The association between small vessel disease and obstructive sleep apnea: a peak width of skeletonized mean diffusivity-based study

Purpose Peak width of skeletonized mean diffusivity (PSMD) is a novel marker of small vessel disease in the brain. This study aimed to investigate the association between small vessel disease and obstructive sleep apnea (OSA) using PSMD. Methods We enrolled patients with OSA and age- and sex-matched healthy controls, and performed diffusion tensor imaging (DTI) using a 3-tesla MRI scanner in them. We calculated the PSMD based on DTI in several steps, including preprocessing, skeletonization, application of a custom mask, and histogram analysis using the FSL program. We compared the PSMD between patients with OSA and healthy controls and investigated the correlation between PSMD and clinical factors. Results Thirty-nine patients with OSA (apnea-hypopnea index > 5; mean = 20.5) and 48 healthy controls were enrolled. The PSMD was significantly higher in patients with OSA than that in the healthy controls (2.521 vs. 2.320 x 10(- 4) mm(2)/s, p = 0.013). In addition, PSMD positively correlated with age (r = 0.512, p < 0.001) and body mass index (r = 0.472, p = 0.002). However, PSMD was not associated with polysomnographic measurements. Conclusions The mean PSMD is higher in patients with OSA than that in healthy controls, indicating a white matter injury due to small-vessel disease in patients with OSA. Our study highlights the importance of actively diagnosing and treating OSA. In addition, PSMD can be used to determine the relationship between sleep disorders and small vessel disease.