Sensitivity and specificity of cardiac I-MIBG scintigraphy for diagnosis of early-phase Parkinson's disease.

INTRODUCTION

The purpose of this study was to investigate the diagnostic accuracy of cardiac I-metaiodobenzylguanidine (MIBG) scintigraphy for the diagnosis of Parkinson's disease (PD), especially in the early stages.

METHODS

We investigated 600 patients who underwent cardiac I-MIBG scintigraphy to diagnose their parkinsonism and/or cognitive impairment. Of 600 research subjects, 272 patients were clinically diagnosed with PD. MIBG uptake was compared between patients with PD and other diseases. Furthermore, the sensitivity and specificity of cardiac I-MIBG scintigraphy to diagnose PD was estimated by disease duration (<3 years: early group vs. over 3 years: late group). We also assessed the relationship between MIBG uptake and Hoehn & Yahr stage.

RESULTS

MIBG uptakes of PD patients were significantly decreased compared with those of other diseases except dementia with Lewy bodies and pure autonomic failure (p < .05 for all). In the early group, the sensitivity and specificity of the delayed heart to mediastinum (H/M) ratio were 68.7% and 91.7%, respectively, while in the late group, the sensitivity was 86.3% and the specificity was 74.0%. In addition, the early and delayed H/M ratios were decreased with higher Hoehn & Yahr stages in PD patients.

CONCLUSION

Our findings demonstrated that cardiac I-MIBG scintigraphy had sufficient diagnostic accuracy to detect the early phase of PD. Indeed, this study of a large number of patients provides further external validation that MIBG has diagnostic ability to distinguish PD from atypical parkinsonism.