CT Angiogram - Computed Tomography Heart Scan

What is a CT Angiogram?
An "angiogram" generally refers to an imaging study that is used to look at arteries in the body.  The purpose of an angiogram is to determine if there is narrowing in the arteries or other disease, which is often due to atherosclerosis.  A CT angiogram uses computed tomography technology to look at the blood vessels of the body.

The term angiogram can be confusing as there are two types of angiogams that can be performed, and each can be used to look at arteries and veins throughout the body.   The two main classes of angiograms may be referred to as "catheter" angiograms and "non-invasive" angiograms (See Angiogram vs. CT angiogram).  Non-invasive angiograms use imaging technologies such as CT (computed tomography) or MRI (magnetic resonance imaging).   Catheter angiograms have been present for a longer period of time, and refer to a study where dye is injected into the bloodstream through a vein or artery using a catheter (a small plastic device).  The catheter is introduced into the vein or artery by a small incision, and is moved forward into the artery being studied to inject contrast material (which improves the outline of the artery).  The physician then evaluates the arteries and veins by looking at 2-dimensional X-ray images.  These angiograms are still the diagnostic test of choice under certain conditions as they provide a highly detailed outline of the artery or vein being studied.  The downside to a catheter angiogram is that it is more invasive to the patient and sedation is used.  Catheter angiograms also have a higher risk of serious adverse events, including rupturing a blood vessel and infection.  Although the risks are more serious, they occur relatively infrequently.

CT angiograms refer to angiograms completed using computed tomography technology.  (MRI may be used and is referred to as "MR" angiography, please see our section CT vs. MRI).  These studies are increasing in popularity as CT technology improves and image quality becomes better.  There are multiple areas of the body that may be studied, including a CT angigoram heart,  carotid CT angiogram to evaluate the arteries to the brain, a renal CT angiogram to evaluate the arteries to the kidney, an aortic CT angiogram to evaluate the aorta, and a coronary artery CT angiogram to evaluate the arteries to the heart.  The use of CT coronary angiograms is an example of a study that was almost always performed using catheter techniques until recent advances in CT technology allowed for high quality images.   Coronary arteries supply the heart itself with blood, and an insufficient supply of blood may lead to a heart attack.  A physician usually orders an angiogram to determine the severity of narrowing of the arteries.  If there is narrowing of the coronary arteries, for example, a physician may suggest coronary artery bypass surgery or the placement of a stent to ensure that there is adequate blood supply to the heart.

The advantage to using a CT scan versus catheter angiography is that the physician does not need to insert a catheter directly into a vein or artery to inject dye.  Instead of inserting a catheter into a large vein or artery and advancing the catheter to the area being studied, the physician will administer a contrast agent into an a peripheral vein (usually in the arm) using a small needle.  This contrast agent highlights blood flow in comparison to other organs and structures, and allows the physician to visualize arteries and veins on a CT scan.  Compared to a catheter angiogram, this is a much less invasive procedure and is more "patient-friendly," with a decreased chance of infection or other adverse outcome.  There are, however, certain risks asssociated with CT angiography.  New CT scanners also allow for highly detailed images that may be reconstructed in 3 dimensions, as seen below.  These images give additional information about the structure of the organ being studied.

For more information on the procedure itself, please visit our page on CT angiography procedure.  If you have additional questions, please fill out the comment form below.  We will attempt to provide answers to questions that are asked on our frequently asked questions page.