MRI More Accurate Than CT for Diagnosing Stroke
MRI has higher sensitivity for stroke detection in emergency setting
FRIDAY, Jan. 26 (HealthDay News) -- Magnetic resonance imaging, or MRI, detects acute stroke with higher sensitivity and accuracy than the more widely used computed tomography (CT), which fails to accurately diagnose three in four acute strokes and picks up only 7 percent of ischemic stroke in patients presenting within three hours of symptom onset, researchers report in the Jan. 27 issue of The Lancet.
Steven Warach, M.D., Ph.D., from the National Institutes of Health in Bethesda, Md., and colleagues compared CT and MRI for the emergency diagnosis of 356 patients who were referred for suspected stroke, of whom 90 presented within three hours. Overall, 217 were finally diagnosed with acute stroke.
MRI and CT detected acute intracranial hemorrhage at similar frequencies, but MRI was better at detecting acute ischemic and hemorrhagic stroke and chronic hemorrhage. In patients presenting within three hours, MRI diagnosed acute ischemic stroke with an accuracy of 46 percent compared with only 7 percent for CT. In patients finally diagnosed with stroke, the sensitivity of detecting any acute stroke was 83 percent for MRI and 26 percent for CT, while the accuracy was 89 percent for MRI and 54 percent for CT.
Computerized tomography has been the preferred technique to quickly assess stroke patients, but "this mantle should now be passed to magnetic resonance imaging," Geoffrey A. Donnan, M.D., and colleagues from the University of Melbourne in Australia, write in an accompanying editorial.