Combined application of virtual monoenergetic high keV images and the orthopedic metal artifact reduction algorithm (O-MAR): effect on image quality

Junghoan Park, Se Hyung Kim, Joon Koo Han

Research output: Contribution to journalArticle

2 Scopus citations


Purpose: To determine whether there is any additional metal artifact reduction when virtual monochromatic images (VMI) and metal artifact reduction for orthopedic implants (O-MAR) are applied together compared to their separate application in both phantom and clinical abdominopelvic CT studies. Methods: An agar phantom containing a spinal prosthesis was scanned using a dual-layer, energy CT scanner (IQon, Philips Healthcare), and reconstructed with the filtered back-projection algorithm without O-MAR (FBP), filtered back-projection algorithm with O-MAR (O-MAR), VMI 140 without O-MAR (VMI 140 ), and VMI 140 with O-MAR (VMI 140 + O-MAR). Abdominopelvic CT images of 47 patients with metallic prostheses were also reconstructed in the same manner for clinical study. Noise measured as the standard deviation of CT Hounsfield units was compared between the four reconstruction methods in both phantom and clinical studies. Improvements in metal artifact reduction, image quality, and diagnostic improvement were further analyzed in the clinical study. Results: Noise was significantly decreased when both VMI and O-MAR were applied in conjunction compared to their separate application in both phantom (16.3 HU vs. 25.0 and 26.4 HU) and clinical studies (15.8 HU vs. 19.2 and 26.2 HU). In the clinical study, the qualitative degree of artifacts was also significantly reduced with VMI 140 + O-MAR (2.85 and 2.87) compared to VMI 140 (2.36 and 2.26) or O-MAR (2.13 and 2.04) alone for both reviewers (P < 0.001) and improvements in image quality were observed in all 47 patients, with actual diagnostic improvements observed in three. Conclusions: Metal artifacts can be additionally reduced by applying O-MAR and VMI in conjunction, compared to their separate application, thereby improving diagnostic performance.

Original languageEnglish
Pages (from-to)756-765
Number of pages10
JournalAbdominal Radiology
Issue number2
StatePublished - 15 Feb 2019


  • Artifact reduction
  • Dual-energy CT
  • Metal artifact
  • Virtual monoenergetic image

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