title: Diagnostic accuracy of lateral neck radiography in ruling out supraglottitis: a prospective observational study.
abstract: OBJECTIVE
  To assess the diagnostic accuracy of lateral neck radiographs (LNR) for acute supraglottitis in adults.
  
  
  METHODS
  A single centre prospective observational study.
  
  
  METHODS
  Emergency department at Kurashiki Central Hospital, Japan.
  
  
  METHODS
  Adult patients who underwent LNR to detect supraglottitis.
  
  
  METHODS
  Presence of supraglottitis, based on nasopharyngeal laryngoscopy or a follow-up telephone call, 7-30 days after the visit.
  
  
  RESULTS
  140 patients had LNR during the study period. 35 patients were excluded from further analysis because of lack of consent. Of the 105 eligible patients, 21 patients (20%) were given the diagnosis of supraglottitis: 17 of 29 with a radiographic abnormality, and 4 of 76 patients without a radiographic abnormality. Three of the four cases where LNR was negative was grade 1, and all cases of grade 3 or higher had abnormal LNR. Sensitivity and specificity (95% CI) of LNR for supraglottitis were 81.0% (64.2 to 97.7) and 85.7% (78.2 to 93.2), respectively. The positive predictive value of LNR was 58.6% (40.7 to 76.5) and the negative predictive value was 94.7% (89.7 to 99.8). The positive likelihood ratio of LNR was 5.67 (3.27 to 9.82) and the negative likelihood ratio was 0.22 (0.10 to 0.51).
  
  
  CONCLUSIONS
  LNR showed only moderate sensitivity and specificity for supraglottitis and would miss some cases of supraglottitis if the pre-test probability is high. LNR was very sensitive for grade 3 or higher supraglottitis, but would miss milder cases.
  
  
  BACKGROUND
  UMIN000011928.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Ehime University, Toon City, Ehime, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Department of Emergency Medicine, Kurashiki Central Hospital, Kurashiki City, Okayama, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okamoto
authors.affiliation: Department of Radiology, Kurashiki Central Hospital, Kurashiki City, Okayama, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ohnishi
authors.affiliation: Department of Emergency Medicine, Kurashiki Central Hospital, Kurashiki City, Okayama, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Fukuoka
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Kokura Memorial Hospital, Kitakyushu City, Fukuoka, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Ichimaru
mesh_terms: D000328:Adult; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D007828:Laryngoscopy; D016013:Likelihood Functions; D008297:Male; D009333:Neck / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011859:Radiography; D012680:Sensitivity and Specificity; D059525:Supraglottitis / Q000175:diagnosis*
keywords: Airway; ENT; Imaging, x-ray; Infectious Diseases, Bacterial