title: Estimation of sensitivity and specificity of brain magnetic resonance imaging and single photon emission computed tomography in the diagnosis of olfactory dysfunction after head traumas.
abstract: BACKGROUND
  Olfactory dysfunction has an incidence of 5-10% after head injury. Several objective and subjective tests had been proposed. Recent studies showed that brain single photon emission computed tomography (SPECT) and brain magnetic resonance imaging (MRI) have good diagnostic value in this era in which the most common sites of involvement were olfactory bulb and olfactory nerve in MRI and frontal lobe in SPECT. This study aimed to estimate the sensitivity and specificity of brain MRI and brain SPECT in the diagnosis of traumatic hyposmia and anosmia.
  
  
  METHODS
  From February 2009 to March 2011, 63 patients with head injury and smell complaint were selected for this study. Using an identification test and a threshold smell test, 28 were anosmic and 27 had hyposmia and the remaining 8 were normosmic. All of them underwent brain MRI and SPECT.
  
  
  RESULTS
  The sensitivity of SPECT was 81.5 and 85.7% in hyposmia and anosmia, respectively. Its specificity was 87.5% in anosmia and 87.7% in anosmia. MRI sensitivity was 66.7% in hyposmia but 82.1% in anosmia. Its specificity was 85.7% in anosmia and 87.7% in anosmia. If MRI and SPECT were considered together, the sensitivity was 92.3% in hyposmia and 92% in anosmia, but the specificity was 87% in both cases.
  
  
  CONCLUSIONS
  According to our study, both brain MRI and SPECT have high sensitivity and specificity in the diagnosis of traumatic anosmia, although brain SPECT is slightly superior to MRI. If the two techniques are applied together, the accuracy will be increased.
authors.affiliation: Department of Otolaryngology, Rhinology Research Center, Shahid Sadooghi Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, Iran.
authors.forename: Saeid
authors.initials: S
authors.lastname: Atighechi
authors.forename: Aliasghar
authors.initials: A
authors.lastname: Zolfaghari
authors.forename: Mohammadhossein
authors.initials: M
authors.lastname: Baradaranfar
authors.forename: Mohammadhossein
authors.initials: M
authors.lastname: Dadgarnia
mesh_terms: D000328:Adult; D000377:Agnosia / Q000175:diagnosis* / Q000209:etiology; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology; D006259:Craniocerebral Trauma / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon