title: Improved image quality in abdominal CT in patients who underwent treatment for hepatocellular carcinoma with small metal implants using a raw data-based metal artifact reduction algorithm.
abstract: OBJECTIVE
  To determine the value of a raw data-based metal artifact reduction (SEMAR) algorithm for image quality improvement in abdominal CT for patients with small metal implants.
  
  
  METHODS
  Fifty-eight patients with small metal implants (3-15 mm in size) who underwent treatment for hepatocellular carcinoma were imaged with CT. CT data were reconstructed by filtered back projection with and without SEMAR algorithm in axial and coronal planes. To evaluate metal artefact reduction, mean CT number (HU and SD) and artefact index (AI) values within the liver were calculated. Two readers independently evaluated image quality of the liver and pancreas and visualization of vasculature using a 5-point visual score. HU and AI values and image quality on images with and without SEMAR were compared using the paired Student's t-test and Wilcoxon signed rank test. Interobserver agreement was evaluated using linear-weighted κ test.
  
  
  RESULTS
  Mean HU and AI on images with SEMAR was significantly lower than those without SEMAR (P < 0.0001). Liver and pancreas image qualities and visualizations of vasculature were significantly improved on CT with SEMAR (P < 0.0001) with substantial or almost perfect agreement (0.62 ≤ κ ≤ 0.83).
  
  
  CONCLUSIONS
  SEMAR can improve image quality in abdominal CT in patients with small metal implants by reducing metallic artefacts.
  
  
  CONCLUSIONS
  • SEMAR algorithm significantly reduces metallic artefacts from small implants in abdominal CT. • SEMAR can improve image quality of the liver in dynamic CECT. • Confidence visualization of hepatic vascular anatomies can also be improved by SEMAR.
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan. keitarosofue@gmail.com.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Sofue
authors.affiliation: Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.|Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.affiliation: Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.|Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Division of Radiology, Kobe University Hospital, Kobe, Hyogo, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Negi
authors.affiliation: Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Inokawa
authors.affiliation: Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sugihara
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging*; D000368:Aged; D000465:Algorithms; D016477:Artifacts; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008670:Metals; D008875:Middle Aged; D019736:Prostheses and Implants; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000592:standards*
chemical_list: D008670:Metals
keywords: Abdominal; Computed tomography; Hepatocellular carcinoma; Liver; Metal artefact reduction