Colorado State University, Fort Collins, CO, USA.
Imaging Scientist, inviCRO, LLC, Boston, MA, USA.
Cartilage. 2021 Apr;12(2):211-221. doi: 10.1177/1947603518812562. Epub 2018 Dec 2.
To investigate the diffusion trajectory of a cationic contrast medium (CA4+) into equine articular cartilage, and to assess normal and degenerative equine articular cartilage using cationic contrast-enhanced computed tomography (CECT).
In the first experiment (Exp1), equine osteochondral specimens were serially imaged with cationic CECT to establish the diffusion time constant and time to reach equilibrium in healthy articular cartilage. In a separate experiment (Exp2), articular cartilage defects were created on the femoral trochlea (defect joint) in a juvenile horse, while the opposite joint was a sham-operated control. After 7 weeks, osteochondral biopsies were collected throughout the articular surfaces of both joints. Biopsies were analyzed for cationic CECT attenuation, glycosaminoglycan (GAG) content, mechanical stiffness (E), and histology. Imaging, biochemical and mechanical data were compared between defect and control joints.
Exp1: The mean diffusion time constant was longer for medial condyle cartilage (3.05 ± 0.1 hours) than lateral condyle cartilage (1.54 ± 0.3 hours, = 0.04). Exp2: Cationic CECT attenuation was lower in the defect joint than the control joint ( = 0.005) and also varied by anatomic location ( = 0.045). Mean cationic CECT attenuation from the lateral trochlear ridge was lower in the defect joint than in the control joint (2223 ± 329 HU and 2667 ± 540 HU, respectively; = 0.02). Cationic CECT attenuation was strongly correlated with both GAG (ρ = 0.79, < 0.0001) and E (ρ = 0.61, < 0.0001).
The equilibration time of CA4+ into equine articular cartilage is affected by tissue volume. Quantitative cationic CECT imaging reflects the biochemical, biomechanical and histological state of normal and degenerative equine articular cartilage.
研究阳离子对比剂（CA4+）在马关节软骨中的扩散轨迹，并利用阳离子对比增强计算机断层扫描（CECT）评估正常和退行性马关节软骨。
在第一个实验（Exp1）中，对马的骨软骨标本进行阳离子 CECT 序列成像，以确定健康关节软骨中的扩散时间常数和达到平衡的时间。在另一个实验（Exp2）中，在幼年马的股骨滑车（病变关节）上创建关节软骨缺损，而对侧关节为假手术对照。7 周后，采集两个关节的整个关节表面的骨软骨活检。对活检进行阳离子 CECT 衰减、糖胺聚糖（GAG）含量、机械硬度（E）和组织学分析。比较病变关节和对照关节的成像、生化和力学数据。
Exp1：内侧髁软骨的平均扩散时间常数较长（3.05 ± 0.1 小时），而外侧髁软骨较短（1.54 ± 0.3 小时， = 0.04）。Exp2：病变关节的阳离子 CECT 衰减低于对照关节（ = 0.005），且与解剖位置有关（ = 0.045）。病变关节外侧滑车嵴的阳离子 CECT 衰减低于对照关节（分别为 2223 ± 329 HU 和 2667 ± 540 HU， = 0.02）。阳离子 CECT 衰减与 GAG（ρ = 0.79， < 0.0001）和 E（ρ = 0.61， < 0.0001）均呈强相关。
CA4+在马关节软骨中的平衡时间受组织体积的影响。定量阳离子 CECT 成像反映了正常和退行性马关节软骨的生化、生物力学和组织学状态。
