Cardiac computed tomography (CT) is an imaging process that uses X-rays to show details of the arteries and veins of the heart. The images are used to determine whether plaque or calcium deposits are present in your blood vessels and whether they are causing a blockage.
The CT scanner has a large opening that a flat platform or table moves through. Some people refer to this opening as the “donut hole.” The patient lies on the table while undergoing a scan. When the machine is turned on, an X-ray tube inside the donut-shaped part of the machine spins rapidly around and the patient while the table moves through it. X-rays pass though the patient at different angles and strike specialized detectors. The images captured during the scan produce detailed cross-sectional views, or three-dimensional views, of the heart and blood vessels in a short amount of time.
- A nurse, medical radiation technologist, or doctor will explain the test and, if necessary, have you sign an informed consent form. This form may be required before the scan can be performed. This is a good time for you to ask any additional questions you may have.
- Most cardiac CT scans require the use of a substance called a contrast agent to improve image quality. You will receive the contrast agent through an intravenous (IV) line in your arm. The nurse or technologist will set this up.
- You will be brought into the scanner room and asked to lie on the table.
- The table will slowly slide through the scanner. You will be asked to lie very still during this time to ensure that the resulting images are clear.
- You will be asked to hold your breath periodically throughout the scan. The technologist in the control room will be able to speak to you, hear you, and observe you at all times.
- The images will be reviewed at by a radiologist (a doctor that specializes in reading medical images) or cardiologist. A report will be sent to the doctor(s) involved in your care.
When booking your appointment
- Please inform us if you have a contrast-dye allergy and ensure that you can provide your pharmacy information. If you are allergic, you will be treated with prednisone prior to the test and will receive more on the day of the test.
- Please inform us if you are claustrophobic or discuss this with your physician.
Before your test
- For 48 hours prior to your test: Stop the following drugs if you take them: Viagra, Cialis and Levitra.
- You will be asked to obtain blood work prior to your test. This is done to ensure that it is safe for you to receive the contrast injection which contains iodine.
On the day of your test
- For six hours prior to your test: Do not consume anything with caffeine.
- You can have breakfast and/or lunch. Please drink water prior to your appointment.
- Do not take Metformin if you are taking it.
- Take your other usual medications unless directed by your doctor. Bring all of your medications with you in the original bottles.
After your test
- Do not take Metformin on the day after your test.
- Otherwise, there are no restrictions after the cardiac CT.
- The cardiac CT takes anywhere from one to three hours to complete.
- Check in with your health card at the reception desk in the S-Level (Basement). For more information, see Coming for a Diagnostic Test.
- If you have any questions prior to your cardiac CT, please call 613-761-4325, Monday to Friday, 9:00 a.m. to 4:00 p.m.