Quantification of mitral regurgitation with MR phase-velocity mapping using a control volume method

Reliable diagnosis and quantification of mitral regurgitation are important for patient management and for optimizing the time for surgery. Previous m ethods have often provided suboptimal results. The aim of this in vitro stu dy was to evaluate MR phase-velocity mapping in quantifying the mitral regu rgitant volume (MRV) using a control volume (CV) method, A number of contig uous slices were acquired with all three velocity components measured. A CV was then selected, encompassing the regurgitant orifice. Mass conservation dictates that the net inflow into the CV should be equal to the regurgitan t now. Results showed that a CV, the boundary voxels of which excluded the region of now acceleration and aliasing at the orifice, provided accurate m easurements of the regurgitant now. A smaller CV provided erroneous results because of now acceleration and velocity aliasing close to the orifice. A large Cv generally provided inaccurate results because of reduced velocity sensitivity far from the orifice. Aortic outflow, orifice shape, and valve geometry did not affect the accuracy of the CV measurements. The CV method is a promising approach to the problem of quantification of the MRV.