CT Scanning for Coronary Artery Disease

CT Scan (Computerized Axial Tomography) consists of many radiographs shot at the same time from different angles. Later, a computer gathers all the images and reconstructs them in only one image, summing up the images obtained from the different angles.

CT is now available to diagnose coronary artery disease. In the past, noninvasive functional tests of the heart were used, such as treadmill tests and nuclear studies, to indirectly assess if there were blockages in the coronary arteries. The only way to directly look at the coronary arteries was via a cardiac catheterization.

While cardiac catherization  and angiography is the standard of reference for evaluation of coronary artery disease, and has a small risk of complications, it is an invasive procedure with substantial costs. A noninvasive technique for the anatomic assessment of coronary arteries is therefore highly desirable.

CT scans have been used to look at various anatomic regions, but until recently have not been useful for the heart because the heart is continuously in motion. A new generation of CT scanners which can take 64 pictures a minute is now available; with the use of a little medication to slow the heart rate to less than 64, CT images of the coronary arteries are now possible.This procedure uses intravenous dye which contains iodine and CT scanning to show the coronary arteries.

Risks & Benefits

• Allergic reactions to intravenous dye containing Iodine
• Kidney fucntion damage
• Radiation exposure similar to a conventional coronary angiogram
• CTA is generally a non-nvasive and very safe test
• CTA is considerably less expensive than cardiac catherization ($500 vs. $3000)
• CTA may be a superior alternative in the evaluation of some patients with “Intermediate Risk” for CAD