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

人体组织的正常机械性能往往与癌症肿瘤的不同。这项研究项目的一个目标是创造一种新的方法来测量活体患者体内组织的机械性能。现有的一种测量机械性能的方法被称为“磁共振(MR)弹性成像”，因为它不使用破坏性辐射，因此很有吸引力。然而，现在测量肿瘤和正常组织之间的界面属性还不够准确。需要克服的问题之一是，当组织均匀时，磁共振弹性成像是准确的，但在正常组织和肿瘤之间的界面上是不准确的。这种界面的不准确使人们更难看到小肿瘤，而这些肿瘤恰恰是那些需要早期治疗而需要检测的肿瘤。这项研究项目将通过实验确定图像在界面上退化的原因，然后创建一种理论来改善图像。新方法将使用从患者那里收集的真实数据进行测试，以确定它是否不仅改善了实验系统的成像，也改善了患者的成像。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，并为通过推动医疗技术进步来促进国民健康的目标做出贡献。该项目还将为不同的K12、本科生和研究生提供外展、培训和指导机会。研究小组还将与国内和国际媒体合作，向公众传播研究结果。该项目将提供一种新的方法，将生物界面的机械强度和柔顺性与非侵入性波散射数据联系起来，从而为此类界面的物理化学性质的诊断提供安全的手段。特别是，波在粘结-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性质。此外，还将利用一种先进的激光测振技术(多点激光测振)来测量软合成界面上的剪切波散射。这些测量将作为定性方法的验证数据集。最后，将通过磁共振弹性成像测量来检验该方法的有效性。这最后一步将揭示目前实践中的局限性，并为下一代基于MR的诊断提供指导。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.