Detection of Soft-Tissue Infections and Osteomyelitis Usinga ...

Imaging of osteomyelitis and soft-tissue infections can beprob lematicwith currently available agents; bone scans are often false-positive, lndium-111-oxineand""Tc-HMPAO white blood cell (WBC) scans require ex vivo handling of blood with potential exposure to infectious agents, and "Tc-antigranulocyte (lgG1) antibodies need 24 hrforfinal diagnosis. Methods: Weinvesti gated the use of"Tc-murine anti-granulocyte monoclonal Fab' fragment in 20 patients with suspected osteomyelitis of soft- tissue infections. All patients also had ""Tebonescansand 111ln-oxineor""Tc-HMPAO white blood cell scans. The final diagnosis was confirmed by culture, biopsy, surgery, follow-up, x-rays, CT orMR). In vitro studies performed on granulocytes demonstrated no effect on their function when the anti-granulo cytemonoclonal antibody fragment was added. Results: Sen sitivity, specificity and diagnostic accuracy to detect infection was 88%, 75%and 80%, respectively. All lesions could be detected as early as 1hr after injection of the antibody fragment. In comparison, WBC scanning had values of 86%, 78%and 81%, respectively. Some lesions could only be detected 24 hr following the injection of labeled WBCs. LeukoScanhad three false-positives and WBC scanning had two false-positives. Conclusions: Immunoscintigraphy with ""Tc-NCA-QOFab' fragments offers rapid localization of foci, rapid and simple use, a negligible HAMA response rate, no effect on granulocytefunc tionandan accuracy comparable to WBC scanning