Diagnosis of bone infection by complementary role of technetium-99m MDP and technetium-99m hexamethylpropylene-amineoxime-leukocytes

PURPOSE: Valuate complementary role of (99m)Tc-MDP bone scan and (99m)Technetium hexamethylpropylene-amineoxime ((99m)Tc-HMPAO) labeled leukocyte scintigraphy in diagnosis of bone infection. PATIENTS AND METHODS: Ninety one sites suspected to have bone infection were divided in to two groups: Group I 49 sites with current endo-prothesis; and group II 42 sites with no prosthesis. All patients were subjected to serial images of (99m)Tc-HMPAO labeled leukocyte ((99m)Tc-white blood cells (WBCs)), triple phase bone scan ((99m)Tc-MDP) and plain X-ray, in addition to clinical and bacteriological assessment, together with follow-up. RESULTS: The overall sensitivity (Sn) was found to be 34.9%, 95.4%, and 86% for plain X-ray, (99m)Tc-MDP, and (99m)Tc-WBCs respectively. Concerning specificity (Sp) was found to be 47.9%, 45.8%, and 91.7% respectively for the three imaging modalities. (99m)Tc-WBCs showed better Sn, Sp, and accuracy in group I (95%, 93.1% and 93.9%, respectively) compared to 40%, 41.4%, and 40.8% for plain X-ray and 90%, 62%, and 73.5% respectively for (99m)Tc-MDP. On the other hand, (99m)Tc-MDP proved to have best Sn 100% versus 78.3% and 30.4% for (99m)Tc-WBCs and plain X-ray respectively. Yet, Sp and accuracy was found to best for (99m)Tc-WBCs (89.5% and 83.3% respectively) compared to 57.9% and 42.9% for plain X-ray and 21.1% and 64.3% for (99m)Tc-MDP. CONCLUSION: Combined imaging with (99m)Tc-WBCs and (99m)Tc-MDP proved to be effective in early detection of bone infection in the presence or absence of prosthesis.