title: Acoustic rhinometry: impact of external nasal dilator on the two first notches of the rhinogram.
abstract: BACKGROUND
  Acoustic rhinometry is more accurate in the anterior portion of the nasal cavities, from the nostril to the nasal valve (NV), the most important site of nasal obstruction. Literature presents different opinions regarding the anatomical correlation of the two notches  at the beginning of the rhinogram curve in normal adult white individuals. The aim of this study was to present new data for a better understanding of the anatomic correlation of these two notches.
  
  
  METHODS
  This prospective study included 32 nasal cavities under the following  conditions: (1) basal condition, (2) with external nasal dilator strip (ENDS), (3) after decongestion (0.05% oxymetazoline chloride applied as an aerosol spray), and (4) after decongestion with ENDS.
  
  
  RESULTS
  No statistically significant variation was observed in the cross-sectional  area of the first notch (CSA1) after decongestion. However, there was a statistically significant increase in the CSA2 after ENDS.
  
  
  CONCLUSIONS
  Analysis of the results suggested that the first notch of the rhinogram refers to the nostril and the second notch refers to the  NV as a whole. This study was part of the clinical trial NCT01411969 registered at http://www.clinicaltrials.gov.
authors.affiliation: Division of Otolaryngology Clinic, Hospital of University of São Paulo, SP, Brazil. carlosnigro@uol.com.br
authors.forename: Carlos E N
authors.initials: CE
authors.lastname: Nigro
authors.forename: Olavo
authors.initials: O
authors.lastname: Mion
authors.forename: João Ferreira
authors.initials: JF
authors.lastname: Mello
authors.forename: Richard L
authors.initials: RL
authors.lastname: Voegels
authors.forename: Renato
authors.initials: R
authors.lastname: Roithmann
mesh_terms: D000328:Adult; D001938:Brazil; D006801:Humans; D009296:Nasal Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014663:Nasal Decongestants / Q000008:administration & dosage / Q000009:adverse effects; D010109:Oxymetazoline / Q000008:administration & dosage / Q000009:adverse effects; D011446:Prospective Studies; D011934:Reagent Strips / Q000008:administration & dosage* / Q000009:adverse effects; D023842:Rhinometry, Acoustic; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D014663:Nasal Decongestants; D011934:Reagent Strips; D010109:Oxymetazoline