Surowiec Rachel K, Swallow Elizabeth A, Warden Stuart J, Allen Matthew R
Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States.
Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States.
Bone Rep. 2022 Nov 2;17:101633. doi: 10.1016/j.bonr.2022.101633. eCollection 2022 Dec.
High-resolution peripheral quantitative computed tomography (HR-pQCT) is a powerful tool that has revolutionized 3D longitudinal assessment of bone microarchitecture. However, cortical porosity, a common characteristic of cortical bone loss, is still often determined by static evaluation of overall porosity at one timepoint. Therefore, we sought to 1) describe a technique to evaluate individual cortical pore dynamics in aging females over one year using HR-pQCT imaging and 2) determine whether formation and expansion of pores would exceed contraction and infilling of pores.
HR-pQCT (60.7 μm resolution) images were acquired one year apart at the distal tibia and distal radius in seven female volunteers (60-72 years of age). Baseline and one-year images were registered at each bone site and a custom software was used to quantify dynamic activity of individual cortical pores using the following categories: developed, infilled, expanded, contracted, and static.
Over the one-year period, cortical pores actively developed, contracted, expanded, and infilled. More pores expanded and developed vs. infilled or contracted leading to increased pore area in both tibial and radial sites ( = 0.0034 and = 0.0474, respectively). Closed pores in the tibia, those that were not connected to the endosteal or periosteal surfaces, were the most dynamic of any pores type (open/closed) at either bone site.
This study demonstrates an approach to longitudinally track individual cortical pore activity in tibial and radial sites. These data expand conventional parameters for assessing cortical porosity and show increased porosity in one year of aging is caused by newly developed pores and expansion of existing pores.
高分辨率外周定量计算机断层扫描（HR-pQCT）是一种强大的工具，它彻底改变了对骨微结构的三维纵向评估。然而，皮质骨孔隙率作为皮质骨丢失的一个常见特征，仍然常常通过在一个时间点对整体孔隙率进行静态评估来确定。因此，我们试图：1）描述一种使用HR-pQCT成像在一年时间内评估老年女性个体皮质孔隙动态变化的技术；2）确定孔隙的形成和扩大是否会超过孔隙的收缩和填充。
对7名女性志愿者（60 - 72岁）的胫骨远端和桡骨远端进行HR-pQCT（分辨率60.7μm）成像，间隔一年采集图像。在每个骨部位对基线图像和一年后的图像进行配准，并使用定制软件根据以下类别量化单个皮质孔隙的动态活动：形成、填充、扩大、收缩和静态。
在一年期间，皮质孔隙有活跃的形成、收缩、扩大和填充。与填充或收缩相比，扩大和形成的孔隙更多，导致胫骨和桡骨部位的孔隙面积增加（分别为 = 0.0034和 = 0.0474）。胫骨中不与骨内膜或骨膜表面相连的封闭孔隙是两个骨部位中所有孔隙类型（开放/封闭）中最具动态变化的。
本研究展示了一种纵向跟踪胫骨和桡骨部位单个皮质孔隙活动的方法。这些数据扩展了评估皮质骨孔隙率的传统参数，并表明在一年的衰老过程中孔隙率增加是由新形成的孔隙和现有孔隙的扩大所致。
