CT angiography is an imaging study of blood vessels in the key areas of the body, like the brain, kidneys, heart, pelvis, etc. It is mainly performed on the outpatient basis, and works very much like x-ray examinations. While explaining the CT angiogram procedure, this HealthHearty article also presents information on the benefits as well as risks and limitations of the procedure.
CT angiography uses computed tomography technology to examine the arteries and veins in the body. Angiography is used to determine any kind of narrowing in the blood vessels, or disease due to atherosclerosis. It is an invasive medical test which helps the physicians in diagnosing and treating medical conditions.
Angiography is performed by using any of the three methods; x-rays with catheters, computer tomography (CT), and magnetic resonance imaging (MRI). It is mainly used for following reasons:
- It helps in identifying disease and aneurysm in the aorta or any other blood vessels.
- It detects atherosclerosis disease in the carotid artery of the neck, which limits the blood flow to the brain and causes a stroke.
- It is used to sample blood from specific veins in the body to detect any kind of endocrine disease.
- It identifies a small aneurysm or arteriovenous malformation inside the brain.
- It indicates any abnormality in the renal artery and visualizes blood flow to help prepare for a kidney transplant.
- It examines pulmonary arteries in the lungs to detect pulmonary embolism (blockage of the pulmonary artery by a blood clot).
Computed Tomography Angiogram
You should inform the doctor about your health problems and regular medicines, and ask him whether you can take the medicines before the procedure or not. Normal medicines should not create any problem. Three hours before the procedure, the patient is asked to drink only water (no food). He /she will be asked to remove all metal objects (chains, bracelets, rings) off his/her body. The physician should make sure that the patient isn’t allergic to the contrast material that is used during the angiography procedure. Before a CT angiogram that is designed to check the heart and the coronary arteries, the patient may be given a medicine classified as a beta-blocker, as it helps slow the heart rate during the procedure. The physician places an IV into a peripheral vein in the patient’s forearm. Then the patient is brought near the CT scanner and a dose of contrast agent (dye) is administered into the IV. This is done to ensure that the arteries will stand out, when the physician reads the scan. The patient may experience a warm sensation all over his/her body and a metal taste in his/her mouth. The patient has to lay down and the scanner will be rotated around his body. A large number of X-ray images are taken and sent to the computer. The patient may be asked to hold his/her breath for a short time, while the scanner takes a series of images.The images are taken from different angles to create a 3-dimensional image of the patient, which is extremely beneficial while diagnosing the disease. This procedure usually takes approximately 15-30 minutes. During the procedure, images would be reviewed, and certain images would be repeated, if required.
- Angiography almost eliminates the need for surgery, and in case surgery is needed, it can be done more accurately after this procedure.
- It detects narrowing of blood vessels in time which helps in taking necessary and preventive measures.
- It is more accurate than the MRI, and gives an exact anatomical detail of the blood vessels.
- CT angiography is less invasive and more patient-friendly as compared to the catheter angiography procedures, which require placing of the catheter (plastic tube) and injecting of the contrast material into the blood vessels.
- After the examination, there are no radiation remains in the patient’s body.
- CT angiography is safe, less time-consuming, and more cost-effective.
Risks and Limitation
- There may be a slight risk of cancer due to excessive exposure to radiation. But the advantage of a correct diagnosis outweighs this risk.
- It can cause skin allergies, especially if a person is allergic to the contrast material used in the process. Hence, a different procedure that does not call for contrast material injection can be followed.
- Sometimes leakage of the contrast material from the vessel can damage the skin, blood vessels, and nerves. In such cases, the physician should be informed immediately, and the procedure should be stopped at once.
- After contrast material injection, nursing mothers have to wait for 24 hours before resuming breast-feeding.
- CT angiography should be avoided in patients suffering with kidney diseases or diabetes, as the contrast material used during the scanning can further damage the kidney functioning.
- If a patient is suffering from severe heart disease or multiple blocked blood vessels, CT angiograms can be hard to interpret.
Modern CT angiograms use multiple detectors to capture images from different rotations of the CT scanner. These machines use 64 detectors or scanners which help in reducing the scanning time and increase the efficiency to a high level.