A carotid angiogram is a specialized diagnostic imaging test that allows physicians to visualize the internal structure of the carotid arteries in the neck. These large arteries supply oxygen-rich blood directly to the brain and head. The procedure uses X-ray technology combined with a special contrast dye to create a detailed map of the blood vessels. The test is performed by an interventional radiologist or cardiologist and is considered an invasive method for examining the cerebrovascular system. Unlike non-invasive imaging, the angiogram provides highly specific, real-time images that guide treatment decisions.
Purpose and Diagnostic Use
A physician recommends a carotid angiogram when a disorder affecting blood flow to the brain requires precise visualization. The most common condition evaluated is carotid artery stenosis, a narrowing of the vessel typically caused by the buildup of plaque known as atherosclerosis. This narrowing can significantly raise the risk of a stroke.
The procedure is also used to assess the presence of aneurysms, which are bulges in the vessel wall, or vasculitis, which is inflammation of the blood vessels. While non-invasive tests like carotid ultrasound provide a good initial overview, the angiogram is often the definitive method to confirm the severity and exact location of a blockage. The detailed images are necessary for planning subsequent procedures, such as stenting or surgery, and determining whether treatment is needed to reduce the patient’s stroke risk.
Patient Preparation
Preparation for a carotid angiogram begins well before the day of the procedure to ensure patient safety and clear imaging. Patients are instructed not to eat or drink anything for several hours leading up to the test, often starting after midnight. This fasting period prevents complications should sedation be necessary during the procedure.
Patients must discuss all current medications with their care team, especially blood thinners (anticoagulants or anti-platelet drugs) and certain diabetes medications. A physician may instruct the patient to temporarily stop or adjust the dosage of these drugs to minimize the risk of bleeding or adverse reactions. It is also important to disclose any known allergies, particularly to iodine or contrast dye, as a pre-procedure medication regimen may be needed. Finally, arranging for a responsible adult to provide transportation home is mandatory, as sedatives are often used.
Step-by-Step Procedure
The carotid angiogram is performed in a sterile environment, typically a specialized angiography suite, and takes approximately 60 to 90 minutes. The patient is positioned on an X-ray table, and an intravenous line is started to administer fluids and a mild sedative. The medical team cleans and sterilizes the puncture site, which is most commonly the femoral artery in the groin or sometimes the radial artery in the wrist.
A local anesthetic is injected to numb the skin at the access point. A small incision is then made, and a thin, flexible catheter is inserted into the artery. Using fluoroscopy (continuous X-ray imaging), the physician guides the catheter through the blood vessels toward the neck until the tip is positioned near the carotid artery.
The patient does not feel the catheter moving because the inside of blood vessels lacks nerve endings. Once in place, the specialized contrast dye is injected through the tube. This dye highlights the blood vessels, making them visible on the X-ray monitor for image capture (a carotid arteriogram). During the injection, patients may experience a fleeting sensation of warmth or flushing, which is a normal, temporary effect. After all images are captured, the catheter is removed, and pressure is applied to the insertion site to stop bleeding.
Risks and Post-Procedure Care
Like any invasive medical procedure, a carotid angiogram carries certain risks, although they are low when performed by experienced professionals. The most common complications occur at the insertion site, including bleeding, bruising, or the formation of a hematoma. More serious, though rare, risks include an allergic reaction to the contrast dye, ranging from mild itching to a severe reaction.
A small risk of stroke or a transient ischemic attack (TIA) exists if plaque is dislodged during catheter manipulation or if a blood clot forms. The medical team takes precautions, such as administering blood thinners, to mitigate this risk during the procedure. After the angiogram, the patient is moved to a recovery area and must lie flat for several hours (typically two to six hours) to reduce the chance of bleeding from the arterial puncture site.
The recovery period includes close monitoring of heart rate, blood pressure, and the insertion site. Patients are encouraged to drink plenty of fluids to help flush the contrast dye from their system. For a few days following the procedure, patients should avoid strenuous activity, heavy lifting, and bending at the waist if the groin was the access point. Any signs of significant swelling, pain, fever, or weakness on one side of the body should prompt immediate medical attention.