Cortical hypoperfusion in patients with idiopathic rapid eye movement sleep behavior disorder detected with arterial spin-labeled perfusion MRI

Idiopathic rapid eye movement sleep behavior disorder (iRBD) is an important risk factor for α-synucleinopathy. We investigated alterations in the cerebral blood flow (CBF) based on arterial spin-labeled (ASL) imaging in patients with iRBD to determine brain perfusion changes associated with the disorder. Fifteen patients with iRBD and twenty age–gender-matched healthy controls were enrolled. Cortical perfusions were compared between the two groups after the ASL data was co-registered to the high-resolution T1-weighted images. No significant differences were detected between the groups in regard to age, gender, education, or UPDRS-III score. The iRBD group showed a lower MMSE score than the healthy controls (27.07 ± 2.25 vs. 28.55 ± 1.23, p < 0.05). Compared with the healthy controls, the iRBD group showed significantly decreased CBF values in the right inferior frontal gyrus, right middle frontal gyrus, and right insula (p < 0.05 corrected). The cortical hypoperfusion areas in patients with iRBD were similar to the patterns in patients with α -synucleinopathies. ASL perfusion MRI is a potential approach to find biomarkers in preclinical stages of α -synucleinopathies.