Differential Diagnosis of Dementia with Lewy Bodies and Alzheimer Disease Using Combined MR Imaging and Brain Perfusion Single-Photon Emission Tomography

BACKGROUND AND PURPOSE: Diagnostic performance by MR imaging or by SPECT alone in discriminating DLB patients from AD patients has been estimated previously. However, the performance of a combination of MR imaging and SPECT has not yet been evaluated. Our aim was to evaluate the usefulness of combining MR imaging and SPECT to discriminate mild DLB from AD. MATERIALS AND METHODS: Nineteen patients with mild DLB and 19 age- and cognitive decline-matched patients with mild AD underwent both SPECT and MR imaging. Hippocampal, occipital, and striatal volume and SPECT count ratios were compared. Linear discriminant and ROC analyses were performed by using the parameters of striatal volume and the occipital SPECT ratio. RESULTS: The striatal volume ratio in the DLB group was significantly lower than that in the AD group. The occipital SPECT ratio in the DLB group was lower than that in the AD group. The mean area under the ROC curve from combined MR imaging and SPECT (AUC = 0.898) was higher than that from MR imaging (AUC = 0.679) or SPECT (AUC = 0.798) alone. CONCLUSIONS: By combining MR imaging and SPECT, we were able to distinguish patients with mild DLB from those with AD with a high level of accuracy. Our findings suggest that combining MR imaging and SPECT modalities is a useful and practical approach for diagnostically differentiating DLB from AD.