Let's Talk About Stroke Diagnosis

Updated:Jan 29,2018

It’s critical to diagnose a stroke in progress because the treatment for stroke depends on the type, and, in some cases, the location of the injury to the brain.

Other conditions with similar symptoms to stroke and transient ischemic attack (TIA) will need to be ruled out to diagnose stroke. Some of these include seizures, fainting, migraine headaches, drug overdose, heart problems or other general medical conditions.

How is a stroke diagnosed?

The type of stroke must be determined. Ischemic strokes are caused by a blocked artery in the brain. A ruptured blood vessel causes a hemorrhagic stroke. Treatment for ischemic stroke is different than it is for a hemorrhagic stroke.   

Ischemic strokes may be treated with a clot-busting drug, called IV Alteplase (tPA). So, it’s important to receive a correct diagnosis before treatment begins. To receive IV Alteplase, a doctor must diagnose your stroke as an ischemic stroke and treat you within 3 to 4.5 hours of the onset of stroke symptoms. This treatment usually takes place in the hospital emergency department. If more than 4.5 hours passes, it can’t be given.

For people with blood clots in larger arteries, Altaplase may not dissolve them completely. In this case, a procedure, called mechanical thrombectomy, should be done within six to 24 hours of the first symptoms of stroke. Patients must meet certain criteria to be eligible for this procedure.

In the emergency room, your doctor or stroke emergency team may:

  • Ask you when the symptoms of the stroke started. This is critical in determining what treatment is best for you.
  • Ask you about your medical history.
  • Do a physical and neurological examination.
  • Have certain lab (blood) tests done.
  • Do a CT (computed tomography) or MRI (magnetic resonance imaging) brain scan. This determines what kind of stroke a person has had (ischemic or hemorrhagic).
  • Study the results of other diagnostic tests that might be needed.

What are the types of diagnostic tests?

Diagnostic tests examine how the brain looks, works and gets its blood supply. Most are safe and painless. These tests fall into two categories: 1) imaging tests and 2) blood flow tests.

Imaging Tests 

  • CT (computed tomography) or CAT scan. It uses radiation to create a picture (like an X-ray) of the brain. It’s usually one of the first tests given to a patient with stroke symptoms. CT test results give valuable information about the cause of stroke and the location and extent of brain injury. 
  • MRI (magnetic resonance imaging). This test uses a large magnetic field to produce an image of the brain. Like the CT scan, it shows the location and extent of brain injury. The image produced by MRI is sharper and more detailed than a CT scan, so it’s often used to diagnose small, deep injuries.
  • CTA (computed tomographic angiography). In CTA,  a special contrast material (dye) is injected into a vein and images are taken of the blood vessels to look for abnormalities such as an aneurysm. 
  • MRA (magnetic resonance angiography). In this test, the blood vessels are imaged through a magnetic resonance scanner to locate a cerebral aneurysm.  
Additional advanced tests that may be done include CT perfusion, diffusion-weighted MRI or MRI perfusion.

Blood Flow Tests

These tests give information about the condition of arteries in your head and neck that supply blood to your brain. 

  • Cerebral angiography (or cerebral arteriography). Special substances are injected into the blood vessels and an X-ray is taken. This test gives a picture of the blood flow through the vessels. This allows the size and location of blockages to be reviewed. This test is very valuable in diagnosing aneurysms and malformed blood vessels.

How can I learn more?

  1. Call 1-888-4-STROKE (1-888-478-7653) to learn more about stroke or find local support groups, or visit StrokeAssociation.org.
  2. Sign up to get Stroke Connection magazine, a free magazine for stroke survivors and caregivers at strokeconnection.org.
  3. Connect with others sharing similar journeys with stroke by joining our Support Network at strokeassociation.org/supportnetwork.

We have many other fact sheets to help you make healthier choices to reduce your risk, manage disease or care for a loved one. Visit strokeassociation.org/letstalkaboutstroke to learn more. 

Do you have questions for your doctor or nurse?

Take a few minutes to write your own questions for the next time you see your healthcare provider:

Do these tests cause any complications?
©2018, American Heart Association

Multi-language Fact Sheet Topics

Heart-related Conditions
What is Angina?
What is an Arrhythmia?
What Is Atrial Fibrillation?
What Do My Cholesterol Levels Mean?
How Can I Improve My Cholesterol?
What Are High Blood Cholesterol and Triglycerides?
What Is High Blood Pressure?
How Can I Reduce High Blood Pressure?
High Blood Pressure and Stroke
What Is Diabetes and How Can I Manage It?
How Can I Live With Heart Failure?
What Is Heart Failure?
What Is a Heart Attack?
How Will I Recover From My Heart Attack?
What Are the Warning Signs of Heart Attack?
What Are Heart Disease and Stroke?
What is Metabolic Syndrome?
What is Peripheral Artery Disease?

Stroke, Recovery and Caregiving
Hemorrhagic Stroke
Ischemic Stroke
Stroke, TIA and Warning Signs
What Are the Warning Signs of Stroke?
Stroke Risk Factors
Lifestyle Changes to Prevent Stroke
Stroke Diagnosis
Complications After Stroke
Changes Caused by Stroke
Emotional Changes After Stroke
Feeling Tired After a Stroke
Stroke and Aphasia
Stroke and Rehabilitation
Stroke Family Caregivers
How Should I Care for Myself as a Caregiver?

Treatment, Tests and Procedures
What is Cholesterol-Lowering Medicine?
What is High Blood Pressure Medicine?
What Are Anticoagulants and Antiplatelet Agents?
How Do I Manage My Medicines?
What Is an Implantable Cardioverter Defibrillator?
What Is a Pacemaker?
What Is Coronary Angioplasty?
What is a Stent?
What is Coronary Bypass Surgery?
What is a Coronary Angiogram?
How Can I Recover From Heart Surgery?
What is Carotid Endarterectomy?

Healthy Lifestyle and Risk Reduction
How Can I Manage My Weight?
How Can Physical Activity Become a Way of Life?
Why Should I Be Physically Active?
How Do I Follow a Healthy Diet?
How Can I Cook Healthfully?
Why Should I Limit Sodium?
How Do I Understand "Nutrition Facts" Labels?
How Can I Quit Smoking?
How Can I Manage Stress?
How Can I Make My Lifestyle Healthier?
How Can I Monitor My Cholesterol, Blood Pressure and Weight?