磁共振形态和功能成像技术评估家兔膝关节软骨缺损修复的价值

The value of morphological and functional magnetic imaging assessment in articular carti⁃lage defect repair of rabbits

目的:基于3.0T高场强磁共振,通过研究磁共振动态观察软骨缺损修复过程,评价不同磁共振序列评估软骨修复的可行性、准确性。方法:在新西兰大白兔双侧膝关节股骨内侧髁建立全层软骨缺损模型,术后2~8周,每周定期采用质子加权序列(PDWI)、T2加权双稳态3D成像序列(3D-T2-DESS)、T1加权三维梯度回波容积内插屏气呼吸序列(3D-T1-VIBE)、T1 mapping、T2 mapping、T2*mapping行形态及功能磁共振检查。术后第8周处死兔子,对再生软骨行大体病理、组织病理评分。结果:术后8周,3D-T1-VIBE与3D-T2-DESS的软骨修复磁共振评分(MOCART)评分具有良好的一致性(r=0.722,P<0.01),但两者总体评分比较,差异有统计学意义(P<0.01)。3D-T1-VIBE、3D-T2-DESS序列与ICRS大体评分(r=-0.655,P<0.01;r=-0.717,P<0.01)和Wakitani组织病理评分(r=-0.772,P<0.01;r=-0.833,P<0.01)相关性较好。原始T1 mapping值2~8周比较,差异无统计学意义(P>0.05),T2 mapping、T2^(*)mapping值各周间比较,差异有统计学意义(P<0.01)。结论:3D-T1-VIBE与3D-T2-DESS磁共振序列评估软骨修复情况明显优于2D的PDWI序列;T2 mapping、T2*mapping值前8周随时间变化明显,适合用于监测、评估软骨修复疗效。

Objective:Based on 3.0T high-field magnetic resonance imaging,feasibility and accuracy of different magnetic resonance imaging sequences in cartilage repair assessment were evaluated by observing dynamically the repair process of cartilage defects.Methods:A full-thickness cartilage defect model was created in both keen joint of medial femoral condyle in New Zealand white rabbits.Morphological and functional MRI were carried out one time per week from weeks 2-8:using PDWI,3D-T2-DESS,3D-T1-VIBE,T1 mapping,T2mapping,and T2*mapping.All rabbits were sacrificed at 8 weeks post-surgery,and gross pathologic,histopathology scores were calculated.Result:At 8 weeks after surgery,the scores of magnetic resonance observation of cartilage repair tissue(MOCART)between 3D-T1-VIBE and 3D-T2-DESS had excellent agreement(r=0.722,P<0.01),but difference was statistically significant(t=2.55,P<0.01).Sequences of 3D-T1-VIBE and 3D-T2-DESS were both well correlated with gross pathologic(r=-0.655,P<0.01;r=-0.717,P<0.01)and Wakitani histopathology(r=-0.772,P<0.01;r=-0.833,P<0.01).There was no significant difference in native T1 mapping value among 2-8 weeks(P>0.05).But significant differences in T2 mapping and T2*mapping were observed(P<0.01).Conclusion:Cartilage repair assessments of 3D-T1-VIBE and 3D-T2-DESS are better than 2D PDWI sequences.T2 mapping and T2*mapping values varied over time,and suitable for monitoring and assessing the efficacy of cartilage repair.