Iobenguane I-123

Metaiodobenzylguanidine (MIBG) is an analog of norepinephrine that accumulates in sympathetic nerve endings soon after intravenous administration. The degree of accumulation reflects the uptake, storage and release of transmitters by noradrenergic neurons. Myocardial imaging with ¹²³I labeled MIBG ( ¹²³I-MIBG) can be used to estimate the extent of local myocardial sympathetic nerve damage, which has been widely used in the diagnosis and treatment of various heart diseases. In recent years, numerous studies have been carried out on the application of ¹²³I-MIBG in the diagnosis of degenerative diseases of the nervous system (such as Parkinson's disease and dementia of Lewy body), and have made some achievements. The purpose of this review is to summarize the current clinical application of ¹²³I-MIBG myocardial imaging in the diagnosis of dementia with Lewy bodies, the problems in imaging technology and the possible research directions in the future, so as to provide valuable reference information for clinicians to reasonably and accurately apply this technology in the early diagnosis and discrimination of dementia.

¹²³I-metaiodobenzylguanidine (MIBG) cardiac scintigraphy was a useful imaging modality for the diagnosis of Parkinson's disease, but its diagnostic performances were variably reported. This retrospective study compared the diagnostic performances and investigated the optimal imaging protocol of ¹²³I-MIBG cardiac scintigraphy at various imaging time points in patients suspected of Parkinson's disease in clinical practice.

In patients suspected of Parkinson's disease, clinical records, autonomic function tests, and ¹²³I-MIBG cardiac scintigraphy were retrospectively reviewed. Semi-quantitative parameters such as heart-to-mediastinum ratio (HMR) and washout rate (WR) were calculated and compared at 15 min, 1 h, 2 h, 3 h, and 4 h post-injection (p.i.). of ¹²³I-MIBG cardiac scintigraphy. Group A consisted of Parkinson's disease (PD), Parkinson's disease dementia (PDD), and dementia with Lewy body (DLB), and group B consisted of non-Parkinson's diseases such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), drug-induced parkinsonism (DIP), essential tremor (ET), Parkinson-plus syndrome (PPS), and unspecified secondary parkinsonism (NA). The diagnostic performances of HMR and WR were compared for differentiation of group A from group B, and their clinical usefulness and optimal imaging time points were explored.

Seventy-eight patients were included in group A (67 PD, 7 PDD, 4 DLB), and 18 patients were included in group B (5 MSA, 3 PSP, 2 DIP, 2 ET, 1 PPS, and 1 NA). Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value of HMR and WR were maximized at 4 h p.i., (82.1%, 85.7%, 82.6%, 97.0%, and 46.2%; cutoff threshold < 1.717; area under curve 0.8086) and at the time interval between 1 and 4 h p.i. (65.4%, 85.7%, 68.5%, 96.2%, and 30.8%; cutoff threshold > 24.1%; area under curve 0.8246), respectively, and PPVs of both HMR and WR persistently showed greater than 92.7% at earlier time points and shorter time intervals.

This study reassured that 4-h-delayed imaging is recommended for the best diagnostic performances in ¹²³I-MIBG cardiac scintigraphy. Although it showed suboptimal diagnostic performances to differentiate PD, PDD, and DLB from non-Parkinson's diseases, it can be useful as an auxiliary measure for the differential diagnosis in usual clinical practice.

The online version contains supplementary material available at 10.1007/s13139-023-00790-w.