Hong Taehwa, Han Dongyeob, Kim Min-Oh, Kim Dong-Hyun
Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Republic of Korea.
Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Republic of Korea.
Magn Reson Imaging. 2017 Sep;41:73-79. doi: 10.1016/j.mri.2017.04.001. Epub 2017 Apr 5.
The radio frequency (RF) slice profile effects on T1 and T2 estimation in magnetic resonance fingerprinting (MRF) are investigated with respect to time-bandwidth product (TBW), flip angle (FA) level and field inhomogeneities. Signal evolutions are generated incorporating the non-ideal slice selective excitation process using Bloch simulation and matched to the original dictionary with and without the non-ideal slice profile taken into account. For validation, phantom and in vivo experiments are performed at 3T. Both simulations and experiments results show that T1 and T2 error from non-ideal slice profile increases with increasing FA level, off-resonance, and low TBW values. Therefore, RF slice profile effects should be compensated for accurate determination of the MR parameters.
针对时间带宽积(TBW)、翻转角(FA)水平和场不均匀性,研究了射频(RF)切片轮廓对磁共振指纹识别(MRF)中T1和T2估计的影响。利用布洛赫模拟生成包含非理想切片选择性激发过程的信号演变,并在考虑和不考虑非理想切片轮廓的情况下与原始字典进行匹配。为了进行验证,在3T下进行了体模和体内实验。模拟和实验结果均表明,非理想切片轮廓导致的T1和T2误差随FA水平、失谐和低TBW值的增加而增大。因此,为了准确测定磁共振参数,应补偿RF切片轮廓效应。