膝关节前交叉韧带损伤的弥散张量成像观测

目的　为膝关节前交叉韧带损伤分度提供新的影像诊断依据。 方法　选取膝关节弥散张量成像扫描检查正常者100例和单侧前交叉韧带撕裂伤者100例，后者按照损伤程度分为Ⅰ~Ⅳ级，在工作站划分前交叉韧带损伤处及正常组相应部位感兴趣区，测量各向异性分数（fractional anisotropy，FA）和表观弥散系数（apparent diffusion coefficient，ADC），生成纤维示踪图像。 结果　前交叉韧带损伤处与正常组相应部位的FA和ADC差异有统计学意义，损伤处的FA低于正常组，ADC高于正常组。前交叉韧带Ⅰ级、Ⅱ级、Ⅲ级、Ⅳ级损伤处的FA和ADC差异有统计学意义，FA随损伤程度增高而逐渐降低，与损伤程度呈负相关；ADC则逐渐增高，与损伤程度呈正相关。FA和ADC、纤维示踪成像及MRI诊断前交叉韧带损伤程度分级的灵敏度、特异度、准确度、阳性预测值及阴性预测值差异均有统计学意义，从高到低均依次为纤维示踪成像、FA和ADC、MRI。 结论　膝关节前交叉韧带损伤处的FA和ADC与损伤程度密切相关，纤维示踪成像可以提高损伤程度分级的准确率，弥散张量成像可以为前交叉韧带损伤分级提供更准确的影像诊断依据。

Diffusion tensor imaging observation of the anterior cruciate ligament injury of knee joint

Objective　To provide a new imaging diagnostic basis for the classification of anterior cruciate ligament injury of the knee. 　Methods　One hundred cases of normal knee joint and one hundred cases of unilateral anterior cruciate ligament laceration were selected to perform diffusion tensor imaging scanning, the latter were divided into I grade, II grade, III grade and IV grade according to the damage degree. At the workstation, the regions of interest of the anterior cruciate ligament injury and the corresponding position of the normal group were divided, the fractional anisotropy(FA) values and apparent diffusion coefficient(ADC) values were measured, and the tractography images were generated.　Results There were significant differences in the FA values and ADC values between the anterior cruciate ligament injury and the normal group. The FA values of anterior cruciate ligament injury was lower than that of the normal group, while the ADC values was higher than that of the normal group. There were significant differences in the FA values and ADC values of the anterior cruciate ligament injure at I grade, II grade, III grade and IV grade, the FA values decreased gradually with the increasing of damage degree, which was negatively correlated with the damage degree. The ADC values increased gradually, which was positively correlated with the damage degree. There were significant difference in the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the FA values and ADC values, tractography imaging and MRI in the diagnosis of degree classification of the anterior cruciate ligament injury, it was the tractography imaging, FA values and ADC values, MRI in order from high to low.　Conclusions　The FA values and ADC values of anterior cruciate ligament injure of knee joint are closely related to the damage degree, the tractography imaging can improve the diagnostic rate of the degree classification of anterior cruciate ligament injury, and the diffusion tensor imaging can provide a more accurate imaging diagnostic basis for degree classification of anterior cruciate ligament injury.