Phase-Contrast X-ray Micro-Computed Tomography for Enhanced 3D Microstructural Analysis of Bone and Joint Tissues

由于衰老、损伤和疾病，数百万加拿大人的日常生活能力受到骨骼和关节组织力学改变或破坏的痛苦影响。这些变化通常发生在硬组织(如骨)和软组织(如软骨)的复杂微结构中。我们滑铁卢大学的研究团队正在领导创新的生物医学工程研究项目，以更好地了解骨骼和关节组织力学，新的发现带来了用于损伤预防、康复和修复的改进工具和设备。然而，我们的研究受限于现有的用于骨和关节组织的非破坏性微结构分析的微型计算机断层扫描(µCT)成像设备。使用传统的µCT设备对生物组织进行显微成像通常会受到重要组织边界图像质量差(例如对比度、失真、噪声)以及较长扫描时间(1-5小时以上)的阻碍，这限制了我们对组织结构、完整性和对机械载荷的响应做出重要区分的能力。我们的研究小组已经申请资助一种新型的µCT成像系统，该系统使用独特的相衬X射线技术，以更快、更准确地更好地解析生物组织的微结构和成分。相衬X射线技术可实现近乎实时的微结构成像，比传统的µCT成像系统效率高得多(100倍)。目前，加拿大还没有现有的研究机构能够获得用于生物组织表征的相衬X射线微CT成像，使拟议的设备成为全国首个设备。通过相衬X射线微CT成像，我们将获得对生物组织力学的重要新理解，包括微结构几何、组成以及硬组织和软组织的耐受性。建议的设备显著提高了软生物组织和新型生物材料等低密度材料的图像对比度，这是传统µCT成像的主要限制。此外，相衬X射线微CT提供的近乎实时的成像将首次使生物组织微结构在不同载荷条件下的渐进性变化的表征实验更加准确和高效。有了这一设备，加拿大将继续在生物医学工程研究方面保持国际领先地位，展示一种生物组织表征的新变革性技术，解决目前设备的缺陷以及骨和关节组织力学方面的知识空白。预计第一年将有近20名学员使用这种设备，为他们提供医学成像、图像处理、计算建模和机器学习方面的适销对路的尖端技能，这些技能受到附近多伦多-滑铁卢创新走廊上越来越多的生物医学公司的追捧。

Activities of daily living for millions of Canadians are painfully affected by altered or disrupted bone and joint tissue mechanics from aging, injury, and disease. These changes often occur in the complex microstructure of hard (e.g., bone) and soft (e.g., cartilage) tissues. Our team of researchers at the University of Waterloo are leading innovative biomedical engineering research programs to better understand bone and joint tissue mechanics, with new discoveries leading to improved tools and devices for injury prevention, rehabilitation, and repair. However, our research is constrained by available micro-computed tomography (µCT) imaging equipment for non-destructive microstructural analysis of bone and joint tissues. Microstructural imaging of biological tissues with traditional µCT equipment is commonly hindered by poor image quality (e.g., contrast, distortion, noise) at important tissue boundaries as well as long scanning times (1-5+ hours), which limits our ability to make important distinctions about the tissue architecture, integrity, and response to mechanical loading. Our group of researchers have requested funding for a new type of µCT imaging system that uses unique phase-contrast X-ray technology to better resolve biological tissue microstructure and composition more quickly and more accurately. The phase-contrast X-ray technology enables near real-time microstructural imaging, at much greater efficiency (100x) than traditional µCT imaging systems. Currently, there are no existing research facilities in Canada with access to phase-contrast X-ray µCT imaging for biological tissue characterization, making the proposed equipment a national first. With phase-contrast X-ray µCT imaging we will achieve crucial new understanding of biological tissue mechanics, including microstructural geometry, composition, and tolerance of hard and soft tissues. The proposed equipment significantly improves image contrast of low-density materials like soft biological tissues and novel biomaterials, which to date has been a major limitation with traditional µCT imaging. Further, the near real-time imaging provided by phase-contrast X-ray µCT will enable, for the first time, more accurate and efficient characterization experiments of progressive changes in biological tissue microstructure under different loading conditions. With this equipment Canada will continue international leadership in biomedical engineering research, demonstrating a new transformative technology for biological tissue characterization that addresses shortcomings with current equipment as well as knowledge gaps in bone and joint tissue mechanics. Nearly 20 trainees are expected to use this equipment in the first year, providing them marketable, cutting-edge skills in medical imaging, image processing, computational modeling and machine learning, highly sought after by the growing number of biomedical companies in the nearby Toronto-Waterloo innovation corridor.