Diagnostic usefulness of diffusion-weighted magnetic resonance imaging in influenza-associated acute encephalopathy or encephalitis

A magnetic resonance imaging (MRI) study was performed for a 20-month-old g irl with an influenza type A infection who presented acute encephalopathy. Conventional MRI performed 8 days after the onset of encephalopathy, includ ing T1-weighted, T2-weighted, and fluid-attenuated inversion recovery imagi ng, revealed only vague lesions in the right frontal, temporal, and parieta l lobes. In contrast, diffusion-weighted imaging (DWI) then demonstrated th e lesions much more intensively. On the 26th day, the lesions previously ob served on DWI had become less discernible. The hyperintensity observed on D WI might reflect cytotoxic edema. Thus, DWI may be useful for evaluation of acute influenzal encephalopathy/encephalitis. (C) 2000 Elsevier Science B. V. All rights reserved.