Magnetic Resonance Imaging of Diabetic Foot Osteomyelitis: Imaging Accuracy in Biopsy-Proven Disease

Magnetic resonance imaging (MRI) is the recommended diagnostic imaging technique for diabetic foot osteomye-litis (DFO). The gold standard to diagnose osteomyelitis is bone biopsy with a positive culture and/or histopathol-ogy finding consistent with osteomyelitis. The purpose of this study is to assess the accuracy of MRI readings in biopsy-proven diabetic foot osteomyelitis with a second read done by a blinded, expert musculoskeletal radiolo-gist. A retrospective chart review of 166 patients who received a bone biopsy to confirm the diagnosis of a sus-pected DFO at a large county hospital between 2010 and 2014. A second, blinded musculoskeletal radiologist reviewed the images for accuracy, once the official reading was recorded. Imaging results were correlated with the final diagnosis of osteomyelitis determined by bone biopsy. In 17 of 58 patients (29.3%), the diagnosis of DFO by MRI was not confirmed by bone biopsy. There were 12 false positives and 5 false negatives. After the second expert read, there were 5 false positives and 4 false negatives. The overall accuracy was 84% for the second read. Our study demonstrated results comparable to the previously reported meta-analysis findings. There is a clear var-iation on the read of MRI that could lead to an incorrect diagnosis of DFO. An integrated approach with evaluation of clinical findings, communication with radiologist about the MRI results when indicated, and bone biopsy is war-ranted for accurate diagnosis management of DFO. (c) 2020 by the American College of Foot and Ankle Surgeons. All rights reserved.