title: Combined use of iterative reconstruction and monochromatic imaging in spinal fusion CT images.
abstract: BACKGROUND
  Spinal fusion surgery is an important procedure for treating spinal diseases and computed tomography (CT) is a critical tool for postoperative evaluation. However, CT image quality is considerably impaired by metal artifacts and image noise.
  
  
  OBJECTIVE
  To explore whether metal artifacts and image noise can be reduced by combining two technologies, adaptive statistical iterative reconstruction (ASIR) and monochromatic imaging generated by gemstone spectral imaging (GSI) dual-energy CT.
  
  
  METHODS
  A total of 51 patients with 318 spinal pedicle screws were prospectively scanned by dual-energy CT using fast kV-switching GSI between 80 and 140 kVp. Monochromatic GSI images at 110 keV were reconstructed either without or with various levels of ASIR (30%, 50%, 70%, and 100%). The quality of five sets of images was objectively and subjectively assessed.
  
  
  RESULTS
  With objective image quality assessment, metal artifacts decreased when increasing levels of ASIR were applied (P < 0.001). Moreover, adding ASIR to GSI also decreased image noise (P < 0.001) and improved the signal-to-noise ratio (P < 0.001). The subjective image quality analysis showed good inter-reader concordance, with intra-class correlation coefficients between 0.89 and 0.99. The visualization of peri-implant soft tissue was improved at higher ASIR levels (P < 0.001).
  
  
  CONCLUSIONS
  Combined use of ASIR and GSI decreased image noise and improved image quality in post-spinal fusion CT scans. Optimal results were achieved with ASIR levels ≥70%.
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Beijing, PR China.
authors.forename: Fengdan
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Beijing, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Beijing, PR China.
authors.forename: Huadan
authors.initials: H
authors.lastname: Xue
authors.affiliation: Statistics Office, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Han
authors.affiliation: Department of Pathophysiology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China.
authors.forename: Xianda
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Beijing, PR China pumchradiology@126.com.
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Department of Radiology, Austin Health, Victoria, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Zwar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016477:Artifacts; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013122:Spinal Diseases / Q000000981:diagnostic imaging* / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D008670:Metals
keywords: Image noise; dual-energy computed tomography; iterative reconstruction; metal artifacts