COMPARISON OF TECHNETIUM-99M-MDP, TECHNETIUM-99M-WBC AND TECHNETIUM-99M-HIG IN MUSCULOSKELETAL INFLAMMATION

This study compared three radionuclide techniques in distinguishing mu sculoskeletal infection from noninfectious inflammation. Methods: Thir ty-five orthopedic patients with suspected musculoskeletal infection w ere examined using three radionuclide techniques in sequence: triphasi c bone scintigraphy, Tc-99m radioleukocytes (Tc-99m-WBc) scintigraphy and Tc-99m human immunoglobulin (Tc-99m-Hig) scintigraphy. Two ''early '' and ''late'' acquisitions were performed, at 4-6 hr and 20-24 hr po stinjection, respectively. Patients who were diagnosed as suffering fr om noninflammatory lesions became the controls. We calcu''late''d for all studies one index of inflammation (Infl) as the ratio between coun ts in the uptake area and counts in an equal area of normal tissue. Re sults: The ''early'' radiolabeled leukocytes and ''late'' Hig scintigr aphy allowed the greatest ability to distinguish between infections an d noninfectious inflammations (p < 0.011 and p < 0.016) with a sensiti vity of 96.6% and 96.5% and specificity of 71% and 100%, respectively. Hig and radioleukocytes allowed distinguishing infections from noninf lammatory diseases at both examinations. Conclusion: The ''early'' rad ioleukocyte scintigraphy allowed us to separate infections from noninf ectious inflammations. In contrast, the same result can be obtained on ly with the ''late'' scan in the Hig study, but Hig mapped the spread of the inflammation into soft tissues better. Hig might be an alternat ive to radioleukocytes because of its simple preparation, similar accu racy and safety.