RESUMEN
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 from 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 measured by two radiologists and hemodynamic parameters at the same plane of AVF by 4D flow MRI and ultrasonography were analyzed by paired t test. The morphological parameters of AVF were acquired from black blood sequence, and they were used for Pearson correlation analysis with the hemodynamic parameters obtained from 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 parameters by two radiologists was good (all P=0.000), and all hemodynamic parameters measured by 4D flow MRI and ultrasonography were in good agreement (r=0.292-0.569, all P0.05). 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, r=0.482, both P<0.05), and the wall shear stress (WSS) near the anastomosis was correlated with the anastomosis angle and wall thickness (r=0.530, r=0.462, 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.
RESUMEN
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 from 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 measured by two radiologists and hemodynamic parameters at the same plane of AVF by 4D flow MRI and ultrasonography were analyzed by paired t test. The morphological parameters of AVF were acquired from black blood sequence, and they were used for Pearson correlation analysis with the hemodynamic parameters obtained from 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 parameters by two radiologists was good (all P=0.000), and all hemodynamic parameters measured by 4D flow MRI and ultrasonography were in good agreement (r=0.292-0.569, 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, r=0.482, both P＜0.05), and the wall shear stress (WSS) near the anastomosis was correlated with the anastomosis angle and wall thickness (r=0.530, r=0.462, 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.
RESUMEN
Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.