive Resolution (>150 um) Catheter size

Magnetic resonance angiography(MRA)

MRA categories

Its divided into 2 categories:1- flow dependant MRA2-flow independent MRA

Flow dependant MRA

A- TOF MRAB- PC MRA

TOF MRA pulse sequence

TOF MRA image

PC MRA

CE MRA:Contrast enhanced MRA uses gd chalate as

contrast decreases makes its transverse magnetization small which we will increase repetition time

Flow Independant MRA

Flow independent MRA image

Neuclear angiography

Introduction A Nuclear angiography is a time-proven nuclear medicine test

designed to evaluate the function of the right and left ventricles of the heart, thus allowing informed diagnostic intervention in heart failure.

Nuclear angiography is typically ordered for the following patients:

Known or suspected coronary artery disease, to diagnose the disease and predict outcomes

With lesions in their heart valves With congestive heart failure Who have had a cardiac transplant

Introduction,cont.Nuclear angiography involves two techniques: First pass radionuclide angiography (FPRNA) Gated blood-pool imaging (GBPI)

GBPI is more widely used than FPRNA because multiple projections are possible and because the effects of various interventions can be assessed. Also, most laboratories have a single-crystal Anger camera, which is better suited to GBPI.

First pass radionuclide angiography (FPRNA)

radionuclide technetium 99m pertechnetate is used in FPRNA because it remains in the intravascular and extracellular spaces.

The camera is appropriately positioned against the chest and a bolus of radionuclide injected rapidly into a vein.

The bolus passes freely through the right side of the heart, lungs, left atrium and left ventricle

The changes in radioactivity with passage of the bolus through the heart can be stored in a computer, which can then be instructed to display a time-activity curve of the particular section of the heart under study.

Analysis of these time activity or recirculation curves facilitates detection of both left-to-right and right-to-left shunts

First pass radionuclide angiography (FPRNA),cont.

With FPRNA, pulmonary transit times can be measured by recording the time between the appearance of the bolus of radionuclide in the right ventricle and its appearance in the left ventricle.

FPRNA can also be used to determine right-left stroke-count ratios and ventricular volumes at different stages of the cardiac cycle.

On first pass the highest resolution for assessing regional wall motion is obtained with a multi crystal camera, which has a high temporal but a poor spatial resolution

Gated blood-pool imaging Patients are injected first with a tin preparation that adheres to the

red blood cells and then with 99mTc, which labels those cells. Gated studies can be performed in conjunction with, but following,

FPRNA. A high count rate permits high spatial resolution. Separation of the images of the cardiac chambers depends critically

on the position of the patient and the camera. In GBPI, data collection is "gated" to the R wave of the

electrocardiogram, and the time from one R wave to the next is divided into a series of intervals or frames.

The main use of GBPI is in the evaluation of many facets of coronary artery disease, such as the detection of myocardial ischemia with stress.

Gated blood-pool imaging,cont.

The assessment of biventricular performance during exercise is one of the more exciting uses of nuclear cardiology. It can be performed with the patient either upright or supine on a bicycle and is the first technique to allow continuous assessment of ventricular function while many different interventions are made.

The patient exercises for 3 minutes at increasing workloads: the first minute allows for stabilization of the heart rate; the next 2 minutes allows for data collection.

Advantages and drawbacks of Nuclear Angiography

Radionuclide techniques are useful alternatives or complements to conventional and invasive investigations of the heart.

One advantage of measurements from FPRNA is an acceptably low intrinsic variability (+5%) for sequential long-term evaluation of patients with cardiac diseases.

evaluation of many facets of coronary artery disease, such as the detection of myocardial ischemia with stress.

A major limitation of GBPI is the need for an appropriate correction for background activity, which can be up to 50% of the activity from regions of the left ventricle.

Serial studies require repeated injections, which increase background activity and the patient's exposure to radiation, thus limiting the ability to use multiple projections or multiple physiologic or pharmacologic interventions.

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angiography. outlines introduction x-ray aniography ct angiography ultrasound angiography mr...

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