Benefits of iterative metal artifact reduction and dual-energy CT towards mitigating artifact in the setting of total shoulder prostheses

Objective: To determine the utility of iterative metal artifact reduction and 130 keV dual-energy virtual monoenergetic images to improve bone and soft tissue visualization in CT scans affected by metal artifacts. Material and methods: Thirteen females and 6 males with a history of total shoulder prosthesis who underwent dual-energy shoulder CT were included. Four sets of images were reconstructed for each patient: (1) original polychromatic kV images reconstructed with weighted filtered back projection; (2) polychromatic kV images with iterative metal artifact reduction; (3) 130 keV dual-energy virtual monoenergetic; (4) combined iterative metal artifact reduction and 130 keV dual-energy virtual monoenergetic. Three readers blindly reviewed all image sets and graded the extent of artifact and image quality. Results: Mean artifact score and median overall image quality score were better in 130 keV dual-energy virtual monoenergetic with iterative metal artifact reduction compared with those in original polychromatic kV images (3.02 vs 4.28, P < 0.001 and 3.00 vs 4.33, P < 0.001, respectively). The median difference in CT numbers between regions affected by artifacts and normal regions was lowest in 130 keV dual-energy virtual monoenergetic with iterative metal artifact reduction compared with that in original polychromatic kV images (72.28 vs 252.08, P < 0.001 for bony regions and 15.09 vs 324.38, P < 0.001 for soft tissue). Conclusion: In patients with metal artifacts due to shoulder replacement surgery, the use of dual-energy monoenergetic images and iterative metal artifact reduction reconstruction significantly improves both subjective and objective indicators of image quality.