1. CARDIOVASCULAR IMAGING WITH COMPUTED TOMOGRAPHY(CT)
Hakan SOLMAZ,
Institude of Biomedical Engineering,
Boğaziçi University

2. Computed Tomography of the Heart Key Points
greater spatial and temporal resolution
detailed anatomic information
image reconstruction in 3-D
estimation of calcified and noncalcified plaque in coronary arteries

3. Computed Tomography of the Heart A Brief History of CT
Comes from the Greek word "tomos" meaning "slice" or "section" and graphia meaning "describing".
The first clinical CT scanners were installed between 1974 and 1976, were dedicated to only head imaging.
The first CT scanner developed by Hounsfield.

4. Computed Tomography of the Heart How Does CT Work?
combines the use of a digital computer together with a rotating x-ray device
cross sectional images or "slices"
lungs, liver, kidneys, pancreas, pelvis, extremities, brain, spine, and blood vessels .

5. Computed Tomography of the Heart How Does CT Work?

6. Computed Tomography of the Heart How Does a CT Look Like
Outside view of a CT system Inside view of a CT system
showing the patient table showing the X-ray tube and detector

7. Computed Tomography of the Heart Why is CT Performed?
CT has the unique ability to image a combination of soft tissue, bone, and blood vessels
Conventional X-Ray imaging shows the dense bone structures,
X-ray angiography depicts the blood vessels,
MR imaging is excellent in showing soft tissue and blood vessels

8. Computed Tomography of the Heart Why is CT Performed?
CT can provide detailed cross sectional images and diagnostic information for nearly every part of the body;
the brain, vessels of the brain, eyes, inner ear, sinuses
the neck, shoulders, cervical spine and blood vessels of the neck
the chest, heart, aorta, lungs, mediastinum
the thoracic and lumbar spine
the upper abdomen, liver, kidney, spleen, pancreas and other abdominal vessels

9. Computed Tomography of the Heart CT of the Heart
Planar Imaging vs CT Imaging
Planar image processors can not show smaller structures
They create images of the silhouette of the contrastfilled vessels
3-D CT image can reveal complex anatomy and spatial relationships

10. Computed Tomography of the Heart CT of the Heart
Planar Imaging vs CT Imaging
CT imaging is slower than planar imaging
planar radiograph ~ 4 to 10 ms exposure time
tomographic image slice ~ 50 to 250 ms
each image slice must be acquired during the late diastole

11. Computed Tomography of the Heart CT of the Heart
standard chest radiograph
which is a planar projection
three-dimensional computed
tomographic image

12. Computed Tomography of the Heart Two Types of CT Scanners
Electron-beam CT
developed for cardiac imaging; ms per image slice
reflecting electron beam onto a stationary tungsten target
Multidetector CT
developed for body imaging
mechanically rotating an x-ray tube

13. Computed Tomography of the Heart Two Types of CT Scanners
new multidetector CT scanners;
high spatial and temporal resolution

14. two Acquisition modes; The sequential 2-D mode The spiral 3-D mode
Computed Tomography of the Heart Principles of Cardiovascular CT Examination
the image data are acquired during one breath-hold within a chosen scan protocol
most protocols require iodinated contrast agents to enhance cardiovascular structures
two Acquisition modes;
The sequential 2-D mode
The spiral 3-D mode

15. A smaller slice thickness allows better resolution
Computed Tomography of the Heart Principles of Cardiovascular CT Examination
A smaller slice thickness allows better resolution
radiation exposure and scan time increase
volume covered is reduced
A slower heart rate allows better CT image quality
betablockers are desirable to slow the heart rate

16. Computed Tomography of the Heart Clinical Cardiovascular Indications
CT can be used for a number of cardiovascular indications, but sometimes with another imaging test;
Hypertension; CT + MRI
acute midsternal chest; CT + angiography

17. Computed Tomography of the Heart Clinical Cardiovascular Indications
Cardiac CT is especially useful in evaluating the
myocardium,
coronary arteries,
pulmonary veins,
thoracic aorta,
pericardium

18. Computed Tomography of the Heart Clinical Cardiovascular Indications
Cardiomyopathy with contrast enhanced CT
ischemic cardiomyopathy, CT typically shows;
Focal ventricular wall thinning
Fibrous or calcified replacement of myocardium
Aneurysm formation

19. Computed Tomography of the Heart Clinical Cardiovascular Indications
non-ischemic cardiomyopathy, CT typically shows;
global dilatation and myocardial thinning,
focal myocardial hypertrophy

20. Computed Tomography of the Heart Clinical Cardiovascular Indications
two chamber view three chamber view

21. Computed Tomography of the Heart Clinical Cardiovascular Indications
four chamber view short-axis view

22. Computed Tomography of the Heart Clinical Cardiovascular Indications
Coronary artery stenosis with contrast enhanced CT scan
allow one to assess stenosis
Coronary CT angiography is challenging
the blood vessels are small, tortuous, and in rapid motion during the cardiac cycle
CT doesn’t have enough spatial and temporal resolution to show all the coronary
segments
There may be plaque calcification

23. Computed Tomography of the Heart Clinical Cardiovascular Indications
Uses of CT angiography;
To rule out severe proximal stenosis
To assess anomalous coronary arteries and to determine their origins and their relationship
evaluate the severity of stenosis in venous aortocoronary grafts

24. Computed Tomography of the Heart Clinical Cardiovascular Indications
Coronary CT can exclude significant obstructive disease and assess atherosclerotic plaque

25. Computed Tomography of the Heart Clinical Cardiovascular Indications
The smaller images are the views at the level of aortic valve

26. Computed Tomography of the Heart Clinical Cardiovascular Indications
Pericardial diseases;
Detailed anatomic information about the pericardium
Inflammation of the pericardium can be detected with contrast-enhanced CT

27. Computed Tomography of the Heart Clinical Cardiovascular Indications
Cardiac masses can be described on CT according to their,
size, density, and spatial relationship to adjacent structures
Although CT can also detect tumors, it is limited

28. Computed Tomography of the Heart Clinical Cardiovascular Indications
additionaly;
valve stenosis and regurgitation,
aortic disease,
pulmonary embolism,
pulmonary veins imaging

29. Computed Tomography of the Heart Frequently Asked Questions
Does the CT examination hurt?
No, it does not, except the case of iodine contrast injection, which is discomfortable during the needle is placed
Is CT Imaging Safe?
the diagnostic benefit of a CT scan usually outweighs the risk of x-ray radiation exposure or injections of imaging contrast

30. Computed Tomography of the Heart Frequently Asked Questions
How long will the CT examination take?
the actual procedure will typically be between 10 minutes and 45 minutes
Can I Move While I am in the CT Scanner?
You should not move when you are on the CT table and the images are being acquired. CT exams of the chest and abdomen require the patient to hold their breath for a short period of time, for example, 10 to 25 seconds

31. Computed Tomography of the Heart References
Physical Principles of Medical Imaging; Perry Sprawls, Proff. Of Radiology, Emory University School of Medicine