Subzone based magnetic resonance elastography using a Rayleigh damped material model
Subzone based magnetic resonance elastography using a Rayleigh damped material model
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DOI：
10.1118/1.3557469
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发表时间：
2011-04-01
期刊：
影响因子：
3.8
通讯作者：
Paulsen, K. D.
中科院分区：
文献类型：
--
作者：
Van Houtena, Elijah E. W.;Viviers, D. vR.;Paulsen, K. D.
目的：最近，在磁共振弹性成像中，软组织的衰减行为已经通过在用于重建所得到的机械特性图像的方法中包含了阻尼机制而得到了解决。到目前为止，这种机制一直基于材料行为的粘弹性模型。瑞利(Rayleigh)或成比例的衰减为弹性能量衰减提供了一个更普遍的模型，该模型使用两个参数来表征与弹性力和惯性力成比例的贡献。在时间简谐振动情况下，这两个参数导致弹性模数和密度都是复数(而在纯粘弹性情况下，只有弹性模数是复数)。方法：本文描述了时间简谐情况下的Rayleigh阻尼，讨论了该模型与粘弹性阻尼器模型的区别。结果：体模和组织研究表明，不同材料类型之间的瑞利阻尼结构存在差异，豆腐和健康组织的瑞利组成值低于明胶和癌组织。结论：瑞利阻尼弹性成像和伴随的瑞利组成图像可能为区分组织结构提供了一种机制，除了测量弹性刚度和衰减之外。这些信息在使用瑞利衰减磁共振弹性成像作为诊断成像工具方面可能是有价值的。(C)2011年美国医学物理学家协会。[DOI：10.1118/1.3557469]
Purpose: Recently, the attenuating behavior of soft tissue has been addressed in magnetic resonance elastography by the inclusion of a damping mechanism in the methods used to reconstruct the resulting mechanical property image. To date, this mechanism has been based on a viscoelastic model for material behavior. Rayleigh, or proportional, damping provides a more generalized model for elastic energy attenuation that uses two parameters to characterize contributions proportional to elastic and inertial forces. In the case of time-harmonic vibration, these two parameters lead to both the elastic modulus and the density being complex valued (as opposed to the case of pure viscoelasticity, where only the elastic modulus is complex valued).Methods: This article presents a description of Rayleigh damping in the time-harmonic case, discussing the differences between this model and the viscoelastic damping models. In addition, the results from a subzone based Rayleigh damped elastography study of gelatin and tofu phantoms are discussed, along with preliminary results from in vivo breast data.Results: Both the phantom and the tissue studies presented here indicate a change in the Rayleigh damping structure, described as Rayleigh composition, between different material types, with tofu and healthy tissue showing lower Rayleigh composition values than gelatin or cancerous tissue.Conclusions: It is possible that Rayleigh damping elastography and the concomitant Rayleigh composition images provide a mechanism for differentiating tissue structure in addition to measuring elastic stiffness and attenuation. Such information could be valuable in the use of Rayleigh damped magnetic resonance elastography as a diagnostic imaging tool. (C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3557469]