Compensation of slice profile mismatch in combined spin- and gradient-echo echo-planar imaging pulse sequences.
Compensation of slice profile mismatch in combined spin- and gradient-echo echo-planar imaging pulse sequences.
复制标题
DOI：
10.1002/mrm.23012
复制
发表时间：
2012-02
影响因子：
3.3
通讯作者：
Bammer, Roland
中科院分区：
文献类型：
--
作者：
Schmiedeskamp, Heiko;Straka, Matus;Bammer, Roland
MRI时间序列中梯度回波和自旋回波信号的组合采集揭示了灌注加权成像和功能性磁共振成像的额外信息，这是由于梯度回波和自旋回波测量对基础血管结构属性的灵敏度差异。在一个时间帧内采集多个回波串有助于同时估计横向弛豫参数R2和R2*。然而，这些参数的同时估计往往是不正确的，在信号激励和随后的重聚焦脉冲之间的切片轮廓失配的存在。这里示出了脉冲设计的改进减少了R2和R2* 估计误差。通过引入额外参数δ来校正切片轮廓中的不一致性以促进更多定量测量，从而通过增强参数估计实现了进一步改进。此外，对时间分辨采集的分析表明，R2估计的时间稳定性可以通过改进脉冲设计来提高，从而抵消基于自旋回波的灌注和功能性MRI中的低对比度噪声比。
Combined acquisition of gradient-echo and spin-echo signals in MRI time series reveals additional information for perfusion-weighted imaging and functional magnetic resonance imaging due to differences in the sensitivity of gradient-echo and spin-echo measurements to the properties of the underlying vascular architecture. The acquisition of multiple echo trains within one time frame facilitates the simultaneous estimation of the transversal relaxation parameters R2 and R2*. However, the simultaneous estimation of these parameters tends to be incorrect in presence of slice profile mismatches between signal excitation and subsequent refocusing pulses. It is shown here that improvements in pulse design reduced R2 and R2* estimation errors. Further improvements were achieved by augmented parameter estimation through the introduction of an additional parameter δ to correct for discordances in slice profiles to facilitate more quantitative measurements. Moreover, the analysis of time-resolved acquisitions revealed that the temporal stability of R2 estimates could be increased with improved pulse design, counteracting low contrast-to-noise ratios in spin-echo-based perfusion and functional MRI.
登录
查看更多内容
影响因子：
3.3
作者：
Newbould, Rexford D.;Skare, Stefan T.;Bammer, Roland
通讯作者：
Bammer, Roland
影响因子：
3.3
作者：
Griswold, MA;Jakob, PM;Haase, A
通讯作者：
Haase, A
影响因子：
2.2
作者：
MANSFIELD, P;PYKETT, IL
通讯作者：
PYKETT, IL
影响因子：
2.2
作者：
Sukstanskii, AL;Yablonskiy, DA
通讯作者：
Yablonskiy, DA
影响因子：
3.3
作者：
SHINNAR, M;BOLINGER, L;LEIGH, JS
通讯作者：
LEIGH, JS