Beam hardening and motion artifacts in cardiac CT: Evaluation and iterative correction method

Zeyang Shen, Okkyun Lee, Katsuyuki Taguchi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

For myocardial perfusion CT exams, beam hardening (BH) artifacts may degrade the accuracy of myocardial perfusion defect detection. Meanwhile, cardiac motion may make BH process inconsistent, which makes conventional BH correction (BHC) methods ineffective. The aims of this study were to assess the severity of BH artifacts and motion artifacts and propose a projection-based iterative BHC method which has a potential to handle the motion-induced inconsistency better than conventional methods. In this study, four sets of forward projection data were first acquired using both cylindrical phantoms and cardiac images as objects: (1) with monochromatic x-rays without motion; (2) with polychromatic x-rays without motion; (3) with monochromatic x-rays with motion; and (4) with polychromatic x-rays with motion. From each dataset, images were reconstructed using filtered back projection; for datasets 2 and 4, one of the following BHC methods was also performed: (A) no BHC; (B) BHC that concerns water only; and (C) BHC that takes both water and iodine into account, which is an iterative method we developed in this work. Biases of images were quantified by the mean absolute difference (MAD). The MAD of images with BH artifacts alone (dataset 2, without BHC) was comparable or larger than that of images with motion artifacts alone (dataset 3): In the study of cardiac image, BH artifacts account for over 80% of the total artifacts. The use of BHC was effective: with dataset 4, MAD values were 170 HU with no BHC, 54 HU with water BHC, and 42 HU with the proposed BHC. Qualitative improvements in image quality were also noticeable in reconstructed images.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2016: Physics of Medical Imaging
PublisherSPIE
Volume9783
ISBN (Electronic)9781510600188
DOIs
StatePublished - 2016
EventMedical Imaging 2016: Physics of Medical Imaging - San Diego, United States
Duration: Feb 28 2016Mar 2 2016

Other

OtherMedical Imaging 2016: Physics of Medical Imaging
CountryUnited States
CitySan Diego
Period2/28/163/2/16

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Keywords

  • beam hardening artifacts
  • beam hardening correction
  • cardiac computed tomography
  • motion artifacts

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Shen, Z., Lee, O., & Taguchi, K. (2016). Beam hardening and motion artifacts in cardiac CT: Evaluation and iterative correction method. In Medical Imaging 2016: Physics of Medical Imaging (Vol. 9783). [978336] SPIE. https://doi.org/10.1117/12.2217150