Effects from RF spoiling disequilibrium in the background offsets of phase-contrast velocity imaging
نویسندگان
چکیده
Background Phase-contrast imaging normally uses gradient-echoes with RF spoiling and phase-encode rewinding with a fixed dephasing by gradient “spoiler” pulses in each TR (time between RF pulses) studied in detail (1) where effective artifact suppression in magnitude images required >≈ 8PI dephasing over the slice thickness, with >≈ 2PI dephasing over an FE pixel. However, the effectiveness of spoiling depends on establishing a steadystate. In phase-contrast imaging, background offsets are known to stabilise in continuous scanning such as retrospective gating, but sequence interruptions can be necessary eg in navigator-gating or slice-tracking. Unsteady background offsets are generally ascribed to disturbed equilibrium in eddy-current effects. This abstract is a first investigation of contributions from disequilibrium in spoiling.
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