Differences in magnetization transfer ratios of the hippocampus between dementia with Lewy bodies and Alzheimer's disease.

We compared magnetization transfer ratios (MTRs) in the brains of patients with dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) to determine whether regional differences in the brain structures between DLB and AD are detectable with magnetization transfer imaging. Seventeen patients with DLB, 31 patients with AD and 18 elderly normal controls were included. Although no significant differences were found in MTRs in the frontal white matter between the three groups, MTRs in the hippocampus, parahippocampus, and posterior cingulate white matter in both patients with DLB and AD were significantly lower than those in age-matched control subjects. However, MTRs in the hippocampus of patients with DLB were significantly higher than those in patients with AD. Logistic regression analysis revealed that hippocampal MTR yielded a sensitivity of 76% and a specificity of 71% in discriminating DLB from AD. These results may reflect underlying histopathological differences with less severe neuronal degeneration in the hippocampus of DLB. MTR measurement of the hippocampus may contribute to the clinical differentiation between DLB and AD.