Seifert M H, Jakob P M, Jellus V, Haase A, Hillenbrand C
Lehrstuhl für Experimentelle Physik V, Physikalisches Institut der Universität Würzburg, Germany.
J Magn Reson. 2000 Jun;144(2):243-54. doi: 10.1006/jmre.2000.2041.
This work describes a segmented radial turbo-spin-echo technique (DW-rTSE) for high-resolution multislice diffusion-weighted imaging and quantitative ADC mapping. Diffusion-weighted images with an in-plane resolution of 700 microm and almost free of bulk motion can be obtained in vivo without cardiac gating. However, eddy currents and pulsatile brain motion cause severe artifacts when strong diffusion weighting is applied. This work explains in detail the artifacts in projection reconstruction (PR) imaging arising from eddy currents and describes an effective eddy current compensation based on the adjustment of gradient timing. Application of the diffusion gradients in all three orthogonal directions is possible without degradation of the images due to eddy current artifacts, allowing studies of the diffusional anisotropy. Finally, a self-navigation approach is proposed to reduce residual nonrigid body motion artifacts. Five healthy volunteers were examined to show the feasibility of this method.
这项工作描述了一种用于高分辨率多层扩散加权成像和定量表观扩散系数(ADC)映射的分段径向涡轮自旋回波技术(DW-rTSE)。无需心脏门控即可在体内获得平面分辨率为700微米且几乎无整体运动的扩散加权图像。然而,当应用强扩散加权时,涡流和搏动性脑运动会导致严重伪影。这项工作详细解释了投影重建(PR)成像中由涡流引起的伪影,并描述了一种基于梯度定时调整的有效涡流补偿方法。在所有三个正交方向上应用扩散梯度时,不会因涡流伪影而导致图像质量下降,从而可以研究扩散各向异性。最后,提出了一种自导航方法以减少残留的非刚体运动伪影。对五名健康志愿者进行了检查,以证明该方法的可行性。