Marijn P. Rolf1, Mark B.M. Hofman1,
Peter D. Gatehouse2, Albert C. van Rossum3, Rob M.
Heethaar1
1Physics and Medical Technology,
ICaR-VU, VU University Medical Center, Amsterdam, Netherlands; 2Cardiovascular
Magnetic Resonance Unit, Royal Brompton Hospital, London, United Kingdom; 3Department
of Cardiology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands
Uncompensated
eddy-currents cause velocity offsets, resulting in significant errors in clinical
flow quantification. To reduce these offsets, the influence of velocity
encoding gradient settings was studied in detail. Specifically the bipolar
gradient timing, velocity encoding strategy (asymmetric or symmetric), and
gradient amplitude and slew rate were studied. Timing showed no correlation
with offset. Symmetrical encoding resulted in significantly lower offsets.
Velocity offsets were also reduced by lowering the gradient amplitude and
slew rate, however those protocols are not always compatible with the
time-constraints of breath-hold imaging.