title: The application of CT to localize the upper airway obstruction plane in patients with OSAHS.
abstract: OBJECTIVE
  To identify a correlation in terms of airway obstruction between awake and sleep apnea using spiral computed tomography (CT).
  
  
  METHODS
  Case series with planned data collection.
  
  
  METHODS
  College medical center.
  
  
  METHODS
  Sixty-one patients diagnosed with obstructive sleep apnea/hypopnea syndrome (OSAHS) underwent CT scans under 3 conditions: quiet breathing while awake, the end of deep inspiration during wakefulness, and apnea while asleep. The upper airway morphology under the 3 conditions was compared, and the accuracy of the obstructive planes as determined by CT scans under the 2 awake conditions was analyzed while considering the obstructive planes that occurred during apnea as a reference.
  
  
  RESULTS
  The differences in the anteroposterior diameter, lateral dimension, and cross-sectional area of the retropalatal and retroglossal regions among the 3 states were statistically significant. Obstruction of the retropalatal region occurred in 100%, whereas retroglossal obstruction occurred in 44.3% of the 61 cases during sleep apnea. The coincidence rate between the awake quiet breathing and the sleep apnea was 85.2% in the retropalatal obstruction and 52.5% in the retroglossal obstruction. The coincidence rate between the awake deep inspiration and the sleep apnea was 82.0% in the retropalatal obstruction and 54.1% in the retroglossal obstruction.
  
  
  CONCLUSIONS
  The main obstructive plane in patients with OSAHS was the retropalatal region. An awake upper airway CT scan can properly diagnose palatopharyngeal obstruction; however, it is not suitable for detecting retroglossal obstruction.
authors.affiliation: Department of Otolaryngology, Affiliated Shanghai Sixth People's Hospital of Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xu Lan
authors.initials: XL
authors.lastname: Tang
authors.forename: Hong Liang
authors.initials: HL
authors.lastname: Yi
authors.forename: Hui Ping
authors.initials: HP
authors.lastname: Luo
authors.forename: Yuan Ping
authors.initials: YP
authors.lastname: Xiong
authors.forename: Li Li
authors.initials: LL
authors.lastname: Meng
authors.forename: Jian
authors.initials: J
authors.lastname: Guan
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Shan Kai
authors.initials: SK
authors.lastname: Yin
mesh_terms: D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D001239:Inhalation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009960:Oropharynx / Q000000981:diagnostic imaging; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D036542:Tomography, Spiral Computed; D014851:Wakefulness