使用磁共振指纹技术在 9.4T 场强下对整个猕猴大脑进行三维高分辨率 T1 和 T2 mapping。
Three-dimensional high-resolution T and T mapping of whole macaque brain at 9.4 T using magnetic resonance fingerprinting.
机构信息
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA.
High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.
出版信息
Magn Reson Med. 2022 Jun;87(6):2901-2913. doi: 10.1002/mrm.29181. Epub 2022 Feb 7.
PURPOSE
Quantitative T and T mapping in non-human primates with whole-brain coverage is challenged by the requirement of sub-millimeter resolution and the inhomogeneity of the transmit magnetic field (B ) covering a large field of view. The goal of the current study is to develop a magnetic resonance fingerprinting (MRF) method for simultaneous T and T mapping of the entire macaque brain within feasible scan time.
METHODS
A three-dimensional (3D) MRF sequence with both inversion- and T -preparation modules was developed and evaluated on a 9.4 T preclinical scanner. Data acquisition used a 3D stack-of-spirals trajectory, with undersampling along both the in-plane and the through-plane directions. The effect of B inhomogeneity was accounted for by matching the acquired fingerprint to a dictionary simulated with the B factors measured from a separate scan. In vitro and ex vivo studies were performed to evaluate the accuracy and the undersampling capacity of the MRF method. The application of the MRF method for in vivo, brain-wide T and T mapping was demonstrated on macaques at 4, 6, and 12 years of age.
RESULTS
The MRF method enabled highly repeatable T and T mapping at high spatial resolution (0.35 × 0.35 × 1 mm ) with an acceleration factor of 24. In vivo studies showed significant age-related T reduction in deep gray nuclei including the globus pallidus, the putamen, and the caudate nucleus.
CONCLUSIONS
This study demonstrates the first MRF study for brain-wide, multi-parametric quantification in non-human primates with sub-millimeter resolution.
目的
在具有全脑覆盖范围的非人类灵长类动物中进行定量 T 1 和 T 2 映射，需要亚毫米分辨率和覆盖大视野的不均匀传输磁场 (B ) 的要求。本研究的目的是开发一种磁共振指纹（MRF）方法，用于在可行的扫描时间内同时对整个猕猴大脑进行 T 1 和 T 2 映射。
方法
在 9.4 T 临床前扫描仪上开发并评估了具有反转和 T 准备模块的三维（3D）MRF 序列。数据采集使用 3D 堆叠螺旋轨迹，沿平面内和贯穿平面方向进行欠采样。通过将获得的指纹与从单独扫描中测量的 B 因子模拟的字典进行匹配，来考虑 B 不均匀性的影响。进行了体外和离体研究，以评估 MRF 方法的准确性和欠采样能力。在 4、6 和 12 岁的猕猴中，展示了 MRF 方法在体内进行全脑 T 1 和 T 2 映射的应用。
结果
MRF 方法能够以高空间分辨率（0.35×0.35×1mm）进行高度可重复的 T 1 和 T 2 映射，加速因子为 24。体内研究表明，深灰质核（包括苍白球、壳核和尾状核）中的 T 1 随年龄的相关性降低。
结论
本研究首次在具有亚毫米分辨率的非人类灵长类动物中进行了全脑、多参数定量 MRF 研究。
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