Purpose. Dual-energy CT imaging tends to suffer from much lower signal-to-noise ratio than single-energy CT. In this paper, we\npropose an improved anticorrelated noise reduction (ACNR)method without causing cross-contamination artifacts. Methods. The\nproposed algorithm diffuses both basis material density images (e.g., water and iodine) at the same time using a novel correlated\ndiffusion algorithm. The algorithm has been compared to the original ACNR algorithm in a contrast-enhanced, IRB-approved\npatient study. Material density accuracy and noise reduction are quantitatively evaluated by the percent density error and the\npercent noise reduction. Results. Both algorithms have significantly reduced the noises of basis material density images in all\ncases. The average percent noise reduction is 69.3% and 66.5% with the ACNR algorithmand the proposed algorithm, respectively.\nHowever, the ACNR algorithm alters the original material density by an average of 13% (or 2.18mg/cc) with a maximum of 58.7%\n(or 8.97mg/cc) in this study. This is evident in the water density images as massive cross-contaminations are seen in all five clinical\ncases. On the contrary, the proposed algorithm only changes the mean density by 2.4% (or 0.69mg/cc) with amaximum of 7.6% (or\n1.31mg/cc). The cross-contamination artifacts are significantly minimized or absent with the proposed algorithm. Conclusion. The\nproposed algorithm can significantly reduce image noise present in basis material density images from dual-energy CT imaging,\nwith minimized cross-contaminations compared to the ACNR algorithm.
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