Evaluation Of Orthopedic Metal Artifact Reduction In 256-slice Spiral CT Imaging Of Hip Prostheses

Objective: To evaluate the orthopedic metal artifact reduction in 256-slice spiral CT imaging of hip prostheses.So as to achieve the purpose of better image quality without increasing the radiation dose.Thus,it helps imaging evaluation of the hip replacement effectively.Materials and methods: The study included 40 patients(male female ratio,21:19)who received total hip replacements.All patients took the examination of Philips 256 i CT.All scans were obtained using the same technique.The system reconstructed the O-MAR-processed images in addition to the uncorrected images.They can regard as two groups,namely non O-MAR group and O-MAR group.The evaluation of image quality is carried out in two different ways: objective evaluation and subjective evaluationTo compare quantitative measures of image quality,in terms of objective image noises(OINs).Subjective evaluation was performed by two blinded,independent readers evaluating axial CT images for streaking artifacts,image sharpness,texture naturalness,and diagnostic confidence.They graded all images and recorded them for statistical analysis.Results: Adjacent to the hardware where there was extensive streak artifact,compared with non O-MAR group,the O-MAR group showed lower OIN(59.90±21.51 and 81.12±26.00,t=17.17,P=0.00).Away from the hardware where there were nearly no streak artifacts,the results were very similar between the two groups in all locations.In particular,OIN:35.40±0.97 and 35.37±0.96,t=1.94,P=0.06.Better qualitative scores were obtained in the streaking artifacts,image sharpness,and texture naturalness with O-MAR compared with non-O-MAR.Both readers identified the anatomical structures with higher confidence(P ≤ 0.01)with O-MAR than non-O-MAR,streaking artifacts score: 4(1)and 2(1),Z=-5.90,P=0.00;image sharpness score: 3(1)and 2(1),Z=-5.47,P =0.00;texture naturalness score: 3(1)and 2(1),Z=-5.62,P =0.00;diagnostic confidence score:4.00(1)and 2.50(1),Z =-5.96,P =0.00.But orthopedic MAR–related new artifacts were seen in 9 patients.Conclusion: The O-MAR technique provided lower noise values,better image quality,and less streak artifact near hip arthroplasties.O-MAR also increased observer ability and confidence to identified the anatomical structures near arthroplasties,thus improving diagnostic performance in patients with severe metallic artifacts.