Three-dimensional magnetic resonance flow-contrast angiography with suppression of stationary material

摘要

A metod for providing a three-dimensional nuclear magnetic resonance (NMR) flow-contrast angiograph of fluid flowing substantially only in a predetermined direction, with suppression of stationary material surrounding the fluid, uses the steps of: acquiring a first set of image data from NMR responses generated from a volume-to-be-imaged by a three- dimensional volume imaging sequence preceded by a saturation portion saturing nuclear spins in a volume adjacent to, and in the direction from which the desired flow will enter, the volume-to-be- imaged; acquiring a second set of image data from other NMR responses generated by the same volume imaging sequence, but devoid of any preceding saturating portion; and subtracting one of the first and second data sets from the other to generate a difference data set from which a final image is displayed. Advantageously, a 3DET volume imaging sequence is used, with bipolar flow- compensation used along both axes of flow encodation. The total first moment of all magnetic field gradient pulses, from volume selection tie to echo time, on each of the separate three Cartesian gradient axes, is nulled, with the total area (the amplitude- time integrated product) of the pulses being set substantially equal to zero alaong two of the three axes. The non-zero pulse area difference along the one selected non- readout axis is balanced by a rewind gardient pulse after completion of the response signal readout.