JOINT ESTIMATION OF IMAGE AND COIL SENSITIVITIES IN PARALLEL SPIRAL MRI
JOINT ESTIMATION OF IMAGE AND COIL SENSITIVITIES IN PARALLEL SPIRAL MRI
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并行螺旋 MRI 中图像和线圈灵敏度的联合估计
DOI：
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发表时间：
2006
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通讯作者：
Bo Liu
中科院分区：
文献类型：
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作者：
J. Sheng;L. Ying;E. Wiener;Bo Liu
螺旋MRI由于其减少的T2 * 衰减和对大体积生理运动的鲁棒性而受到越来越多的关注。在并行成像中，螺旋轨迹由于其固有的自校准能力而特别令人感兴趣，这对于诸如fMRI和心脏成像的动态成像应用特别有用。现有的螺旋线自校准技术使用在加速采集中密集采样的k空间中心数据来估计线圈灵敏度。在选择中心数据的半径时存在权衡：它必须足够大以包含线圈灵敏度的所有主要空间频率，但又不能太大，以免在轨迹远离中心k空间时由于低于奈奎斯特速率的欠采样而导致显著的混叠伪影。为了解决这个权衡，我们推广的JSENSE方法，这已经证明了成功的笛卡尔的情况下，螺旋轨迹。具体地，该方法联合地估计线圈灵敏度并通过交叉验证重建期望的图像，使得灵敏度是从由SENSE恢复的完整数据而不是仅从中心k空间数据估计的，从而增加高频信息而不引入混叠伪影。我们使用实验结果表明，该方法提高了灵敏度，从而导致更准确的SENSE重建
Spiral MRI has received increasing attention due to its reduced T 2*-decay and robustness against bulk physiologic motion. In parallel imaging, spiral trajectories are especially of great interest due to their inherent self-calibration capabilities, which is especially useful for dynamic imaging applications such as fMRI and cardiac imaging. The existing self-calibration techniques for spiral use the k-space center data that are sampled densely in the accelerated acquisition for coil sensitivity estimation. There exists a trade-off in choosing the radius of the center data: it must be sufficiently large to contain all major spatial frequencies of coil sensitivity, but not too large to cause significant aliasing artifacts due to undersampling below Nyquist rate as the trajectory moves away from the center k-space. To address this tradeoff, we generalize the JSENSE approach, which has demonstrated success in Cartesian case, to spiral trajectory. Specifically, the method jointly estimates the coil sensitivities and reconstructs the desired image through cross validations so that the sensitivities are estimated from the full data recovered by SENSE instead of the center k-space data only, thereby increasing high frequency information without introducing aliasing artifacts. We use experimental results to show the proposed method improves sensitivities, which leads to a more accurate SENSE reconstruction