A COMPLEX DIFFERENCE PHASE-CONTRAST TECHNIQUE FOR MEASUREMENT OF VOLUME FLOW-RATES

Magnetic resonance (MR) phase-difference methods work well for measuri ng volumetric flow rates when the vessel diameter is large compared wi th the in-plane voxel dimensions. For small vessels (eg, coronary arte ries), partial-volume effects introduce substantial errors in the meas ured volume flow rate. To correctly measure flow rates through a voxel , both the fraction of the voxel containing moving spins and the phase shift imparted to those spins must be known, The authors propose a fl ow measurement method that combines information obtained with both the complex-difference and phase-difference processing techniques and the reby provides the fractional volume occupied by the moving spins and t he phase of those spins, The complex-difference flow map method propos ed results in improved accuracy of MIR phase-contrast flow measurement s in the presence of partial-volume effects,