摘要目的：总结幼年特发性关节炎（JIA）患儿膝关节受累的MRI表现，探讨其与临床实验室炎症指标的相关性。方法回顾性分析临床表现为膝关节疼痛、肿胀或活动受限，并确诊为JIA的50例患儿的临床和影像资料，所有患儿均进行了膝关节MRI增强检查（共计50个膝关节）。对MRI图像中所表现的滑膜增生、关节积液、骨髓水肿、软骨损伤和骨侵蚀程度进行半定量评价，同时收集与MRI检查同期的红细胞沉降率（ESR）、C反应蛋白（CRP）等数据。利用Spearman相关分析法进行MRI评分与实验室指标的相关性分析。结果50个JIA受累膝关节的MRI征象中，以滑膜增生（43例，86%）和关节积液（40例，80%）为主要改变，6个膝关节出现骨髓水肿，12个膝关节出现软骨损伤，未发现骨侵蚀征象。滑膜增生、关节积液、骨髓水肿、软骨损伤的评分分别为7（0～12）、3（0～7）、0（0～6）、0（0～10）分，滑膜增生与关节积液具有明显相关性（r=0.719，P=0.001）。滑膜增生评分与ESR、CRP呈正相关（r值分别为0.306、0.285，P值分别为0.031、0.043）；其他征象与ESR和CRP无相关性（P值均>0.05）。结论 MRI可以对JIA受累膝关节进行全面评价。对于未行增强MRI检查的患儿，可以在平扫MRI中参考关节积液累及范围对滑膜炎程度进行评估。

abstractsObjective To semi-quantitatively assess the MRI manifestations of knee in patients with juvenile idiopathic arthritis (JIA) and to explore the relationship between the semi-quantitative scores with clinical inflammatory biomarkers. Methods Fifty children diagnosed as JIA and presented with knee pain, swelling or limitation were enrolled and their clinical and imaging findings were retrospectively analyzed. Contrast-enhanced MRI scan of the knee were performed in all cases (a total of 50 knees). MRI abnormalities, including synovial hypertrophy, joint effusion, bone marrow edema, joint cartilage injury and bone erosion, were assessed with a semi-quantitative score system. The erythrocyte sedimentation rate (ESR) and C reactive protein (CRP) at the same period with MRI were collected. The relationships between the MRI scores and laboratory biomarkers (CRP and ESR) were analyzed with Spearman correlation analysis. Results In MR images of all the 50 knees with JIA, synovial hypertrophy(43, 86%)and joint effusion(40, 80%)were major abnormalities, bone marrow edema was seen in 6 knees, joint cartilage injury in 12 knees and no bone erosion was seen. The scores of synovial hypertrophy, joint effusion, marrow edema, joint cartilage injury and bone erosion were 7(0-12), 3(0-7), 0(0-6), 0(0-10), 0, respectively. There was significant correlation between synovial hypertrophy and joint effusion(r=0.719, P=0.001). There were positive relationship between synovial hypertrophy and ESR and CRP(r=0.306 and 0.285; P=0.031 and 0.043, respectively).Other indexes had no significant relationship with ESR or CRP. Conclusions MRI could comprehensively evaluate knee involvement in patients with JIA. Joint effusion could be a useful reference to evaluate the condition of synovitis for pediatric patients with non-enhanced MR images.