131I-MIBG myocardial scintigraphy in patients with Parkinson's disease

Background 131 I-metaiodobenzylguanidine ( 131 I-MIBG), which can be taken by cardiac sympathetic postganglionic fibers, is an imaging agent to assess the cardiac sympathetic nerve function. The present study is to assess the cardiac sympathetic nerve function of patients with Parkinson's disease (PD) by  131 I-MIBG myocardial scintigraphy and preliminarily explore its applications in the early diagnosis of PD.  Methods Twenty-one eligible PD patients (16 early PD and 5 late PD) and 9 normal controls were enrolled in the study. Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn-Yahr stage were used to evaluate the severity of PD. Planar images of chest were obtained at different time points (15 min, 4 h and 24 h) after injection of 3 mCi 131 I-MIBG, and then the 131 I-MIBG myocardial uptake ratios were calculated. Results 1) The 131 I-MIBG myocardial uptake ratios in PD group at 15 min (1.67 ± 0.38), 4 h (1.53 ± 0.47) and 24 h (1.35 ± 0.42) after injection were lower than those in the normal control group respectively ( P = 0.000, 0.000, 0.000), and the 131 I-MIBG myocardial uptake ratios in the PD group reduced over time ( P = 0.002, 0.000, 0.000). 2) The  131 I-MIBG myocardial uptake ratios in the early and late PD groups at 15 min [(1.73 ± 0.40) and (1.50 ± 0.30)], 4 h [(1.58 ± 0.51) and (1.37 ± 0.31)], 24 h [(1.39 ± 0.46) and (1.24 ± 0.29)] after injection were lower than those in the normal control group respectively (early PD: P = 0.000, 0.000, 0.000; late PD: P = 0.000, 0.000, 0.000), and the  131 I-MIBG myocardial uptake ratios in the early and late PD groups reduced over time (early PD: P = 0.012, 0.000, 0.000; late PD: P = 0.039, 0.001, 0.024).  Conclusions Cardiac sympathetic nerve damage could occur in PD patients, even at an early stage of PD.  131 I-MIBG myocardial scintigraphy may help in the early diagnosis of PD. DOI: 10.3969/j.issn.1672-6731.2016.06.008