Spatial and temporal variations of flip-angle distributions in the human brain using an eight-channel parallel transmission system at 7T: comparison of three radiofrequency excitation methods
Spatial and temporal variations of flip-angle distributions in the human brain using an eight-channel parallel transmission system at 7T: comparison of three radiofrequency excitation methods
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使用 7T 八通道并行传输系统的人脑翻转角分布的时空变化：三种射频激励方法的比较
DOI：
10.1007/s12194-021-00612-8
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发表时间：
2021
影响因子：
1.6
通讯作者：
Sasaki Makoto
中科院分区：
文献类型：
--
作者：
Matsuda Tsuyoshi;Uwano Ikuko;Iwadate Yuji;Yoshioka Kunihiro;Sasaki Makoto
我们研究了翻转角（FA）分布在人脑中的空间和时间的变化，从多个扫描，使用八通道并行传输（pTx）系统在7 T。9名健康志愿者进行了扫描，在五个会话中使用三个射频激发技术，每次：圆极化（CP），静态pTx和动态pTx。我们计算了大脑区域内FA值的变异系数，以评估变异，以及FA值的最大会话间差异（Dmax），比较三种方法之间的差异。变异系数按以下顺序降低：CP、静态pTx和动态pTx（中位数：分别为20.1%、13.6%和5.7%;p< 0.001）。静态pTx（5.4°）的平均Dmax值显著高于动态pTx（2.8°）和CP（1.7°）方法（分别为p= 0.004和0.001）。与CP方法相比，在7 T下的动态pTx方法可以有效地最小化FA分布中的空间变化，而时间变化略有增加。静态pTx方法表现出非常宽的时间变化。
We investigated the spatial and temporal variations of flip-angle (FA) distributions in the human brain from multiple scans, using an eight-channel parallel transmission (pTx) system at 7T. Nine healthy volunteers were scanned in five sessions using three radiofrequency excitation techniques each time: circular polarization (CP), static pTx, and dynamic pTx. We calculated the coefficients of variation of the FA values within the brain area to evaluate the variations, and the maximum intersession differences in the FA values (Dmax), comparing them between the three methods. The coefficients of variation decreased in the following order: CP, static pTx, and dynamic pTx (median: 20.1%, 13.6%, and 5.7%, respectively;p< 0.001). The average Dmaxvalues were significantly higher for the static pTx (5.4°) than for the dynamic pTx (2.8°) and CP (1.7°) methods (p= 0.004 and 0.001, respectively). Compared to the CP method, the dynamic pTx method at 7T can efficiently minimize spatial variations in the FA distribution with a mild increase in temporal variations. The static pTx method exhibited a remarkably wide temporal variation.