Neuroimaging markers of cerebral small-vessel disease in obstructive sleep apnea: a narrative review

Abstract Obstructive Sleep Apnea (OSA) is a common sleep-related breathing disorder marked by upper airway obstruction, fragmented sleep, intermittent hypoxia, and sympathetic overactivity. Growing evidence supports the link between OSA and cerebral small vessel disease (CSVD), highlighting common mechanisms, including oxidative stress, endothelial dysfunction, inflammation, and disrupted cerebral perfusion. CSVD has a wide range of systemic and neurological manifestations, namely stroke and cognitive decline. The shared biological mechanisms between OSA and CSVD may contribute to some similar patterns on neuroimaging, and the OSA severity is strongly related to CSVD markers, for instance, white matter hyperintensities (WMH) represent the most correlated one, lacunes, enlarged perivascular spaces (EPVS), cerebral microbleeds (CMBs), and silent cerebral infarcts (SCI). Knowledge and early detection of neuroimaging biomarkers in patients with OSA may facilitate early diagnosis of CSVD. However, advanced neuroimaging modalities, including diffusion tensor imaging (DTI), functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), transcranial Doppler sonography (TCD), and arterial spin labeling (ASL), can also be utilized to detect microvascular CNS changes, and may inform early and precise diagnosis, as well as support the development of personalized and accurate prognostic and therapeutic plan for patients with OSA. Moreover, tracking neuroimaging biomarkers of CSVD throughout OSA treatment, i.e., continuous positive airway pressure (CPAP), may help to gauge the efficacy of OSA treatment on brain health. The multidisciplinary approach for the management of OSA and CSVD emphasizes the requirement for a standard neuroimaging protocol for the OSA population. Monitoring the pick width of skeletonized mean diffusivity (PSMD) and machine-learning-based strategies of perivascular spaces are the frontiers in the field of OSA and CSVD connection. Therefore, novel neuroimaging modalities facilitate early CSVD detection, enable tracking of how effectively OSA therapy reduces CSVD burden, and result in clinical applications for developing neuroprotective methods, preventing stroke, avoiding cognitive deterioration, and leading to enhanced quality of life (QOL) in patients with OSA.