To evaluate the effect of the single energy metal artifact reduction (SEMAR) algorithm with a multide‑ tector CT (MDCT) for knee tumor prostheses. Methods: First, a phantom of knee tumor prosthesis underwent a MDCT scan. The raw data was reconstructed by iterative reconstruction (IR) alone and IR plus SEMAR. The mean value of the CT number and the image noise were measured around the prosthesis at the stem level and articular level. | Zhang et al. BMC Cancer 2021 21 1288 https s12885-021-09029-3 RESEARCH Open Access Reduction of metal artifacts from knee tumor prostheses on CT images value of the single energy metal artifact reduction SEMAR algorithm Fang ling Zhang Ruo cheng Li Xiao ling Zhang Zhao hui Zhang Ling Ma and Lei Ding Abstract Background To evaluate the effect of the single energy metal artifact reduction SEMAR algorithm with a multide tector CT MDCT for knee tumor prostheses. Methods First a phantom of knee tumor prosthesis underwent a MDCT scan. The raw data was reconstructed by iterative reconstruction IR alone and IR plus SEMAR. The mean value of the CT number and the image noise were measured around the prosthesis at the stem level and articular level. Second 95 consecutive patients with knee tumor prostheses underwent MDCT scans. The raw data were also reconstructed by the two methods. Periprosthetic structures were selected at the similar two levels. Four radiologists visually graded the image quality on a scale from 0 to 5. Additionally the readers also assessed the presence of prosthetic complication and tumor recurrence on a same scale. Results In the phantom when the SEMAR was used the CT numbers were closer to normal value and the noise of images using soft and sharper kernel were respectively reduced by up to and at the stem level and by up to and at the articular level. The subjective scores increased 1 3 points and 1 4 points at the two levels respectively. Prosthetic complications and tumor recurrence were diagnosed in 66 patients. And the SEMAR increased the diagnostic confidence of prosthetic complications and tumor recurrence 4 5 vs. 1 . Conclusions The SEMAR algorithm can significantly reduce the metal artifacts and increase diagnostic confidence of prosthetic complications and tumor recurrence in patients with knee tumor prostheses. Keywords Metal artifact reduction Tumor prosthesis Knee Computed tomography Image quality .
