Musculoskeletal and Quantitative Imaging Group (MQIR), Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
Osteoarthritis Cartilage. 2019 May;27(5):737-745. doi: 10.1016/j.joca.2018.10.016. Epub 2019 Feb 23.
To investigate compositional changes of knee cartilage at the site of newly appearing cartilage lesions and the surrounding cartilage 1-4 years prior to lesion onset using quantitative T2-measurements.
Fifty-seven cartilage plates with newly appearing cartilage lesions from 45 knees (cases) and 52 plates from 26 control knees from the Osteoarthritis Initiative (OAI) cohort (controls) were evaluated. Using MRI T2-mapping, composition of local (the site of future lesions) and surrounding cartilage (remainder of the cartilage plate) was assessed 1-4 years prior to lesion onset. Analogous cartilage ROIs in control plates without cartilage lesions were assessed over 1-4 years. Mixed models were used to compare T2-means and change rates between local and surrounding cartilage within cases and controls, and to compare change rates in local and surrounding cartilage between cases and controls, adjusting for covariates.
Four years prior to lesion onset, we found that local cartilage ROIs had higher T2-values compared to the surrounding cartilage. No such differences were found in control plates. In cases mean local T2-values were persistantly elevated compared to the surrounding cartilage prior to lesion onset reaching significance 1 year prior (+2.94 ms, p = 0.012). T2-values of the surrounding cartilage were also persistantly higher in cases compared to controls, reaching significance 2 years prior to lesion onset (+3.61 ms, p = 0.003).
The findings of our study support the concept of compositional cartilage changes as a mechanism for cartilage degradation and that both diffuse and focal changes of cartilage composition within a cartilage plate precede the development of cartilage lesions.
使用定量 T2 测量技术，研究新出现的软骨病变部位及病变前 1-4 年周围软骨的成分变化。
从 Osteoarthritis Initiative（OAI）队列中，评估了 45 个膝关节的 57 个软骨板（病例）和 26 个对照膝关节的 52 个软骨板（对照），这些软骨板上出现了新的软骨病变。通过 MRI T2 映射，评估了局部（未来病变部位）和周围软骨（软骨板的其余部分）在病变前 1-4 年内的成分。在对照软骨板中，没有软骨病变的类似软骨 ROI 也在 1-4 年内进行了评估。使用混合模型比较病例和对照中局部和周围软骨的 T2 平均值和变化率，并调整协变量后比较病例和对照中局部和周围软骨的变化率。
在病变前 4 年，我们发现与周围软骨相比，局部软骨 ROI 的 T2 值更高。在对照软骨板中没有发现这种差异。在病例中，与周围软骨相比，局部 T2 值在病变前持续升高，在病变前 1 年达到显著水平（+2.94ms，p=0.012）。在病变前 2 年，与对照相比，病例中周围软骨的 T2 值也持续升高（+3.61ms，p=0.003）。
本研究的结果支持了成分性软骨变化作为软骨降解机制的概念，并且软骨板内的弥散和局灶性软骨成分变化都先于软骨病变的发生。
