1.5T MR研究健康人膝关节软骨T_2值空间分布

目的 研究健康成人膝关节软骨T2弛豫时间(T2值)空间分布.方法 1.5T场强下对21名健康男性(年龄24～39岁,平均30岁±4岁)行膝关节矢状位多回波多层面SE序列扫描,使用Profile软件测量股骨非承重软骨的前部、股骨承重软骨、胫骨承重软骨、髌软骨的T2弛豫时间(即T2值),采用方差分析检验各部位软骨深层和浅层T2值、承重软骨和非承重软骨的T2值空间分布的差异.结果 健康人膝关节软骨T2值空间分布呈浅凹形曲线,即近软骨下骨质T2值较高,随后T2值从软骨深层到浅层逐渐增高,并且各层T2值存在差异(F=70.892,P＜0.05).髌软骨T2值空间分布变化最大,股胫关节承重软骨和股骨前部非承重软骨T2值的空间分布变化较平缓.髌软骨深层T2值[(26.56±4.4) ms]明显低于所有软骨深层T2值(P=0.001).股骨外髁承重软骨浅层T2值[(35.2±6.31) ms]明显低于髌软骨[(40.78±3.56) ms]和股骨非承重软骨前部[(42.31±2.4) ms](P=0.002,P=0.000).胫骨外髁承重部软骨浅层T2值[37.11±6.6) ms]明显低于股骨非承重前部(P=0.000).结论 1.5T 场强下健康人膝关节软骨T2值具有特定空间分布,对量化研究退行性骨关节炎和其他关节病变具有参考价值.

Spatial Variation of T2 Values of Knee Joint Cartilage in Healthy Adults with .5T MR System

Objective To study the spatial variation of T2 relaxation time of cartilage of knee in healthy adults.Methods T2 values of cartilage of knee in 21 asymptomatic young male adults ( age ranged 24 to 39 years ; mean age , 30 years) were calculated by using a multiecho,spin-echo MR imaging sequence at 1.5T MR scanner on sagittal T2 maps,including the patellar,distal femoral weight and non-weight-bearing as well as proximal tibial weight-bearing cartilages,the differences in the spatial variation between them were analysed using F test.Results All 21 asymptomatic volunteers demonstrated a consistent pattern of spatial variation of T2 values cartilage of knee with longer T2 values near the subchondral bone,decreased in deep zoon and increased in articular surface , there was difference between them (F=70.892 , P＜0.05 ) . The greates spatial variation occurred in the patella.T2 value(26.56 ms±4.4 ms) in the deeper zoon of cartilage of the patella was obviously lower than that of the weight-and non-weight-bearing articular cartilage (P = 0.001 ) . Lateral femoral weight-bearing articular cartilage showed lower T2 value ( 35.2 ms ± 6.31 ms) in the outer transitional superficial zone than thatof the patella and non-weight-bearing cartilage,P=0.002,P=0.000 respectively.Lateral tibial weight-bearing articular cartilage showed showed lower T2 value(37.11 ms±6.6 ms)in the outer transitional superficial zone than that of non-weight-bearing cartilage(P=0.000). Conclusion The spatial variation of T2 relaxation time of cartilage of knee in the vivo in the asymptomatic young adults is like slightly concave curve at 1.5T MR system,that is of reference value in study of degenerative osteoarthritis.