title: Diffusion-weighted Magnetic Resonance Imaging as a Novel Imaging Modality in Assessing Treatment Response in Necrotizing Otitis Externa.
abstract: To report our initial experience of diffusion-weighted magnetic resonance imaging (DW-MRI) as a novel imaging tool for assessing and monitoring treatment response in necrotizing otitis externa (NOE).
  
  
  
  Seven adults with a diagnosis of NOE on both clinical and computed tomography (CT) criteria who were subsequently monitored with at least two echoplanar DW-MRI investigations were included in this retrospective longitudinal observational study.
  
  
  
  Patients underwent magnetic resonance imaging (MRI), including echoplanar diffusion-weighted sequences, within 2 weeks of diagnosis of NOE to determine the extent of infection and to provide a baseline scan for monitoring response to treatment. Repeated imaging was undertaken after the agreed initial course of antimicrobial therapy was completed.
  
  
  
  The primary outcome measure for complete treatment response was complete resolution of high inflammatory signal on the DW-MRI apparent diffusion coefficient (ADC) map. This was correlated to clinical, biochemical, and other MRI measures of disease resolution.
  
  
  
  Baseline DW-MRI was carried out in all but one patient within 2 weeks of the initial diagnostic CT scan. Patients had between one and three further DW-MRI scans, at a mean interval of 4.4 months from the initial scan (range, 2-8 months). The decision to terminate or continue therapy correlated with ADC signal findings on DW-MRI in all cases. In comparison, conventional MRI sequences performed less well, as there was some degree of persistent residual soft tissue changes in all cases.
authors.affiliation: *Department of Otolaryngology, Head and Neck Surgery, Northwick Park and Central Middlesex Hospitals, London Northwest Healthcare NHS Trust, London, U.K.†Department of Radiology, Northwick Park and Central Middlesex Hospitals, London Northwest Healthcare NHS Trust, London, U.K.
authors.forename: Matthew
authors.initials: M
authors.lastname: Cherko
authors.forename: Robert
authors.initials: R
authors.lastname: Nash
authors.forename: Arvind
authors.initials: A
authors.lastname: Singh
authors.forename: Ravi Kumar
authors.initials: RK
authors.lastname: Lingam
mesh_terms: D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010032:Otitis Externa / Q000000981:diagnostic imaging*; D012189:Retrospective Studies