About the Examination
The cardiac CT examination is performed on new state of the art multidetector CT scanners in the radiology department. As a patient, you will be asked to not eat anything for 3 hours before the study. When you arrive in the department, you will meet with a radiologist and cardiologist who will discuss the study with you and take your pulse and blood pressure. To get the best images possible for the study, your heart rate may need to be lowered. Should you need assistance in lowering your heart rate, the cardiologist and radiologist may give you medication to take by mouth (called a beta blocker) one hour before your study. This is a very safe medication that many heart patients normally take every day. Before the study begins, sticky electrode pads will be placed on your chest so that your heart rate can be monitored before and during the cardiac CT study. In addition, a small intravenous catheter will be placed into your arm. Occasionally, if the beta blocker that you took by mouth didn't lower your heart rate enough, additional beta-blocker will be administered to you through the intravenous catheter in your arm in order to further slow your heart rate.
The cardiac CT study consists of two parts. The first part is called a coronary calcium score. The purpose of this part of the study is to see how much calcified plaque (a marker of atherosclerosis) is present in your coronary arteries. For this part of the study, you will be asked to hold your breath for about 10 seconds as your heart is quickly scanned. The second part of the study is the coronary CT angiogram. This test will start immediately after the calcium score. The radiologist and cardiologist may give you a nitroglycerine tablet to put under your tongue before this part starts. The purpose of the nitroglycerine tablet is to cause your coronary arteries to dilate (become bigger), so they can be more easily seen. Intravenous contrast material will be given to you through the catheter in your arm for this part of the study. The purpose of the contrast material is to fill your coronary vessels and heart so that the inside of these structures can be seen and evaluated. You will again be asked to hold your breath (for about 10-15 seconds) for this part of the study as your heart is quickly scanned. You should expect to be on the CT table for no more than 20 to 30 minutes for the two parts of the study. You may return to your normal activity immediately following the examination. Your doctor will receive the results of your study within 24 hours of your examination.
If you have a history of kidney failure, cardiac arrhythmias, or a history of a very severe intravenous contrast allergy you may not be able to have a cardiac CT examination. You should be sure to bring these problems to your doctor's attention so that it can be discussed before the study is ordered.