Quantitative measurements on the human ascending aortic flow using 2D cine phase-contrast magnetic resonance imaging

The flow in the human ascending aorta was quantified using two-dimensional (2D) cine phase-contrast magnetic resonance imaging (MRI). The quality and reliability of the method were demonstrated with a specially designed phantom model; the flow rate determined with the MRI agreed well with that obtained with a measuring cylinder. The method was then used to measure the aortic blood flow of three healthy human volunteers. The velocity profiles at the supra-aortic valvular plane and ascending aortic plane (approximately 2 and 5 cm distal to the aortic valve, respectively) were significantly different. At the peak of systole, the profile was almost axisymmetric at the supra-aortic valvular plane, while it was skewed towards the anterior side of the vessel at the ascending aorta. The Reynolds number, volume flow rate, and stroke volume were all within the normal physiological range. This study demonstrated that the 2D cine phase-contrast MRI technique can be used to provide detailed information on the flow velocity and configuration of a blood vessel, making it a promising tool for analyzing complex hemodynamics in the aorta.