title: Upper Airway Elasticity Estimation in Pediatric Down Syndrome Sleep Apnea Patients Using Collapsible Tube Theory.
abstract: Elasticity of the soft tissues surrounding the upper airway lumen is one of the important factors contributing to upper airway disorders such as snoring and obstructive sleep apnea. The objective of this study is to calculate patient specific elasticity of the pharynx from magnetic resonance (MR) images using a 'tube law', i.e., the relationship between airway cross-sectional area and transmural pressure difference. MR imaging was performed under anesthesia in children with Down syndrome (DS) and obstructive sleep apnea (OSA). An airway segmentation algorithm was employed to evaluate changes in airway cross-sectional area dilated by continuous positive airway pressure (CPAP). A pressure-area relation was used to make localized estimates of airway wall stiffness for each patient. Optimized values of patient specific Young's modulus for tissue in the velopharynx and oropharynx, were estimated from finite element simulations of airway collapse. Patient specific deformation of the airway wall under CPAP was found to exhibit either a non-linear 'hardening' or 'softening' behavior. The localized airway and tissue elasticity were found to increase with increasing severity of OSA. Elasticity based patient phenotyping can potentially assist clinicians in decision making on CPAP and airway or tissue elasticity can supplement well-known clinical measures of OSA severity.
authors: Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA.
authors: Dhananjay Radhakrishnan
authors: DR
authors: Subramaniam
authors: Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA.
authors: Goutham
authors: G
authors: Mylavarapu
authors: Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors: Keith
authors: K
authors: McConnell
authors: Division of Pediatric Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors: Robert J
authors: RJ
authors: Fleck
authors: Department of Pediatric Otolaryngology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors: Sally R
authors: SR
authors: Shott
authors: Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.|Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.
authors: Raouf S
authors: RS
authors: Amin
authors: Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA. ephraim.gutmark@uc.edu.|UC Department of Otolaryngology-Head and Neck Surgery, Cincinnati, OH, USA. ephraim.gutmark@uc.edu.
authors: Ephraim J
authors: EJ
authors: Gutmark
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology; D004548:Elasticity; D004562:Electrocardiography; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010614:Pharynx / Q000000981:diagnostic imaging / Q000503:physiopathology; D012891:Sleep Apnea Syndromes / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: CPAP; Elastic modulus; Finite element analysis; MRI; OSA; Tube law