Value of multi-parameter I-MIBG scintigraphy in the differential diagnosis of Parkinson's disease.

BACKGROUND

I-MIBG scintigraphy plays a significant role in diagnosing Parkinson's disease (PD), with most studies primarily targeting cardiac uptake and relying on traditional ratio-based parameters for assessment. However, due to variations in scanning conditions and image processing methodologies, the clinical utility of different parameters remains a subject of debate. This study aims to evaluate the diagnostic accuracy of multi-parameter I-3-Iodobenzylguanidine (MIBG) scintigraphy and to identify the most reliable metrics for distinguishing PD from Parkinson-plus syndromes.

RESULT

We recruited 56 PD patients and 44 non-PD controls, who underwent I-MIBG scintigraphy and clinical evaluation. MIBG uptake and washout rates (WR) for the heart, salivary glands, and thyroid were assessed, with semi-quantitative methods used to calculate heart-to-mediastinum (H/M) and gland-to-background (P/B, S/B, T/B) ratios. Diagnostic efficacy was evaluated using receiver operating characteristic (ROC) curves. The H/M ratio and cardiac WR parameters scintigraphy exhibited excellent diagnostic efficacy for PD and PPS. The 4 h H/M ratio showed superior diagnostic performance with an area under the ROC curve (AUC) of 0.980. Background and time decay correction improved cardiac WR diagnostic performance (AUC = 0.963). Although P/B, S/B, and T/B ratios showed no significant differences for differential diagnosis, the WR values of the parotid and thyroid glands exhibited moderate diagnostic efficacy with AUCs of 0.648 and 0.638, respectively.

CONCLUSION

The heart H/M ratio and cardiac WR in I-MIBG scintigraphy show high diagnostic efficacy for both diagnosing and differentiating PD. Including cardiac WR in routine assessments is recommended. The diagnostic potential of WR in the parotid and thyroid glands also holds promise for PD diagnosis. Incorporating these parameters could enhance the accuracy of PD diagnosis, particularly in clinical scenarios where concurrent cardiac disease may confound the diagnosis.