基于图像加权的多能光子计数X线CT全能谱图像重建改进方法  

Improved image-based weighting method for full spectral image reconstruction of multi-energy photon counting X-ray CT

作　　者：周正东[1] 管绍林 涂佳丽 李剑波 张雯雯[1] 

机构地区：[1]南京航空航天大学核科学与工程系,南京210016

出　　处：《东南大学学报（自然科学版）》2017年第5期892-896,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51575256);中央高校基本科研业务费专项资金资助项目(NZ2016102)

摘　　要：为了提高基于图像加权的多能光子计数X线CT全能谱重建图像的质量,提出了一种图像重建改进方法.首先,对每个能量段的投影数据采用最大后验概率(MAP)统计重建算法进行图像重建;然后,对各能量段图像进行优化加权求和,获得全能谱图像.仿真实验结果表明,MAP统计重建算法可显著提高全能谱重建图像的对比噪声比(CNR).与滤波反投影算法相比,当能量段数分别为2,4,6,9时,MAP统计重建算法使得钙图像的CNR分别提高659.7%,643.4%,621.2%,586.1%,碘图像的CNR分别提高663.8%,648.6%,635.1%,600.9%,软组织图像的CNR分别提高596.2%,638.5%,592.6%,596.3%;与能量积分法相比,当能量段数分别为2,4,6,9时,M AP统计重建算法使得钙图像的CNR分别提高43.3%,49.1%,49.3%,44.5%,碘图像的CNR分别提高43.2%,45.7%,45.7%,40.2%,软组织图像的CNR分别提高21.5%,28.9%,25.5%,26.2%.To improve the full spectral reconstruction image quality for the image-based weighting multienergy photon counting X-ray computed tomography（ CT）,an improved image reconstruction method was proposed. First,the maximum a posteriori probability（ MAP） statistical reconstruction algorithm was used to reconstruct the image in each energy bin. Then,the images from each energy bin were summarized with optimal weights to obtain the full spectral image. The simulation experimental results demonstrate that the MAP statistical reconstruction algorithm can significantly improve the contrast-to-noise ratio（ CNR） of the full spectral reconstruction image. Compared with the filtered back projection（ FBP） algorithm,for the cases with the energy spectrum split into 2,4,6 and 9 bins,the MAP statistical reconstruction algorithm can offer the CNR improvement up to 659. 7%,643. 4%,621. 2% and 586. 1% for calcium,663. 8%,648. 6%,635. 1% and 600. 9% for iodine,596. 2%,638. 5%,592. 6% and 596. 3% for soft tissue,respectively. Compared with the energy-integrating method,for the energy-resolved cases with 2,4,6 and 9 energy bins,the MAP statistical reconstruction algorithm can offer the CNR improvement up to43. 3%,49. 1%,49. 3% and 44. 5% for calcium,43. 2%,45. 7%,45. 7% and 40. 2% for iodine,21.5%,28. 9%,25. 5% and 26. 2% for soft tissue,respectively.

关 键 词：光子计数X线CT 基于图像加权 最大后验概率 对比噪声比 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]