RESUMO
OBJECTIVE: The purpose of this study was to validate diffusion-weighted magnetic resonance imaging in the prediction of the evolutive course of brain edema and to establish its pathophysiologic presence in patients with eclampsia/severe preeclampsia. STUDY DESIGN: Seventeen patients with a clinical diagnosis of severe eclampsia/preeclampsia and T2 hyperintense brain lesions on routine magnetic resonance imaging were evaluated at hospital admission and 8 weeks later. RESULTS: Brain edema was reversible in 13 patients and irreversible in 4 patients, as indicated on follow-up magnetic resonance imaging. Sixteen of 17 patients were differentiated accurately into reversible and irreversible groups on the basis of diffusion imaging on hospital admission. Diffusion-weighted magnetic resonance imaging demonstrated a significant increase in water mobility in abnormal regions compared with normal-appearing brains in patients in the reversible group (1.34+/-0.10 mm(2) vs 0.79+/-0.08 mm(2)/s x 10(-3), P<.001). In the irreversible group, restricted water diffusion was present, which was consistent with cytotoxic edema and early brain infarction in 3 of 4 patients. CONCLUSION: Diffusion-weighted magnetic resonance imaging can predict successfully the evolutive course of brain edema in an acute setting in these patients. Our findings indicate that brain edema is vasogenic, although ischemic/cytotoxic edema was observed less commonly.