Resting cerebral blood flow alteration in severe obstructive sleep apnoea: an arterial spin labelling perfusion fMRI study

The aim of this study is to investigate changes in regional cerebral blood flow (rCBF) in awake people with untreated severe obstructive sleep apnoea (OSAs) compared with good sleepers (GSs). Arterial spin labelling perfusion imaging was used to quantify cerebral perfusion based on resting-state functional magnetic resonance imaging (MRI). Lying supine in a 3.0-T magnetic resonance imaging scanner in the night was done. Included in this study were 30 subjects with OSA (males; mean age 38.4 years, range 25-55) and 30 controls (males; mean age: 38.3 years, range 26-52) matched for age and years of education. Compared with GSs, participants with severe OSA had reduced rCBF in the left cerebellum posterior lobe, left temporal lobe, right medial frontal gyrus, and bilateral parahippocampal gyrus and increased rCBF in the bilateral superior frontal gyrus. The lower mean CBF in the right parahippocampal gyrus exhibited a significant positive correlation with arousal index (r = 0.365, P = 0.047). The increased mean CBF in the left superior frontal gyrus exhibited a significant positive correlation with the longest apnoea time (r = 0.422, P = 0.020), and the increased mean CBF in the right superior frontal gyrus exhibited a significant positive correlation with the longest apnoea time (r = 0.447, P = 0.013). Our results show that the altered rCBF pattern in the left cerebellum posterior lobe, left temporal lobe, left medial frontal gyrus, bilateral parahippocampal gyrus and superior frontal gyrus in patients have with severe OSA. The arterial spin labelling perfusion imaging method is a useful non-invasive imaging tool for detection of early changes in the regional cerebral blood flow in patients with OSA.