Objective To investigate the feasibility of non-contrast-enhanced renal MR angiography (NCE-MRA) using time spatial labeling inversion pulse (Time-SLIP) technique,and to discuss the optimized inversion time (TI) and its relationship with age.Methods A total of 61 healthy volunteers were divided into two groups by age,22-50 years (n=32)and 51 80 years (n=29).All volunteers underwent 3.0T MRI examination with 6 different TIs sequences (1 200,1 300,1 400,1 600,1 600,1 700 ms).The vessel to-kidney signal ratio (VKR),grade of renal artery branches,grade of renal artery imaging quality were measured and analyzed.Results The VKR values were the highest at TI=1 500 ms in both sides ot kidneys.The scores of renal artery branches were gradually rising up but tending to be steady higher than 1 400 ms.Among all the subjects,the highest score of renal artery imaging quality was at TI=1 500 ms.In 22-50 years group,the highest score of renal artery imaging quality was at TI=1 500 ms.Meanwhile,the highest score was found at TI=1 600 ms in 51 80 years group.Moreover,the grade of renal artery imaging in the 22-50 years group acquired better scores compared to the 51 80 years group (all P＜0.05).Conclusion Time-SLIP technique is helpful to obtain renal MRA without contrast medium.The optimized TI value is 1 500 ms.Moreover,age can affect the optimized TI value.