Acceptance and image quality of high-resolution peripheral quantitative computed tomography of the metacarpophalangeal joints in rheumatoid arthritis

Objective High-resolution peripheral quantitative computed tomography (HR-pQCT) requires longer immobilization time than conventional radiography, which challenges patient acceptance and image quality. Therefore, the aim was to investigate the acceptance of HR-pQCT in patients with rheumatoid arthritis (RA), and secondly the effect of an inflatable hand immobilization device on motion artefacts of the metacarpophalangeal (MCP) joints. Methods Fifty patients with established RA and a median (interquartile range) age of 64.3 (55.0-71.2) years had their MCP joints scanned by HR-pQCT with the hand positioned with and without an inflatable immobilization device followed by a full radiographic examination and a questionnaire on the imaging experience. The comparability of the erosion measures was investigated with and without the immobilization device using Bland-Altman plot and intrareader repeatability by intraclass correlation coefficient. The motion artefacts were graded for each acquisition, and intrareader repeatability was investigated by Cohen's kappa coefficient. Results Forty percent of the patients preferred HR-pQCT imaging, only 6% preferred conventional X-ray. Seventy-four percent reported it was not difficult to keep their fingers steady during the scan. Sixty percent of the patients reported the immobilization device helped keep their fingers steady. However, as motion artefacts were sparse, no clinically relevant difference was observed concerning the effect of the immobilization device on readability. The intrareader repeatability and comparability for the erosion measures were excellent. Conclusion The high patient acceptance adds to the feasibility of HR-pQCT imaging of MCP joints in RA. The inflatable immobilization device did not reduce motion-induced image degradation.

Automated summary

The study revealed that many patients with rheumatoid arthritis prefer HR-pQCT imaging over conventional X-rays, with a high level of acceptance. Most patients reported no difficulty in keeping their fingers steady during the scan, and the inflatable immobilization device helped some patients in this aspect. However, the immobilization device did not significantly reduce motion-induced image degradation, as motion artefacts were minimal.