The role of bone SPECT/CT in the evaluation of painful joint prostheses.

Objective: In this study, we aimed to evaluate the contribution of single-photon emission computerized tomography/computed tomography (SPECT/CT) to three-phase planar bone scintigraphy/SPECT in the assessment of aseptic and septic prosthesis loosening in patients with painful hip and knee prostheses.

Methods: Fifty patients who had undergone arthroplasties (20 hips and 30 knees) and were suspected to have complications and had undergone revision surgery were included in this study. Technetium-99m methylene diphosphonate three-phase bone scintigraphy and SPECT/CT were performed at the region of prostheses in all patients. Planar bone/SPECT and SPECT/CT images were separately assessed by two nuclear medicine physicians. SPECT/CT findings were compared with the findings of planar images/SPECT. Both planar bone scan/SPECT and SPECT/CT findings were divided into three groups: aseptic loosening, septic loosening, and miscellaneous. In all patients, scintigraphic diagnosis was confirmed by surgical findings.

Results: SPECT/CT changed the diagnosis and treatment plan in 8/50 (16%) patients. SPECT/CT was significantly better than planar scan/SPECT imaging for the diagnosis of aseptic and septic loosening in both joints (κ value: 0.477 for planar scan/SPECT; κ value: 0.717 for SPECT/CT). Moreover, both planar scan/SPECT and SPECT/CT were statistically successful in knee prostheses than in hip prostheses (κ value: 0.271 vs. 0.579 for planar/SPECT; κ value: 0.579 vs. 0.80 for SPECT/CT). For the hip, SPECT/CT was successful on the acetabular component than on the femoral component. For the knee, the results of SPECT/CT were similar for the femoral and tibial components.

Conclusions: SPECT/CT increases diagnostic accuracy in the evaluation of aseptic and septic loosening in hip and knee prostheses compared with three-phase bone scintigraphy/SPECT.