Improved measurements of pressure gradients in aortic coarctations by magnetic resonance imaging

A controlled laboratory study was conducted on models of aortic coarctations to determine the value of the loss coefficients as a function of stenosis severity. The values obtained for the loss coefficients were applied to a series of patients with aortic coarctation who underwent evaluation with magnetic resonance imaging (MRI) then the pressure gradient across the coarctation was estimated. Severity-based loss coefficients were found to allow a more accurate determination of pressure gradient across stenosis. Both the generated in-vitro and in-vivo data suggest that MRI and MR phase velocity mapping can perform complete evaluation of aortic coarctation by determining stenosis location, stenosis severity, and providing an accurate estimate of pressure gradient across the stenosis.