European Radiology

, Volume 27, Issue 7, pp 2978–2988 | Cite as

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

  • Keitaro SofueEmail author
  • Takeshi Yoshikawa
  • Yoshiharu Ohno
  • Noriyuki Negi
  • Hiroyasu Inokawa
  • Naoki Sugihara
  • Kazuro Sugimura
Computed Tomography



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.


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.


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).


SEMAR can improve image quality in abdominal CT in patients with small metal implants by reducing metallic artefacts.

Key Points

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.


Computed tomography Metal artefact reduction Liver Hepatocellular carcinoma Abdominal 



Artefact index


Contrast-enhanced computed tomography


Filtered back projection


Hepatocellular carcinoma


Single-energy metal artefact reduction



The authors wish to thank to Sumiaki Matsumoto, MD, PhD (Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, and Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine), Koji Sugimoto, MD, PhD, Masato Yamaguchi, MD, PhD (Center for Endovascular Therapy, Kobe University Hospital), Yonson Ku, MD, PhD, Takumi Fukumoto, MD, PhD (Division of Hepato-Biliary-Pancreatic Surgery, Department of Surgery, Kobe University Graduate School of Medicine), and Yoshihiko Yano, MD, PhD (Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate, School of Medicine) for their contributions to this work.

The scientific guarantor of this publication is Keitaro Sofue. The authors of this manuscript declare relationships with the following companies: Toshiba Medical Systems – research support for Takeshi Yoshikawa and Yoshiharu Ohno, and employment for Hiroyasu Inokawa and Naoki Sugihara. This work was technically and financially supported by Toshiba Medical Systems Corporation, and financially supported by Bayer Pharma, Daiichi-Sankyo, Co. Ltd. and Eisai Co. Ltd. in the form of research grants. No complex statistical methods were necessary for this paper. Institutional Review Board approval was obtained. Written informed consent was obtained from all patients in this study. No study subjects or cohorts have been previously reported. Methodology: prospective, observational study, performed at one institution.


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Copyright information

© European Society of Radiology 2016

Authors and Affiliations

  • Keitaro Sofue
    • 1
    Email author
  • Takeshi Yoshikawa
    • 2
    • 3
  • Yoshiharu Ohno
    • 2
    • 3
  • Noriyuki Negi
    • 4
  • Hiroyasu Inokawa
    • 5
  • Naoki Sugihara
    • 5
  • Kazuro Sugimura
    • 1
  1. 1.Department of RadiologyKobe University Graduate School of MedicineKobeJapan
  2. 2.Advanced Biomedical Imaging Research CenterKobe University Graduate School of MedicineKobeJapan
  3. 3.Division of Functional and Diagnostic Imaging Research, Department of RadiologyKobe University Graduate School of MedicineKobeJapan
  4. 4.Division of RadiologyKobe University HospitalKobeJapan
  5. 5.Toshiba Medical Systems CorporationOtawaraJapan

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