Imaging of musculoskeletal bacterial infections by [124I]FIAU-PET/CT

Abstract

Background: Traditional imaging techniques for the localization and monitoring of bacterial infections, although reasonably sensitive, suffer from a lack of specificity. This is particularly true for musculoskeletal infections. Bacteria possess a thymidine kinase (TK) whose substrate specificity is distinct from that of the major human TK. The substrate specificity difference has been exploited to develop a new imaging technique that can detect the presence of viable bacteria.

Methodology/principal findings: Eight subjects with suspected musculoskeletal infections and one healthy control were studied by a combination of [(124)I]FIAU-positron emission tomography and CT ([(124)I]FIAU-PET/CT). All patients with proven musculoskeletal infections demonstrated positive [(124)I]FIAU-PET/CT signals in the sites of concern at two hours after radiopharmaceutical administration. No adverse reactions with FIAU were observed.

Conclusions/significance: [(124)I]FIAU-PET/CT is a promising new method for imaging bacterial infections.

Figure 1. [¹²⁴I]FIAU signal in established infections as imaged by PET/CT: Fused PET and CT images, taken at 2 hours after radiotracer administration, are shown for the following cases.

(a) septic arthritis (right knee, Patient 1), (b) septic arthritis (right knee, Patient 4), (c) osteomyelitis (left distal tibia, Patient 5), (d) cellulitis (left lower extremity, Patient 6), (e) necrotizing septic arthritis (left knee, Patient 8).