Assessment of bone micro-structure using ultrasonic methods

骨质疏松症越来越普遍。它改变了微结构和骨密度， 准确预测骨能力需要两者的结合。一些研究已经证明了这种关系 骨骼微结构和骨骼强度之间的联系。然而，目前骨折风险的黄金标准 评估仅依赖于骨矿物质密度的X射线表征。一种定量的，非侵入性的， 骨微结构的非电离表征目前在体内是不可能的。因此， 未满足的需求 我们建议通过开发一种新的骨微生物学评估技术来满足这一需求。 使用超声的多重散射的架构。我们假设当多重散射发生时 在超声参数之间存在可测量的关系，例如散射平均自由 路径和微结构参数，例如各向异性、连通性和小梁分离。 我们的方法基于以下双重范式： 第一：将骨微结构的表征与目前可用的评估相结合， 骨密度可提高骨折风险的诊断。 第二：MHz范围内的超声波受到微结构的多次散射 在骨骼中传播。由此产生的超声波信号是复杂的，并在微结构上嵌入信息。 架构 我们将有以下具体目标： SA.1使用数值模拟，我们将建立骨微观结构之间的定量关系， 结构和超声参数。我们将创建骨状数字媒体，我们将在其中改变 微观结构和材料特性独立，研究其对超声的个别影响 传播 SA.2使用3D打印，我们将创建具有任意和完全受控微架构的骨模型。 微结构和超声参数之间的关系将在 体外模型和真实的标本。 SA.3使用机械测试，我们将研究超声参数、微机械参数和微机械参数之间的关系。 建筑和机械能力。 如果成功，这项研究将导致定量和非电离超声为基础的方法 来表征骨骼微结构。最终，开发的方法将用于筛选， 诊断和监测骨质疏松症。这项研究旨在限制使用电离和昂贵的 骨质疏松症的诊断方法

Osteoporosis is increasingly prevalent. It modifies microarchitecture and bone density and the assessment of both is required to predict bone competence accurately. Several studies have demonstrated the relationship between bone micro-architecture and bone strength. However, the current gold standard for fracture risk assessment relies on the X-ray characterization of bone mineral density alone. A quantitative, non-invasive and non-ionizing characterization of bone micro-architecture is currently not possible in vivo. There is therefore an unmet need. We propose to address this need by developing a novel technique for the assessment of bone micro- architecture using multiple scattering of ultrasound. We hypothesize that when multiple scattering occurs there is a measureable relationship between ultrasonic parameters, such as the scattering mean free path, and micro-architectural parameters, such as anisotropy, connectivity and trabecular separation. Our approach is based on the following two-fold paradigm: First: Combining the characterization of bone micro-architecture to the currently available assessment of bone mineral density would improve the diagnosis of fracture risk. Second: Ultrasound waves in the MHz range are subjected to multiple scattering by the micro-structure during propagation in bone. The resulting ultrasonic signals are complex and embed information on the micro- architecture. We will have the following specific aims: SA.1 Using numerical simulations, we will establish a quantitative relationship between bone micro- architecture and ultrasound parameters. We will create bone-like numerical media in which we will vary the micro-architectural and material properties independently, to study their individual influence on ultrasound propagation. SA.2 Using 3D printing, we will create bone phantoms with arbitrary and fully controlled micro-architecture. The relationship between the micro-architecture and ultrasound parameters will be experimentally studied in vitro in phantoms and real specimen. SA.3 Using mechanical testing, we will investigate the relationship between ultrasound parameters, micro- architecture and mechanical competence. If successful, this research will lead to a quantitative and non-ionizing ultrasound-based method to characterize bone micro-architecture. Ultimately, the methods developed will be used for screening, diagnosis and monitoring of osteoporosis. This research aims at limiting the use of ionizing and costly techniques for the diagnosis of osteoporosis.