title: Prognostic value of olfactory bulb volume measurement for recovery in postinfectious and posttraumatic olfactory loss.
abstract: OBJECTIVE
  Several prognostic factors influencing the recovery from olfactory dysfunction have been described. The aim of this study was to investigate whether olfactory bulb volume could be used as a new predictor of olfactory recovery in postinfectious and posttraumatic olfactory loss.
  
  
  METHODS
  Cohort study; Level of evidence, 4. Setting Tertiary university clinic, department of otolaryngology.
  
  
  METHODS
  A cohort of 60 patients with postinfectious (n = 28) and posttraumatic olfactory loss (n = 32) was investigated. Assessment of olfactory function was performed using orthonasal (Sniffin' Sticks test) and retronasal psychophysical olfactory tests, at the time of the diagnosis (t1) and 15 months later (t2). All patients were examined on 3 tesla magnetic resonance imaging, and the olfactory bulbs volume was assessed using planimetric contouring at the time of the diagnosis (t1).
  
  
  RESULTS
  Recovery rate was 25% in patients with posttraumatic olfactory loss and 36% in patients with postinfectious olfactory loss. There was a correlation between both orthonasal and retronasal olfactory testing and the initial measurement of the total olfactory bulb volume. In addition, we observed a significant correlation between changes in olfactory functions and initial measurement of the total olfactory bulb volume, with larger volumes relating to higher improvement of olfactory function. Finally, we found that none of the patients with a total olfactory bulb volume of 40 mm(3) or less exhibited recovery of olfactory function.
  
  
  CONCLUSIONS
  Olfactory bulb volume seems to be a predictor of olfactory recovery in patients with postinfectious and posttraumatic olfactory loss.
authors.affiliation: Université Catholique de Louvain, Institute of Neurosciences, Unit of Otorhinolaryngology, Cliniques Universitaires St Luc, Brussels, Belgium. philippe.rombaux@uclouvain.be
authors.forename: Philippe
authors.initials: P
authors.lastname: Rombaux
authors.forename: Caroline
authors.initials: C
authors.lastname: Huart
authors.forename: Naima
authors.initials: N
authors.lastname: Deggouj
authors.forename: Thierry
authors.initials: T
authors.lastname: Duprez
authors.forename: Thomas
authors.initials: T
authors.lastname: Hummel
mesh_terms: D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000150:complications; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D000857:Olfaction Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D009830:Olfactory Bulb / Q000473:pathology*; D009929:Organ Size; D011379:Prognosis; D011446:Prospective Studies; D011601:Psychophysics; D020127:Recovery of Function / Q000502:physiology*; D012141:Respiratory Tract Infections / Q000150:complications; D012903:Smell / Q000502:physiology*; D055815:Young Adult