Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA.
Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA.
Magn Reson Med. 2017 Nov;78(5):1870-1876. doi: 10.1002/mrm.26572. Epub 2016 Dec 26.
The purpose of this study is to accelerate an MR fingerprinting (MRF) acquisition by using a simultaneous multislice method.
A multiband radiofrequency (RF) pulse was designed to excite two slices with different flip angles and phases. The signals of two slices were driven to be as orthogonal as possible. The mixed and undersampled MRF signal was matched to two dictionaries to retrieve T and T maps of each slice. Quantitative results from the proposed method were validated with the gold-standard spin echo methods in a phantom. T and T maps of in vivo human brain from two simultaneously acquired slices were also compared to the results of fast imaging with steady-state precession based MRF method (MRF-FISP) with a single-band RF excitation.
The phantom results showed that the simultaneous multislice imaging MRF-FISP method quantified the relaxation properties accurately compared to the gold-standard spin echo methods. T and T values of in vivo brain from the proposed method also matched the results from the normal MRF-FISP acquisition.
T and T values can be quantified at a multiband acceleration factor of two using our proposed acquisition even in a single-channel receive coil. Further acceleration could be achieved by combining this method with parallel imaging or iterative reconstruction. Magn Reson Med 78:1870-1876, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
本研究旨在通过使用并行采集技术加速磁共振指纹成像(MRF)采集。
设计了一种多频带射频(RF)脉冲,以不同的翻转角和相位激励两个层面。使两个层面的信号尽可能正交。混合的欠采样 MRF 信号被匹配到两个字典中,以获取每个层面的 T 和 T图。在体模中,使用金标准自旋回波方法对所提出方法的定量结果进行了验证。还将两个同时采集的层面的体内人脑 T 和 T图与使用单频带 RF 激励的基于稳态进动的快速磁共振指纹成像(MRF-FISP)的结果进行了比较。
体模结果表明,与金标准自旋回波方法相比,并行采集磁共振指纹成像-FISP 方法能够准确地量化弛豫特性。该方法还可以匹配正常 MRF-FISP 采集的活体脑 T 和 T*值。
即使在单通道接收线圈中,我们的采集方法也可以使用多频带加速因子 2 来定量 T 和 T*值。通过将该方法与并行成像或迭代重建相结合,可以进一步提高加速效果。磁共振医学杂志 78:1870-1876,2017。© 2016 国际磁共振学会。