Diffusion-Weighted MR Imaging Can Detect Stroke

In a study of 122 patients, 12 had suffered a stroke. Diffusion-weighted MRI was 91% accurate if the test was performed 0-6 hours after the first symptoms, 89% accurate after 6-12 hours, and 90% accurate after 12-24 hours. These results are superior to previous studies on computed tomography (CT), which has a 40-60% accuracy rate in detecting stroke. The earlier stroke can be identified, the less likely the stroke will be debilitating.

"Diffusion-weighted MRI was 100% specific, meaning that every patient identified as having had a stroke indeed had one. The technique was 90% sensitive,” said lead author Mark Mullins, M.D., Ph.D., of Massachusetts General Hospital (Boston, USA). "The technique allows us to create two sequences of images. We can tell if a patient has had a stroke because in one sequence there is a very bright spot. We call it the light bulb sign. In the other sequence, that same area is dark.” The study was presented at the annual meeting of the American Roentgen Ray Society in Dan Diego (CA, USA).