摘要
目的探索超微超顺磁性氧化铁粒子(USPIO)增强 MRI 监测兔抗原诱导性膝关节炎的可行性及理想成像序列。方法 9只雌性新西兰大白兔,后腿右膝关节(简称右膝关节)腔注入甲基化小牛血清蛋白(mBSA)0.5 ml(2 mg/ml)诱导关节炎模型,后腿左膝关节(简称左膝关节)作为对照。另选3只制成假模型组。模型成功后9～28 d(平均21.3 d)经静脉注入 USPIO(0.3 ml/kg),分别于增强前、增强后24 h 行 MRI 扫描,其中2只于48、72 h 再行 MRI 扫描。扫描方案包括 T_1WI、FSET_2WI、短时反转恢复(STIR)序列及梯度回波(GRE)T_2WI。测量 USPIO 增强前后滑膜的信噪比(SNR)及 SNR 变化(ASNR),行配对 t 检验,并与病理结果相对照。结果 9只大白兔右膝均成功诱导关节炎模型,病理显示滑膜增生,血管翳形成,有大量吞噬 USPIO 的滑膜巨噬细胞浸润;MRI 示滑膜增厚,厚度为(2.07±0.97)mm;关节囊积液。注射 USPIO 后24 h,T_1WI 信号升高[ASNR 为(41.91±27.94)%],T_2WI 和 T_2WI 信号下降[△SNR 分别为(-34.92±11.77)%和(-57.24±16.05)%],各序列增强前后 SNR 差异有统计学意义(P<0.05)。注射后48 h,信号强度开始恢复,72 h 信号基本同增强前。模型组左膝关节及假模型组双膝关节滑膜正常,关节囊无明显积液。结论滑膜巨噬细胞吞噬氧化铁粒子是引起 USPIO 增强 MRI 信号改变的基础,GRE 序列是反映 USPIO 增强效应的敏感序列。
Objective To investigate the feasibility of uhrasmall superparamagnetic iron oxide-enhanced（USPIO） -enhanced MR imaging for monitoring synovitis of antigen-induced arthritis in rabbit model and explore the optimal MR imaging sequences. Methods Nine female white rabbits with antigen （0. 5 ml mBSA, 2 mg/ml） induced arthritis of the right knees were used in the study. The left knees of these rabbits and both knees of another 3 rabbits served as the control. Nine to 28 days （ mean 21.3 d） after successful model induction, all knees were imaged before and 24 h after intravenously injection of USPIO （0. 3 ml/kg）, among which 2 rabbits were also imaged at 48 and 72 h after administration of USPIO respectively. The MR protocol included spin-echo （SE） T1WI, fast spin-echo （FSE） T2WI, gradient echo （GRE） T2^＊ WI and short tau inversion recovery （STIR）. Images were analyzed quantitatively and qualitatively based on signal characteristics and patterns of the synovium. Paired t-test was used for the analysis of the signal intensity of inflammatory synovial membrane before and 24 h after injection of USPIO. MR findings were correlated with histopathology. Results Arthritis was successfully induced in all 9 right knees with intraarticular injection of mBSA. Pathological examination revealed hyperplasia of synovium with infiltration of USPIO-loaded-macrophages. MR depicted synovial thickening （ thickness 2. 07 ± 0. 97 mm） and joint effusion. Synovium and joint fluid appeared as slightly hypo- or iso-intense on T1WI and hyper-intense on T2WI or T2^＊ WI. Twenty four hours after USPIO injection, significant T1 enhancement （△SNR 41.91% ±27.94% ） ,negative T2 and T2^＊ enhancement （△SNR - 34. 92% ± 11.77% and - 57.24% ±16. 05% ） were demonstrated in the region of synovial inflammation respectively. The signal at 48 h and 72 h changed less than that at hour 24. No signs of arthritis occurred in all left knees and in all knees of the artificial model group. Conclusion Iron oxide phagocytized into macrophages can be a root cause resulted in signal change on USPIO-enhanced MR images. The gradient echo sequence should be the optimal sequence to be used in USPIO-enhanced MR imaging in antigen-induced arthritis.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2007年第10期1124-1128,共5页
Chinese Journal of Radiology
基金
安徽省高校自然科学基金资助项目（2006KJ305B）
安徽省重点科研项目（7020303072）
关键词
造影剂
关节炎
滑膜炎
磁共振成像
膝关节
动物实验
Contrast media
Arthritis
Synovitis
Magnetic resonance imaging
Knee joint
Animal experimentation
