What is a Coronary CT Angiography?
During a CT angiogram pictures are taken of cross sections or slices of the heart. When contrast is used during a CT scan pictures of the heart are highlighted even more.
Benefits of Coronary CT Angiography
- CT angiography is faster, non-invasive and has fewer complications.
- CT Angiography is a useful way of detecting arterial (such as narrowing of blood vessels in the heart) and venous disease, as well as structural abnormalities of the heart before there are symptoms or when symptoms are not clearly related to blood vessel disease.
- CT angiography can be very useful when there is suspicion of coronary heart disease (causing Angina) & patient does not want to go in for conventional coronary angiography.
- It causes less discomfort because contrast material is injected into an arm vein.
- No radiation remains in a patient's body after heart and vascular CT angiography.
- X-rays used in standard CT scans have no immediate side effects.
Are there any precautions required before getting the test?
- You need to have a recent ECG and serum creatinine levels.
- Avoid caffeine sources for 6 hours prior to this test. This includes coffee, tea, herbal tea, soda pop and chocolate.
- Avoid any nicotine sources for 6 hours prior to this test.
- Drink two glasses of water 1 hour before the test.
- You may be asked to take certain medications before the test.
What is done during the test?
- The nurse or assistant will explain to you the procedure before the CT angiogram is begun.
- You will be required to give a written consent. Ask questions if you don’t understand.
- Before the test you will need to remove all clothing and jewelry from the waist up. You will be given a hospital gown to wear.
- You will be monitored closely during the procedure. The nurse will start an IV in the elbow area. You will have ECG leads placed on your chest to monitor your heart. You will have a blood pressure cuff to monitor your blood pressure.
- You may receive oxygen during the CT scan with a nasal cannula to help you hold your breath at times.
- The IV will be used to give you the contrast media. Many people feel a warm “flush” as the contrast media is injected. This is normal and passes quickly.
- You may also be given IV medication to slow your heart rate. In addition, you will be given a nitroglycerine pill under your tongue.
- The CT scan will be done at certain times while the contrast media and medications are given.
- The CT scanner includes a table you will lie on and a doughnut shaped ring that will move over the table. You will lie still on the table. The technologist will give you instructions during the test.
- You will also be asked to hold your breath for 10 to 12 seconds several times. While you hold your breath the images are taken. It is important to lie still while the images are taken.
How long will the test take?
A CT angiogram takes about 2½ - 3 hours. This includes 1 hour for the test and 1½ to 2 hours for preparation and recovery.
Are there any risk of getting this test done?
- There is possible risk of serious allergic reaction to contrast materials that contain iodine, but this is extremely rare.
- If you have a history of allergy to contrast material, your doctor may advise you to take special precautionary medication, such as a steroid, for a few hours or the day before CT angiography to lessen the chances of allergic reaction.
- In patients who are at risk for kidney failure and who already have borderline kidney functions; administering iodinated contrast material could potentially further damage kidney functions. Women should always inform their radiologist if there is any possibility that they are pregnant.
- There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis will generally outweigh the risk.