膝关节前交叉韧带撕裂的MRI诊断

目的　研究膝关节前交叉韧带 (ACL)撕裂的MRI表现及其诊断价值。方法　对 32例手术或关节镜证实的ACL撕裂和 2 0例ACL正常病例的膝关节MRI资料进行分析 ,对ACL的形态特征、走行、信号强度以及ACL撕裂的伴随征象均作了观察与分析 ,并判断有无ACL撕裂。结果　MRI诊断ACL完全性撕裂的敏感性、特异性和准确性分别为 92 % ,95 %和 93%。MRI诊断ACL部分性撕裂与手术、关节镜完全符合 4例 ,1例诊断为完全性撕裂 ,2例假阴性。ACL撕裂的伴随征象主要有胫骨平台骨折 ,骨挫伤 ,半月板、侧副韧带损伤 ,PCL曲度异常 ,胫骨前移或外侧半月板后角后移等。结论　MRI诊断急性完全性ACL撕裂的准确性均较高 ,对于慢性或部分性撕裂 ,其诊断准确性相对较低。

MR Diagnosis of Tears of Anterior Cruciate Ligament of the Knee

Objective To investigate the MR findings of anterior cruciate ligament (ACL) tears and the value of MRI in diagnosis of ACL tears. Methods MR images of 32 patients with ACL tears and 20 patients with intact ACL proved surgically or arthroscopically were reviewed retrospectively.The morphological features, course and signal intensity of ACL, and associated signs of ACL tears were noted and analyzed. Results The sensitivity, specificity and accuracy of MR diagnosis of complete ACL tears were 92%, 95% and 93% respectively. Four of seven patients with partial ACL tears manifested partial disruption or bowing of ACL with increased signal intensity within the ligament, while the other one appeared to be complete ACL disruption and two appeared to be normal appearance. Four of seven patients were diagnosed as partial ACL tears correctly with MR imaging, while the othe one was diagnosed as complete ACL tear, and two false negative. Associated signs of ACL tears mainly included fractures of tibial plateaus, bone bruises, injuries of menisci and collateral ligaments, abnormal curvature of PCL, anterior translation of the tibia and posterior displacement of the lateral meniscus, etc. Conclusion The accuracy of MRI for diagnosis of acute complete ACL tears were high but relatively low for chronic or partial ACL tears.