Coronary Angiography

Coronary CT Angiography

CT combines the use of x-rays with computerized analysis of the images. Beams of x-rays are passed from a rotating device through the area of interest in the patient’s body from several different angles to obtain projection images, which then are assembled by computer into a three-dimensional picture of the area being studied.

The scan is performed simultaneously with a high speed contrast media injection using a technique called Bolus Tracking. Compared to catheter angiography, which involves placing a sizable catheter and injecting contrast material into a large artery or vein, CTA is a much less invasive and more patient-friendly procedure. The contrast material is injected into a small peripheral vein by using a small needle or cannula. This type of exam has been used to screen large numbers of individuals for arterial disease.

CTA can be used to visualize the coronary arteries. This requires high-speed hardware and a special analysis program as the heart moves constantly. Lowering of the heart rate to < 60 bpm is usually required. Indications for this technique are

• Rule-out of coronary artery disease in low-probability cases.
• Visualization of coronary artery bypass grafts.

This technique should not be employed in cases with a high probability of coronary artery disease; these patients should proceed to direct cardiac catheterization and coronary angiography.