Contrast solution properties and scan parameters influence the apparent diffusivity of computed tomography contrast agents in articular cartilage

The inability to detect early degenerative changes to the articular cartilage surface that commonly precede bulk osteoarthritic degradation is an obstacle to early disease detection for research or clinical diagnosis. Leveraging a known artifact that blurs tissue boundaries in clinical arthrograms, contrast agent diffusivity can be derived from computed tomography arthrography (CTa) scans. Â We combined experimental and computational approaches to study protocol variations that may alter the CTa-derived apparent diffusivity. In experimental studies on bovine cartilage explants, we examined how contrast agent dilution and transport direction (absorption vs. desorption) influence the apparent diffusivity of untreated and enzymatically digested cartilage. Using multiphysics simulations, we examined mechanisms underlying experimental observations and the effects of image resolution, scan interval and early scan termination. The apparent diffusivity during absorption decreased with increasing...无法检测通常先于骨性关节炎大面积退变出现的关节软骨表面早期退行性改变，是制约疾病早期研究与临床早期诊断的核心瓶颈之一。利用临床关节造影中已知的会模糊组织边界的伪影，可通过计算机断层关节造影（CTa）扫描推导对比剂扩散率。本研究结合实验与计算方法，探究可能改变CTa衍生表观扩散率的扫描方案变量。在牛软骨外植体的实验研究中，本团队考察了对比剂稀释度与转运方向（吸收vs解吸）对未处理及酶解软骨表观扩散率的影响。通过多物理场模拟，本团队分析了实验观测结果背后的机制，以及图像分辨率、扫描间隔与提前终止扫描带来的影响。吸收过程中的表观扩散率随……升高而降低