0550 Dynamic Upper Airway MRI (DUAM) of OSA During Natural Sleep Is Suitable for Clinical Use

Abstract Introduction Accurate determination of the collapse pattern of upper airway is a prerequisite for some obstructive sleep apnea (OSA) therapies. Dynamic upper airway magnetic resonate imaging (DUAM) is a powerful research tool and can quantify the collapse pattern in high resolution. However, DUAM has not been applied in clinical arena, partly due to a common assumption that MRI is too loud to allow natural sleep. We aim to develop and validate a pragmatic, patient-friendly protocol of DUAM during natural sleep. Methods Unselected patients with diagnosed moderate or severe OSA were recruited. Each MRI session started within two hours after the self-reported usual sleep onset time, and comprised 8-minute DUAM scans that acquired multiple axial slices over the upper airway (2x2x6 mm, 0.18 s resolutions), separated by 1-minute technical breaks. Patient was instructed to stay awake for the first DUAM scan, then sleep during all remaining scans. To maximize comfort, only oxygen saturation (SpO2), pulse rate, chest and abdomen movements were recorded. In post-processing, OSA events were scored as events with >= 3% or 2% drops of SpO2 and concurrent characteristic changes in chest and/or abdomen motion. Results Ten patients (age: 33-54 years; all male by coincidence) were recruited as of December 2025. All (100%) completed the study. After the first six 8-minute DUAM scans (including the awake first scan), six patients (60%) showed at least 16 OSA events with >= 3% SpO2 drop (mean: 38, std.: 12 events). For the other patients, when using the criterion of >= 2% SpO2 drop, there were 14, 17, 18, 27 OSA events in each patient respectively. When surveyed after the MRI, patients commonly cited loud noise and back discomfort from having to lie supine as factors that may prohibit sleep. Conclusion In unselected patients with moderate or severe OSA, a one-hour MRI session comprising 40 minutes of DUAM with attempted natural sleep sufficiently captures upper airway collapse events with >= 2% oxygen desaturation. Thus, DUAM of OSA during natural sleep is clinically practical. While the standard MRI setup is well tolerated, noise abatement and allowing non-supine positions would enhance the patient experience. Support (if any) NIH R01-HL173483 (Lingala); AASM (Liu)