What is a CT Scan?
Computed tomography (CT), also referred to as computerized axial tomography (CAT), is an x-ray technique that uses a special scanner and a computer to create cross-sectional images of the body. Unlike standard x-rays, which take a two dimensional projected picture of the part of the body being examined, the CT has the ability to image that same structure as a series of cross-sectional images. The CT Scan produces clearer, more detailed images of the part of the body being examined than can be accomplished by x-rays and is the preferred cross-sectional imaging test in most cases for examination of the chest, abdomen, pelvis, sinus, ear and some bones. Return to CT FAQ
What is a 64-Slice CT Angiogram?
An "angiogram" generally refers to a medical imaging study that is used to look at arteries in the body. The purpose of an angiogram is to usually to determine if there is narrowing in arteries or some other disease that may impair blood flow.
Narrowing of arteries is often due to atherosclerosis.
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, which include CT (computed tomography) and MRI (magnetic resonance imaging) angiograms. 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).
A physician then evaluates the arteries and veins by looking at 2-dimensional X-ray images of the blood vessels. Catheter angiograms are still the diagnostic test of choice under certain conditions. The downside to a catheter angiogram is that it is more invasive to the patient and sedation is used. Catheter angiograms 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. 64 Slice CT angiograms refer to angiograms completed using computed tomography technology.
These studies are increasing in use because of the excellent image quality. 64 Slice CT coronary angiograms were previously performed using catheter techniques until recent advances in 64 slice 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 64 slice 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.
Return to CT FAQ
Can anyone have a CT Scan?
As a general rule, anyone can have a CT Scan. We prefer not to scan pregnant women, especially in their first trimester. Decisions as to whether it is prudent to scan a pregnant woman will be made in each case based upon the part of the body being examined, the stage of the pregnancy and the medical necessity of the exam. Return to CT FAQ
What happens during a CT Scan?
You will be asked to lie on a table that slides into a large, circular opening in the doughnut shaped CT scanner. Just prior to the study you will be asked to hold your breath for up to 20 seconds. Cross sectional x-ray pictures are collected as the table moves through the scanner. Detectors in the scanner receive these beams and send signals to a computer. The computer processes these signals and produces a cross-sectional image on a viewing monitor. The electronic digital images are then recorded for the radiologist to interpret. Return to CT FAQ
