title: Reduction of metal artifacts from alloy hip prostheses in computer tomography.
abstract: OBJECTIVE
  The objective of this study was to evaluate the feasibility of reducing artifacts from large metal implants with gemstone spectral imaging (GSI) and metal artifact reduction software (MARS).
  
  
  METHODS
  Twenty-three in-vivo cobalt-chromium-molybdenum alloy total hip prostheses were prospectively scanned by fast kV-switching GSI between 80 and 140 kVp. The computed tomography images were reconstructed with monochromatic energy and with/without MARS. Both subjective and objective measurements were performed to assess the severity of metal artifacts.
  
  
  RESULTS
  Increasing photon energy was associated with reduced metal artifacts in GSI images (P < 0.001). Combination of GSI with MARS further diminished the metal artifacts (P < 0.001). Artifact reduction at 3 anatomical levels (femoral head, neck, and shaft) were evaluated, with data showing that GSI and MARS could reduce metal artifacts at all 3 levels (P = 0.011, P < 0.001, and P = 0.003, respectively). Nevertheless, in certain cases, GSI without MARS produced more realistic images for the clinical situation.
  
  
  CONCLUSIONS
  Proper usage of GSI with/without MARS could reduce the computed tomography artifacts of large metal parts and improve the radiological evaluation of postarthroplasty patients.
authors.affiliation: From the *Department of Radiology, Peking Union Medical College Hospital, †Department of Pathophysiology, Institute of Basic Medical Sciences, ‡Statistics Office, and §Department of Orthopedics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Fengdan
authors.initials: F
authors.lastname: Wang
authors.forename: Huadan
authors.initials: H
authors.lastname: Xue
authors.forename: Xianda
authors.initials: X
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Han
authors.forename: Bing
authors.initials: B
authors.lastname: Qi
authors.forename: Yu
authors.initials: Y
authors.lastname: Fan
authors.forename: Wenwei
authors.initials: W
authors.lastname: Qian
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Wu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Jin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys; D016477:Artifacts; D005240:Feasibility Studies; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D000497:Alloys