Magnetic resonance imaging findings in Reye syndrome: case report and review of the literature.

Magnetic resonance imaging findings in Reye syndrome have been reported only infrequently. A previously well 8-year-old boy presented with repeated episodes of vomiting and abdominal pain followed by altered sensorium and tonic spasms. This occurred 5 days after upper respiratory tract infection. His laboratory data revealed elevated liver enzymes, prolonged prothrombin time, and high blood ammonia levels. Magnetic resonance imaging of the brain done on the day of admission revealed diffuse cerebral edema and signal alterations in brainstem, bilateral thalami, medial temporal lobes, parasagittal cortex, and cerebellar and subcortical white matter. Diffusion restriction was seen in thalami, midbrain, cerebellar white matter, subcortical white matter, and parasaggital cortex in the watershed territory. The patient made a full recovery. Follow-up magnetic resonance imaging after a week revealed complete resolution of all except thalamic lesions. Although diffusion restriction in thalami and midbrain has been reported previously, this is the first report indicating diffusion restriction in subcortical white matter and the parasagittal cortex.