Objective To evaluate the injury of unilateral testicular torsion on the contralateral testes with contrast-enhanced ultrasound.Methods Twenty-eight male rabbits were enrolled in this study.They were randomly divided into the control group,the detorsion after 3 hours group,the detorsion after 6 hours group,the detorsion after 24 hours group and the permanent torsion group.There were 8 rabbits in the control group,and 5 rabbits in each of the other groups.Just before torsion,immediately after torsion,just before detorsion,immediately after detorsion,and delay(6-12 hours after detorsion.the permanent torsion group was also at the corresponding time),contrast-enhanced ultrasound was used to observe the perfusion of contralateral testes.The control group was also performed contrast-enhanced ultrasound just before the shame operation and immediately after that.The time-intensity curves were draw according to the contrastenhanced ultrasound images.The parameters including arrival time(AT),time to peak intensity(TTP),peak intensity(PI),half time of descending peak intensity(HT)were yielded automatically,and the changes of them were analyzed.Results①There was no significance of enhancement AT,TTP,PI,and HT between pre-operation and post-operation in the control group(P＞0.05).②When the parameters of immediately after torsion compared with those of before torsion in the groups of torsion,the perfusion was increased significantly displaying by PI increasing(P＜0.05).③The longer time the duration of unilateral testicular torsion,the more obviously the perfusion of the contralateral testes increased.Conclusions The timeintensity curve of contrast-enhanced ultrasound is valuable in assessing of the injury of unilateral testicular torsion on the contralateral testis.