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	Reduced aliasing artifacts using shaking projection k-space sampling trajectory
	Zhu YC(朱艳春) ; Du J(杜江) ; Yang WC(杨文超) ; Duan CJ(段侪杰) ; Wang HY(王浩宇) ; Gao S(高嵩) ; Bao SL(包尚联) ; Zhu Yan-Chun ; Du Jiang ; Yang Wen-Chao ; Duan Chai-Jie ; Wang Hao-Yu ; Gao Song ; Bao Shang-Lian
	2016-03-30 ; 2016-03-30
关键词	shaking projection radial sampling gridding reconstruction point spread function TP391.41
其他题名	Reduced aliasing artifacts using shaking projection k-space sampling trajectory
中文摘要	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.A SP 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 reconstruction. 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.; 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.A SP 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 reconstruction. 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.
语种	英语 ; 英语
内容类型	期刊论文
源URL	[http://ir.lib.tsinghua.edu.cn/ir/item.do?handle=123456789/148203]
专题	清华大学
推荐引用方式 GB/T 7714	Zhu YC,Du J,Yang WC,et al. Reduced aliasing artifacts using shaking projection k-space sampling trajectory[J],2016, 2016.
APA	朱艳春.,杜江.,杨文超.,段侪杰.,王浩宇.,...&Bao Shang-Lian.(2016).Reduced aliasing artifacts using shaking projection k-space sampling trajectory..
MLA	朱艳春,et al."Reduced aliasing artifacts using shaking projection k-space sampling trajectory".(2016).

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