Diagnostic accuracy of DAT-SPECT and MIBG scintigraphy for dementia with Lewy bodies: an updated systematic review and Bayesian latent class model meta-analysis

Purpose: Imperfect clinical reference standards can preclude accurately estimating the diagnostic accuracy of DAT-SPECT and MIBG myocardial scintigraphy for diagnosing DLB. To investigate the validity of unadjusted accuracy, we updated our previous meta-analysis. Methods: Literature search was updated to March 18, 2018. We also examined published systematic review reports. Two investigators extracted data and rated study validity using the QUADAS-2 tool. We performed a Bayesian latent class model meta-analysis accounting for imperfect reference standards. Results: We evaluated 27 studies including 2236 patients. With the exception of two DAT-SPECT studies that involved postmortem neuropathological verification, studies were susceptible to bias from imperfect reference standards. Compared with the unadjusted accuracy estimates, the adjusted sensitivity values were similar, whereas the adjusted specificity values were generally lower for detecting α-synuclein pathology in the brain. The adjusted summary sensitivity and specificity were 0.86 (95% credible interval [CrI], 0.76–0.95) and 0.81 (CrI, 0.70–0.92), and 0.93 (CrI, 0.74–1.00) and 0.75 (CI, 0.47–0.94) for visual and semi-quantitative assessments of DAT-SPECT, respectively; 0.92 (CrI, 0.81–0.99) and 0.80 (CrI, 0.67–0.93), and 0.87 (CrI, 0.74–0.98) and 0.80 (CrI, 0.69–0.93), for delayed- and early-phase scans of MIBG scintigraphy, respectively. When diagnosing the typical clinical syndrome, the adjusted accuracy values were similar to the unadjusted estimates. The adjusted sensitivity and specificity were 0.89 (CrI, 0.75–0.98) and 0.87 (CrI, 0.72–0.97), and 0.97 (CrI, 0.78–1.0) and 0.70 (CrI, 0.43–0.92) for visual and semi-quantitative assessments of DAT-SPECT, respectively; and 0.93 (CrI, 0.81–0.98) and 0.90 (CrI, 0.73–0.97), and 0.85 (CrI, 0.66–0.96) and 0.96 (95% CI, 0.83–1.0) for delayed- and early-phase scans of MIBG scintigraphy, respectively. Conclusions: In our adjusted analyses, both imaging biomarkers had high diagnostic accuracy for detecting the hallmark pathology in the brain and for diagnosing the typical clinical syndrome.