Specific Imaging Findings
In Wernicke encephalopathy (WE, Wernicke-Korsakoff syndrome) symmetric signal intensity alterations in the mammillary bodies, medial thalami, periventricular regions of the third ventricle, tectal plate, and periaqueductal gray matter are typical MRI findings. Selective involvement of the cranial nerve nuclei, cerebellum, dentate nuclei, fornix, splenium of the corpus callosum, cerebral cortex, and basal ganglia characterize nonalcoholic WE. Lesions in the basal ganglia mainly affect the putamen and are most frequently observed in children. The lesions are iso to hypointense to the gray matter on T1-weighted images and T2 hyperintense. DWI also shows high signal intensity in the acute phase with variable ADC values. Enhancement of the mammil-lary bodies is most frequently observed in the alcholic population and may be the only imaging finding. Degree of enhancement is quite variable. Hemorrhagic transformation is rare.
Brain atrophy develops in chronic WE, in particular of the fornices and mammillary bodies, while T2 hyperintensity becomes less obvious.
Pertinent Clinical Information
WE is an acute neurologic disorder resulting from thiamine (vitamin B1) deficiency and its incidence is underestimated in both adult and pediatric patients. Clinical presentation is characterized by changes in consciousness, ocular dysfunction, and ataxia. However, this triad is not present in many patients. The most common presenting symptom is nonspecific mental status changes. Untreated patients can progress to irreversible brain damage leading to Korsakoff syndrome and, eventually, to death.