Stroke

Diagnosis

The following screening tools are most often used to determine stroke risk, but they also become diagnostic tools if a person is having a stroke:

Physical examination

The physician will listen to the heart, look into the eyes and do a general exam to evaluate the patient for other signs of vascular disease. A stethoscope may be used to listen for a bruit - a sound made by turbulence in the carotid arteries. A bruit often indicates atherosclerosis.

Basic laboratory tests

In addition to checking blood pressure and cholesterol levels, a doctor may test for diabetes or check the blood for an elevated level of the amino acid homocysteine. A high level of this substance is a risk factor for stroke, but homocysteine level may be modifiable with certain treatments.

Computed Tomography (CT) Scan

This is generally the first diagnostic test done after a patient with a suspected stroke arrives in the emergency room. It is used to quickly distinguish between an ischemic or hemorrhagic stroke. The test involves low-dose X-rays to visualize the brain.

Computed tomographic angiography (CTA)

A dye is injected into the blood vessels, and X-ray beams create a three-dimensional image of blood vessels in the neck and brain. CTAs are used to look for aneurysms, arteriovenous malformations and arterial narrowing.

Magnetic Resonance Imaging (MRI)

Using a strong magnetic field, an MRI can generate a three-dimensional view of the brain. This test is used to detect an area of brain tissue damaged by an ischemic stroke. It provides a high level of anatomic detail for precisely locating the stroke and determining the extent of damage.

The procedure involves use of a strong magnetic field, and is performed in a special room free of metallic equipment. Recently, there have been great advances in the early detection of stroke using diffusion and perfusion weighted imaging. These techniques are available at Mayo Clinic.

Magnetic Resonance Angiography (MRA)

A new, noninvasive technology for imaging the cerebral (head) arteries and veins, which also yields valuable information regarding collateral (alternative) arteries supplying the brain. This procedure uses a strong magnetic field, similar to MRI. Mayo Clinic has been at the forefront of research that has optimized the clarity of MRA images.

Carotid Ultrasonography

An ultrasound of the neck. The sound waves pass through tissue and then return, creating on-screen images that show any narrowing or clotting in the carotid (neck) arteries and how fast blood is flowing through them to the brain.

Transcranial Doppler (TCD)

An ultrasound procedure that shows blood flow through the cerebral vessels via a small probe placed against the skull. TCD is a portable test, which can be performed at a patient's bedside to follow the progress of medical treatment for stroke.

PET Scanning

This test measures brain cell metabolism, showing if brain tissue is functioning even though blood flow to that area appears diminished.

Arteriography

This procedure produces a detailed view of arteries in the brain not normally seen in X-rays. A catheter is inserted in an artery in the arm or leg, and a dye is injected into the blood vessels leading to the brain. X-ray images show any abnormalities of the blood vessels, including narrowing, blockage or malformations (such as aneurysms or arteriovenous malformations).

Echocardiogram

An (ECG) is an ultrasound of the heart to determine whether an underlying heart problem is contributing to the risk of stroke. A wandlike device (transducer) collects reflected sound waves (echoes) from the heart and transmits them to a machine. The ultrasound probe may be placed on your chest (trans-thoracic echocardiogram, TTE) or deep in your throat (trans-esophageal echocardiogram, TEE).