Body diffusion-weighted imaging using magnetization prepared single-shot fast spin echo and extended parallel imaging signal averaging.
Body diffusion-weighted imaging using magnetization prepared single-shot fast spin echo and extended parallel imaging signal averaging.
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DOI：
10.1002/mrm.26971
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发表时间：
2018-06
影响因子：
3.3
通讯作者：
Kerr AB
中科院分区：
文献类型：
--
作者：
Gibbons EK;Vasanawala SS;Pauly JM;Kerr AB
这项工作证明了磁化准备扩散加权单次快速自旋回波（SS-FSE）脉冲序列的身体成像的应用，以提高几何失真的鲁棒性。这项工作还提出了一种扫描平均技术，是上级幅度平均，是不受工件由于对象相位。该单次激发序列对于违反Carr-Purcell-Meiboom-Gill（CPMG）条件是稳健的。这是通过在扩散加权后使信号失相并将信号的MG分量倾斜到纵轴上而非MG分量被破坏来实现的。然后使用传统的SS-FSE序列激发和捕获MG信号分量，尽管需要在每个回波之前调用回波。在将多个采集的线圈灵敏度连接成一个大型并行成像（PI）问题的情况下，使用扩展并行成像（ExtPI）平均。PI问题的大小通过基于SVD的线圈压缩来减小，该线圈压缩还提供背景噪声抑制。在模拟、体模扫描和体内腹部临床病例中评估该序列和重建。仿真结果表明，该序列在整个回波链中产生稳定的信号，从而获得良好的图像质量。该序列固有地是低SNR的，但是可以通过扫描平均和所提出的ExtPI重建来恢复大部分SNR。在体内的结果表明，所提出的方法是能够提供扩散编码的图像，同时减轻几何失真的文物相比，EPI。这项工作提出了一种扩散准备的SS-FSE序列，该序列对违反CPMG条件具有鲁棒性，同时在临床病例中提供扩散对比。
This work demonstrates a magnetization prepared diffusion-weighted single-shot fast spin echo (SS-FSE) pulse sequence for the application of body imaging to improve robustness to geometric distortion. This work also proposes a scan averaging technique that is superior to magnitude averaging and is not subject to artifacts due to object phase. This single-shot sequence is robust against violation of the Carr-Purcell-Meiboom-Gill (CPMG) condition. This is achieved by dephasing the signal after diffusion weighting and tipping the MG component of the signal onto the longitudinal axis while the non-MG component is spoiled. The MG signal component is then excited and captured using a traditional SS-FSE sequence, although the echo needs to be recalled prior to each echo. Extended Parallel Imaging (ExtPI) averaging is used where coil sensitivities from the multiple acquisitions are concatenated into one large parallel imaging (PI) problem. The size of the PI problem is reduced by SVD-based coil compression which also provides background noise suppression. This sequence and reconstruction are evaluated in simulation, phantom scans, and in vivo abdominal clinical cases. Simulations show that the sequence generates a stable signal throughout the echo train which leads to good image quality. This sequence is inherently low-SNR, but much of the SNR can be regained through scan averaging and the proposed ExtPI reconstruction. In vivo results show that the proposed method is able to provide diffusion encoded images while mitigating geometric distortion artifacts compared to EPI. This work presents a diffusion-prepared SS-FSE sequence that is robust against the violation of the CPMG condition while providing diffusion contrast in clinical cases.
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影响因子：
3.3
作者：
Buehrer, Martin;Pruessmann, Klaas P.;Kozerke, Sebastian
通讯作者：
Kozerke, Sebastian
影响因子：
2.2
作者：
CONOLLY, S;NISHIMURA, D;GLOVER, G
通讯作者：
GLOVER, G
影响因子：
10.6
作者：
Gibbons, Eric K.;Le Roux, Patrick;Kerr, Adam B.
通讯作者：
Kerr, Adam B.
影响因子：
3.3
作者：
NORRIS, DG;BORNERT, P;LEIBFRITZ, D
通讯作者：
LEIBFRITZ, D
影响因子：
2.2
作者：
Le Roux, P.;McKinnon, G.;Fernandez, B.
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Fernandez, B.