title: Asymmetric hearing loss: toward cost-effective diagnosis.
abstract: OBJECTIVE
  Unilateral audiovestibular symptoms are commonly seen in clinical practice, and the treating physician frequently considers retrocochlear disease in the differential diagnosis. These considerations often precipitate a lengthy and expensive battery of tests. This study was conducted to evaluate the diagnostic yield of the various tests available in the investigation of these symptoms and to recommend changes to practice patterns, if appropriate.
  
  
  METHODS
  We examined a cohort of 310 patients with unilateral audiovestibular symptoms who were referred to our radiology department for investigation. All patients had complete auditory assessments, and 144 underwent auditory evoked potential testing (ABR). There were 258 contrast-enhanced CT (CECT) scans and 86 gadolinium-enhanced MRI (Gd-MRI) scans performed.
  
  
  RESULTS
  A total of 12 cerebellopontine angle (CPA) tumours were diagnosed.
  
  
  CONCLUSIONS
  MRI is the diagnostic tool of choice in patients with asymmetric sensory neural hearing loss (ASHL), but it is expensive and not always easily available. Analysis of diagnostic accuracy of CECT and ABR, both used as screening tests, demonstrate their limitations and reveals that CECT is no more accurate than ABR, although it is three times more costly. Based on these data, we have changed our diagnostic approach to patients with unilateral audiovestibular symptoms. Patients are either evaluated with MRI or are screened initially with ABR based on clinical suspicion. CECT is no longer routinely included in the evaluation of patients with ASHL. Finally, newer emerging MRI techniques promise faster and less expensive examinations with increased diagnostic accuracy.
authors.affiliation: Department of Radiology, University of Calgary, Alberta.
authors.forename: E
authors.initials: E
authors.lastname: Raber
authors.forename: J C
authors.initials: JC
authors.lastname: Dort
authors.forename: R
authors.initials: R
authors.lastname: Sevick
authors.forename: R
authors.initials: R
authors.lastname: Winkelaar
mesh_terms: D000465:Algorithms; D002528:Cerebellar Neoplasms / Q000150:complications; D002530:Cerebellopontine Angle; D003362:Cost-Benefit Analysis; D003937:Diagnosis, Differential; D005072:Evoked Potentials, Auditory; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000191:economics*; D008403:Mass Screening / Q000191:economics*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000191:economics*