Prompt medical diagnosis of a stroke is essential: the sooner stroke treatment begins, the better the chance of survival. This is especially true since the treatments for ischemic and hemorrhagic strokes are very different. Determining the type and severity of a stroke is the first step in minimizing damage from the event.
The diagnostic work-up begins as soon as stroke symptoms are reported. Symptoms such as a sudden and severe headache, weakness or paralysis on one side of the body, loss of speech, incontinence, or numbness suggest a stroke. Once a stroke is suspected, brain-imaging tools such as magnetic resonance imaging or computed tomography provide further clues about the nature of the stroke.
The hallmark of a stroke is the sudden onset of neurologic symptoms. Stroke symptoms should be reported to medical professionals immediately. Many people wait up to 24 hours before reporting stroke symptoms, a delay which results in severe stroke damage and high fatality rates.
Magnetic resonance imaging, or MRI, is the most sensitive imaging tool for the medical diagnosis of ischemic stroke. Magnetic resonance imaging techniques generate images of the brain using magnetic fields. Areas of ischemia in the brain can be visualized with MRI.Magnetic resonance imaging can detect an ischemic stroke within six to twelve hours of onset of the stroke. While this is more sensitive than other tests, such as computed tomography, the time delay somewhat limits the effectiveness of MRI for stroke diagnosis. Nearly all current stroke treatments are most effective if started within three hours of stroke onset.
All stroke symptoms occur suddenly and without warning.
Although it is sometimes the second choice for medical imaging of a suspected ischemic stroke, computed tomography is more often available for diagnosis of a stroke than an MRI. Computed tomography, also known as a CT or CAT scan, uses multiple x-rays to take images of "slices" of the brain. The major limitation in using computed tomography to diagnose an ischemic stroke is that evidence of the stroke takes between 24 to 36 hours to appear on a CT scan. In addition, the brain stem and cerebellum cannot be viewed using computed tomography. These "blind spots" mean that ischemic strokes in the brain stem or cerebellum may be overlooked.Computed tomography is, however, the preferred imaging tool for diagnosis of hemorrhagic stroke. Hemorrhagic strokes can be detected quickly and definitively using CT scanning.
In addition to magnetic resonance imaging and computed tomography, other tests help make a medical diagnosis of stroke.
American Stroke Association. (nd). Diagnosis. Retrieved February 17, 2004, from www.strokeassociation.org/presenter.jhtml?identifier=2552.
Fauci, A., Braunwald, E., Isselbacher, K., Wilson, J., Martin, J., Kasper, D., Hauser, S.
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