Published ahead of print on October 20, 2005, doi:10.1164/rccm.200507-1148OC
© 2006 American Thoracic Society doi: 10.1164/rccm.200507-1148OC
Quantitative Upper Airway Imaging with Anatomic Optical Coherence TomographyOptical+Biomedical Engineering Laboratory, School of Electrical, Electronic, and Computer Engineering, and School of Anatomy and Human Biology, University of Western Australia, Crawley; and West Australian Sleep Disorders Research Institute, Department of Pulmonary Physiology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia Correspondence and requests for reprints should be addressed to Julian Armstrong, B.Sc., B.E. (Hons), Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic, and Computer Engineering, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009. E-mail: julian-a{at}ee.uwa.edu.au Background: Measurements of upper airway size and shape are important in investigating the pathophysiology of obstructive sleep apnea (OSA) and in devising, applying, and determining the effectiveness of treatment modalities. We describe an endoscopic optical technique (anatomic optical coherence tomography, aOCT) that provides quantitative real-time imaging of the internal anatomy of the human upper airway. Methods: Validation studies were performed by comparing aOCT- and computed tomography (CT)–derived measurements of cross-sectional area (CSA) in (1) conduits in a wax phantom and (2) the velo-, oro-, and hypopharynx during wakefulness in five volunteers. aOCT scanning was performed during sleep in one subject with OSA. Results: aOCT generated images of pharyngeal shape and measurements of CSA and internal dimensions that were comparable to radiographic CT images. The mean difference between aOCT- and CT-derived measurements of CSA in (1) the wax phantom was 2.1 mm2 with limits of agreement (2 SD) from –13.2 to 17.4 mm2 and intraclass correlation coefficient of 0.99 (p < 0.001) and (2) the pharyngeal airway was 14.1 mm2 with limits of agreement from –43.7 to 57.8 mm2 and intraclass correlation coefficient of 0.89 (p < 0.001). aOCT generated quantitative images of changes in upper airway size and shape before, during, and after an apneic event in an individual with OSA. Conclusions: aOCT generates quantitative, real-time measurements of upper airway size and shape with minimal invasiveness, allowing study over lengthy periods during both sleep and wakefulness. These features should make it useful for study of upper airway behavior to investigate OSA pathophysiology and aid clinical management.
Key Words: optical coherence tomography • sleep apnea • upper airway anatomy This article has been cited by other articles:
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