Reduced aliasing artifacts using shaking projection k-space sampling trajectory

作     者：朱艳春 杜江 杨文超 段侪杰 王浩宇 高嵩 包尚联 

作者机构：Beijing Key Laboratory of Medical Physics and Engineering School of Physics Peking University Department of Radiology University of California Institute of Computational Physics and Complex Systems Lanzhou University Shenzhen Key Laboratory for Minimal Invasive Medical Technologies Tsinghua University Medical Imaging Physics Laboratory Health Science Center of Peking University 

基　　金：Project supported by the National Basic Research Program of China(Grant No.2011CB707701) the Innovation Fund for Technology Based Firms,China(Grant No.11C26221103870) the National High Technology Research and Development Program of China(Grant Nos.2011BAI12B05 and 2011BAI23B07) the National Natural Science Foundation of China(Grant Nos.81171330,81271664,and 81230035) 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2014年第23卷第3期

页      码：656-662页

摘      要：Radial imaging techniques, such as projection-reconstruction （PR）, are used in magnetic resonance imaging （MRI） for dynamic imaging, angiography, and short-T2 imaging. They are less sensitive to flow and motion artifacts, and support fast imaging with short echo times. However, aliasing and streaking artifacts are two main sources which degrade radial imaging quality. For a given fixed number of k-space projections, data distributions along radial and angular directions will influence the level of aliasing and streaking artifacts. Conventional radial k-space sampling trajectory introduces an aliasing artifact at the first principal ring of point spread function （PSF）. In this paper, a shaking projection （SP） k-space sampling trajectory was proposed to reduce aliasing artifacts in MR images. SP sampling trajectory shifts the projection alternately along the k-space center, which separates k-space data in the azimuthal direction. Simulations based on conventional and SP sampling trajectories were compared with the same number projections. A significant reduction of aliasing artifacts was observed using the SP sampling trajectory. These two trajectories were also compared with different sampling frequencies. ASP trajectory has the same aliasing character when using half sampling frequency （or half data） for reconstruction. SNR comparisons with different white noise levels show that these two trajectories have the same SNR character. In conclusion, the SP trajectory can reduce the aliasing artifact without decreasing SNR and also provide a way for undersampling recon- struction. Furthermore, this method can be applied to three-dimensional （3D） hybrid or spherical radial k-space sampling for a more efficient reduction of aliasing artifacts.

主 题 词：shaking projection radial sampling gridding reconstruction point spread function 

学科分类：08[工学] 080203[080203] 0802[工学-机械学] 0823[工学-农业工程类] 

核心收录：

D　O　I：10.1088/1674-1056/23/3/038702

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