Specific Magnetic Resonance Imaging Findings as Predictors of Osteomyelitis in Routine Clinical Practice

Abstract

Background: The gold standard for the diagnosis of osteomyelitis is histopathology combined with positive bone cultures. Magnetic Resonance Imaging (MRI) is often used to aide diagnosis and guide treatment decisions. The purpose of the study was to examine the association of MRI findings with, and their sensitivity and specificity in identifying osteomyelitis as proven by bone histopathology and bone culture in routine clinical practice. Materials and Methods: A retrospective analysis of patients with bone specimens obtained by biopsy or at resection for suspected osteomyelitis during 2010-2014 at an academic medical center in New York City. We used bivariate analysis to compare findings of patients who did or did not have osteomyelitis confirmed on histopathology (Analysis 1) and those who had either bone histopathology demonstrating osteomyelitis, positive bone cultures or both or who had neither (Analysis 2). Results: We identified 103 patients with an MRI in the week prior to bone biopsy or bone resection. In Analysis 1, 52 (50.5%) of 103 patients had osteomyelitis confirmed on histopathology. In Analysis 2, 72 (70%) patients had proven osteomyelitis. These groups with and without osteomyelitis did not differ significantly with respect to the frequency of marrow edema, cortical erosions, decreased T1 signal or increased T2 signal in either analysis and the sensitivity and specificity of MRI findings for detecting osteomyelitis was lower than reported in prior studies. Conclusions: Based on the above results, clinicians should be aware that the sensitivity and specificity of MRI findings for histologic and microbiologic osteomyelitis may be less in real world practice than is reported in formal studies.