Single-photon emission computed tomography in the differential diagnosis of dementia with Lewy Bodies

BackgroundThe study is aimed at assessing the usefulness of 99mTc-ECD SPECT in distinguishing patients with: Dementia with Lewy Bodies (DLB), Alzheimer's disease (AD) and Parkinson's disease with dementia (PD-D).MethodsFifty patients participated in the study: 13 patients with DLB (aged 74 ± 4 years), 19 patients with AD (aged 75 ± 7 years), 18 patients with PD-D (aged 72 ± 3 years) and 14 healthy individuals (aged 70 ± 6 years). A neuropsychological examination was conducted on all patients. Motor function of DLB and PD-D patients was assessed using the Hoehn-Yahr scale, Unified Parkinson's Disease Rating Scale and Schwab and England Activities of Daily Living Scale. 99mTc-ECD SPECT was performed on all subjects. Statistical analysis of radiotracer uptake was performed for 16 regions of interest. To differentiate patients with DLB, PD-D and AD discriminate analysis was conducted.ResultsSPECT showed global hypoperfusion in all patient groups when compared to control group. In DLB perfusion was significantly lower within the left temporal region as compared to AD and within the right parietal region, left temporo-occipital junction and left thalamus as compared to PD-D. A significant decrease of perfusion in both thalami was found in PD-D in comparison to AD. Discriminate analysis allowed for the proper classification in 68% of all patients: PD-D was classified the most accurately (83%) and DLB with least precision (46%).Conclusions99mTc-ECD SPECT did not allow us to differentiate precisely among DLB, PD-D and AD. Overlapping neuropathological features of DLB, PD-D and AD may account for this pattern of perfusion.