Abstract
Purpose: Valuate complementary role of Tc-99m-MDP bone scan and (99)(m)Technetium hexamethylpropylene-amineoxime (Tc-99(m)-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 Tc-99m-HMPAO labeled leukocyte (Tc-99(m)-white blood cells (WBCs)), triple phase bone scan (Tc-99(m)-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, Tc-99m-MDP, and Tc-99m-WBCs respectively. Concerning specificity (Sp) was found to be 47.9%, 45.8%, and 91.7% respectively for the three imaging modalities. Tc-99(m)-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 99 mTc-MDP. On the other hand, Tc-99(m)-MDP proved to have best Sn 100% versus 78.3% and 30.4% for Tc-99m-WBCs and plain X-ray respectively. Yet, Sp and accuracy was found to best for Tc-99m-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 Tc-99(m)-MDP. Conclusion: Combined imaging with Tc-99m-WBCs and Tc-99m-MDP proved to be effective in early detection of bone infection in the presence or absence of prosthesis.