The utility of chemical shift imaging and related Dixon images in evaluation of bone marrow edema-like changes in diabetic foot

Abstract

Abstract Background Magnetic resonance imaging (MRI) is the best diagnostic tool for suspected diabetic foot osteomyelitis (DFO); adding T1-based Dixon to MR technique can identify the bone marrow edema-like signal observed in neuropathic joints and differentiate it from that observed in DFO. The aim of this study was to assess the diagnostic efficacy of chemical shift imaging (T1 in-phase and out-of-phase) and related Dixon sequence in differentiation between infectious edema-like signal found in osteomyelitis and bland edema signals observed in osteomyelitis mimickers (as neuropathic arthropathy). The study was conducted on 50 patients who were referred by surgical outpatient clinics between January 2020 and January 2022; they underwent MRI of the foot including T1-Dixon sequence. Results There were variable bone and joint affection, and the most common location of bony affection in the study was the hind-foot. Forty-four out of fifty patients had bone marrow edema-like signals. Thirty-seven patients (74%) were diagnosed with osteomyelitis, whereas seven (14%) patients were diagnosed with non-infective/bland bone marrow edema signals which were related to Charcot arthropathy and/or nearby infection. Both visual and quantitative assessments of chemical shift imaging showed high sensitivity and specificity in diagnosis of DFO. The optimal cut-off point of signal intensity ratio for diagnosis of DFO was 1.005 with high sensitivity and specificity. Conclusions Chemical shift imaging and related Dixon sequence were reliable methods in diabetic foot evaluation; they could help differentiate infectious edema-like changes of osteomyelitis from and bland edema of osteomyelitis mimickers with high sensitivity and specificity especially on using quantitative analysis of their signal abnormality.