[Diffusion-weighted magnetic resonance imaging findings at early stage of acute Wernicke encephalopathy].

We describe a patient with acute Wernicke encephalopathy (WE) in whom diffusion-weighted magnetic resonance imaging (DWI) were helpful for early diagnosis. A 66-year-old alcoholic man was admitted to our department because of recurrent mild drowsiness. Thiamine concentrations in blood were at the lower limit of normal. DWI demonstrated an abnormal signal intensity in the dorsal part of the midbrain, and high-dose thiamine therapy was started. These lesions disappeared on DWI after one month of follow-up, in association with clinical improvement. These findings suggest that DWI is useful for detecting WE at the early stage when high-dose thiamine treatment can improve the prognosis of WE.