The diagnostic value of SNpc using NM-MRI in Parkinson's disease: meta-analysis

The main purpose of this study was to systematically evaluate the accuracy of neuromelanin-sensitive magnetic resonance imaging (NM-MRI) in Parkinson's disease (PD) diagnosis using a meta-analysis method. In PubMed, Web of Science, Embase, and Google Scholar, the literatures were searched for the diagnostic value of neuromelanin-sensitive magnetic resonance imaging in PD. The literatures were screened in the light of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Data analysis was processed by Stata 12.0 software to obtain meta-analysis, heterogeneity analysis, and publication bias. Meta-analysis results showed by using NM-MRI observed substantia nigra pars compacta (SNpc) on PD, the pooled diagnostic sensitivity and specificity were 0.82 (95% CI, 0.74-0.87) and 0.82 (95% CI, 0.73-0.89), respectively. And the pooled positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 4.58 (95% CI, 3.08-6.82) and 0.22 (95% CI, 0.16-0.31), respectively. Moreover, subgroup analysis according to the measurement criteria of SNpc showed the SNpc volume should be used as good a marker for diagnosing PD. Finally, Fagan test demonstrated that when PLR was equal to 5, the posterior probability is significantly enhanced to 53%, compared with prior probability (20%). As for NLR (0.22), the prior probability is 20%, while the posterior probability remarkably dropped to 5%. In conclusion, SNpc signal detected by NM-MRI exhibited high sensitivity and specificity for diagnosis of PD, which was a high-performance imaging diagnostic method for PD. We recommend NM-MRI imaging technology to be widely used in Parkinson's diagnosis.