BACKGROUND AND PURPOSE: We tested the hypothesis that early diffusion- and perfusion-weighted MRI (DWI and PWI, respectively) allows the prediction of malignant middle cerebral artery (MCA) infarction (MMI). METHODS: Thirty-seven patients with acute MCA infarction and proximal vessel occlusion (carotid-T, MCA main stem) were studied by DWI, PWI, and MR angiography within 6 hours of symptom onset. Eleven patients developed MMI, defined by decline of consciousness and radiological signs of space-occupying brain edema. Lesion volumes were retrospectively defined as apparent diffusion coefficient +4 seconds (TTP>+4s) compared with the unaffected hemisphere. ADC decrease within the infarct core (ADCcore) and relative ADC within the ADC+4s (208 versus 125 mL; P82 mL, 87%, 91%; TTP>+4s >162 mL, 83%, 75%; TTP/ADC mismatch ratio or =19, 96%, 72%. CONCLUSIONS: Quantitative analysis of early DWI and PWI parameters allows the prediction of MMI and can help in the selection of patients for aggressive tissue-protective therapy.
