Iodine-123 Metaiodobenzylguanidine Scintigraphy and Iodine-123 Ioflupane Single Photon Emission Computed Tomography in Lewy Body Diseases: Complementary or Alternative Techniques?

PURPOSE: To compare myocardial sympathetic imaging using (123) I-Metaiodobenzylguanidine (MIBG) scintigraphy and striatal dopaminergic imaging using (123) I-Ioflupane (FP-CIT) single photon emission computed tomography (SPECT) in patients with suspected Lewy body diseases (LBD). METHODS: Ninety-nine patients who performed both methods within 2 months for differential diagnosis between Parkinson's disease (PD) and other parkinsonism (n= 68) or between dementia with Lewy bodies (DLB) and other dementia (n= 31) were enrolled. Sensitivity, specificity, accuracy, positive and negative predictive values of both methods were calculated. RESULTS: For (123) I-MIBG scintigraphy, the overall sensitivity, specificity, accuracy, positive and negative predictive values in LBD were 83\%, 79\%, 82\%, 86\%, and 76\%, respectively. For (123) I-FP-CIT SPECT, the overall sensitivity, specificity, accuracy, positive and negative predictive values in LBD were 93\%, 41\%, 73\%, 71\%, and 80\%, respectively. There was a statistically significant difference between these two methods in patients without LBD, but not in patients with LBD. CONCLUSIONS: LBD usually present both myocardial sympathetic and striatal dopaminergic impairments. (123) I-FP-CIT SPECT presents high sensitivity in the diagnosis of LBD; (123) I-MIBG scintigraphy may have a complementary role in differential diagnosis between PD and other parkinsonism. These scintigraphic methods showed similar diagnostic accuracy in differential diagnosis between DLB and other dementia.