Diagnostic Performance of Putaminal Hypointensity on Susceptibility MRI in Distinguishing Parkinson Disease from Progressive Supranuclear Palsy: A Meta‐Analysis

BACKGROUND: Idiopathic Parkinson's disease (IPD) and progressive supranuclear palsy (PSP) have similar clinical signs and symptoms, making accurate clinical diagnosis difficult. T2* gradient echo (T2* GRE), susceptibility‐weighted imaging (SWI), and quantitative susceptibility mapping (QSM) are susceptibility MR imaging sequences that provide more information about brain iron levels than other conventional MR imaging. OBJECTIVE: This study aimed to evaluate the diagnostic power of putaminal hypointensity on T2* GRE, SWI, and QSM in distinguishing PSP from IPD. METHODS: Eligible studies were identified via systematic searches of PubMed and Clarivate Analytics® Web of Science® Core Collection. Studies that satisfied the inclusion and exclusion criteria were reviewed. A meta‐analysis was conducted using the hierarchical summary receiver operating characteristic curve approach. RESULTS: Our literature search of the two databases yielded 562 primary articles, 10 of which were deemed relevant and only six were eligible for further analyses. We performed a meta‐analysis of putaminal hypointensity measurements: 438 patients with IPD and 109 patients with PSP were enrolled in the quantitative synthesis. The meta‐analysis of six studies with 547 patients revealed a sensitivity of 69% (95% confidence interval (CI): 33%–90%) and specificity of 91% (95% CI: 80%–96%) for putaminal hypointensity on T2* GRE, SWI, or QSM distinguishing PSP from IPD. CONCLUSIONS: Putaminal hypointensity on T2* GRE, SWI, or QSM is able to distinguish patients with PSP from those with IPD with high specificity. Further multicenter prospective studies on patients are needed to verify our results.