Enhancing Bone Quality Assessment Using Quantitative Ultrasound

描述（由申请人提供）：与骨质疏松症相关的骨折风险代表了一个可能随着国家人口老龄化而变得越来越严重的问题。FDA已经批准了7种旨在减缓或逆转骨质疏松症的药物。监测药物治疗的金标准是双能x射线吸收仪（DEXA），它提供了骨矿物质密度（BMD）的测量。原则上，骨声测量能够提供有关骨质量的额外信息，因为它不仅对骨矿物质密度敏感，而且对影响骨折风险的微观结构和方向也敏感。然而，尽管声速测量技术很有前景，但它尚未被证明能提供如此额外的骨质量信息，部分原因是在拟议的研究中需要解决的具体限制。接收换能器的相位消除对骨超声有负面影响。超声通过骨的传输会产生多种传播模式，包括快波和慢波、模式转换和多重散射效应，这些效应可以掩盖决定骨折风险的骨的潜在材料特性。目前，声速测量仅限于允许通过传播的部位，如cancanus，而髋部等骨折风险最高的部位只能使用反向散射超声。因此，我们确定了三个具体目标：1)识别、分离并克服基于电流传输的跟骨声速测量因接收换能器相位抵消而产生的局限性；2)对超声信号进行贝叶斯反演，从接收到的传输声速测量信号中估计出潜在的骨材料特性；3)验证、扩展、改进基于后向散射超声的髋部等高危部位骨折风险评估方法。本研究的长期目标是在药物干预的帮助下，增强和扩展骨测声技术，以促进其在监测骨质量和骨质疏松症潜在消退方面的作用。公共卫生相关性：骨质疏松性骨折降低生活质量并带来巨大的医疗费用。声速测量可以改善骨质量评估，因为与DEXA不同，它对骨的微观结构和取向敏感。本研究提出了对现有声压测量技术的基本改进，并探索了适用于髋部和脊柱的新技术，这些髋部和脊柱骨折的风险相对较高，但目前还无法监测。

DESCRIPTION (provided by applicant): Fracture risk associated with osteoporosis represents a concern that is likely to become ever more serious as the nation's population ages. The FDA has approved 7 drugs designed to slow or reverse osteoporosis. The gold standard for monitoring pharmacological treatment is Dual Energy X-ray Absorptiometry (DEXA), which provides a measure of bone mineral density (BMD). In principle, bone sonometry is capable of providing additional information regarding bone quality because it is sensitive not only to bone mineral density but also to microstructure and orientation which influence fracture risk. In spite of its promise, however, sonometry has not yet been shown to provide such additional bone quality information, in part because of the specific limitations to be addressed in the proposed research. Phase cancellation at the receiving transducer has a negative impact on bone sonography. Transmission of ultrasound through bone is results in the generation of multiple modes of propagation including fast and slow waves, mode convertion, and multiple scattering - effects that can mask the underlying material properties of bone that determine fracture risk. At present, sonometry is limited to sites permitting through transmission such as the cancaneus, whereas sites at highest risk of fracture such as the hip would be accessible only to backscattered ultrasound. We have therefore identified three specific aims: 1) Identify, segregate, and overcome limitations of current transmission-based calcaneus sonometry arising from phase cancellation at the receiving transducer, 2) implement Bayes inversion of the ultrasonic signals to estimate the underlying bone material properties from received transmission sonometry signals complicated by the presence of multiple modes, and 3) validate, expand, and refine methods for estimating fracture risk in high risk sites such as the hip based on backscattered ultrasound. The long-term goal of the proposed research is to enhance and expand bone sonometry to facilitate its role in monitoring bone quality and the potential regression of osteoporosis with the aid of pharmacological interventions. PUBLIC HEALTH RELEVANCE: Osteoporotic fractures reduce quality of life and carry enormous health care costs. Sonometry could improve bone quality assessment because, unlike DEXA, it is sensitive to bone microstructure and orientation. The proposed research addresses fundamental improvements to existing sonometry techniques, and explores new techniques applicable to the hip and spine that are at relatively high risk of fracture but currently cannot be monitored.