Diagnosis of Stroke
If stroke is suspected, prompt, accurate diagnosis and treatment is necessary to minimize brain tissue damage. Diagnosis includes a medical history and a physical examination including neurological examination to evaluate the level of consciousness, sensation, and function (visual, motor, language) and determine the cause, location, and extent of the stroke.
Physical examination includes assessing the airway, breathing, and circulation (ABCs) and the vital signs (i.e., pulse, respiration, temperature). The head (including ears, eyes, nose, and throat) and extremities are also examined to help determine the cause of the stroke and rule out other conditions that produce similar symptoms (e.g., Bell's palsy).
Blood tests (e.g., complete blood count) and imaging procedures (e.g., CT scan, ultrasound, MRI) help the physician determine the type of stroke and rule out other conditions, such as infection and brain tumor.
Imaging Procedures to Diagnose Stroke
When stroke is suspected, computed tomography (CT scan) is performed as soon as possible. CT scan produces x-ray images of the brain and is used to determine the location and extent of hemorrhagic stroke. CT scan usually cannot produce images showing signs of ischemic stroke until 48 hours after onset, so a repeat scan may be performed.
Ultrasound uses high-frequency sound waves to produce images of blood flow through the arteries in the neck that supply blood to the brain (i.e., carotid arteries) and may be used to detect blockage.
Magnetic resonance imaging (MRI scan) with magnetic resonance angiography (MRA) uses a magnetic field to produce detailed images of brain tissue and arteries in the neck and brain, allowing physicians to detect small-vessel infarct (i.e., stroke in small blood vessels deep in brain tissue).
Angiogram involves injecting a contrast agent (dye) into the bloodstream and taking a series of x-rays of blood vessels. This test is used to identify the source and location of arterial blockage and to detect aneurysms and blood vessel defects.
An electrocardiogram may be performed to detect reduced blood flow to the heart (myocardiac ischemia) or irregular heartbeat (cardiac arrhythmia).
Single photon emission computed tomography (SPECT) and positron emission tomography (PET) involve injecting a radioactive substance into the bloodstream and monitoring it as it travels through blood vessels in the brain. These tests allow physicians to detect damaged regions of the brain resulting from reduced blood flow.