OSTEOMYELITIS OF THE DIABETIC FOOT - MR-IMAGING - PATHOLOGICAL CORRELATION

PURPOSE: To evaluate the efficacy of magnetic resonance (MR) imaging f or the diagnosis of osteomyelitis in the diabetic foot by using anatom ic and histologic studies of the resected tissue as a standard of refe rence. MATERIALS AND METHODS: Thirteen diabetic patients with high cli nical suspicion of osteomyelitis underwent a total of 15 MR examinatio ns before surgery. Correlation was made between MR findings and the hi stologic features of the resected tissue, which included 57 bones. RES ULTS: Maximum signal intensity on the T2-weighted or short inversion t ime inversion-recovery images of the bones was due to osteomyelitis (p rospective sensitivity, 90%; specificity, 71%). Eighteen bones with in creased signal intensity showed only edema of the marrow. The range of signal intensity in edema overlapped that in osteomyelitis but was lo wer. The use of gadopentetate dimeglumine improved delineation of soft -tissue inflammatory masses, but this contrast material was not useful in distinguishing osteomyelitis from edema. CONCLUSION: Marrow edema cannot be reliably distinguished from osteomyelitis with MR imaging. G adopentetate dimeglumine is of limited use. Some previously published false-positive reports of osteomyelitis were most likely due to edema of the marrow. MR imaging is useful in planning surgery of the infecte d diabetic foot, as it enables reliable distinction between normal and abnormal areas.