WEDNESDAY, Dec. 13, 2006 (HealthDay News) -- Ischemic stroke patients who have recurrent asymptomatic brain lesions within three months of their initial stroke are at increased risk for subsequent strokes, says a U.S. study in the December issue of the journal Archives of Neurology.
An ischemic stroke occurs as a result of inadequate blood flow to the brain.
Previous research found that asymptomatic (silent) brain lesions -- changes in brain tissue that occur in areas where blood flow is blocked or reduced -- occur more frequently than symptomatic lesions up to three months after a stroke, according to background information in the article.
The authors of this current study investigated whether silent brain lesions detected by MRI scans could help predict stroke patients' risk for subsequent strokes.
Researchers at the National Institute of Neurological Disorders and Stroke studied 120 ischemic stroke patients. Each patient had an MRI brain scan within 24 hours of the stroke and five days after the stroke. Of those patients, 68 had a follow-up MRI after 30 days or up to 90 days after the stroke.
The study found that patients who had silent ischemic lesions on the 30- or 90-day MRI were about 6.5 times more likely than other patients to suffer a subsequent ischemic stroke. Patients with silent lesions on any of the MRI scans (24 hours, five days, 30 days, or 90 days) had an increased risk of death from vascular causes, recurrent ischemic stroke or transient ischemic attack.
"It is a matter of circumstance, rather than tissue pathological features, that determines whether cerebral ischemia is symptomatic or silent," the study authors wrote. "Clinical symptoms depend on the size, location and number of new lesions. Thus, we assume that the pathological process that causes silent lesion recurrence on MRI is the same as the process that causes clinical recurrent strokes. Magnetic resonance imaging may depict pathological changes before the development of clinical stroke symptoms."
The Washington University School of Medicine has more about ischemic stroke.