A CT-angiogram is a way to use imaging techniques to view blood vessels in a particular part of the body. Often, this procedure is used to evaluate the blood vessels around the heart.
This kind of CT is usually scheduled as an outpatient. Typically, you will go to the imaging facility on the day of your exam and be asked to change into a hospital gown (removing all jewelry, watches, etc as the metal can interfere with the images). You will have an IV placed, usually into one of the veins in your lower arm. Depending on what part of your body is being imaged, you may also be given a medication to slow down your heart to help improve the quality of the images that the machine can capture (usually this is a beta-blocker, something you may already be taking at home).
The actual process of obtaining the CT images is quite simple. You will lay on a long table that can move in and out of the actual scanner which usually looks like a doughnut-shaped tube. The table moves automatically through the scanner for the series of pictures that are required, and during this time your only job will be to lay perfectly still. Before the test starts, you will be given IV contrast dye through your IV. This can sometimes feel a little strange--most people describe it as a feeling of warmth throughout their body--but it is not painful. In general the test takes about 10 minutes of scanning time, so most of your time at the procedure will involve getting you ready for the scan.