Abstract: Objective　To provide image data for grading diagnosis in the different degree of anterior cruciate ligament injury.   Methods   One hundred normal knee joint and one hundred unilateral anterior cruciate ligament laceration in the Affiliated Hospital of Xinxiang Medical University were selected by diffusion tensor imaging scanning, and 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 and its injury were divided, the tractography images were generated and the fractional anisotropy (FA) values and apparent diffusion coefficient (ADC) values of the regions of interest were measured. The FA values and ADC values were compared in different position and different degree damage position of the anterior cruciate ligament.    Results    There were significant differences in the FA values and ADC values of the anterior cruciate ligament among the upper ends, upper-middle position, middle position, lower-middle position and lower ends (P<0.05), the FA values was negatively correlated with the decreasing of anterior cruciate ligament from top to bottom, while the ADC values was positively correlated with the increasing of anterior cruciate ligament. There was no significant difference in the FA values and ADC values between the upper ends and upper-middle position of the groups (P>0.05), and it was significant difference in the FA values and ADC values between the other position (P<0.05). 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 (P<0.05), the FA values decreased with the increasing of damage degree, while the ADC values increased. There was no significant difference in the FA values and ADC values between the I grade and II grade (P>0.05), and it was significant differences in the FA values and ADC values between the other damage grades (P<0.05).    Conclusions    The FA values and ADC values of anterior cruciate ligament are closely related to the damage location and damage degree. Diffusion tensor tractography imaging can provide an objective imaging diagnosis basis for the changes of the microstructure of anterior cruciate ligament injury.

Key words: Anterior cruciate ligament, 　Diffusion tensor tractography imaging, 　Anterior cruciate ligament injury, 　Diffusion tensor imaging, 　Magnetic resonance imaging