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Proceedings Paper

Dual energy x-ray imaging and scoring of coronary calcium: physics-based digital phantom and clinical studies
Author(s): Bo Zhou; Di Wen; Katelyn Nye; Robert C. Gilkeson; David L. Wilson
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Paper Abstract

Coronary artery calcification (CAC) as assessed with CT calcium score is the best biomarker of coronary artery disease. Dual energy x-ray provides an inexpensive, low radiation-dose alternative. A two shot system (GE Revolution-XRd) is used, raw images are processed with a custom algorithm, and a coronary calcium image (DECCI) is created, similar to the bone image, but optimized for CAC visualization, not lung visualization. In this report, we developed a physicsbased, digital-phantom containing heart, lung, CAC, spine, ribs, pulmonary artery, and adipose elements, examined effects on DECCI, suggested physics-inspired algorithms to improve CAC contrast, and evaluated the correlation between CT calcium scores and a proposed DE calcium score. In simulation experiment, Beam hardening from increasing adipose thickness (2cm to 8cm) reduced Cg by 19% and 27% in 120kVp and 60kVp images, but only reduced Cg by <7% in DECCI. If a pulmonary artery moves or pulsates with blood filling between exposures, it can give rise to a significantly confounding PA signal in DECCI similar in amplitude to CAC. Observations suggest modifications to DECCI processing, which can further improve CAC contrast by a factor of 2 in clinical exams. The DE score had the best correlation with "CT mass score" among three commonly used CT scores. Results suggest that DE x-ray is a promising tool for imaging and scoring CAC, and there still remains opportunity for further DECCI processing improvements.

Paper Details

Date Published: 31 March 2016
PDF: 10 pages
Proc. SPIE 9783, Medical Imaging 2016: Physics of Medical Imaging, 978342 (31 March 2016); doi: 10.1117/12.2217023
Show Author Affiliations
Bo Zhou, Case Western Reserve Univ. (United States)
Di Wen, Case Western Reserve Univ. (United States)
Katelyn Nye, GE Healthcare (United States)
Robert C. Gilkeson, Univ. Hospitals of Cleveland, Case Medical Ctr. (United States)
David L. Wilson, Case Western Reserve Univ. (United States)

Published in SPIE Proceedings Vol. 9783:
Medical Imaging 2016: Physics of Medical Imaging
Despina Kontos; Thomas G. Flohr, Editor(s)

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