三种新型磁共振功能成像技术对早期膝关节软骨损伤的诊断价值分析

Analysis on the diagnostic value of three kinds of new magnetic resonance functional imaging techniques for cartilage injury of knee joint at early stage

目的:探讨弥散加权成像(DWI)、弥散张量成像(DTI)和T2 mapping成像3种新型磁共振(MR)功能成像技术在早期膝关节软骨损伤诊断中的应用价值。方法:选择92例骨性关节炎早期膝关节软骨损伤患者将其纳入观察组,另选50名健康志愿者将其纳入健康对照组。采用3.0T MR成像系统进行DWI、DTI和T2 mapping成像技术,测量膝关节股骨及胫骨的内外侧软骨面和髌骨软骨面的表观弥散系数(ADC)、各向异性分数(FA)和弛豫时间(T2)值,并进行软骨损伤分级诊断。结果:健康对照组均为0级正常软骨,观察组软骨损伤Ⅰ级16例(占17.39%),Ⅱ级38例(占41.30%),Ⅲ级24例(占26.09%),Ⅳ级14例(占15.22%)。观察组在股骨内侧面、股骨外侧面、胫骨内侧面、胫骨外侧面和髌骨面的ADC值和T2值均大于健康对照组,差异均有统计学意义(tADC值=16.679,t=14.538,t=17.055,t=11.612,t=10.930;tT2值=25.104,t=29.683,t=17.866,t=16.527,t=24.424;P<0.05);FA值均小于健康对照组,差异均有统计学意义(t=20.454,t=17.773,t=16.010,t=17.101,t=17.079;P<0.05)。结论:DWI、DTI及T2 mapping成像,对于无明显形态学改变的早期膝关节软骨损伤均具有重要的诊断价值。

Objective: To investigate the application value of three kinds of new magnetic resonance(MR) functional imaging techniques, included diffusion-weighted imaging(DWI), diffusion tensor imaging(DTI) and T2 mapping imaging, in the diagnosis of cartilage injury of knee joint at early stage. Methods: 92 patients with osteoarthritis cartilage injury of knee joint at early stage were selected and were included in observation group. And 50 healthy volunteers were selected and were included in healthy control group. The 3.0 T MR imaging system was applied to conduct DWI, DTI and T2 mapping imaging. The apparent diffusion coefficient(ADC), fractional anisotropy(FA) and relaxation time(T2) of medial and lateral cartilage surfaces in femur and tibia of knee joint, and cartilage surfaces in patella were measured. And the cartilage injury was graded and diagnosed. Results: All the cartilages of healthy control group were grade 0. And in observation group, there were 16 cases(17.39%) with cartilage injury at grade Ⅰ, 38 cases(41.30%) with cartilage injury at grade Ⅱ, 24 cases(26.09%) with cartilage injury at grade Ⅲ and 14 cases(15.22%) with cartilage injury at grade IV. ADC values and T2 values of medial and lateral surfaces of femur, medial and lateral surfaces of tibia, and patella surface of observation group were significantly larger than those of healthy control group(tADC value=16.679, t=14.538, t=17.055, t=11.612, t=10.930, tT2 value=25.104, t=29.683, t=17.866, t=16.527, t=24.424, P<0.05), while FA values of observation group were significantly smaller than those of control group(t=20.454, t=17.773, t=16.010, t=17.101, t=17.079, P<0.05). Conclusion: DWI, DTI and T2 mapping imaging have important diagnostic value for cartilage injury of knee joint without obvious morphological changes at early stage.