Low yield of ED magnetic resonance imaging for suspected epidural abscess

PurposeThe 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.Basic ProcedureWe 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.Main FindingsFourteen 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).ConclusionEmergency department MRI for suspected SEA has a low yield. Clinical guidelines are needed to improve efficiency.