Computed tomography angiography (CTA) is another way of imaging arteries. CT allows us to obtain 3D images and to clearly delineate the degree of narrowing (stenosis). It also allows us to see the relationships of the arteries or veins to other structures, information which may be helpful in surgical planning. Additionally, it allows us to see some areas we cannot see by ultrasound (inside the brain, and inside the chest).
CTA involves ionizing radiation and the use of contrast (x-ray dye). It also costs more than ultrasound. For this reason, we consider it a “higher power” study, not used for routine testing and surveillance. In general, we prefer CT to MRI for imaging of blood vessels.
If you are scheduled for a CT scan
CTs can be performed in the hospital or at an outside facility. You will need to have a blood test to measure your kidney function (creatinine) before you can have the scan. If your kidney function is impaired, you may be given additional instructions. Mucomyst® is a medication we frequently prescribe to patients who have mild kidney impairment and require a CT scan. If you are allergic to iodinated contrast or to shellfish, please advise us. We may prescribe medication (steroids, diphenhydramine, or an H2 blocker) prior to the CT scan to reduce your risk of having an adverse reaction.
You do not need to fast for vascular CT studies, and you will not need to drink a contrast agent. An intravenous (IV) line will be placed in your arm and then you will lie on a narrow bed. The bed will slide into a big “donut” which spins around you, acquiring images. You will be given instructions to hold your breath momentarily for the study. You will feel a transient warm sensation in your chest as the contrast agent goes through the IV; sometimes you may also feel like you need to urinate. The study generally takes about 10-15 minutes. Most people who have mild claustrophobia have no issues with the CT scan. If you feel that your claustrophobia is severe, you may need a light sedative for the study, and you will need someone to take you home afterwards.