目的:探讨 MR T2 mapping 定量评估运动对膝关节软骨组织构成的影响。方法26例正常志愿者运动前后及运动后静息15 min 分别行3.0T MR 膝关节矢状面 T2 mapping 序列扫描,原始图像经后处理分别获得3个阶段膝关节软骨的 T2图,测量关节软骨表浅层、中层及深层各感兴趣区(ROI)的 T2值(T2 pre ,T2 post ,T2 delay ),应用单因素方差分析进行统计学处理,组间比较采用 LSD检验。结果志愿者膝关节胫骨面软骨表浅层的 T2 pre 、T2 post 、T2 delay 分别为(49.71±1.95)ms、(44.30±2.56)ms、(49.41±1.62)ms,中层分别为(42.43±2.23)ms、(39.01±2.37)ms、(41.90±2.28)ms,差异均有统计学意义(F =55.673,16.759,P 均<0.001);深层分别为(19.39±2.13)ms、(19.20±2.22)ms、(19.49±2.05)ms,差异无统计学意义(F =0.122,P =0.886),其中胫骨面软骨浅、中层的 T2 pre 与 T2 delay差异无统计学意义(P 分别为0.610、0.403),T2 pre 和 T2 post 、T2 post 和 T2 delay差异均有统计学意义(P 均<0.001)。膝关节股骨面软骨表浅层的 T2 pre 、T2 post 、T2 delay分别为(50.22±1.47)ms、(45.60±2.82)ms、(49.84±1.84)ms,中层分别为(42.67±2.23)ms、(39.36±1.98)ms、(42.40±2.57)ms,差异均有统计学意义(F=37.976,16.987,P 均<0.001);深层分别为(20.30±2.73)ms、(20.60±2.44)ms、(20.51±2.24)ms,差异无统计学意义(F =0.098,P =0.907),其中股骨面软骨浅、中层的 T2 pre 与 T2 delay 差异无统计学意义(P 分别为0.520,0.679),T2 pre 和 T2 post 、T2 post 和 T2 delay 差异均有统计学意义(P 均<0.001)。软骨各层 T2值的空间分布为关节软骨深层至表浅层呈递升的趋势,T2图显示了 T2值变化的空间分布趋势。结论 T2 mapping 序列可以定量监测软骨受力后软骨分子结构的变化。运动引起关节软骨 T2值变化是不均匀的,可使关节软骨组成结构发生可复性变化。
Objective To investigate the effects of exercise on knee cartilage tissue structure using quantitative MR T2 mapping. Methods Sagittal T2 maps of the knee joints of 26 healthy volunteers were obtained by using 3.0T MR before,immediately after, and 1 5 min after running.The original images were classified into three terms of knee cartilage T2 map after postreconstruction.The T2 values of regions of interest (ROC)(T2 pre ,T2 post ,T2 delay )in the superficial,middle and deep cartilage of femoral and tibial joint were measured.Statistical differences of cartilage T2 values of three terms after running were analyzed.Results For the tibial joint cartilage,the T2 pre ,T2 post ,T2 delay were (49.71 ± 1.95)ms,(44.30 ± 2.56)ms,(49.41 ± 1.62)ms in the superficial layer,respectively.The three terms T2 were (42.43 ± 2.23)ms,(39.01 ± 2.37)ms,(41.90±2.28)ms in the middle layer,respectively.The differences were statistically significant(F=55.673,16.759 respectively.P<0.001).While the three terms T2 were (19.39±2.13)ms,(19.20±2.22)ms, (19.49±2.05)ms in the deep layers cartilage,respectively.The differences were not statistically significant(F =0.122,P =0.886).And the differences between T2 pre and T2 post ,T2 post and T2 delay were statistically significant (all P <0.001)in superficial and middle alyers,but there were no significant difference between the T2 pre and T2 delay (P =0.610,0.403,respectively).For the femoral joint cartilage,the T2 pre ,T2 post ,T2 delay were (50.22 ± 1.47)ms,(45.60 ± 2.82)ms,(49.84 ± 1.84)ms in superficial layers,respectively.The three terms T2 were (42.67±2.23)ms,(39.36 ± 1.98)ms,(42.40 ± 2.57)ms in the middle layer,respectively.The differences were statistically significant (F=37.976,16.987 respectively,P<0.001).While the three terms T2 were (20.30±2.73)ms,(20.60±2.44)ms,(20.51± 2.24)ms in the deep layer,the differences were not statistically significant (F =0.098,P =0.907).And the differences between T2 pre and T2 post ,T2 post and T2 delay were statistically significant (all P <0.001)in superficial and middle layers,but there were no significant difference between the T2 pre and T2 delay (P=0.520,0.679,respectively). Spatial distribution of T2 values of articular cartilage from deep to superficial layers showed a ascending trend.T2 maps showed the spatial distribution trend of T2 value change.Conclusion T2 mapping can monitor quantitatively the changes of articular cartilage molecular structure after running.The change of articular cartilage T2 value after exercise is uneven and the change of articular cartilage structure after exercise is reversible.