title: [Real-time CT of upper airway in patients with obstructive sleep apnea hypopnea syndrome].
abstract: OBJECTIVE
  To explore the technology and clinical application of real-time CT scan in obstructive sleep apnea hypopnea syndrome during awake and drug induced sleep state.
  
  
  METHODS
  Sixty-two patients with OSAHS diagnosed by polysomnography underwent 256 layer spiral CT scan during awake and drug-induced sleep apnea state, and multiplanar reconstruction and volume rendering of computed tomography images were performed. To observe the dynamic changes of upper airway and locate the sites of airway obstruction in patients with OSAHS, the minimum section area, diameter and volume of pharynx cavity were measured on reconstructed 3-dimensional computed tomography.
  
  
  RESULTS
  Real-time CT scans were completed successfully in all of the patients. It was revealed that airway obstruction frequently occurred at retropalatal and retroglottal region. Real-time CT scans revealed 29 cases with airway obstruction at isolated retropalatal region, 19 cases with airway obstruction at retropalatal and retroglottal region simultaneously, 6 cases with airway obstruction at retropalatal and epiglottal region simultaneously, 7 cases with airway obstruction at retropalatal, retroglottal and retroglottal region simultaneously, 1 case without airway obstruction. There was no airway obstruction at retroglottal or retroglottal region isolatedly. Rate of single region airway obstruction was 46.8% (29/62), and rate of multiple regions airway obstruction 51.6% (32/62). The real-time CT results showed that starting from Friedman tongue position I to IV, the percentage of obstruction at retroglottal and (or) retroglottal region simultaneously were increasing, the percentage of obstruction were 0/6, 8/25, 13/20, 11/11, respectively (χ(2) = 22.00, P < 0.005). The minimum section area, volume, minimum anteroposterior diameter and left-right diameter of pharynx cavity between awake and drug-induced sleep apnea state had statistically significant difference in all region.
  
  
  CONCLUSIONS
  Real-time CT scans in drug-induced sleep state could get more information about the anatomical and pathological changes of upper airway, providing relatively objective morphological basis for the diagnosis and treatment of patients with OSAHS. Therefore, real-time CT scans have important value in practical application.
authors.affiliation: Center of Otorhinolaryngology of People's Liberation Army, Naval General Hospital, Beijing 100048, China.
authors.forename: Zhi-qiang
authors.initials: ZQ
authors.lastname: Yan
authors.forename: Jian-jun
authors.initials: JJ
authors.lastname: Sun
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Yan-qun
authors.initials: YQ
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Yuan
authors.forename: Hong-hong
authors.initials: HH
authors.lastname: Wang
authors.forename: Lei-lei
authors.initials: LL
authors.lastname: Yu
mesh_terms: D000402:Airway Obstruction; D006801:Humans; D010614:Pharynx; D017286:Polysomnography; D012137:Respiratory System / Q000033:anatomy & histology; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D036542:Tomography, Spiral Computed; D014059:Tongue