Artifacts in T1ρ-weighted imaging:: correction with a self-compensating spin-locking pulse
Artifacts in T1ρ-weighted imaging:: correction with a self-compensating spin-locking pulse
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DOI：
10.1016/s1090-7807(02)00197-0
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发表时间：
2003-05-01
影响因子：
2.2
通讯作者：
Reddy, R
中科院分区：
文献类型：
--
作者：
Charagundla, SR;Borthakur, A;Reddy, R
当章动角与其预期值有微小偏差时，T-1 rho加权成像会出现显著伪影。这些伪影随自旋锁定时间和振幅而变化，严重限制了进行定量成像或测量T-1 rho弛豫时间的尝试。解释这些伪影的起源的理论模型的背景下，T-1 rho准备的快速自旋回波成像序列。实验获得的文物进行比较，理论预测和相关的B-1的不均匀性。最后，提出了一种“自补偿”自旋锁定预备脉冲簇，其中自旋锁定脉冲的后半部分相移180 °。尽管翻转角变化较大，但使用该脉冲序列可保持相对均匀的信号强度，从而大大减少T-1 rho加权成像中的伪影。(C)2003 Elsevier Science（美国）。All rights reserved.
Significant artifacts arise in T-1rho-weighted imaging when nutation angles suffer small deviations from their expected values. These artifacts vary with spin-locking time and amplitude, severely limiting attempts to perform quantitative imaging or measurement of T-1rho relaxation times. A theoretical model explaining the origin of these artifacts is presented in the context of a T-1rho-prepared fast spin-echo imaging sequence. Experimentally obtained artifacts are compared to those predicted by theory and related to B-1 inhomogeneity. Finally, a "self-compensating" spin-locking preparatory pulse cluster is presented, in which the second half of the spin-locking pulse is phase-shifted by 180degrees. Use of this pulse sequence maintains relatively uniform signal intensity despite large variations in flip angle, greatly reducing artifacts in T-1rho-weighted imaging. (C) 2003 Elsevier Science (USA). All rights reserved.