Veterinary Clinical Sciences Department, University of Minnesota, Saint Paul, MN, USA.
Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA.
Magn Reson Med. 2020 Sep;84(3):1235-1249. doi: 10.1002/mrm.28198. Epub 2020 Feb 12.
To introduce a new approach called tailored variable flip-angle (VFA) scheduling for SNR-efficient 3D T mapping of the brain using a magnetization-prepared gradient-echo sequence.
Simulations were used to assess the relative SNR efficiency, quantitative accuracy, and spatial blurring of tailored VFA scheduling for T mapping of brain tissue compared with magnetization-prepared angle-modulated partitioned k-space spoiled gradient-echo snapshots (MAPSS), a state-of-the-art technique for accurate 3D gradient-echo T mapping. Simulations were also used to calculate optimal imaging parameters for tailored VFA scheduling versus MAPSS, without and with nulling of CSF. Four participants were imaged at 3T MRI to demonstrate the feasibility of tailored VFA scheduling for T mapping of the brain. Using MAPSS as a reference standard, in vivo data were used to validate the relative SNR efficiency and quantitative accuracy of the new approach.
Tailored VFA scheduling can provide a 2-fold to 4-fold gain in the SNR of the resulting T map as compared with MAPSS when using identical sequence parameters while limiting T quantification errors to 2% or less. In vivo whole-brain 3D T maps acquired with tailored VFA scheduling had superior SNR efficiency than is achievable with MAPSS, and the SNR efficiency improved with a greater number of views per segment.
Tailored VFA scheduling is an SNR-efficient GRE technique for 3D T mapping of the brain that provides increased flexibility in choice of imaging parameters compared with MAPSS, which may benefit a variety of applications.
介绍一种新方法，称为定制可变翻转角（VFA）调度，用于使用磁化准备梯度回波序列进行大脑 SNR 高效的 3D T 映射。
使用仿真来评估与磁化准备角调制分区 k 空间扰动脉冲梯度回波快照（MAPSS）相比，针对脑组织 T 映射的定制 VFA 调度的相对 SNR 效率、定量准确性和空间模糊度，MAPSS 是一种用于准确 3D 梯度回波 T 映射的最新技术。仿真还用于计算定制 VFA 调度与 MAPSS 的最佳成像参数，无需和有脑脊液抑制。在 3T MRI 上对 4 名参与者进行成像，以证明定制 VFA 调度用于大脑 T 映射的可行性。使用 MAPSS 作为参考标准，体内数据用于验证新方法的相对 SNR 效率和定量准确性。
与 MAPSS 相比，当使用相同的序列参数时，定制 VFA 调度可以使所得 T 图的 SNR 提高 2 倍至 4 倍，同时将 T 定量误差限制在 2%或更小。使用定制 VFA 调度获得的全脑 3D T 图具有优于 MAPSS 的 SNR 效率，并且 SNR 效率随分段中每段视图数量的增加而提高。
定制 VFA 调度是一种 SNR 高效的 GRE 技术，用于大脑的 3D T 映射，与 MAPSS 相比，它在成像参数的选择方面提供了更大的灵活性，这可能有益于各种应用。
