正常膝关节后外侧部解剖结构的MR成像研究

MR imaging study of the posterolateral structures of the normal knee

目的 研究膝后外侧部结构的MRI表现及其定位 ,为这些结构的完整显示提供可行的方法。方法 观察 30例胫骨标本确定定位膝关节的骨性标志 ;采用 5 0例尸膝标本 ,测量膝后外侧部结构中各结构长轴与骨性标志所成的角度 ;根据上述结果制定MR斜位像的扫描方案 ;对 4 0例正常膝进行常规和斜位T1WI,观察不同方位图像上膝后外侧部结构的显示效果及MRI表现。结果 胫骨外侧平台可以作为膝关节测量和定位的稳定的骨性标志。在 4 0个正常膝中 ,34个 (85 % )外侧副韧带在 70°后斜冠状斜面像上可以完整显示 ,34个 (85 % )和 36个 (90 % )肌分别在 4 5°内斜矢状和 6 0°后斜冠状斜面像上得到较完整显示 ,32个 (80 % )和 34个 (85 % )腓韧带分别在 6 0°后斜冠状和 70°外斜矢状斜面像上得到完整显示 ;弓状韧带 (冠状面像显示 8个 ,2 0 % )和小豆腓骨韧带 (70°外斜矢状斜面像显示 10个 ,2 5 % )在常规像和斜面像上虽可显示 ,但显示率低 ,且不完整。结论 MR斜位像可完整显示膝后外侧部主要结构 ,可作为诊断该类结构损伤的有效手段。

Objective To provide a practicable method for the complete display and localization of the posterolateral structures (PLS) of the normal knee through MRI study. Methods 30 tibial bone specimens were observed to establish the bony landmark for localizing the knee. In 50 cadaver knees, the angles between lateral tibial plateau and the long axis of the individual structure of PLS were measured. Then the scan methods of the oblique MR images were determined based on above results. The routine and oblique scans of T 1WI were performed in 40 normal knees. The display effect and appearance of the PLS were observed on MRI. Results The lateral tibial plateau was a stable bony landmark for measuring and localizing of the knee. In the 40 normal knees, The fibular collateral ligament could be intactly displayed on 70° posterior coronal oblique images in 34 cases (85%). The popliteus could be better seen on either 45° medial sagittal oblique in 34 cases (85%) or 60° posterior coronal oblique planes in 36 cases (90%). The popliteofibular ligament could be intactly appreciated on both 60° posterior coronal oblique in 32 cases (80%) and 70° lateral sagittal oblique images in 34 cases (85%). Although the arcuate ligament and the fabellofibular ligament could occasionally be seen on routine and oblique images, but the display rate was lower. Conclusion The oblique MR imaging can intactly display the main structures of PLS, and can be useful in diagnosing the injuries in those structures.