Utility of PET/CT with fluorine-18-fluorodeoxyglucose-labeled autologous leukocytes for diagnosing diabetic foot osteomyelitis in patients with Charcot's neuroarthropathy.

OBJECTIVE: Diabetic foot osteomyelitis (DFO) is difficult to diagnose in the presence of Charcot's neuroarthropathy (CN) and bone biopsy is not always possible. We aimed to assess the efficacy of PET/computed tomography using F-fluoride (F-fluoride PET/CT) and fluorine-18-fluorodeoxyglucose-labeled autologous leukocytes (F-FDG-LL PET/CT) in comparison with contrast-enhanced MRI (CEMRI) for the detection of DFO.

PATIENTS AND METHODS: Thirty-two patients with chronic CN and foot ulcer suspected of having DFO were prospectively evaluated. All patients underwent radiography, CEMRI, F-fluoride PET/CT, and F-FDG-LL PET/CT of the feet. Bone biopsy and microbiological culture from the suspected site of osteomyelitis was considered the gold standard.

RESULTS: Twenty-three patients fulfilled the inclusion criteria. Bone culture was suggestive of DFO in 12 patients. CEMRI identified 10 of the 12 cases of osteomyelitis. F-fluoride PET/CT and F-FDG-LL PET/CT showed increased tracer uptake (SUVmax=22.7±18.1 and 8.4±4.7, respectively) at the clinically involved site in 10 of the 12 patients (TP). Among 11 biopsy-negative patients, CEMRI reported DFO in four (false positive); there were no false positives with F-FDG-LL PET/CT. The sensitivity and specificity of F-FDG-LL PET/CT was 83.3 and 100% compared with 83.3 and 63.6% for CEMRI, respectively, for the diagnosis of DFO in the background of CN.

CONCLUSION: F-FDG-LL PET/CT has high specificity for the diagnosis of DFO in complicated diabetic foot. The F-fluoride PET/CT helps in the characterization the extent of underlying CN. An early and accurate diagnosis with F-FDG-LL PET/CT aids the rational initiation of antibiotics for DFO.