Spatial or flow velocity phase encoding gradients in NMR imaging

Further improvement of high‐speed NMR flow‐velocity measurement using a differential phase‐encoding technique

“…[2] or [ 31 will now be utilized for flow-velocity imaging. When the rf-dependent phase error 40(x, y ) and spin-echo phase density aF are assumed to be negligible or known, 9 can simply be expressed as…”

“…Recently a number of phase-encoding techniques for flow-velocity measurement using NMR imaging techniques (1)(2)(3)(4)(5)(6)(7)(8) have been reported. All of these flow-imaging techniques use phase encoding of some kind either by inserting a phase encoding bipolar gradient (1)(2)(3)(4) or using the selection gradient together with the selective 180" rf pulse (5, 6).…”

“…All of these flow-imaging techniques use phase encoding of some kind either by inserting a phase encoding bipolar gradient (1)(2)(3)(4) or using the selection gradient together with the selective 180" rf pulse (5, 6). In our laboratory, we have developed a new flow-imaging technique based on the phase-encoding effect of the selective 180" rf pulse in combination with the slice-selection gradient as a means of measuring high-velocity flow (5, 6).…”

Flow compensation in MRI using a phase‐corrected real reconstruction

“…Early work on this technique was presented by Constantinesco et aJ. (6). Two later papers describing the technique in detail were presented by Pattany et aJ.…”

Multidimensional MR mapping of multiple components of velocity and acceleration by fourier phase encoding with a small number of encoding steps

“…Since bipolar gradients can encode velocity by the magnetization phase in the same way as spatial position, he suggested encoding the six components of position and velocity for each voxel simultaneously. An algorithm for such a phase-encoding has been described (9) and implemented in a 1D version (10). However, to obtain a high resolution in velocity measurements, a large number of velocity encoding steps were required, resulting in a prohibitive acquisition time in the multidimensional approach.…”