title: A comparative study of brain perfusion single-photon emission computed tomography and magnetic resonance imaging in patients with post-traumatic anosmia.
abstract: BACKGROUND
  Loss of smell is a problem that can occur in up to 30% of patients with head trauma. The olfactory function investigation methods so far in use have mostly relied on subjective responses given by patients. Recently, some studies have used magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) to evaluate patients with post-traumatic anosmia. The present study seeks to detect post-traumatic anosmia and the areas in the brain that are related to olfactory impairment by using SPECT and MRI as imaging techniques.
  
  
  METHODS
  The study was conducted on 21 patients suffering from head injury and consequently anosmia as defined by an olfactory identification test. Two control groups (traumatic normosmic and nontraumatic healthy individuals) were selected. Brain MRI, qualitative and semiquantitative SPECT with 99mtc-ethyl-cysteinate-dimer were taken from all the patients. Then the brain SPECT and MRI were compared with each other.
  
  
  RESULTS
  Semi-quantitative assessment of the brain perfusion SPECT revealed frontal, left parietal, and left temporal hypoperfusion as compared with the two control groups. Eighty-five percent of the anosmic patients had abnormal brain MRI. Regarding the MRI, the main abnormality proved to be in the anterior inferior region of the frontal lobes and olfactory bulbs.
  
  
  CONCLUSIONS
  The findings of this study suggest that damage to the frontal lobes and olfactory bulbs as shown in the brain MRI and hypoperfusion in the frontal, left parietal, and left temporal lobes in the semiquantitative SPECT corresponds to post-traumatic anosmia. Further neurophysiological and imaging studies are definitely needed to set the idea completely.
authors: Shahid Sadughi Hospital, Yazd, Iran. atighechi@ssu.ac.ir
authors: Saeid
authors: S
authors: Atighechi
authors: Hadi
authors: H
authors: Salari
authors: Mohammad Hossein
authors: MH
authors: Baradarantar
authors: Rozita
authors: R
authors: Jafari
authors: Ghasem
authors: G
authors: Karimi
authors: Mehdi
authors: M
authors: Mirjali
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D006259:Craniocerebral Trauma / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000473:pathology; 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 / Q000000981:diagnostic imaging / Q000473:pathology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012903:Smell / Q000502:physiology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D015599:Trauma Severity Indices; D055815:Young Adult