ABSTRACT:Background:Idiopathic rapid eye move-ment sleep behavior disorder is an early sign of neurodegen-erative disease. This study aimed to quantitatively evaluateiron content in idiopathic rapid eye movement sleep behaviordisorder patients using quantitative susceptibility mappingand to examine the potential of this technique to identify theprodromal stage ofα-synucleinopathies.Methods:Twenty-five idiopathic rapid eye movement sleepbehavior disorder patients, 32 Parkinson’s disease patients,and 50 healthy controls underwent quantitative susceptibilitymapping. The mean magnetic susceptibility values withinthe bilateral substantia nigra, globus pallidus, red nucleus,head of the caudate nucleus,and putamen were calculatedand compared among groups. The relationships betweenthe values and the clinical features of idiopathic rapid eyemovement sleep behaviordisorder and Parkinson’s diseasewere measured using correlation analysis.Results:Idiopathic rapid eye movement sleep behavior dis-order patients had elevated iron in the bilateral substantianigra compared with healthy controls. Parkinson’sdiseasepatients had increased iron in the bilateral substantia nigra,globus pallidus, and left red nucleus compared with healthycontrols and had elevated iron levels in the bilateral sub-stantia nigra compared with idiopathic rapid eye movementsleep behavior disorder patients. Mean magnetic suscepti-bility values were positively correlated with disease durationin the left substantia nigra in idiopathic rapid eye movementsleep behavior disorder patients.Conclusions:Quantitative susceptibility mapping candetect increased iron in the substantia nigra in idiopathicrapid eye movement sleep behavior disorder, whichbecomes more significant as the disorder progresses. Thistechnique has the potential to be an early objective neuro-imaging marker for detectingα-synucleinopathies. © 2019International Parkinson and Movement Disorder Society
Key Words:idiopathic rapid eye movement sleepbehavior disorder (iRBD); iron content; Parkinson’s dis-ease (PD); quantitative susceptibility mapping (QSM)
