Department of Radiology, Boston University Medical Center, Boston, MA 02118, USA.
Biomed Res Int. 2013;2013:417278. doi: 10.1155/2013/417278. Epub 2013 Jun 19.
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.
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.
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.
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.
与单能 CT 相比，双能 CT 成像往往会遭受更低的信噪比。在本文中，我们提出了一种改进的抗相关降噪（ACNR）方法，不会造成交叉污染伪影。
该算法使用一种新的相关扩散算法同时扩散基物质密度图像（例如水和碘）。该算法已在一项对比增强、IRB 批准的患者研究中与原始 ACNR 算法进行了比较。通过密度误差百分比和噪声降低百分比来定量评估材料密度准确性和噪声降低。
两种算法都显著降低了所有情况下基物质密度图像的噪声。ACNR 算法和所提出的算法的平均噪声降低率分别为 69.3%和 66.5%。然而，ACNR 算法在这项研究中平均改变原始材料密度 13%（或 2.18mg/cc），最大改变 58.7%（或 8.97mg/cc）。这在水密度图像中很明显，所有五个临床病例都出现了大量的交叉污染。相反，所提出的算法仅将平均密度改变 2.4%（或 0.69mg/cc），最大改变 7.6%（或 1.31mg/cc）。与 ACNR 算法相比，所提出的算法显著减少或消除了交叉污染伪影。
与 ACNR 算法相比，所提出的算法可以显著降低双能 CT 成像中基物质密度图像中的图像噪声，并且交叉污染最小。
