Tc-99m ciprofloxacin in clinically selected patients suspected for peripherial osteomyelitis, spondylodiscitis and fever of unknown origin: preliminary results

Abstract

Retrospective evaluation of Tc-99m ciprofloxacin (infection) scintigraphy consecutively performed in a series of patients clinically suspected for peripheral osteomyelitis (OM), spondylodiscitis (SD) and fever of unknown origin (FUO). A total of 20 patients clinically suspected for OM (n = 12), SD (n = 3) and FUO (n = 5) were included in our retrospective analysis. The additional criterion was a positive 3-phase bone scan for OM, or a 2-phase bone scan in case of SD. Planar whole body scans and static acquisitions were performed 1 and 4 h after application of 370 MBq Tc-99m ciprofloxacin. In 10 patients with suspected OM, additional immunoscintigraphy using Tc-99m labelled monoclonal antibodies (Mab BW 250/183) was performed and the correlation of infection to bloodpool and antigranulocyte scintigraphy was analysed. OM: Bacterial infection was confirmed in 8 of 15 lesions. Infection demonstrated true positive (TP) results in 7 of 8, true negative (TN) results in 2 of 7, false positive (FP) results in 5 of 7 patients and one false negative (FN) result. A strong correlation could be demonstrated between T/NT ratios of infection and bloodpool Tc-99m medronate imaging (r = 0.84, 0.88) and between infection and BW 250/183 (r = 0.92, 0.90). Using a threshold of 2.0 for T/NT ratio, only TP results could be observed whereas a T/NT in the range of 1.0-2.0 could not discriminate between septic and aseptic inflammation. Concordant results with Mab BW 250/183 could only be observed in 5 of 10 patients (4 TP, 1 TN) by showing 4 FP and 1 FN lesions with IF. Non-specific uptake of infection can be observed in a variety of clinical situations with moderate uptake, by showing a strong correlation with blood-pool imaging. Nevertheless, intense uptake may be specific for septic inflammation.