Diagnostic accuracy of combined 99mTc-sulesomab and 99mTc-nanocolloid bone marrow imaging in detecting prosthetic joint infection.

OBJECTIVE(S): Autologous-labeled leukocytes combined with sulfur colloid bone marrow scan is the current nuclear medicine gold standard for the diagnosis of prosthetic joint infection. The goal of this study is to assess the diagnostic accuracy of a new nuclear medicine modality for detecting infection in this context.

METHODS: Twenty-seven patients with suspicious hip and knee arthroplasties were enrolled prospectively and underwent nuclear medicine testing using 99mTc-sulesomab and 99mTc-nanocolloids sequentially. These results were then crossed with the final diagnosis to determine the test(s) diagnostic accuracy.

RESULTS: An isolated 99mTc-sulesomab scan shows 100% sensitivity (0.40-1) and negative predictive value (0.31-1) but only 20% specificity (0.05-0.48). Combining it with a 99mTc-nanocolloid bone marrow scan increases the specificity (0.75-1) and the positive predictive value (0.40-1) to 100%. Furthermore, the combined test has fewer equivocal readings and higher interreader agreement: κ test value 0.59 vs. 0.44.

CONCLUSION: The results support the hypothesis that these technically simpler and ready-to-use products may be an alternative to autologous-labeled leukocytes/sulfur colloid marrow scan.