Four-dimensional velocity encoded magnetic resonance imaging for more accurate blood flow quantification in complex flow

Materials and methods Maximal flow velocities (Vmax) and flow volumes (SV) were quantified by 2D and 4D VEC MRI in healthy volunteers (n=7) and patients with aortic (n=7) or pulmonary valve stenosis (n=10). Measurements were performed immediately above the aortic or pulmonary valve (=level 1). Using 4D VEC MRI additional measurements were performed at 3 further levels in the ascending aorta (levels 2-4) and at 2 in the MPA (levels 2-3). In each patient flow volumes measured in the nonpathologic MPA or Aorta served as internal control for expected flow volumes in the absence of shunt flow.