This study addressed difficulties in evaluating osteoarthritis (OA) progression in species with thin cartilage. Feasibility of using short, nonequilibrium contrast-enhanced micro–computed tomography (CE-μCT) to evaluate the physical and biochemical properties of cartilage was investigated. A preliminary in vitro study using CE-μCT study was performed using bovine osteochondral blocks with intact, mildly damaged (fibrillated), or severely damaged (delaminated) cartilage. Delamination of the superficial zone resulted in elevated apparent density compared with intact cartilage after 10 minutes of anionic contrast exposure (P < 0.01). OA was induced by unilateral meniscal destabilization in n = 20 sheep divided into: early phase OA (n = 9) and late phase OA (n = 11), while n = 4 remained as naive controls. In vivo anionic nonequilibrium contrast CT of the operated stifle was conducted in the early phase sheep 13 weeks postoperatively using clinical resolution CT. Cartilage visibility in the contrasted leg was significantly improved compared with the noncontrasted contralateral stifle (P < 0.05). Animals were sacrificed at 3 months (early phase) or 12 months (late phase) for additional ex vivo CE-μCT, and correlative tests with biochemical and histological measures. Concentration of sulfated glycosaminoglycan (sGAG) significantly varied between control, early, and late phase OA (P < 0.005) and showed a negative (r = −0.56) relationship with apparent density in the medial tibial plateau (R² = 0.28, P < 0.001). Histologically, parameters in proteoglycan and cartilage surface structure correlated with increasing attenuation. While previous studies have shown that CE-CT increases the apparent density of proteoglycan-depleted cartilage, we concluded that superficial zone disruption also contributes to this phenomenon.

这项研究解决了评估薄软骨物种骨关节炎 (OA) 进展的困难。研究了使用短的、非平衡的对比增强显微计算机断层扫描 (CE-μCT) 来评估软骨的物理和生化特性的可行性。使用 CE-μCT 研究的初步体外研究是使用具有完整、轻度受损（纤维化）或严重受损（分层）软骨的牛骨软骨块进行的。阴离子造影剂暴露 10 分钟后，与完整的软骨相比，表层区域的分层导致表观密度升高（P < 0.01）。OA 是由n = 20 只绵羊的单侧半月板不稳定引起的，分为：早期 OA（n= 9）和晚期 OA（n = 11），而n = 4 仍然是幼稚的对照。术后 13 周，使用临床分辨率 CT 在早期绵羊中进行手术膝关节的体内阴离子非平衡对比 CT。与未对比对侧膝关节相比，对比腿的软骨可见度显着提高（P < 0.05）。在 3 个月（早期）或 12 个月（晚期）处死动物以进行额外的离体CE-μCT，以及与生化和组织学测量的相关测试。硫酸化糖胺聚糖 (sGAG) 浓度在对照、早期和晚期 OA 之间存在显着差异 ( P < 0.005)，呈阴性 (r = -0.56) 与内侧胫骨平台表观密度的关系 ( R ² = 0.28, P < 0.001)。组织学上，蛋白聚糖和软骨表面结构的参数与衰减增加相关。虽然先前的研究表明 CE-CT 增加了蛋白多糖耗尽软骨的表观密度，但我们得出结论，表面区域破坏也促成了这种现象。