膝关节软骨负荷运动前后磁共振T_2时间与容积变化研究

目的通过比较分析负荷运动前后膝关节软骨磁共振T2时间和软骨容积变化,探讨利用T2时间和容积变化反映负荷作用下软骨形态变化的可行性。方法选择20例健康志愿者,其中男性16例,女性4例;年龄为20.1~30.4岁,平均年龄25.7岁。在同等运动负荷前后进行软骨T2mapping序列成像,测量股骨内外侧髁、胫骨平台和髌软骨T2时间;以三维脂肪抑制快速扰相梯度回波(3D-FS-SPGR)序列扫描并采用最大信号强度投影法(MIP)重建后测量髌软骨及股骨髁软骨容积。比较负荷前后软骨T2时间变化、软骨容积差异,并分析软骨容积与T2时间变化间的相关性。结果运动前与运动后髌软骨T2时间最长,胫骨外侧平台最短;运动后不同部位软骨T2时间均降低(P=0.000),股骨内侧髁软骨下降幅度最大(t=-27.96,P=0.000);运动后膝关节软骨容积减小(P=0.000),股骨髁软骨容积变化程度(t=-86.71,P=0.000)大于髌软骨(t=-9.42,P=0.000);软骨容积与T2时间变化间无线性相关性(P0.05)。结论运动后膝关节软骨各部位T2时间和局部软骨容积均减少,但软骨容积与T2时间变化间无相关性;软骨T2mapping和软骨容积变化磁共振成像技术对评价负荷作用下软骨形态变化有一定的意义。

Study on the change of T2 time and cartilage volume by magnetic resonance imaging for knee cartilage after loading

Objective To study the changes in T2time and volume response of knee cartilage by magnetic resonance imaging（MRI）after loading exercise, and explore the feasibility of evaluating the morphological changes of cartilage after loading by T2time response and volume change. Methods A total of 20 healthy adult volunteers were enrolled, which included 16 males and 4females; aged 20.1- 30.4 years old with mean age of 25.7. T2mapping sequential imaging was performed to measure the T2time of medial and lateral femoral condyle, medial and lateral tibial plateau and patellar cartilage before and after loading exercise. Threedimensional fat-suppressed fast spoiled gradient echo（3D-FS- SPGR） sequence scan reconstructed by maximum intensity projection（MIP） was employed to measure the volume of patellar cartilage and femoral condoyle cartilage. Bilateral knee cartilage MRI T2time and cartilage volumes were compared, and the correlation between volume and T2time changes were analyzed. Results The T2time of patellar cartilage was longer than that of the other compartments, and the T2time of lateral tibial plateau cartilage was the shortest before and after loading exercises. The T2times decreased in all the groups after loading exercise（P = 0.000）, and that of medial femoral cartilage showed the largest decline（t =- 27.96, P = 0.000）. In addition, cartilage volume demonstrated similar decrease after loading exercise（P = 0.000）, and the volume decrease in femoral cartilage（t =- 86.71, P = 0.000） was more significant than that of patellar cartilage（t =- 9.42, P = 0.000）. There was no correlation revealed between cartilage T2time and volume（P ＆gt; 0.05）.Conclusion It is demonstrated that after loading exercises, the partial cartilage volume and all cartilage T2time are decreased, but there is no linear correlation between the changes of cartilage volume and T2time. T2mapping and cartilage volume by MRI are the certain significance for evaluation of cartilage shape change after loading exercise.