title: Low yield of ED magnetic resonance imaging for suspected epidural abscess.
abstract: OBJECTIVE
  The aim of this study was to estimate the yield of emergency department (ED) magnetic resonance imaging (MRI) in detecting spinal epidural abscess (SEA) and to identify clinical factors predicting positive MRI results.
  
  
  METHODS
  We examined a cohort of patients who underwent MRI to rule out SEA, followed by a nested case-control comparison of those with positive results and a sample with negative results. A positive result was defined as osteomyelitis, discitis, or SEA. Predictor variables included temperature, presenting complaint, drug abuse status, history of SEA or back surgery, midline back tenderness, neurologic deficit, MRI level, mean white blood cell count, erythrocyte sedimentation rate, and C-reactive protein level.
  
  
  RESULTS
  Fourteen of the 120 available MRIs were excluded; 7 (6.6%) of the remaining 106 were positive. Temperature was 1.1°C higher in cases than controls (95% CI, 0.6-1.7).
  
  
  CONCLUSIONS
  Emergency department MRI for suspected SEA has a low yield. Clinical guidelines are needed to improve efficiency.
authors.affiliation: Emergency Medicine, University of Maryland Medical Center, Baltimore, MD, USA. melsayed@bu.edu
authors.forename: Mazen
authors.initials: M
authors.lastname: El Sayed
authors.forename: Michael D
authors.initials: MD
authors.lastname: Witting
mesh_terms: D000328:Adult; D001831:Body Temperature; D016022:Case-Control Studies; D004636:Emergency Service, Hospital; D020802:Epidural Abscess / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000175:diagnosis* / Q000473:pathology; D018709:Statistics, Nonparametric