How is a Stroke Diagnosed?
Your doctor will diagnose a stroke based on your signs and symptoms, your medical history, a physical exam, and test results.
Your doctor will want to find out the type of stroke you’ve had, its cause, the part of the brain that's affected, and whether you have bleeding in the brain.
If your doctor thinks you’ve had a transient ischemic attack (TIA), he or she will look for its cause to help prevent a future stroke.
Medical History and Physical Exam
Your doctor will ask you or a family member about your risk factors for stroke. Examples of risk factors include high blood pressure, smoking, heart disease, and a personal or family history of stroke. Your doctor also will ask about your signs and symptoms and when they began.
During the physical exam, your doctor will check your mental alertness and your coordination and balance. He or she will check for numbness or weakness in your face, arms, and legs; confusion; and trouble speaking and seeing clearly.
Your doctor will look for signs of carotid artery disease, a common cause of ischemic stroke. He or she will listen to your carotid arteries with a stethoscope. A whooshing sound called a bruit (broo-E) may suggest changed or reduced blood flow due to plaque buildup in the carotid arteries.
Diagnostic Tests and Procedures
Your doctor may recommend one or more of the following tests to diagnose a stroke or TIA.
Brain Computed Tomography
A brain computed tomography (to-MOG-rah-fee) scan, or brain CT scan, is a painless test that uses x rays to take clear, detailed pictures of your brain. This test often is done right after a stroke is suspected.
A brain CT scan can show bleeding in the brain or damage to the brain cells from a stroke. The test also can show other brain conditions that may be causing your symptoms.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) uses magnets and radio waves to create pictures of the organs and structures in your body. This test can detect changes in brain tissue and damage to brain cells from a stroke.
An MRI may be used instead of, or in addition to, a CT scan to diagnose a stroke.
Computed Tomography Arteriogram and Magnetic Resonance Arteriogram
A CT arteriogram (CTA) and magnetic resonance arteriogram (MRA) can show the large blood vessels in the brain. These tests may give your doctor more information about the site of a blood clot and the flow of blood through your brain.
Carotid ultrasound is a painless and harmless test that uses sound waves to create pictures of the insides of your carotid arteries. These arteries supply oxygen-rich blood to your brain.
Carotid ultrasound shows whether plaque has narrowed or blocked your carotid arteries.
Your carotid ultrasound test may include a Doppler ultrasound. Doppler ultrasound is a special test that shows the speed and direction of blood moving through your blood vessels.
Carotid angiography (an-jee-OG-ra-fee) is a test that uses dye and special x rays to show the insides of your carotid arteries.
For this test, a small tube called a catheter is put into an artery, usually in the groin (upper thigh). The tube is then moved up into one of your carotid arteries.
Your doctor will inject a substance (called contrast dye) into the carotid artery. The dye helps make the artery visible on x-ray pictures.
An EKG is a simple, painless test that records the heart's electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through each part of the heart.
An EKG can help detect heart problems that may have led to a stroke. For example, the test can help diagnose atrial fibrillation or a previous heart attack.
Echocardiography (EK-o-kar-de-OG-ra-fee), or echo, is a painless test that uses sound waves to create pictures of your heart.
The test gives information about the size and shape of your heart and how well your heart's chambers and valves are working.
Echo can detect possible blood clots inside the heart and problems with the aorta. The aorta is the main artery that carries oxygen-rich blood from your heart to all parts of your body.
Your doctor also may use blood tests to help diagnose a stroke.
A blood glucose test measures the amount of glucose (sugar) in your blood. Low blood glucose levels may cause symptoms similar to those of a stroke.
A platelet count measures the number of platelets in your blood. Blood platelets are cell fragments that help your blood clot. Abnormal platelet levels may be a sign of a bleeding disorder (not enough clotting) or a thrombotic disorder (too much clotting).
Your doctor also may recommend blood tests to measure how long it takes for your blood to clot. Two tests that may be used are called PT and PTT tests. These tests show whether your blood is clotting normally.
Source: National Institutes of Health