MIBG Myocardial Scintigraphy can Predict the Occurrence of Wearing-off Phenomenon in Early-stage Parkinson’s Disease

Background: Iodine-123 metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy has been accepted as one of the most useful methods for the diagnosis of Parkinson’s disease (PD). Moreover, the accumulated evidence has indicated that the heart-to-mediastinum (H/M) ratio correlates with the disease severity of hypokinesia/ bradykinesia and rigidity. The present report describes the wearing-off predictions obtained from MIBG in patients with early-stage PD. Methods: 13 males and 10 females with PD whose onset ages between 45 and 70 years were enrolled. They were separated into two groups according to their H/M ratios (less than 1.7 or 1.7 or higher). We generated KaplanMeier survival curves for the times of the onset of the wearing-off phenomenon, and survival differences were analyzed by the log-rank test. The onset of the wearing-off phenomenon was defined as an event during the 71month observation. Results: There was a significant difference in the wearing-off occurrence between the 2 groups that were divided by the H/M ratio (P=0.016). This result might reflect the existence of PD patients who do not show reductions in the H/M ratios at earlier stages and who do not manifest the wearing-off phenomenon later. Conclusions: Our study suggests the possibility that patients with good prognoses represent those with almost normal H/M ratios, even though they are affected with PD. MIBG could be a valuable method for predicting prognoses as well as for diagnoses.