Pixel-wise absolute pressures in the aortic arch from 3D MRI velocity data and carotid artery applanation tonometry

A pixel-wise method for absolute and local aortic pressures estimation using 3D velocities in MRI and carotid pressure curves to set-up reference pressure values is presented. This method is based on the Navier-Stokes equation and a fast iterative algorithm. Its reliability was demonstrated: 1) in a synthetic phantom by comparison against simplified Bernoulli equation applied at peak velocities, and 2) in a healthy subject and a patient with aortic coarctation, in which absolute pressure distribution within the aortic arch was consistent with established physiopathological knowledge. Such local absolute aortic pressures may be useful in the understanding of hemodynamic changes secondary to cardiovascular alterations. Also, their addition to the already available indices of risk of aortic complications such as dilatation and dissection definition may prove of major clinical usefulness.