1Brain Imaging & Analysis Center, Duke University, Durham, NC, United States; 2Radiology, Duke University, Durham, NC, United States
Phase images of gradient-recalled echo (GRE) have provided a new contrast for MRI. It is well known that the magnitude contrast of GRE signal changes as a function of sequence parameters including TR, TE and flip angle. The dependence of phase contrast on these parameters, however, has not been explored. In fact, phase contrast has largely been assumed in the literature to be insensitive to sequence parameters. We show that phase contrast has a profound dependence on sequence parameters that can be described by a multi-compartment model. This dependence may provide further insights of the mechanisms of susceptibility contrast.