使用多重复时间梯度回波序列校正 T1 校正 B1 映射。
T1 corrected B1 mapping using multi-TR gradient echo sequences.
机构信息
Institute of Biomedical Engineering, University of Karlsruhe, Karlsruhe, Germany.
出版信息
Magn Reson Med. 2010 Sep;64(3):725-33. doi: 10.1002/mrm.22333.
This work presents a new approach toward a fast, simultaneous amplitude of radiofrequency field (B(1)) and T(1) mapping technique. The new method is based on the "actual flip angle imaging" (AFI) sequence. However, the single pulse repetition time (TR) pair used in the standard AFI sequence is replaced by multiple pulse repetition time sets. The resulting method was called "multiple TR B(1)/T(1) mapping" (MTM). In this study, MTM was investigated and compared to standard AFI in simulations and experiments. Feasibility and reliability of MTM were proven in phantom and in vivo experiments. Error propagation theory was applied to identify optimal sequence parameters and to facilitate a systematic noise comparison to standard AFI. In terms of accuracy and signal-to-noise ratio, the presented method outperforms standard AFI B(1) mapping over a wide range of T(1). Finally, the capability of MTM to determine T(1) was analyzed qualitatively and quantitatively, yielding good agreement with reference measurements.
本研究提出了一种新的快速、同步射频场(B(1))和 T(1) 映射技术的方法。新方法基于“实际翻转角成像”(AFI)序列。然而,标准 AFI 序列中使用的单个重复时间(TR)对被多个重复时间集所取代。这种新方法被称为“多 TR B(1)/T(1) 映射”(MTM)。在这项研究中,在模拟和实验中对 MTM 进行了研究和比较。在体模和活体实验中证明了 MTM 的可行性和可靠性。应用误差传播理论来确定最佳序列参数,并便于与标准 AFI 进行系统的噪声比较。在准确性和信噪比方面,所提出的方法在广泛的 T(1)范围内优于标准 AFI B(1)映射。最后,对 MTM 确定 T(1)的能力进行了定性和定量分析,与参考测量值吻合良好。