Using standardized ultrasound imaging to correlate OSA severity with tongue morphology

Background: Ultrasound imaging has been explored as a potential diagnostic tool for obstructive sleep apnea (OSA); we reported backscatter ultrasound imaging (BUI) of the tongue correlates with OSA severity in adults. We focus on anatomical features of the tongue using standardized ultrasonography and hypothesize that differences in morphology correlate with OSA severity.

Methods: This prospective study was IRB approved (53,172) and conducted at Stanford University Sleep Surgery Clinic. Patients ≥18 years with polysomnography (PSG) underwent a standardized submental ultrasound scan using a laser alignment tool to observe the upper airway in supine position during tidal respiration. Images acquired from this scan were divided into 4 equiangular regions (A-D).

Results: A total of 144 patients (30 women) July 2020-December 2022 were included with mean age 41.6 years (±12.9 SD), BMI 27.2 kg/m²(±4.7 SD), and AHI 19.7 (±20.0 SD). Moderate-to-severe OSA patients had significantly narrower airspace at regions A, B and C with p-values ranging from <0.0001 to 0.0003. These patients had a significantly wider (p = 0.0021-0.0045 for regions A, B and C) tongue and thicker (p = 0.0403 for region B) deep tissue. The predictive model to assess the risk of moderate-to-severe OSA achieved an area under the receiver operating characteristic curve of 0.839 (95 % CI: 0.769 to 0.895).

Conclusions: With standardized, computerized ultrasound imaging of the shape and configuration of the tongue, we identified regions that correlated well with OSA severity. Further research is needed to determine the clinical implications of such pathophysiological findings.