Diagnostic value of 99mTc-ubiquicidin scintigraphy for osteomyelitis and comparisons with 99mTc-methylene diphosphonate scintigraphy and magnetic resonance imaging.

Objective: The discrimination of bacterial infections from sterile inflammatory processes is of great importance in the management of inflammation. Currently available techniques cannot decisively address this issue. In this respect, antimicrobial peptide Tc-ubiquicidin (UBI) 29-41 scans have been showing interesting results. The aim of this study was to determine the accuracy of Tc-UBI scan in the detection of osteomyelitis and to compare it with Tc-methylene diphosphonate scan and magnetic resonance imaging (MRI).

Methods: Twenty patients (mean age=48.90 years) with suspected osteomyelitis were included in this study. After evaluation of each patient through history taking, physical examination, appropriate laboratory tests, and other processes including bone probing, wound culture, and plain film radiography, MRIs, Tc-UBI scans, and Tc-methylene diphosphonate scans were performed. For quantitative analysis, the mean count of abnormal-to-normal (A/N) region was calculated for images acquired at 15, 30, 45, 60, 120, and 240 min to obtain the most favorable time for imaging.

Results: In total, osteomyelitis was detected in the Tc-UBI scans of 17 patients, indicating 100% accuracy, compared with an accuracy of 90% for osteomyelitis detected in three-phase bone scans. The maximum mean A/N was observed at 15 min after intravenous injection (median: 1.91; interquartile range: 1.54-2.94). MRI was performed in 12 cases only with 75% accuracy. In addition, the A/N ratios for the Tc-UBI scans were not significantly different between patients with or without Staphylococcus aureus growth on wound cultures.

Conclusion: For fast imaging with high accuracy, Tc-UBI 29-41 is a suitable choice for the detection of osteomyelitis.