MRI Features of Posterior Reversible Encephalopathy Syndrome in 33 Patients

Abstract

BACKGROUND AND PURPOSE We report the clinical and radiological features of posterior reversible encephalopathy and compare our findings to the literature. METHODS The brain magnetic resonance imaging and clinical records of 33 patients were retrospectively evaluated. Twenty-four patients had follow-up imaging, which confirmed the reversibility of the lesions; 9 patients were clinically followed and recovered. The clinical records were analyzed for the age, sex, gender, underlying etiology, and clinical symptoms. MR images were evaluated for the distribution of the lesions, contrast enhancement and diffusion-weighted-imaging (DWI) features, reversibility, and complications. RESULTS The most commonly involved localizations were frontal lobe in 51.5%, parietal lobe in 84.8%, occipital lobe in 72.7%, temporal lobe in 33.3%, and cerebellum in 33.3%. Nineteen patients had DWI, which showed vasogenic edema in 17 and cytotoxic edema in 2. Sixteen patients had contrast-enhanced images; 4 of them showed focal enhancement. Nine patients had the complication of hemorrhage. CONCLUSION The involvement of different localizations formerly known as atypical is now commonly encountered. Intravenous contrast administration may be of use to demonstrate focal enhancement and exclude other diseases in the differential. DWI is essential to distinguish the type of edema. Repeat imaging including DWI should be performed to follow the response to therapy. J Neuroimaging 2010;20:22-28.