TUESDAY, Nov. 2 (HealthDay News) -- MRI images can serve as a "surrogate clock" to pinpoint stroke onset in patients whose symptoms began during sleep, increasing the number of patients eligible for highly effective clot-busting therapy, according to a new study.
Researchers found that MRI data could accurately determine if patients had experienced stroke symptoms within a three-hour period or less, which would allow the use of a clot-busting drug that works best if administered within that window of time. Tissue plasminogen activator, known as tPA, can dramatically reverse stroke symptoms in those whose strokes are caused by blood clots and blockages, which account for an estimated 85 percent of all strokes.
Strokes strike about 795,000 Americans each year, killing 137,000, according to the U.S. Centers for Disease Control and Prevention. The condition is a leading cause of serious, long-term disability in the United States.
"A tool that can estimate the age of stroke would be of great value in cases of unknown stroke onset time," said lead researcher Dr. Catherine Oppenheim, professor of radiology at Universite Paris Descartes in France. "This concerns as many as a quarter of all stroke patients who cannot be given tPA because they wake up with stroke symptoms or are unable to say when their stroke began."
Under current guidelines, patients who awaken with symptoms are arbitrarily excluded from tPA therapy, Oppenheim said, because the onset is considered to be the last time the patient was symptom-free, which might have been the night before.
The clot-busting drug is recommended for use only within 4.5 hours of stroke onset because it carries a risk of brain hemorrhage, a potentially fatal prospect, with the risk increasing as more time passes.
The study, reported online Nov. 2 and in the December issue of the journal Radiology, reinforces results
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