Dealing with the subvoxel vessel position relative to the reconstruction voxel grid in 2D MR quantitative flow measurements

A method is introduced that quantifies the error in 2D MR Quantitative Flow measurements induced by the position of the vessel relative to the reconstruction voxel grid, called the subvoxel vessel position. In this method, the vessel area and the volume flow rate are determined for all possible subvoxel vessel positions resulting in a mean value with standard deviation. Since the subvoxel vessel position in standard MR image reconstruction is completely arbitrary, the standard deviation can be considered as a measure of its random error contribution. Simulation studies and in vivo measurements show that our method can be used to quantify and subsequently eliminate this random error. It is further quantitatively shown that, for low noise levels, Fourier interpolation to a higher reconstruction matrix also decreases the random error. We conclude that the precision of a 2D MR Quantitative Flow measurement is improved either by using our method or by reconstruction to a higher matrix.