Cone Beam Computed Tomography Analysis of Upper Airway Measurements in Patients With Obstructive Sleep Apnea

Abstract

Purpose: To explore the validity of cone beam computed tomography (CBCT) as one of many predictive tools that can be used (alone or in conjunction) to help in identifying high-risk cases of obstructive sleep apnea (OSA) that should get the earliest possible referral to a sleep specialist for standard diagnostic polysomnography, and to identify imaging airway parameters that may be predictive of OSA severity.

Methods: Using a case-control design, 45 subjects matched by age and sex (22 OSA cases and 23 controls) were included in this study. Subjects were assigned as cases depending on a sleep study with apnea-hypopnea index (AHI)>5 and as controls depending on a Berlin questionnaire score identifying low risk or no risk of OSA. All subjects had CBCT scans. Airway and craniofacial parameters as assessed by CBCT were compared between the 2 groups. Significant CBCT variables were entered into a logistic regression model to identify risk factors of OSA and the correlations of variables with AHI were evaluated using multiple linear regression. For all tests P ≤ 0.05 was considered statistically significant.

Results: OSA cases had larger body mass index and neck circumference than controls. OSA cases showed significantly smaller airway narrowest cross-sectional areas (CSAs) (P < 0.05) and larger posterior nasal spine and the second cervical vertebrae distances (P < 0.001) than those in controls. Airway narrowest CSA showed a significant negative correlation with AHI (r = -0.653, P = 0.001) and was a significant variable for predicting the AHI of OSA cases in multiple regression analysis.

Conclusions: The importance of the narrowest CSA and posterior nasal spine and the second cervical vertebrae distance in the pathogenesis of OSA has been highlighted in the present study. We can conclude that CBCT can provide findings that entail earlier referral of suspected patients with OSA for further assessment.

Keywords: Airway cross-sectional area; Airway length, Total airway volume; Cone beam computed tomography; Obstructive sleep apnea.