Shear wave group velocity inversion in MR elastography of human skeletal muscle
Shear wave group velocity inversion in MR elastography of human skeletal muscle
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DOI：
10.1002/mrm.20993
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发表时间：
2006-09-01
影响因子：
3.3
通讯作者：
Sack, Ingolf
中科院分区：
文献类型：
--
作者：
Papazoglou, Sebastian;Rump, Jens;Sack, Ingolf
在体内量化软组织的各向异性剪切弹性是弹性成像技术的一个吸引人的目标，因为弹性各向异性可能提供关于病变组织结构变化的特定信息。本文介绍了一种应用于骨骼肌磁共振弹性成像(MRE)的方法。用这种方法可以用两个剪切模数(一个平行于肌纤维方向，一个垂直于肌纤维方向)来解释各向异性。该技术是基于应用于体横波的群速度反演，通过在时空尺度上自动分析波相梯度来实现的。然后利用k空间中群速度的解析表达式分析剪切波速的方向相关性，从而得到剪切模数，并将其数值映射到实空间。在5名志愿者的二头肌上进行的MRE实验表明，垂直和平行剪切模量的中位数分别为5.5+/-0.9kPa和29.3+/-6.2kPa(P<；0.05)。该技术结合了快速稳态自由进动(SSFP)MRE实验和各向异性波数据的全自动处理，因此是一种有趣的辅助临床诊断的MRI模式。
In vivo quantification of the anisotropic shear elasticity of soft tissue is an appealing objective of elastography techniques because elastic anisotropy can potentially provide specific information about structural alterations in diseased tissue. Here a method is introduced and applied to MR elastography (MRE) of skeletal muscle. With this method one can elucidate anisotropy by means of two shear moduli (one parallel and one perpendicular to the muscle fiber direction). The technique is based on group velocity inversion applied to bulk shear waves, which is achieved by an automatic analysis of wave-phase gradients on a spatiotemporal scale. The shear moduli are then accessed by analyzing the directional dependence of the shear wave speed using analytic expressions of group velocities in k-space, which are numerically mapped to real space. The method is demonstrated by MRE experiments on the biceps muscle of five volunteers, resulting in 5.5 +/- 0.9 kPa and 29.3 +/- 6.2 kPa (P < 0.05) for the medians of the perpendicular and parallel shear moduli, respectively. The proposed technique combines fast steady-state free precession (SSFP) MRE experiments and fully automated processing of anisotropic wave data, and is thus an interesting MRI modality for aiding clinical diagnosis.