MAGNETIC-RESONANCE VERSUS COMPUTED TOMOGRAPHIC IMAGING IN ACUTE STROKE

Background and Purpose This study was an attempt to determine whether CT and MRI are comparable or if one is superior to the other in the ea rly detection of ischemic stroke or hematoma. Methods Patients with ac ute stroke were sought within 3 hours of onset for clinical examinatio n and prospective evaluation by concurrently performed CT and MRI. Rep eated clinical and imaging studies were undertaken when possible immed iately after imaging and at 24 hours, 3 to 5 days, and 3 months. The s tudy neurologists were blinded to the results of imaging, as were the study radiologists to the clinical findings. The study radiologists re ad the scans in sequence, mapping each imaging on standard templates b efore viewing a later scan. No retrospective revisions of imaging mapp ing of earlier images were undertaken. Results Sixty-eight patients we re recruited within 4 hours and an additional 12 patients within 24 ho urs. Seventy-five strokes were due to infarction and five to hemorrhag e. The median time to first scan was 132 minutes. Although some of the infarctions in 75 patients were detected within 1 hour, the fraction of positive first scans approached an asymptote at 2 to 3 hours. Overa ll, with the use of conventional non-contrast-enhanced CT and T-1- and T-2-weighted MRI, neither was superior in the very early detection of either hematoma or infarction. There was a marginally significant cor relation between early positive brain imaging and the severity of the stroke. Some patients had initially positive CT and/or MRI scans, but their neurological examination had returned to normal by 24 hours. Ove rall, CT was better than baseline MRI at predicting 24-hour outcome. A fter 24 hours, both CT and MR more conspicuously defined the lesion li mits than they did at baseline. Conclusions With the technology availa ble through 1991, neither CT nor MRI proved superior in the detection of the earliest signs of stroke.