Medial temporal and whole-brain atrophy in dementia with Lewy bodies: a volumetric MRI study

Objective: Dementia with Lewy bodies (DLB) is emerging as a common cause of degenerative dementia. A recent pathologic study has indicated that the medial temporal lobe in patients with DLB was less atrophic than that in patients with AD. The purpose of this study was to examine whether medial temporal MRI volumetry was useful to differentiate DLB from AD clinically.Methods: We compared the volumes of the hippocampal formation, amygdaloid complex, and whole brain in 27 patients with probable DLB (based on the criteria of the Consortium on DLB International Workshop), 27 patients with probable AD(based on criteria of the National Institute of Neurological Disease and Stroke/Alzheimer's Disease and Related Disorders Association), and 27 normal elderly subjects using an MRI-based volumetric technique. The three groups were matched for age and sex. Severity of cognitive disturbances represented by their Mini-Mental State Examination score was comparable between the DLB and AD groups.Results: Hippocampal volume (normalized to intracranial volume) in the DLB group was significantly larger than that in the AD group, but significantly smaller than that in the normal control group. There were no significant differences in the amygdala and whole-brain volume between the DLB group and the AD group, but the atrophies of the amygdala and whole brain were more severe in the DLB group than those in the control group.Conclusions: These findings indicate the usefulness of MRI hippocampal volumetry in clinically discriminating patients with DLB from patients with AD.