PURPOSE Biomechanical simulation of anatomical deformations caused by ultrasound probe pressure is of outstanding importance for several applications, from the testing of robotic acquisition systems to multi-modal image fusion and development of ultrasound training platforms. Different approaches can be exploited for modelling the probe-tissue interaction, each achieving different trade-offs among accuracy, computation time and stability. METHODS We assess the performances of different strategies based on the finite element method for modelling the interaction between the rigid probe and soft tissues. Probe-tissue contact is modelled using (i) penalty forces, (ii) constraint forces, and (iii) by prescribing the displacement of the mesh surface nodes. These methods are tested in the challenging context of ultrasound scanning of the breast, an organ undergoing large nonlinear deformations during the procedure. RESULTS The obtained results are evaluated against those of a non-physically based method. While all methods achieve similar accuracy, performance in terms of stability and speed shows high variability, especially for those methods modelling the contacts explicitly. Overall, prescribing surface displacements is the approach with best performances, but it requires prior knowledge of the contact area and probe trajectory. CONCLUSIONS In this work, we present different strategies for modelling probe-tissue interaction, each able to achieve different compromises among accuracy, speed and stability. The choice of the preferred approach highly depends on the requirements of the specific clinical application. Since the presented methodologies can be applied to describe general tool-tissue interactions, this work can be seen as a reference for researchers seeking the most appropriate strategy to model anatomical deformation induced by the interaction with medical tools.

中文翻译：

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超声扫描过程中探针与组织相互作用的生物力学建模。

目的对由超声探头压力引起的解剖变形进行生物力学模拟，对于从机器人采集系统的测试到多模式图像融合以及超声训练平台的开发等多种应用而言，具有极其重要的意义。可以利用不同的方法来建模探针与组织的相互作用，每种方法都在准确性，计算时间和稳定性之间取得了不同的权衡。方法我们基于有限元方法对刚性探针与软组织之间的相互作用进行建模的方法评估不同策略的性能。使用（i）惩罚力，（ii）约束力和（iii）通过规定网格表面节点的位移来建模探针-组织接触。这些方法已在具有挑战性的乳房超声扫描环境中进行了测试，在手术过程中经历大的非线性变形的器官。结果与基于非物理方法的结果进行了评估。尽管所有方法都达到了相似的精度，但是就稳定性和速度而言，性能表现出很高的可变性，尤其是对于那些对触点进行显式建模的方法。总体而言，规定表面位移是具有最佳性能的方法，但它需要先了解接触面积和探针轨迹。结论在这项工作中，我们提出了对探针-组织相互作用建模的不同策略，每种策略都能在准确性，速度和稳定性之间取得不同的折衷。首选方法的选择高度取决于特定临床应用的要求。