Diagnosis of osteomyelitis of the foot in diabetic patients: value of 111In-leukocyte scintigraphy

The noninvasive diagnosis of osteomyelitis of the foot in diabetic patients with currently available radiologic and radionuclide imaging techniques is often difficult. Recently, 111In-labeled leukocyte scintigraphy has been proposed as an attractive alternative. Accordingly, we retrospectively reviewed 51 111In-labeled leukocyte scans, 49 technetium-99m bone scans, and 49 plain radiographs obtained in 51 adults with diabetes in whom osteomyelitis of the foot was suspected. The sensitivity and specificity of these techniques were evaluated in all patients, as well as in a subgroup of 11 patients with neuroarthropathy. Results with 111In-labeled leukocyte scans were also examined in subsets of patients with soft-tissue ulcers (n = 35) and those receiving antibiotics during investigation (n = 20). Confirmation or exclusion of osteomyelitis was made surgically in 28 patients and clinically in 23. Fourteen patients had osteomyelitis. Bone scans were most sensitive (93%) but least specific (43%); plain radiographs were most specific (83%) but least sensitive (43%). 111In-labeled leukocyte scans were both sensitive (79%) and specific (78%), and remained useful in patients with neuroarthropathy, soft-tissue ulcers, and antibiotic treatment. Poor spatial resolution contributed to the false-negative and false-positive 111In-labeled leukocyte scans, suggesting that this technique should not be interpreted independent of other tests. 111In-labeled leukocyte scans are a valuable diagnostic tool for the diagnosis of pedal osteomyelitis in diabetic patients.