30°屈曲体位膝关节MRI对显示前交叉韧带和评价韧带断裂的应用价值

The application value of knee MRI joint in 30° flexion position for displaying anterior cruciate ligament and evaluating ligament rupture

目的探讨在膝关节MRI检查中采取30°屈曲体位对前交叉韧带(ACL)显示及其断裂评价方面的价值。方法选择患膝外伤并行关节镜检查的70例患者,其中男性38例,女性32例;年龄24~56岁,平均年龄35.85岁。指导患者分别采取17°与30°屈曲体位膝关节MRI检查,后由2名影像学医师进行双盲原则下阅片,分别对ACL全长、双束结构、断裂点与残端情况进行评级。基于关节镜检查金标准,统计膝关节MRI不同体位下的疾病诊断准确度、特异度与灵敏度。结果经关节镜检查,确诊ACL断裂者41例,ACL正常者29例;17°屈曲体位MRI检查的准确度为91.43%,特异度为86.21%,灵敏度为95.12%;30°屈曲体位MRI检查的准确度、特异度和灵敏度均为100.00%;30°屈曲体位MRI检查的ACL全长成像优良率(95.71%)高于17°屈曲体位(80.00%),断裂点与残端成像优良率(92.68%)高于17°微屈体位(73.17%),差异有显著统计学意义(P=0.001 <0.01);两组双束结构成像优良率比较,差异无统计学意义(82.86%vs80.00%,P> 0.05)。结论 30°屈曲体位膝关节MRI扫描的准确度、灵敏度与特异度高于17°屈曲体位,且在ACL全长、断裂点与残端成像表现方面更佳,二者双束结构成像表现具有一致性。

Objective To explore the evaluation value in MRI examination of knee joint 30° flexion position for displaying and rupture of anterior cruciate ligament(ACL). Methods A total of 70 knee trauma patients with arthroscopy were enrolled,which included 38 males and 32 females, aged 24-56 years old with mean age of 35.85 years old. All of them performed MRI examinations of knee joint in 17° and 30° flexion position, respectively, and images were double-blindly judged by 2 imaging physicians. The ACL length, bi-beam structure, rupture point and stump were rated. Based on the gold standard of arthroscopy, the diagnostic accuracy, specificity and sensitivity of different positions of knee MRI were statistically calculated.Results The arthroscopy diagnosed ACL fracture in 41 cases and ACL normal in 29;the accuracy of MRI in 17° flexion position was 91.43 %, specificity was 86.21 % and sensitivity was 95.12 %;the accuracy, specificity and sensitivity of MRI in30° flexion position were all 100.00 %;In 30° flexion position, the superior rate of ACL length imaging(95.71 %) was higher than that of 17° flexion position(80.00 %), the superior rate of rupture point and stump imaging(92.68 %) were higher than that in 17° flexion position(73.17 %), the difference was statistically significant(P = 0.001 < 0.01);There was no significant difference in superior rate of bi-beam structure imaging between 2 groups(82.86 % vs 80.00 %, P > 0.05). Conclusion It is demonstrated that the accuracy, sensitivity and specificity of knee MRI joint in 30° flexion position are higher than that in 17°flexion position, which is better to image length, rupture point and stump of ACL, while bi-beam structure imaging is consistent in 2 groups.