Every minute counts when it comes to getting the correct diagnosis for a stroke. Specific imaging tests can not only diagnose a stroke, but can also determine the type of stroke. An accurate diagnosis is essential for ensuring you get the right treatment.
Stroke happens when the blood supply to an area of the brain is interrupted. While symptoms such as weakness on one side of the body or slurred speech might point toward a stroke, specific tests can determine if you had a stroke, and where in the brain it occurred.
Knowing what kind of stroke you had is critical to help guide treatment and to determine whether you are a candidate for lifesaving medications.
This article will take a closer look at the type of tests that can diagnose stroke, as well as the type of stroke, and why that matters.
There are two major types of strokes.
- Ischemic stroke: This type of stroke is caused by a blood clot in your brain or in a blood vessel leading to it. When a clot disrupts the flow of blood — and therefore oxygen — to the brain, stroke symptoms develop. This is the most common form of stroke, accounting for about
80% of all strokes.
- Hemorrhagic stroke: A hemorrhagic stroke is caused by bleeding in your brain. Hemorrhagic strokes are usually the result of weakening and eventual rupture of blood vessels over time. It accounts for about
20% of all strokes.
What’s a mini-stroke?
These mini-strokes resolve on their own, usually within 5 minutes, and the symptoms typically resolve within 24 hours. They are still considered medical emergencies and can be a warning sign of a more severe stroke in the future.
While a physical assessment of various signs and symptoms is a quick indicator to check for the possibility of stroke, specific tests will be able to confirm a stroke diagnosis.
The gold standard for diagnosing a stroke are imaging tests such as:
- Computed tomography (CT scan): A brain CT scan (also called a cranial CT scan) can show if there is damage or bleeding in the brain.
- Magnetic resonance imaging (MRI): Used alone or in addition to a CT scan, an MRI can detect brain tissue changes.
- Cerebral angiography: A cerebral angiography uses contrast dye to create a clear X-ray of the blood vessels in your brain, which allows your doctor to see where the blockages or abnormalities are located.
These tests all produce visual images of blood vessels or tissues in your brain where clots, bleeding, or other blood vessel problems may develop. Imaging studies not only confirm the presence of these issues, but they also help identify the exact type, location, and extent of your stroke.
Blood and heart tests
There are several other tests that might be performed if your doctor suspects you are having a stroke.
These tests don’t necessarily indicate the presence or location of a stroke. Instead, they may be used to pinpoint a trigger for your stroke, such as a blood clotting problem, or to check for other complications like blood clots in the heart.
Some tests that may be done in addition to your stroke assessment tests include:
- Blood tests: Certain blood tests measure general blood health, clotting, electrolyte issues, and heart muscle damage.
- Electrocardiogram (EKG/ECG): An electrocardiogram — a test that measures your heart’s electrical activity —may help diagnose heart problems that can lead to a stroke.
- Echocardiogram: An echocardiogram uses ultrasound to look at heart movement. It can also detect certain abnormalities that could lead to a stroke.
- Carotid ultrasound: This test looks at the blood flow and structure of the carotid arteries. Atherosclerosis can cause clots in these arteries to break and flow to smaller arteries in the brain.
- Lumbar puncture: A lumbar puncture tests your spinal fluid for substances created from broken-down blood cells. It is only used for stroke if no other cause of stroke is found, and the patient has been completely stabilized.
You may also need ongoing tests to monitor conditions that may have contributed to your stroke, including blood pressure and blood glucose monitoring.
Glasgow Coma Scale
While the Glasgow Coma Scale cannot diagnose stroke, it is one of the quickest physical assessments. No machine is needed, and it assigns numeric scores based on:
- eye movements and response
- verbal responses
- motor responses and movement
Once each category is scored, the values are added together to provide a total score that ranges from 3 to 15. A lower score is usually indicative of the most severe injury or brain damage.
National Institutes of Health Stroke Scale (NIHSS)
Specifically, the NIHSS assigns a score for each of the following areas:
- level of consciousness
- questions about time and location
- ability to follow physical commands
- eye movement and visual acuity
- facial movement or paralysis
- arm and leg movement
- speech ability and clarity
- understanding written or verbal communication
- sensation to touch
With an ischemic stroke, damage occurs every moment the blood and oxygen supply to your brain is disrupted. The key to treatment, therefore, is to restore blood flow to the affected brain tissue as quickly as possible. This can be done by surgically removing blood clots, or by dissolving clots with blood-thinning medications.
Ischemic strokes are sometimes treatable, but often the only option available is to stabilize the patient. Time is a significant factor in treating ischemic strokes.
Anticoagulants like Coumadin (warfarin) may even be continued long after your stroke to protect against future, repeated strokes.
However, all blood thinning and anticoagulant medications can cause bleeding. Any part of the brain that’s been damaged by a recent stroke is especially vulnerable, so these medications are used cautiously.
Tissue plasminogen activator (tPA) treatment
For this reason, diagnosis of the type of stroke is essential before someone can be given tPA. There are also other factors that could exclude you from tPA therapy, such as recent surgery.
Most importantly, tPA only works when it’s given within a certain timeframe —
Newer studies echo these results. Stroke surgery for clot removal is a rare, possibly lifesaving procedure, which usually involves the administration of tPA.
Treatment of a hemorrhagic stroke focuses on:
- stopping the bleeding
- reducing the buildup of pressure within the skull
- preventing complications like seizures
- measures to control high blood pressure (hypertension)
Medications such as concentrated saline solutions and mannitol may be used to control intracranial pressure.
The extent of damage from a hemorrhagic stroke will depend on what parts of the brain were affected, how long brain tissue went without oxygen, and how severe or extensive the bleeding was.
Time is critical when it comes to diagnosing and treating strokes. This is because brain tissue is extremely sensitive to a lack of oxygen and nutrients, such as glucose. Your brain needs a sufficient and constant supply of oxygen, which is delivered through your blood.
When blood flow is stopped or disrupted, permanent brain damage and disability can develop in
Restoring blood flow and oxygen to your brain as soon as possible can minimize how much tissue — and therefore brain function — is lost during stroke. This is done through prompt treatment with surgery or medications and, as mentioned above, it’s critical that certain medications like tPA be given within a specific window of time for the greatest effect.
Signs and symptoms of a stroke
- sudden numbness or weakness on one side or in one area of the body
- sudden confusion
- vision changes
- loss of balance
- difficulty walking
- speech changes
- severe headache
If you or someone you know experience these symptoms, get immediate medical attention.
Any delay in care — whether you are having a hemorrhagic or ischemic stroke — can have an impact on the care you are eligible to receive, as well as the level of disability you experience.
Stroke occurs when the blood flow to an area of the brain is interrupted. The key to avoiding permanent damage and disability from a stroke is quick diagnosis and treatment.
There are different ways to diagnose a stroke, but the most accurate are imaging tests such as CT scans or MRIs, which can show brain tissue damage or bleeding.
These tests can help diagnose the presence and type of stroke that’s occurred in order to help medical professionals determine the most effective treatment.