title: Velopharyngeal mucosal surface topography in healthy subjects and subjects with obstructive sleep apnea.
abstract: Macroscopic pharyngeal anatomical abnormalities are thought to contribute to the pathogenesis of upper airway (UA) obstruction in obstructive sleep apnea (OSA). Microscopic changes in the UA mucosal lining of OSA subjects are reported; however, the impact of these changes on UA mucosal surface topography is unknown. This study aimed to1) develop methodology to measure UA mucosal surface topography, and2) compare findings from healthy and OSA subjects. Ten healthy and eleven OSA subjects were studied. Awake, gated (end expiration), head and neck position controlled magnetic resonance images (MRIs) of the velopharynx (VP) were obtained. VP mucosal surfaces were segmented from axial images, and three-dimensional VP mucosal surface models were constructed. Curvature analysis of the models was used to study the VP mucosal surface topography. Principal, mean, and Gaussian curvatures were used to define surface shape composition and surface roughness of the VP mucosal surface models. Significant differences were found in the surface shape composition, with more saddle/spherical and less flat/cylindrical shapes in OSA than healthy VP mucosal surface models (P< 0.01). OSA VP mucosal surface models were also found to have more mucosal surface roughness (P< 0.0001) than healthy VP mucosal surface models. Our novel methodology was utilized to model the VP mucosal surface of OSA and healthy subjects. OSA subjects were found to have different VP mucosal surface topography, composed of increased irregular shapes and increased roughness. We speculate increased irregularity in VP mucosal surface may increase pharyngeal collapsibility as a consequence of friction-related pressure loss.NEW & NOTEWORTHYA new methodology was used to model the upper airway mucosal surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was used to analyze the topography of the models, and a new metric was derived to describe the mucosal surface roughness. Increased roughness was found in the obstructive sleep apnea vs. healthy group, but further research is required to determine the functional effects of the measured difference on upper airway airflow mechanics.
authors.affiliation: Ludwig Engel Centre for Respiratory Research, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia; chris.lambeth@sydney.edu.au.
authors.forename: Christopher
authors.initials: C
authors.lastname: Lambeth
authors.affiliation: Ludwig Engel Centre for Respiratory Research, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.|University of Sydney at Westmead Hospital, Sydney, New South Wales, Australia.|Neuroscience Research Australia and School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Jason
authors.identifier: http://orcid.org/0000-0001-8728-1279
authors.initials: J
authors.lastname: Amatoury
authors.affiliation: University of Sydney, Sydney, New South Wales, Australia; and.
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Radiology, Westmead Hospital, Sydney, New South Wales, Australia.|University of Sydney at Westmead Hospital, Sydney, New South Wales, Australia.
authors.forename: Sheryl
authors.initials: S
authors.lastname: Foster
authors.affiliation: Ludwig Engel Centre for Respiratory Research, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.|University of Sydney at Westmead Hospital, Sydney, New South Wales, Australia.
authors.forename: Terence
authors.initials: T
authors.lastname: Amis
authors.affiliation: Ludwig Engel Centre for Respiratory Research, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.|University of Sydney at Westmead Hospital, Sydney, New South Wales, Australia.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kairaitis
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D008954:Models, Biological; D010614:Pharynx / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D020545:Respiratory Mucosa / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D013499:Surface Properties
keywords: curvature analysis; obstructive sleep apnea; surface reconstruction; surface topography; upper airway modeling