投影数据恢复导引的非局部平均低剂量CT优质重建  

Projection Data Recovery Induced Non-local Means for Low-Dose CT Reconstruction

作　　者：刘楠[1] 黄静[1] 马建华[1] 陈武凡[1] 卢虹冰[2] Zhengrong Liang 

机构地区：[1]南方医科大学生物医学工程学院,广州510515 [2]第四军医大学生物医学工程系,西安710032 [3]Department of Radiology, State University of New York at Stony Brook, Stony Brook, NY 11794 USA

出　　处：《计算机辅助设计与图形学学报》2011年第4期615-621,共7页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家自然科学基金(81000613);国家“九七三”重点基础研究发展计划项目(2010CB732503)

摘　　要：针对低剂量CT成像质量退化问题,将CT投影数据恢复与图像数据恢复巧妙地融合,提出一种投影数据恢复导引的非局部平均(NL-means)低剂量CT重建方法.首先通过非线性Anscombe变换将满足Poisson分布的投影数据转化为Gaussian分布,以便于投影数据噪声的滤除;然后对滤波后的投影数据执行Anscombe逆变换和滤波反投影(FBP)CT图像重建;最后将投影数据滤波后的FBP图像作为先验构建非局部权值矩阵,并将该权值矩阵用于低剂量CT图像的非局部平均成像.仿真和临床实验结果表明,该方法在噪声消除和伪影抑制两方面均有上佳表现.To improve the quality of low-dose computed tomography （CT） image, a novel projection data recovery induced non-local means for low-dose CT reconstruction is proposed. The presented method can take the advantages of data recovery methods in two domains （projection domain and image domain）. Specially, the projection data is first transformed from Poisson distribution to Gaussian distribution using the nonlinear Anscombe transform in order to easily filter the noise of projection data. Second, after Anscombe transformed data is filtered, Anscombe inverse transform is performed, and the reconstructed image is achieved using the classical filtered back projection （FBP） method from filtered projection data. Last, non local means （NL-means） weights of FBP image are computed from the restored projection data to induce the NL-means filtering of directly reconstructed FBP image from the un restored projection data. Simulated and clinical experimental results demonstrate that the proposed method performs very well in lowering the noise and preserving the image edge.

关 键 词：低剂量CT Anscombe变换 投影数据滤波 非局部平均 

分 类 号：R391.4[医药卫生—基础医学]