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BioMed Research International
Volume 2013 (2013), Article ID 417278, 8 pages
http://dx.doi.org/10.1155/2013/417278
Research Article

Simultaneous Reduction in Noise and Cross-Contamination Artifacts for Dual-Energy X-Ray CT

1Department of Radiology, Boston University Medical Center, Boston, MA 02118, USA
2Department of Computer Science & Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
3Department of Radiology, Xijing Hospital, Xi’an, Shaanxi 710049, China
4CT System Lab, GE Global Research Center, Schenectady, NY 12309, USA

Received 4 April 2013; Accepted 6 June 2013

Academic Editor: Gianluca Pontone

Copyright © 2013 Baojun Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. Dual-energy CT imaging tends to suffer from much lower signal-to-noise ratio than single-energy CT. In this paper, we propose an improved anticorrelated noise reduction (ACNR) method without causing cross-contamination artifacts. Methods. The proposed algorithm diffuses both basis material density images (e.g., water and iodine) at the same time using a novel correlated diffusion algorithm. The algorithm has been compared to the original ACNR algorithm in a contrast-enhanced, IRB-approved patient study. Material density accuracy and noise reduction are quantitatively evaluated by the percent density error and the percent noise reduction. Results. Both algorithms have significantly reduced the noises of basis material density images in all cases. The average percent noise reduction is 69.3% and 66.5% with the ACNR algorithm and the proposed algorithm, respectively. However, the ACNR algorithm alters the original material density by an average of 13% (or 2.18 mg/cc) with a maximum of 58.7% (or 8.97 mg/cc) in this study. This is evident in the water density images as massive cross-contaminations are seen in all five clinical cases. On the contrary, the proposed algorithm only changes the mean density by 2.4% (or 0.69 mg/cc) with a maximum of 7.6% (or 1.31 mg/cc). The cross-contamination artifacts are significantly minimized or absent with the proposed algorithm. Conclusion. The proposed algorithm can significantly reduce image noise present in basis material density images from dual-energy CT imaging, with minimized cross-contaminations compared to the ACNR algorithm.