Diagnostic Role of Combined 99mTc-Hmpao Leucocyte Scintigraphy and 99mTc-MDP Bone Scintigraphy in the Diagnosis of Osteomyelitis in the Diabetic Foot

Background: The aim of this study to assess the role of 99mTc-HMPAO leucocyte scintigraphy combined with 99mTcMOP bone scintigraphy in the diagnosis of the diabetic foot infection. Methods: 50 diabetic patients with suspected osteomyelitis were included. The HMPAO-Leucocytes/MOP scan was considered to be consistent with osteomyelitis when the HMPAOLeucocytes uptake was concordant with MOP bone uptake. A HMPAO-Leucocytes uptake without concordant bone MOP activity was considered as a soft-tissue infection. The results of the HMPAO-Leucocytes/MOP scan were compared to the following diagnostic criteria: bone infection was confirmed by radiological follow-up or bone biopsy; the absence of bone infection was confirmed by clinical (healing of the ulcer without antibiotic therapy) and radiological follow-up. Results: According to these criteria, among the 56 ulcers, bone infection was observed in 27 (48.2%): the HMPAOLeucocytes/ MOP scan was positive in 25 cases, including 7 ulcers with normal or equivocal radiographs at inclusion. In the group of 29 ulcers without proven bone infection, the HMPAOLeucocytes/MOP scan was negative in 28 cases, including 8 lesions with a soft-tissue infection. Conclusion: With a sensitivity of 92.6%, a specificity of 96.5%, the HMPAO-Leucocytes/MOP scan is a reliable tool for the diagnosis of osteomyelitis in the diabetic foot. Neuroarthropathy did not affect the performances of the HMPAOLeu/ MDP scan. Owing to a high spatial resolution this test is very helpful to differentiate bone infection from soft- tissue infection especially in case of neuroarthropathy.