MEASUREMENT OF INFARCT SIZE USING MRI PREDICTS PROGNOSIS IN MIDDLE CEREBRAL-ARTERY INFARCTION

Background and Purpose An accurate measure of the severity of ischemic insult and the resulting prognosis is needed to assess the effectiven ess of new treatments for acute stroke. We studied the reproducibility and accuracy of measurements of infarct volume with MRI and correlate d the measurements with outcome.Methods Infarct volume was measured on T-2-weighted images with the ANALYZE image analysis software. This te chnique was found to be highly accurate and reproducible. Results Meas urements of infarct volume were found to be highly accurate and reprod ucible. Twenty-one patients (mean age, 66.5 years; range, 28 to 90 yea rs) with cortical middle cerebral artery territory infarcts in whom ad equate data could be obtained were studied within 72 hours from onset (mean delay to MRI, 27.5 hours; range, 5 to 72 hours). The Scandinavia n Stroke Scale was used to calculate a prognostic score, and clinical outcome was assessed at 3 months. Infarct volume was found to signific antly predict outcome. Mean infarct volume in the independent patients was 35.7+/-29.7 cm(3) compared with 88.3+/-71.3 cm(3) in dependent pa tients and cm 166.5+/-65.9 cm(3) in dead patients (F=10.52, P<.001). P atients with an initial infarct volume less than 80 cm(3) were found t o have a better outcome than those with larger infarct volumes. Second ary hemorrhage visible on MRI also predicted a poor outcome. In contra st, the Scandinavian Stroke Scale did not significantly predict outcom e. Conclusions The results demonstrate that measurement of the size of middle cerebral artery infarction with MRI is a useful tool in assess ing prognosis and will have a valuable role in assessing new therapeut ic agents.