A CT scan (“Cat scan”) is an X–ray technique that uses a computer to create cross–sectional (or slice–like) pictures of the heart.
How does it work?
The Computed Tomography scanner is a large machine that looks like a long, narrow tube, which has an X–ray machine inside. The CT scanner takes many X–ray pictures of thin slices of your heart. A computer then puts these images together to make one detailed picture. In some cases, a contrast dye is injected into the bloodstream to help doctors get a clearer picture.
What should I expect?
If a contrast dye is not going to be used during your CT scan, you should not eat for about 2 hours before the test. If a contrast dye is going to be used, you should not eat for about 4 hours before the test. The contrast dye may cause hot flushing in some patients.
You will be asked to undress and put on a hospital gown. Then, you will lie down on a table, which will be slowly moved through the hollow center of the Computed Tomography scanner. Some people may feel a little closed–in or claustrophobic. You will be asked to lie still and to briefly hold your breath as each picture is taken.
After the test, you may go about your normal activities. Some people find that they have a bad reaction to the contrast dye, but this is rare. If this happens, you will be treated at the hospital after your test. CT scanning is a safe test. Although your exposure to radiation is small, you should not have a CT scan if you are pregnant.
Ultrafast CT scan
Ultrafast Computed Tomography is a faster type of CT scanning, which takes an X–ray of the heart in about one–tenth of a second. Ordinary CT scanning can take anywhere from 1 to 10 seconds. The Ultrafast CT scanner takes pictures so quickly that it can avoid blurred pictures caused by the beating of the heart, a problem with a regular Computed Tomography scan. This type of scanning can also detect calcium buildup in the arteries of the heart (the coronary arteries). The amount of calcium in the coronary arteries has been found to be a marker for the presence of coronary artery disease.