Usefulness of combining ¹²³I-FP-CIT-SPECT striatal asymmetry index and cardiac ¹²³I-metaiodobenzylguanidine scintigraphy examinations for diagnosis of parkinsonisms

Background Although single-photon emission computerized tomography of the dopamine transporter (DAT-SPECT) is useful for diagnosing parkinsonian syndrome, its applicability toward the early phase of Parkinson's disease remains unknown. Methods We enrolled 32 patients showing parkinsonism with normal cardiac ¹²³I-metaiodobenzylguanidine (MIBG) uptake and abnormal DAT-SPECT findings among 84 consecutive patients with parkinsonism. We divided these patients into two groups (group 1: Parkinson's disease, group 2: corticobasal degeneration, progressive supranuclear palsy, multiple system atrophy), and compared their clinical characteristics, specific binding ratios, and striatal asymmetry indexes on DAT-SPECT examinations. Results The striatal asymmetry indexes were significantly lower in group 1 than in group 2 (p < 0.05), but there were no differences in the specific binding ratios between the two groups. Conclusion The combined use of striatal asymmetry index on DAT-SPECT and cardiac MIBG scintigraphy might offer useful clues for the differential diagnosis of the early phase Parkinson's disease from other parkinsonian syndromes.