健康人膝关节股骨内侧髁软骨的T_(2) mapping研究

A study of T_(2) mapping of medial femoral condyle cartilage in healthy knee joints

目的应用T_(2) mapping技术测量健康人膝关节股骨内侧髁负重区与非负重区各层软骨T_(2)值并分析其差异,探讨膝关节软骨分层、分区域MRI定量研究的价值。方法前瞻性纳入22名健康志愿者,其中男、女各11名,平均年龄(27.05±1.05)岁。共纳入38个膝关节,左膝20个,右膝18个。对志愿者行膝关节MRI矢状面T_(2) mapping检查,选取膝关节股骨内侧髁负重区35个、非负重区37个,并测量完整关节软骨上最厚处的T_(2)值。采用独立样本t检验和方差分析分别比较股骨内侧髁负重区与非负重区各层软骨的T_(2)值及各区域内关节软骨浅、中、深层的T_(2)值。结果股骨内侧髁负重区及非负重区的软骨各层T_(2)值由大到小依次为浅层、中层、深层,除非负重区软骨浅层与中层间的T_(2)值差异无统计学意义(P>0.05),余各2层间T_(2)值差异均有统计学意义(均P<0.05);负重区软骨中层、深层T_(2)值均小于非负重区(均P<0.05),负重区与非负重区软骨浅层的T_(2)值差异无统计学意义(P>0.05)。结论健康人膝关节软骨依据T_(2)值差异可分为3层且负重区软骨T_(2)值更低,对膝关节软骨分层、分区域研究具有可行性。

Objective To investigate the differences in T2 values of cartilage between each layer of the weight-bearing and non-weight-bearing areas of the medial femoral condyle in healthy knees measured by T2 mapping,and to explore the value of MRI quantitative study of articular cartilage by dividing it into different layers and areas.Methods A total of 22 healthy volunteers(11 males and 11 females,mean age of 27.05±1.05 years)were prospectively enrolled.The sample included 38 knee joints(20 in the left knee and 18 in the right knee).The volunteers underwent sagittal MRI T2 mapping examinations of knee joints,the thickest part of complete articular cartilage in both weight-bearing and non-weight-bearing areas of the medial femoral condyle were chosen and the T2 values were measured.A total of 35 weight-bearing areas were obtained,while 37 non-weight-bearing areas were obtained.Analysis of variance test was used to analyze the T2 values of the superficial,intermediate,and deep layers of articular cartilages in the same region.Independent sample t-test was used to analyze the T2 values of each articular cartilage layer between the weight-bearing and non-weight-bearing region of the medial femoral condyle.Results The T2 values of each cartilage layer in the weight-bearing and non-weight-bearing areas of the femur medial condyle exhibited a successive gradient from large to small,with superficial layer followed by intermediate layer and then deep layer.There was no significant difference in T2 values between the superficial and intermediate cartilage layers in the non-weight-bearing areas(P>0.05),while there were significant differences in T2 values between the other two layers(all P<0.05).The T2 values in intermediate and deep layers of the weight-bearing area were lower than those in the non-weight-bearing area(all P<0.05),while the T2 values of superficial layer between the weight-bearing area and the non-weight-bearing area were not significantly different(P>0.05).Conclusion The healthy knee cartilage can be divided into three layers based on the difference of T2 values,with the weight-bearing area exhibiting lower T2 values.Therefore,it is feasible to investigate knee cartilage through stratification and subregional analysis.