Suppose you've had warning signs of a stroke (such as a "mini-stroke") or carotid artery disease. In that case, your doctor will use several tools to make a diagnosis to determine whether the arteries in your neck that deliver blood to your brain have become narrowed, putting you at risk for a stroke. Your doctor will take a personal and family medical history, perform a physical exam, and order diagnostic tests.
Personal and family medical history
Your doctor will first take your medical history, noting risk factors such as high blood pressure, diabetes, or a family history of carotid artery disease. Your doctor will also note any previous signs of carotid artery disease, such as strokes or "mini-strokes," which are events with symptoms of a stroke but typically resolve within 24 hours. A mini-stroke is also called a transient ischemic attack (TIA).
Once your medical history has been discussed, your doctor will give you a physical exam. As part of this exam, your doctor may hold a stethoscope over the carotid arteries on each side of your neck and ask you to hold your breath. If your doctor hears a whooshing sound called a bruit, you may have a narrowing of the carotid arteries. This test predicts the narrowing of the arteries better than an impending stroke, and it's used as a starting point for diagnosis rather than as confirmation of a diagnosis. To confirm the diagnosis, your doctor recommends undergoing one or more diagnostic imaging tests to identify decreased blood flow through the carotid arteries.
Carotid artery disease can be confirmed by the following diagnostic tests, which gather images of blood flow through the carotid arteries to reveal narrowing in the arteries:
- Carotid ultrasound – A carotid ultrasound uses harmless sound waves to create pictures of the inside of your carotid arteries. As part of this test, a Doppler ultrasound can assess the quality of blood flow through the carotid arteries. Together, these tests can identify narrowing in the carotid arteries. This effective test, which is generally the first test ordered since it's an excellent screening tool, poses no radiation risks and is painless.
- Computed tomography (CT) angiography – During a CT scan, you lie on a table inside a tube that takes detailed X-rays of portions of the human body at different angles to form 3D images. A CT scan can give your doctor extensive information about where you may have narrowing in the carotid arteries. For the test, you may also be administered contrast dye, a substance that makes it easier to see the blood vessels. A CT scan uses radiation to form images, so the benefits and risks are weighed before this type of scan is performed.
- Magnetic resonance angiography (MRA) – You may have heard of magnetic resonance imaging or MRI. An MRA is an MRI that produces images of blood vessels in the body. It's similar to a CT scan in that it involves having a patient lie on a moveable table that slides into a tube, but unlike the CT scan, it doesn't use radiation. Instead, the MRA machine contains a giant magnet that creates a magnetic field. Pulses of radio waves are then sent and received, and a computer interprets these signals and converts them to images, which show "slices" or sections of the body. This test can add additional information obtained from a vascular ultrasound or CT scan.
- Cerebral angiography – Your doctor will administer contrast dye for this test, usually through a thin, flexible tube called a catheter inserted into an artery in your leg. The catheter is then passed up to your head and neck arteries. X-rays then capture images of the dye traveling through the carotid arteries in your neck. The photos will indicate where narrowing may occur in arteries and prevent enough oxygen-rich blood from reaching your brain.