Inlet and outlet valve flow and regurgitant volume may be directly and reliably quantified with accelerated, volumetric phase-contrast MRI.

Purpose To determine whether it is feasible to use solely an accelerated 4D phase-contrast magnetic resonance imaging (4D-PC MRI) acquisition to quantify net and regurgitant flow volume through each of the cardiac valves. Materials and Methods Accelerated, 4D-PC MRI examinations performed between March 2010 through June 2011 as part of routine MRI examinations for congenital, structural heart disease were retrospectively reviewed and analyzed using valve-tracking visualization and quantification algorithms developed in Java and OpenGL. Excluding patients with transposition or single ventricle physiology, a total of 34 consecutive pediatric patients (19 male, 15 female; mean age 6.9 years; age range 10 months to 15 years) were identified. 4D-PC flow measurements were compared at each valve and against routine measurements from conventional cardiac MRI using Bland-Altman and Pearson correlation analysis. Results Inlet and outlet valve net flow were highly correlated between all valves ( P = 0.940-0.985). The sum of forward flow at the outlet valve and regurgitant flow at the inlet valve were consistent with volumetric displacements in each ventricle ( P = 0.939-0.948). These were also highly consistent with conventional planar MRI measurements with net flow ( P = 0.923-0.935) and regurgitant fractions ( P = 0.917-0.972) at the outlet valve and ventricular volumes ( P = 0.925-0.965). Conclusion It is possible to obtain consistent measurements of net and regurgitant blood flow across the inlet and outlet valves relying solely on accelerated 4D-PC. This may facilitate more efficient clinical quantification of valvular regurgitation. J. Magn. Reson. Imaging 2015;41:376-385.© 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]