Referenceless techniques for flow imaging are described that exploit a
refocusing property of balanced steady state free precession ("SSFP")
magnetic resonance imaging ("MRI"), and achieve up to approximately a 50%
reduction in total scan time. With the echo time set to one half of the
sequence repetition time (TE=TR/2), non-flow-related image phase tends to
vary smoothly across the field-of-view, and can be estimated from static
tissue regions to produce a phase reference for nearby voxels containing
flowing blood. These approaches produce accurate in vivo one-dimensional
velocity estimates in half the scan time compared with conventional
balanced SSFP phase-contrast methods. The feasibility of referenceless
time-resolved 3D flow imaging (called "7D" flow) is demonstrated for a
carotid bifurcation application from just three acquisitions. Related
systems are also described. Other attributes such as blood acceleration
can also be imaged with such techniques.