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是一个令人担忧的问题，随着国家人口老龄化，这一问题可能会变得更加严重。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射线吸收法(DEXA)，它提供了一种测量骨密度(BMD)的方法。原则上，骨超声测量仪能够提供有关骨质量的额外信息，因为它不仅对骨密度敏感，而且对影响骨折风险的微结构和方位也很敏感。然而，尽管声学测量很有希望，但它还没有被证明能提供这种额外的骨骼质量信息，部分原因是在拟议的研究中要解决的具体限制。接收换能器的相位偏差对骨超声检查有负面影响。超声波在骨骼中的传播会导致多种传播模式的产生，包括快波和慢波、模式转换和多次散射--这些效应可以掩盖决定骨折风险的骨骼的潜在材料属性。目前，声学测量仅限于允许传播的部位，如癌症，而骨折风险最高的部位，如髋部，只能通过反向散射超声进行检测。因此，我们确定了三个具体目标：1)识别、隔离和克服当前基于传输的跟骨声学测量因接收换能器的相位抵消而产生的局限性；2)实施超声信号的贝叶斯逆变换，以根据接收到的由于存在多种模式而变得复杂的传输声学测量信号估计潜在的骨材料特性；以及3)验证、扩展和改进基于反向散射超声的高危部位(如髋部)骨折风险评估方法。这项拟议研究的长期目标是加强和扩大骨声学测量，以促进其在监测骨质量和借助药物干预潜在的骨质疏松消退方面的作用。与公共健康相关：骨质疏松性骨折降低了生活质量，并带来了巨大的医疗费用。声学测量可以改进骨质量评估，因为与DEXA不同的是，它对骨的微结构和取向很敏感。这项拟议的研究旨在从根本上改进现有的声学测量技术，并探索适用于髋部和脊柱的新技术，这些技术具有相对较高的骨折风险，但目前无法监测。

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.