Synthetic MRI for Quantitative Assessment of Intrinsic Alterations in Upper Airway Tissues in Obstructive Sleep Apnea

Background : Non-invasive quantitative assessment of intrinsic upper airway tissue alterations in patients with obstructive sleep apnea (OSA) is vital for mechanistic research. This study aims to evaluate the application of synthetic MRI (SyMRI) in this field. Methods : This was a cross-sectional study that prospectively collected data from a single centre. Participants, both with and without OSA, underwent SyMRI of the upper airway to measure quantitative changes in the intrinsic properties (T1, T2, and PD values) of the soft palate and tongue.These changes were annotated using the IDEAL-IQ MRI sequence and histopathology methods, including Masson, H&E and Oil Red O staining. Results : 125 (82 OSA and 43 non-OSA) participants were enrolled. Patients with OSA exhibited higher T2 value in the soft palate and higher T2 and PD values in the tongue compared to non-OSA participants. SyMRI parameters were correlated with the fat fraction derived from IDEAL-IQsequence. A positive correlation was observed between the T2 value and the area of fat, mucous gland and fibrosis in the soft palate. T2 and PD values of tongue showed independent relationship with AHI. The area under curve (AUC) values of T2 and PD of tongue were 0.756. Conclusion : SyMRI could act as an effective noninvasive method to quantify inherent alterations of upper airway tissues in OSA, such as fat infiltration, fibrosis, and mucous gland hypertrophy. SyMRI parameters hold promise as the image biomarker, providing valuable information for differentiating various OSA subtypes and thereby promoting personalized treatment.