Collaborative Research: Mechanical Characterization of Bio-Interfaces by Shear Wave Scattering

人体组织的正常机械特性往往不同于癌变的肿瘤组织。这个研究项目的目标是创造一种新的方法来测量活着的病人身体组织的机械特性。一种现有的测量机械性能的方法被称为“磁共振（MR）弹性成像”，因为它不使用有害的辐射而很有吸引力。然而，目前还不足以精确测量肿瘤和正常组织之间的界面特性。需要克服的一个问题是，当组织是均匀的时，MR弹性成像是准确的，但在正常组织和肿瘤之间的界面上，它是不准确的。这种界面的不准确性使得发现小肿瘤变得更加困难，而这些小肿瘤正是那些需要及早发现以进行治疗的肿瘤。该研究项目将通过实验确定图像在界面处退化的原因，然后创建一个理论来改善图像。新方法将使用从患者身上收集的真实数据进行测试，以确定它是否不仅可以改善实验系统的成像，还可以改善患者的成像。这项研究将支持美国国家科学基金会促进科学进步的使命，并通过推动医疗技术的进步来促进国民健康的目标。该项目将提供外展，培训和指导的机会，以及不同群体的K12，本科生和研究生的研究学生。研究小组还将与国内和国际媒体合作，向公众传播调查结果。该项目将提供一种新的方法，将生物界面的机械强度和顺应性与无创波散射数据联系起来，从而为诊断这些界面的物理化学性质提供安全的方法。特别是，波在黏结摩擦界面上的传播将被建模，并将开发基于波散射的表征方法来识别界面的力学特性。此外，一种先进的激光振动测量技术（多点激光振动测量）将被用于测量剪切波在软合成界面上的散射。这些测量将作为表征方法的验证数据集。最后，该方法的有效性将通过MR弹性成像测量进行测试。这最后一步将揭示目前在实践中的局限性，并为下一代基于核磁共振的诊断提供指导。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The normal mechanical properties of the tissues of the human body are often different from those of cancerous tumors. A goal of this research project is to create a new approach to measuring the mechanical properties of body tissues in living patients. An existing method to measure mechanical properties called "magnetic resonance (MR) elastography" is attractive because it does not use damaging radiation. However, it is not now sufficiently accurate to measure the interface properties between tumors and normal tissue. One of the problems to overcome is that MR elastography is accurate when tissue is uniform, but it is inaccurate at the interface between normal tissue and tumor. This interface inaccuracy makes it more difficult to see small tumors, exactly those that need to be detected for early treatment. This research project will determine experimentally why the image is degraded at an interface, and then create a theory to improve the images. The new method will be tested using real data collected from patients to determine if it improves imaging not only for the experimental system, but also for the patients. The research will support NSF's mission of promoting progress of science and contribute to the goal of advancing national health by enabling advances in medical technologies. This project will provide outreach, training and mentoring opportunities as well for a diverse group of K12, undergraduate and graduate research students. The research team will also collaborate with the national and international media to disseminate the findings to the public. This project will provide a novel methodology for relating mechanical strength and compliance of bio-interfaces to noninvasive wave scattering data, and thus provide safe means for diagnostics of physicochemical nature of such interfaces. In particular, wave-propagation across cohesive-frictional interfaces will be modeled, and a wave-scattering-based characterization methodology will be developed to identify the mechanical properties of the interfaces. Moreover, an advanced laser vibrometry technique (multipoint laser vibrometry) will be utilized to measure shear wave scattering across soft synthetic interfaces. Those measurements will serve as validation datasets for the characterization methodology. Lastly, the efficacy of the methodology will be tested with MR Elastography measurements. This final step will reveal the current limitations in practice, and provide guidelines for the next-generation of MR-based diagnostics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.