Shih-Jou, Chung, Yu-Wen Huang, Pei-Lin Lee, and Pai Chi, LiChung, Yu-Wen Huang, Pei-Lin Lee, and Pai Chi, LiShih-Jou2020-07-202020-07-202020-09https://scholars.lib.ntu.edu.tw/handle/123456789/510109Background, Motivation, Hypothesis/Goal, and Objectives Tongue hypertrophy and upper airway obstruction are important factors causing obstructive sleep apnea (OSA). However, direct ultrasound examinations of the retropharyngeal space have been challenging with limited clinical performance. Currently, the apnea-hypopnea index (AHI) and polysomnography (PSG) are commonly used in the clinical diagnosis but these procedures suffer from limited accuracy and/or long examination time. In this study, we propose a new ultrasound functional imaging approach by measuring dynamics of the tongue thickness deformation using 2D speckle tracking. Statement of Contribution/Methods The strains of the tongue muscle are measured as a function of time at pre-specified reference lines in both sagittal and coronal planes. 2D speckle tracking is performed on submental ultrasound images when the patient is awake. 30 severe and 60 mild-moderate OSA patients, 8 health and 12 health volunteers underwent ultrasound measurements of the tongue motion with normal breathing, Müller Maneuver and Maximum Tongue Pressure Measurement (TP), as well as clinical and polysomnographic assessments at the National Taiwan University Hospital. MRI was also performed for healthy volunteers. Two-third of patients were randomly selected for model-development group which were used to construct model for predicting severe OSA. The results were validated in remaining one-third of patients. Note that MM simulates the upper airway obstruction situation when awake and TP quantifies the Genioglossus muscle collapse level. Speckle tracking is used to determine the extent of muscle contraction. Results, Discussion and Conclusions Speckle tracking was performed to find the dynamic strain curves at anterior tongue (A), posterior tongue base (P) and maximum tongue base apex (TBA) during MM and TP as illustrated in Fig1. The TBA of TP results in Table 1 show that the proposed method is able to distinguish severe and non-severe OSA patients. The area under the receiver operating characteristic curve is 0.81, and sensitivity is 73%, specificity is 78 % for mild-moderate patients, and sensitivity is 80%, specificity is 81 % for severe patients (Table 2). The clinical potential of the proposed method for OSA diagnosis is demonstrated.conference paperconference paper