title: Evaluation of the olfactory bulb volume and olfactory threshold in patients with nasal polyps and impact of functional endoscopic sinus surgery: a longitudinal study.
abstract: BACKGROUND
  Debate still persists on the relation between olfactory bulb volume (OBV) and olfactory function. Many studies suggest that olfactory deprivation decreases the OBV. The aim of this study was to compare the olfactory threshold and OBV of patients with nasal polyps to healthy individuals and to evaluate the impact of functional endoscopic sinus surgery (FESS) on OBV and olfactory threshold.
  
  
  METHODS
  A longitudinal study was carried out in Tehran between 2011 and 2012. Twenty-two patients with nasal polyps were compared with 37 healthy individuals. Olfactory threshold test and magnetic resonance imaging (MRI) were performed on all participants. Twenty-two patients in case group were followed for 6 months after FESS. OBV and olfactory threshold were measured after 6 months.
  
  
  RESULTS
  There was no significant difference between the age, gender, and OBV of the 2 groups. However, the difference between olfactory threshold was significant (p = 0.005). The olfactory threshold showed no significant relation with OBV (p > 0.05). The correlation between Lund-Mackay score and the mean total OBV and left OBV was significant (r = -0.15, p = 0.045; r = -0.22, p = 0.047; respectively). The decrease in olfactory threshold measured after FESS was statistically significant. Right, left, and total OBV significantly increased after FESS.
  
  
  CONCLUSIONS
  The results of our study show that FESS has a significant impact on OBV increment and olfactory threshold decrement. The olfactory bulb is a plastic structure and improvement in peripheral olfactory function results in increase in OBV. However, further studies are mandated, in order to establish this result.
authors.affiliation: Otorhinolaryngology Research Center, Otorhinolaryngology, Head and Neck Surgery Department, Imam Khomeini Hospital Complex, Valiasr Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sadeghi
authors.forename: Amin
authors.initials: A
authors.lastname: Amali
authors.forename: Sara Rahavi
authors.initials: SR
authors.lastname: Ezabadi
authors.forename: Maziar
authors.initials: M
authors.lastname: Motiee-Langroudi
authors.forename: Samireh
authors.initials: S
authors.lastname: Farshchi
authors.forename: Zahra
authors.initials: Z
authors.lastname: Mokhtari
mesh_terms: D000328:Adult; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000601:surgery*; D009830:Olfactory Bulb / Q000503:physiopathology*; D010256:Paranasal Sinuses / Q000601:surgery*; D012903:Smell / Q000502:physiology*
keywords: FESS; nasal polyposis; olfactory bulb; olfactory threshold