Importance of 123I-ioflupane SPECT and Myocardial MIBG Scintigraphy to Determine the Candidate of Deep Brain Stimulation for Parkinson’s Disease

(123)I-ioflupane SPECT (DaTscan) is an examination that detects presynaptic dopamine neuronal dysfunction, and has been used as a diagnostic tool to identify degenerative parkinsonism. Additionally, myocardial (123)I-metaiodobenzyl guanidine (MIBG) scintigraphy measures the concentration of cardiac sympathetic nerve fibers and is used to diagnose Parkinson's disease (PD). These exams are used as adjuncts in the diagnosis of parkinsonism, however, the relationship of these two examinations are not well-known. We investigated the relationship of these two scanning results specifically for determining the use of deep brain stimulation therapy (DBS). Subjects were Japanese patients with suspected striatonigral degeneration, including PD; DaTscans and myocardial MIBG scintigraphy were performed. The mean values of the left-right specific binding ratios (SBRs) from the DaTscan, and the early/delayed heart-to-mediastinum ratios (HMRs) from the MIBG scintigraphy were calculated. Using simple linear regression analysis, we compared the SBR and early/delayed HMR values. Twenty-four patients were enrolled in this study. Twenty-one patients were positive via the DaTscan, and the MIBG scintigraphy results showed 14 patients were positive. SBR and both early and delayed HMR were positively correlated in cases of PD, but negative in non-PD cases. A mean SBR value less than 3.0 and a delayed HMR value less than 1.7 indicated a Hoehn-Yahr stage 3 or 4 for PD, which is commonly regarded as a level appropriate for initiating DBS therapy. Our results indicate that performing both DaTscan and MIBG scintigraphy is useful for the evaluation of surgical intervention in PD.