How is a stroke diagnosed?
Stroke is diagnosed through several techniques: a short neurological examination, blood tests, CT scans (without contrast enhancements) or MRI scans, Doppler ultrasound, and arteriography. Stroke seems to run in some families. Family members may have a genetic tendency for stroke or share a lifestyle that contributes to stroke. The most important risk factors for stroke are hypertension, heart disease, diabetes, and cigarette smoking. Other risks include heavy alcohol
consumption, high blood cholesterol levels, illicit drug use, and genetic or congenital conditions. Some risk factors for stroke apply only to women. Primary among these are pregnancy, childbirth, and the menopause and treatment thereof (HRT).
CT Scan - This technique is usually the first test done when a patient comes to a hospital emergency room with stroke symptoms. The test uses low-dose X-rays to show an image of the brain and it can determine whether a stroke is caused by a blockage or a bleed, and the size and location of the stroke. The test is painless.
Magnetic Resonance Imaging (MRI) - This device uses magnetic fields to detect subtle changes in brain tissue. MRI is useful when the stroke involves small blood vessels. This takes longer to perform than a CT scan and is not as accurate in determining the presence of a bleed. The painless test is done without entering the body and takes between 30 and 90 minutes.
Magnetic Resonance Angiography - Brain surgeons use this technique to detect a blockage of the brain and to map the blood flow in the skull. It gives an accurate picture of cerebral blood vessels. The test is similar in experience to an MRI and does not involve entering the body.
Transcranial Doppler - This is a portable test that can be performed at the bedside to assess blood flow through the vessels in the brain. A small probe is placed against the skull.
Doppler Ultrasound - This is a painless, noninvasive test in which waves of sound above the range of human hearing are sent into the neck. Echoes from the waves bounce off the moving blood and tissue and are formed into an image. It is fast, painless and risk-free but is not as accurate as an Arteriography.
Carotid Ultrasound - This test is conducted without entering the body and it evaluates the blood flow of the carotid arteries. Gel is used on the skin to send an ultrasound signal and a computer can calculate how fast the blood is traveling. This helps doctors determine how narrow an artery has become.
Arteriography - This is an X-ray of the carotid artery taken when a special dye is injected. This technique carries its own small risk of causing a stroke and it's expensive, but it is a reliable way to measure blockage of the carotid arteries. Some people may experience a sensation of pressure or warmth. It involves insertion of a catheter into a blood vessel.