  Wall shear stress (WSS) has been suggested as a potential biomarker in
various cardiovascular diseases and it can be estimated from phase-contrast
Magnetic Resonance Imaging (PC-MRI) velocity measurements. We present a new
parametric sequential method for MRI-based WSS quantification consisting of a
geometry identification and a subsequent approximation of the velocity field.
The new method was validated on well controlled, high resolution in vitro
measurements of turbulent stationary flows and physiological pulsatile flows in
phantoms. Basic applicability to in vivo was demonstrated using 2D PC-MRI data
of the ascending aorta of three volunteers.
