Tests Used in Stroke Diagnosis

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Stroke diagnosis requires a careful and fast medical examination, often with the aid of medical technology. If you ever have a stroke evaluation, your examination would include the following tools.

The Neurological Examination

This test is performed by a physician in order to uncover whether there is problem in brain function which might confirm the suspicion that a person is actually having a stroke.

Each part of the neurological exam tests a different area of the brain, including:

  • Awareness and consciousness
  • Speech, language, and memory function
  • Vision and eye movements
  • Sensation and movement in the face arms and legs
  • Reflexes
  • Walking and sense of balance

Computed Tomography Scan

This test is performed in the emergency room to detect a hemorrhagic stroke.

Computed tomography (CT) scans are good tests for this purpose not only because they easily detect bleeding inside the brain, but also because they can be performed quickly.

CT scans also can reveal ischemic strokes, but they often cannot detect ischemic strokes until approximately 6-12 hours after their onset.

Lumbar Puncture

Also known as a “spinal tap” this test is sometimes performed in the emergency room when there is a strong suspicion for a hemorrhagic stroke. The test involves the introduction of a needle into an area within the lower part of the spinal column where it is safe to collect cerebrospinal fluid (CSF).

When there is bleeding in the brain, blood can be seen in the CSF.

Magnetic Resonance Imaging (MRI)

This is one of the most helpful tests in the diagnosis of stroke because it can detect strokes within minutes of their onset. MRI images of the brain are also superior in quality to CT images. A special type of MRI called magnetic resonance angiography, or MRA, lets doctors visualize narrowing or blockage of blood vessels in the brain.

Transcranial Doppler (TCD):

This test uses sound waves to measure blood flow through the major blood vessels in the brain. Narrow areas inside of a blood vessel demonstrate a different rate of blood flow than normal areas. This information can be used by doctors to follow the progress of partially blocked blood vessels.

Another important use for the TCD is the assessment of blood flow through blood vessels in the area of a hemorrhagic stroke, as these blood vessels have a propensity to undergo “vasospasm” a dangerous and sudden narrowing of a blood vessel which can block blood flow.

Cerebral Angiography:

Stroke doctors use this test to visualize blood vessels in the neck and brain. During this test a special dye, which can be seen using X-rays, is injected into the carotid arteries, which bring blood to the brain. If a person has a partial or a total obstruction in one of these blood vessels, the pattern of dye can help diagnose an abnormal blood vessel.

A common cause of stroke is narrowing of a carotid artery, carotid stenosis, which is usually the result of cholesterol deposits along the walls of these blood vessels.

This condition can also be diagnosed by a test called a Carotid Duplex, by which sound waves are used to evaluate blood flow through these blood vessels.

Depending of the degree of narrowing and on the symptoms felt by a person, surgery might be needed to remove the plaque from the affected artery.

Carotid Stenosis Treatments

Cerebral angiography can also help doctors diagnose the following common conditions known to be associated with hemorrhagic stroke

After a stroke is diagnosed, sometimes, a new battery of tests needs to be performed in order to find out the cause of the stroke.

Electrocardiogram

This test, also known as an EKG or ECG, helps doctors identify problems with the electrical conduction of the heart. Normally, the heart beats in a regular, rhythmic pattern which promotes smooth blood flow towards the brain and other organs. But when the heart has a defect in electrical conduction, it may beat with an irregular rhythm. This is called an arrhythmia, or an irregular heart beat.

Some arrhythmias, such as atrial fibrillation, cause the formation of blood clots inside the heart chambers. These blood clots sometimes migrate to the brain and cause a stroke.

Transthoracic echocardiogram (TTE)

This test, also known as an ‘echo’ uses sound waves to look for blood clots or other sources of emboli inside the heart. It also is used to look for abnormalities in heart function which can lead to blood clot formation inside the heart chambers. TTEs are also used to investigate if blood clots from the legs can travel through the heart and reach the brain.

Leg Ultrasound

Doctors usually perform this test on stroke patients diagnosed with a patent foramen ovale. The test uses sound waves to look for blood clots in the deep veins of the legs, which are also known as deep venous thromboses or DVTs. DVTs can cause strokes by making a long journey which ends up in the brain. First, a small fragment of a DVT breaks off and travels to the heart via the venous circulation. Once in the heart the blood clot crosses from the right side to the left side of the heart via the PFO, where it is propelled out via the aorta and carotids towards the brain, where it can cause a stroke.

Blood Tests

For the most part, blood tests help doctors look for diseases known to increase the risk of stroke, including:

Source

Bradley G Walter, Daroff B Robert, Fenichel M Gerald, Jancovic, Joseph Neurology in clinical practice, principles of diagnosis and management. Philadelphia Elsevier, 2004.

Edited by Heidi Moawad MD

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