PurposeClinical features of Wernicke's encephalopathy (WE) confirmed strictly through the low blood vitamin B1 (VB1) levels are limited. This study aimed to analyse magnetic resonance imaging (MRI) findings, and clinical characteristics, in patients with WE who have confirmed low blood VB1 levels. MethodsClinical and laboratory records of 12 consecutive patients with WE admitted to our hospital during the past 11 years were reviewed. The WE diagnosis was confirmed based on low blood VB1 levels and the presence of at least one of the classical triad. ResultsOphthalmoplegia and nystagmus were recorded in 75% and 50% of the patients, respectively. Eleven of 12 patients presented with consciousness disturbance/memory loss. All patients experienced gait disturbances. Eight of the 12 patients exhibited MRI abnormalities at typical sites (the dorsal midbrain [n = 7], medial thalamus [n = 6], mammillary bodies [n = 5], and dorsal pons [n = 5]). Of the 12 patients, six showed abnormalities at atypical sites (the splenium of the corpus callosum [n = 4], fornix [n = 3], cerebral cortex [n = 2], cerebellar vermis [n = 2], and dorsal medulla [n = 1]). Patients with positive MRI abnormalities had significantly lower blood VB1 levels than those without abnormalities (9.5 vs. 16.0 ng/mL). ConclusionsIn cases of confirmed WE with low blood VB1 levels, the corpus callosum, fornix, and cerebral cortex were more frequently involved than in previous studies. MRI abnormalities at both typical and atypical sites were correlated with low blood VB1 levels in WE, suggesting that lower blood VB1 levels are associated with more severe brain damage in patients with WE.