Estimation of pressure gradients in pulsatile flow from magnetic resonanceacceleration measurements

A method for estimating pressure gradients from MR images is demonstrated. Making the usual assumption that the flowing medium is a Newtonian fluid, a nd with appropriate boundary conditions, the inertial forces (or accelerati on components of the flow) are proportional to the pressure gradients, The technique shown here is based on an evaluation of the inertial forces from Fourier acceleration encoding. This method provides a direct measurement of the total acceleration defined as the sum of the velocity derivative vs, t ime and the convective acceleration. The technique was experimentally valid ated by comparing MR and manometer pressure gradient measurements obtained in a pulsatile flow phantom, The results indicate that the MR determination of pressure gradients from an acceleration measurement is feasible with a good correlation with the true measurements (r = 0.97), The feasibility of the method is demonstrated in the aorta of a normal volunteer. (C) 2000 Wil ey-Liss, Inc.