Abstract: 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.

Key words: Anterior cruciate ligament, 　Diffusion tensor imaging, 　Tractography imaging,  , Knee joint, 　Magnetic resonance imaging