Phase-contrast velocimetry with simultaneous fat/water separation.

Phase-contrast MRI can provide high-resolution angiographic velocity images, especially in conjunction with non-Cartesian k-space sampling. However, acquisitions can be sensitive to errors from artifacts from main magnetic field inhomogeneities and chemical shift from fat. Particularly in body imaging, fat content can cause degraded image quality, create errors in the velocity measurements, and prevent the use of self-calibrated amplitude of static field heterogeneity corrections. To reduce the influence of fat and facilitate self-calibrated amplitude of static field heterogeneity corrections, a combination of chemical shift imaging with phase-contrast velocimetry with nonlinear least-squares estimation of velocity, fat, and water signals is proposed. A chemical shift and first-moment symmetric dual-echo sequence is proposed to minimize the scan time penalty, and initial investigations are performed in phantoms and volunteers that show reduced influence from fat in velocity images. (c) 2010 Wiley-Liss, Inc.