Multimodality imaging characteristics of dementia with Lewy bodies.

Dementia with Lewy bodies (DLB) is the second most common cause of neurodegenerative dementia after Alzheimer's disease (AD). Our objective was to determine whether the (11)C-Pittsburgh Compound-B (PiB) retention and regional hypometabolism on positron emission tomography (PET) and regional cortical atrophy on magnetic resonance imaging (MRI) are complementary in characterizing patients with DLB and differentiating them from AD. We studied age-, gender-, and education-matched patients with a clinical diagnosis of DLB (n = 21), AD (n = 21), and cognitively normal subjects (n = 42). Hippocampal atrophy, global cortical PiB retention and occipital lobe metabolism in combination distinguished DLB from AD better than any of the measurements alone (area under the receiver operating characteristic = 0.98). Five of the DLB and AD patients who underwent autopsy were distinguished through multimodality imaging. These data demonstrate that magnetic resonance imaging and PiB positron emission tomography contribute to characterizing the distinct pathological mechanisms in patients with AD compared with DLB. Occipital and posterior parietotemporal lobe hypometabolism is a distinguishing feature of DLB and this regional hypometabolic pattern is independent of the amyloid pathology.