123I-MIBG Myocardial Scintigraphy for Differentiating Parkinson's Disease from Other Neurodegenerative Parkinsonism: a Systematic Review and Meta-analysis

Objectives: Differential diagnosis of Parkinson's disease (PD) and other neurodegenerative parkinsonism by clinical consensus criteria and diagnostic imaging is often difficult. (123)I-meta-iodobenzylguanidine ((123)I-MIBG) myocardial scintigraphy is a useful imaging tool for differentiating PD from other parkinsonism. The purpose of the present study is to systematically review and perform a meta-analysis of studies on the diagnostic performance of (123)I-MIBG myocardial scintigraphy for the differential diagnosis of PD and other neurodegenerative parkinsonism, specifically multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration.

Methods: A computer literature search of the PubMED/MEDLINE database was conducted to find relevant published articles on (123)I-MIBG myocardial scintigraphy for the differential diagnosis of PD and other neurodegenerative parkinsonism. We used the bivariate random-effects model to obtain the pooled estimates of the sensitivity and specificity and the corresponding 95% confidence intervals.

Results: Thirteen studies comprising 845 patients including 625 PD and 220 other neurodegenerative parkinsonism were analyzed. The pooled sensitivity and specificity to differentiate PD from other neurodegenerative parkinsonism by the early heart-to-mediastinum (H/M) ratio were 82.6% and 89.2%, respectively, and those by the delayed H/M ratio were 89.7% and 82.6%, respectively. When PD was limited to early stage (Hoehn-Yahr stage 1 or 2), the pooled sensitivity and specificity by the delayed H/M ratio were 94.1% and 80.2%, respectively.

Conclusions: The present meta-analysis confirmed high sensitivity and specificity of (123)I-MIBG myocardial scintigraphy for differentiating PD from other neurodegenerative parkinsonism in both early and delayed imaging phases. Furthermore, (123)I-MIBG myocardial scintigraphy was highly effective for distinguishing early PD.