Technetium-99m-Labelled Sulesomab (LeukoScan) in the Evaluation of Soft Tissue Infections

Objective: To perform a retrospective review of all patients receiving technetium-99m ( 99m Tc)-labelled sulesomab over a 4-year period to determine if soft tissue infections can be accurately identified. Methods and Materials: We reviewed the results of 124 99m Tc-sulesomab studies performed over a 4-year period. Of these, 34 were performed for undiagnosed fever in which soft tissue infection was suspected to be the main cause. The patients’ clinical notes, microbiology reports and other imaging findings were reviewed to determine the clinical outcome following the scan. The scans were regarded as being true-positives if (i) uptake correlated with the site from which fluid or tissue was obtained and which grew bacteria, and/or (ii) the site of abnormality was reported as having an infection on other imaging or (iii) there was a clinical correlation with the referring clinician’s evaluation of the patient. Planar imaging was performed using standard protocols, together with single-photon emission computed tomography (if required) at 1 and 4 h after injection of 20–30 mCi (740–1,110 MBq) 99m Tc-sulesomab. Results: Three patients were unevaluable. In the remaining 31 patients, 21 99m Tc-sulesomab studies were regarded as true-positives and 6 patients had true-negative scans. One patient had a false-positive scan (abnormal uptake with negative microbiology) and 3 had false-negative scans (infection confirmed but a negative scan). Conclusion: In suspected soft tissue infection, 99m Tc-sulesomab imaging has a sensitivity of 88% with a specificity of 86% and overall accuracy of 87%. 99m Tc-sulesomab provides an accurate method of imaging for suspected soft tissue infection, which is also fast and convenient, as cell labelling is not required