Diagnostic accuracy of cardiac metaiodobenzylguanidine scintigraphy in Parkinson disease

Background and purpose:  To estimate the diagnostic accuracy of cardiac 123I-metaiodobenzylguanidine (MIBG) scintigram for detection of Parkinson disease. Methods:  A cross-sectional study with index test of MIBG scintigram and reference standard of U.K. Parkinson’s Disease Brain Bank Criteria was performed in 403 patients. Ratio of cardiac-to-mediastinum MIBG accumulation was determined at 20 min (early H/M) and 4 h (late H/M). Area under the receiver-operator characteristic (ROC) curve, sensitivity and specificity in detecting Parkinson disease were analyzed. Accuracy was analyzed in a subgroup of patients with disease duration of 3 years or less. Results:  Area under the ROC curve was 0.89 using either early or late H/M as a diagnostic marker (95% CI 0.85–0.92 for early H/M and 0.86–0.93 for late H/M). Sensitivity and specificity were 81.3% (76.1–85.8%) and 85.0% (77.7–90.6%) for early H/M and 84.3% (79.3–88.4%) and 89.5% (83.01–94.1%) for late H/M. In the subgroup with duration of 3 years or less, the ROC curve area, sensitivity, and specificity were 0.86 (0.79–0.92), 76.0% (64.8–85.1%), and 83.9% (71.7–92.4%) for early H/M and 0.85 (0.78–0.92), 73.3% (61.9–82.9%), and 87.5% (75.9–94.8%) for late H/M. Conclusion:  Although diagnostic accuracy of cardiac MIBG scintigram is high, it is limited because of insufficient sensitivity in patients with short duration.