title: Cervical computed tomography in patients with obstructive sleep apnea: influence of head elevation on the assessment of upper airway volume.
abstract: OBJECTIVE
  Obstructive sleep apnea syndrome (OSAS) has a high prevalence and carries significant cardiovascular risks. It is important to study new therapeutic approaches to this disease. Positional therapy might be beneficial in reducing the apnea-hypopnea index (AHI). Imaging methods have been employed in order to facilitate the evaluation of the airways of OSAS patients and can be used in order to determine the effectiveness of certain treatments. This study was aimed at determining the influence that upper airway volume, as measured by cervical CT, has in patients diagnosed with OSAS.
  
  
  METHODS
  This was a quantitative, observational, cross-sectional study. We evaluated 10 patients who had been diagnosed with OSAS by polysomnography and on the basis of the clinical evaluation. All of the patients underwent conventional cervical CT in the supine position. Scans were obtained with the head of the patient in two positions (neutral and at a 44° upward inclination), and the upper airway volume was compared between the two.
  
  
  RESULTS
  The mean age, BMI, and neck circumference were 48.9 ± 14.4 years, 30.5 ± 3.5 kg/m2, and 40.3 ± 3.4 cm, respectively. The mean AHI was 13.7 ± 10.6 events/h (range, 6.0-41.6 events/h). The OSAS was classified as mild, moderate, and severe in 70%, 20%, and 10% of the patients, respectively. The mean upper airway volume was 7.9 cm3 greater when the head was at a 44° upward inclination than when it was in the neutral position, and that difference (17.5 ± 11.0%) was statistically significant (p = 0.002).
  
  
  CONCLUSIONS
  Elevating the head appears to result in a significant increase in the caliber of the upper airways in OSAS patients.
authors.affiliation: Universidade do Extremo Sul Catarinense, Criciúma, SC, Brasil.
authors.forename: Fábio José Fabrício de Barros
authors.initials: FJ
authors.lastname: Souza
authors.affiliation: Universidade do Extremo Sul Catarinense, Criciúma, SC, Brasil.
authors.forename: Anne Rosso
authors.initials: AR
authors.lastname: Evangelista
authors.affiliation: Universidade do Extremo Sul Catarinense, Criciúma, SC, Brasil.
authors.forename: Juliana Veiga
authors.initials: JV
authors.lastname: Silva
authors.affiliation: Unidade Radiológica Criciúma, Criciúma, SC, Brasil.
authors.forename: Grégory Vinícius
authors.initials: GV
authors.lastname: Périco
authors.affiliation: Universidade do Extremo Sul Catarinense, Criciúma, SC, Brasil.
authors.forename: Kristian
authors.initials: K
authors.lastname: Madeira
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005260:Female; D006257:Head; D006801:Humans; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning / Q000379:methods*; D017286:Polysomnography; D012016:Reference Values; D012137:Respiratory System / Q000000981:diagnostic imaging*; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging*; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*