Physicians have a number of techniques available to them for diagnosing carotid artery disease. 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. At this time, your physician will also make note of any previous signs of carotid artery disease, such as strokes or transient ischemic attacks (TIAs).
Your physician will then 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 narrowing of the carotid arteries. This test predicts narrowing of the arteries better than it does impending stroke, and is used as a starting point for diagnosis, rather than confirmation of a diagnosis. Discovery of a bruit may prompt your physician to refer you for diagnostic tests.
A carotid ultrasound uses harmless sound waves to create pictures of the inside of your carotid arteries. A separate test called a Doppler ultrasound can be used to image blood flow through the carotid arteries. Together, these tests can identify narrowing in the carotid arteries. This effective test poses no radiation risks and is painless.
Computed tomography (CT) angiography
During a CT scan, the patient lies on a table inside a tube. This tube takes detailed X rays of portions of the human body at different angles to form three-dimensional images. A CT scan can give your physician 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. Magnetic resonance angiography (MRA) is an MRI that produces images of blood vessels in the body. MRA, similar to a CT scan, involves having a patient lie on a moveable table that slides into a tube. The machine contains a large 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. The images show "slices" or sections of the body. This test can sometimes view blood vessels more clearly than an ultrasound or CT scan.
For this test, your physician will administer contrast dye, usually through a catheter inserted into a vein in the leg. X rays capture images of the dye traveling through the carotid arteries and indicate places where narrowing may be occurring.