Automatic accurate non-invasive quantitation of blood flow, cross-sectional vessel area, and wall shear stress by modelling of magnetic resonance velocity data

Objectives: to apply a new, automatic and non-invasive method for quantific ation of blood flow, dynamic mass-sectional vessel area, and wall shear str ess (WSS) by in vivo magnetic resonance velocity mapping of normal subjects . Design: prospective, open study. Materials: six young volunteers. Methods: a three-dimensional paraboloid model enabling automatic determinat ion of bloodflow, vessel distensibility and WSS was applied to blood veloci ty determinations in the common carotid artery. Blood flow was also determi ned by a manual edge detection method. Results: using the new method, the common carotid mean blood flow was 7.28 (5.61-9.63) (mean (range)) ml/s. By;the manual method blood flow was 7.21 ( 5.55-9.60) ml/s. Mean luminal vessel area was 26% larger in peak systole th an in diastole. Mean/peak WSS was 0.82/2.28 N/m(2). Manually and automatica lly determined flows correlated (r(2) = 0.998, p < 0.0001). WSS and peak ce ntre velocity were associated (r(2) = 0.805, p < 0.0001). Conclusions: bloodflow, luminal vessel area dilatation, and WSS can be dete rmined by the automatic three-dimensional paraboloid method. The hypothesis of association between peak centre velocity and WSS was not contradicted b y the results of the present study.