Prospective study of bone, Indium-111-labeled white blood cell gallium-67 scanning for the evaluation of osteomyelitis in the diabetic foot

Twenty-two adult diabetic patients with clinical suspicion of foot and/or ankle infection were prospectively evaluated using radiography, technetium-99m methylene diphosphonate bone scanning (Tc-99m), indium-111-labeled leukocyte scanning (In-111), and gallium-67 scanning (Ga-67) to determine the presence of clinically suspected osteomyelitis, Biopsy for culture and histology was performed in 16 patients. The diagnosis of osteomyelitis was confirmed by biopsy in 12 patients, The remaining 10 patients had no evidence of osteomyelitis with long-term follow-up, Tc-99m was shown to be of limited valued when used alone in these patients with peripheral neuropathy, Ga-67, either alone or in combination with Tc-99m bone scanning, was of little diagnostic value and gave no additional information that was not available from In-111, The combination of three-phase Tc-99m and In-111 had the highest diagnostic efficacy (100% sensitivity, 80% specificity, and 91% accuracy), followed closely by In-111 alone (100% sensitivity, 70% specificity, and 86% accuracy). We conclude that for adult diabetic patients with clinical suspicion of osteomyelitis but no radiographic findings of that disease, In-111 alone is an appropriate nuclear medicine evaluation for ruling out infection if it is negative, However, if an area of In-111 white blood cell uptake is present, a ''simultaneous'' Tc-99m is often helpful in providing the anatomic correlation to differentiate osteomyelitis from infection that is limited to soft tissue.