Ultrasound Shear-Wave Elastography of the Tongue in Adults with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a chronic breathing disorder characterized by intermittent sleep state-dependent upper airway (UA) collapse. The tongue comprises the primary UA dilator muscle and plays an essential role in the pathogenesis of OSA. We examined whether tongue stiffness measurement using ultrasound (US) shear wave elastography (SWE) is useful for predicting the existence of OSA. Forty-six participants (20 healthy controls and 26 patients with OSA) underwent transcutaneous submental SWE using a US system. Quantification with a shear modulus of 0–200 kPa was recorded during normal breathing and Müller's maneuver (MM). Polysomnography was used as the reference standard. Mid-sagittal tongue stiffness was significantly higher in awake patients with OSA than in controls during normal breathing and the MM (p < 0.0001). The posterior third of the tongue in patients with OSA had the highest value of shear modulus during the MM (p < 0.001). With cut-offs of 27.6 and 35.2 kPa for the whole tongue and posterior third during the MM, respectively, the sensitivity obtained was 69.2% and 76.9%, and the specificity was 85% and 95%, respectively, for detecting OSA. The corresponding areas under the receiver operating characteristic curve were 0.82 and 0.88, respectively. US SWE may have the potential for non-invasive tongue stiffness measurement in OSA.