Diagnosing diabetic foot infection: the role of imaging and a proposed flow chart for assessment

Diabetes mellitus, a major current epidemic, is frequently complicated by foot infections that are associated with high morbidity. Diagnosing these infections, especially whether or not underlying bone is involved, poses clinical challenges, but is crucial to making proper decisions regarding therapeutic strategies. The most effective means of managing patients with a diabetic foot infection is within the framework of a multidisciplinary team. Present diagnostic efforts are aimed at developing better methods to differentiate uninfected from infected soft tissue wounds, to determine when bone infection is present, and to more clearly define when infection has resolved with treatment. Imaging studies play a major role in diagnosis. This usually begins with plain radiographs, but when advanced imaging is needed, magnetic resonance imaging (MRI) is considered the modality of choice. Newer techniques, such as molecular hybrid imaging, positron emission tomography (PET)/computed tomography (CT) and single photon emission (SPECT)/CT using various radiotracers, play an increasing role. These tests may redefine the non-invasive diagnostic work-up of diabetic foot wounds, potentially leading to substantial improvements in patient management. As experts in infectious diseases, radiology and nuclear medicine, we reviewed the available literature on diagnosing diabetic foot infections, especially the currently available imaging techniques, and developed a proposed diagnostic flow chart, for evaluating patients with a diabetic foot wound.