Advanced three-dimensional tailored RF pulse for signal recovery in T2*-weighted functional magnetic resonance imaging
Advanced three-dimensional tailored RF pulse for signal recovery in T2*-weighted functional magnetic resonance imaging
复制标题
DOI：
10.1002/mrm.21048
复制
发表时间：
2006-11-01
影响因子：
3.3
通讯作者：
Noll, Douglas C.
中科院分区：
文献类型：
--
作者：
Yip, Chun-yu;Fessler, Jeffrey A.;Noll, Douglas C.
T-2（*）加权功能MR图像受到由磁化率诱导的通面减相引起的信号损失伪影的困扰。我们介绍了原始的三维定制射频（3DTRF）脉冲方法的主要进展，该方法使用三维选择性激励预先补偿退相。所提出的3DTRIF脉冲采用非共振合并迭代设计，并采用新颖的回波-体积轨迹，在z位置进行频率编码，在x， y位置进行相位编码。我们还提出了一种加速脉冲设计过程的计算方案。我们利用15.4 ms长的3DTRF脉冲，在幻脑和下脑的5mm切片上展示了有效的信号恢复。与原始方法相比，新方法显著减小了脉冲长度，提高了切片选择性。切片体积的三维图像证实了激发相位模式和切片轮廓的保真度。
T-2(*)-weighted functional MR images are plagued by signal loss artifacts caused by susceptibility-induced through-plane dephasing. We present major advances to the original three-dimensional tailored RF (3DTRF) pulse method that precompensates the dephasing using three-dimensional selective excitation. The proposed 3DTRIF pulses are designed iteratively with off-resonance incorporation and with a novel echo-volumar trajectory that frequency-encodes in z and phase-encodes in x, y. We also propose a computational scheme to accelerate the pulse design process. We demonstrate effective signal recovery in a 5-mm slice in both phantom and inferior brain, using 3DTRF pulses that are only 15.4 ms long. Compared to the original method, the new approach leads to significantly reduced pulse length and enhancement in slice selectivity. 3D images of the slice volume confirm fidelity of the excited phase pattern and slice profile.