Cardiac Scintigraphy in RBD

Abstract

Rapid eye movement sleep behavior disorder (RBD) is a heterogeneous disease entity consisting of a variety of manifestations. Patients with RBD demonstrate clinical and subclinical phenomena suggestive of impending α-synucleinopathy; when fully developed, these disorders manifest as either Parkinson’s disease (PD), multiple system atrophy (MSA), or dementia with Lewy bodies (DLB). In RBD, autonomic dysfunction is consistent with an evolving neurodegenerative disorder. Cardiovascular autonomic dysfunction is particularly common in idiopathic RBD, and cardiac 123I-meta-iodobenzylguanidine (MIBG) scintigraphy enables the quantification of postganglionic cardiac sympathetic innervation. A marked reduction in cardiac 123I-MIBG uptake has been found in most patients with idiopathic RBD compared to control subjects and patients with clinically diagnosed MSA, progressive supranuclear palsy, corticobasal degeneration, and Alzheimer’s disease but is similar to those with clinically diagnosed PD and DLB. Therefore, cardiac 123I-MIBG scintigraphy may be a very useful marker of idiopathic RBD (iRBD) with Lewy body-related syndrome.