Abstract
Purpose The aim of this study was to compare Tc-99m-HMPAO-WBC-SPECT/CT combined with Tc-99m-nanocollloid SPECT/CT and F-18-FDG-WBC-PET/CT combined with Tc-99m-Nanocollloid SPECT/CT for the diagnosis and treatment evaluation of chronic prosthetic joint infection (PJI). Methods Patients with suspected chronic PJI were examined with Tc-99m-HMPAO-WBC SPECT/CT, F-18-FDG-WBC PET/CT, and Tc-99m-nanocolloid SPECT/CT (to visualize bone marrow). The location and patterns of uptake were noted and compared between the two leukocyte examinations. Both leukocyte examinations were evaluated visually for infection. The PET examinations were also evaluated semiquantitatively. Chronic PJI was verified clinically by microbial culture and successfully treated PJI was confirmed by 12 months symptom-free follow-up after cessation of antibiotics. Results Nineteen patients were included with 10 hip prostheses and nine knee prostheses. Fourteen were diagnosed with chronic PJI and five with successfully treated PJI. The sensitivity of visual evaluation of Tc-99m-WBC-HMPAO SPECT/CT for all joints was 0.31 and for F-18-FDG-WBC PET/CT 0.38. The specificity was 0.80 and 0.83, respectively. All patients with a true-positive SPECT examination had a false-negative PET examination and vice versa. Semiquantitative evaluation of the hips gave an area under the curve of 0.905 using the iliac crest as the background. Semiquantitative evaluation of the knees did not produce significant results. Conclusion This pilot study showed no difference in the sensitivity or specificity of Tc-99m-HMPAO-WBC SPECT/CT and F-18-FDG-WBC PET/CT when combined with Tc-99m-nanocollloid SPECT/CT in the diagnosis or treatment evaluation of suspected late chronic PJI.