Fat-saturated diffusion-weighted imaging of the rat pelvis using three-dimensional water-excitation MP-RAGE MR sequence

本研究的目的是开发一种新的技术，脂肪饱和的三维（3D）扩散加权（DW）MRI序列的基础上，三维磁化准备的快速梯度回波（3D-MP-ESTA）方法。为了使脂肪饱和，组成两种技术：FatSat-3D-DWI序列和WE-3D-DWI序列，“化学位移选择性：CHESS（FatSat）方法与水激发：WE方法”。比较FatSat-3D-DWI序列和WE-3D-DWI序列的脂肪抑制程度。在FatSat-3D-DWI序列中，使用具有“CHESS-90 oRF-运动探测梯度：MPG-180 oRF-MPG-90 oRF”脉冲序列的准备阶段来使磁化对脂肪饱和扩散敏感。相反，在WE-3D-DWI序列中，选择具有“二项式脉冲1-1或1-2-1”的RAGE激发脉冲用于水激发（脂肪饱和）扩散成像。从用体模获得的实验结果，证实了扩散加权的效果和脂肪饱和的效果。WE-3D-DWI序列中的脂肪饱和度远优于CHESS-3D-DWI序列。根据使用WE-3D-DWI的动物（大鼠骨盆）实验结果，获得脂肪饱和扩散加权图像数据。该序列可用于体内成像。

The purpose of this study was to develop a novel technique for fat-saturated three-dimensional (3D) diffusion-weighted (DW) MRI sequencing based upon the 3D magnetization-prepared rapid gradient-echo (3D-MP-RAGE) method. In order to saturate fat, two kinds of techniques were composed: the FatSat-3D-DWI sequence and WE-3D-DWI sequence, "chemical shift selective: CHESS (FatSat) method vs water excitation: WE method". The FatSat-3D-DWI sequence and WE-3D-DWI sequence were compared in terms of their degree of fat suppression. In the FatSat-3D-DWI sequence, the preparation phase with a "CHESS-90oRF-motion probing gradient : MPG-180oRF-MPG-90oRF" pulse-train was used to sensitize the magnetization to fat-saturated diffusion. In contrast, in the WE-3D-DWI sequence, a RAGE-excitation pulse with a "binominal-pulse 1-1 or 1-2-1" was selected for water-excited (fat-saturated) diffusion imaging. From experimental results obtained with a phantom, the effect of diffusion weighting and the effect of fat-saturation were confirmed. Fat saturation was much better in the WE-3D-DWI sequence than the CHESS-3D-DWI sequence. From animal (rat pelvis) experimental results using WE-3D-DWI, fat-saturated diffusion-weighted image data were obtained. This sequence was useful for in vivo imaging.