METHODS: The feasibility of the magnitude-phase-based method was assessed by simulations, in phantom and in vivo experiments using skipped-CAIPI three-dimensional-echo-planar imaging (3D-EPI) for rapid GRE imaging. T 2 $$ {\\mathrm{T}}_2 $$ , T 1 $$ {\\mathrm{T}}_1 $$ and PD estimations obtained by our method were compared to T 2 $$ {\\mathrm{T}}_2 $$ of the phase-based method and T 1 $$ {\\mathrm{T}}_1 $$ and PD of spoiled GRE-based multi-parameter mapping using a multi-echo version of the same sequence.
RESULTS: The agreement of the proposed T 2 $$ {\\mathrm{T}}_2 $$ with ground truth and reference T 2 $$ {\\mathrm{T}}_2 $$ values was higher than that of phase-based T 2 $$ {\\mathrm{T}}_2 $$ in simulations and in phantom data. While phase-based T 2 $$ {\\mathrm{T}}_2 $$ overestimation increases with actual T 2 $$ {\\mathrm{T}}_2 $$ and T 1 $$ {\\mathrm{T}}_1 $$ , the proposed method is accurate over a large range of physiologically meaningful T 2 $$ {\\mathrm{T}}_2 $$ and T 1 $$ {\\mathrm{T}}_1 $$ values. At the same time, precision is improved. In vivo results were in line with these observations.
CONCLUSIONS: Accurate magnitude-phase-based T 2 $$ {}_2 $$ mapping is feasible in less than 5 min scan time for 1 mm nominal isotropic whole-head coverage at 3T and 7T.
方法:通过模拟评估了基于幅度相位的方法的可行性,在体模和体内实验中,使用跳过的CAIPI三维回波平面成像(3D-EPI)进行快速GRE成像。T2$${\\mathrm{T}}_2$$,通过我们的方法获得的T1$${\\mathrm{T}}_1$$和PD估计与基于相位的方法的T2${\\mathrm{T}}_2$$和T1$${\\mathrm{T}}_1$$$和PD使用相同序列的多回声版本进行了比较。
结果:建议的T2$${\\mathrm{T}}_2$$与实际值和参考T2$${\\mathrm{T}}_2$$$的一致性高于基于相位的T2$$${\\mathrm{T}}_2$$$$在模拟和幻影数据中的一致性。虽然基于阶段的T2$${\\mathrm{T}}_2$$过估计随着实际的T2${\\mathrm{T}}_2$$和T1$${\\mathrm{T}}_1$$$而增加,所提出的方法在大范围的有生理意义的T2$${\\mathrm{T}}_2$$和T1${\\mathrm{T}}_1$$值上是准确的。同时,精度得到提高。体内结果与这些观察结果一致。
结论:在3T和7T下,在小于5分钟的扫描时间内,基于幅度相位的精确T2$${}_2$$$映射是可行的,用于1mm标称各向同性全头覆盖。