[Clinical application of neuroimaging to alcohol-related dementia]

Alcohol-related dementia (ARD) is one of the most common dementing disorders in middle-aged people and occurs in heavy drinkers who are estimated to be 10 - 15 % of the adult men in a community. While the concept of ARD is multifactorial and includes all cognitive deficits in alcoholics, the central clinical manifestations are exemplified by Korsakoff's syndrome (KS), a persistent neuropsychiatric syndrome, characterized by amnesia and disorientation that is caused by thiamine deficiency along with excessive alcohol consumption. Antemortem detection of intracranial changes has been made possible by MRI and many studies have revealed that alcoholics have atrophic changes in frontal lobe, cerebellum, medial temporal lobe and hippocampus. However, these brain regions are vulnerable to excessive alcohol and seem to be independent of cognitive deficits in alcoholics. This review shows the regional differences in gray matter volumes between cognitively normal alcoholics and patients with KS. By employing a 3-dimensional MRI method for voxel-based morphometry that enables an automated, unbiased, comprehensive assessment, we demonstrate that parahippocampal/hippocampal atrophy is specific to KS and thalamic atrophy and the third ventricle enlargement are more severe in patients with KS than in cognitively normal alcoholics.