Objective · To investigate the feasibility of four-dimensional flow MRI (4D flow MRI) in evaluating the hemodynamics of forearm autologous arteriovenous fistula (AVF) in renal dialysis patients. Methods · Forty-five patients Renal Division of Renji Hospital, Shanghai Jiao Tong University School of Medicine were included. Patients with forearm AVF underwent ultrasonography and MRI. The consistency of 4D flow MRI hemodynamic parameters measuredtwo radiologists and hemodynamic parameters at the same plane of AVF4D flow MRI and ultrasonography were analyzedpaired t test. The morphological parameters of AVF were acquired black blood sequence, and they were used for Pearson correlation analysis with the hemodynamic parameters obtained 4D flow MRI. Results · Forty-two patients completed the forearm AVF ultrasonography and MRI successfully. Paired t test showed that the consistency of 4D flow MRI hemodynamic parameterstwo radiologists was good (all P0.000), and all hemodynamic parameters measured4D flow MRI and ultrasonography were in good agreement (r0.292-0.569, all P<0.05) except for the peak flow velocity at anastomosis (r-0.078, P>0.05). Pearson correlation analysis showed that the cephalic venous flow volume of AVF was correlated with the diameter ratio of the cephalic venous to radial artery and the anastomosis area ( r-0.671, r0.482, both P<0.05), and the wall shear stress (WSS) near the anastomosis was correlated with the anastomosis angle and wall thickness (r0.530, r0.462, both P<0.05). Conclusion · 4D flow MRI can be used to evaluate the hemodynamic parameters of forearm AVF in renal dialysis patients, which can provide a reference for further study of AVF dysfunction. [Key words]four-dimensional flow MRI (4D flow MRI); autologous arteriovenous fistula (AVF); hemodynamics