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MR angiography with adiabatic flow excitation
Author(s) -
Lee James N.,
Parker Dennis L.
Publication year - 1992
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880020412
Subject(s) - spins , adiabatic process , excitation , physics , pulse sequence , dephasing , radio frequency , nuclear magnetic resonance , pulse (music) , signal (programming language) , atomic physics , computational physics , optics , condensed matter physics , telecommunications , quantum mechanics , detector , computer science , programming language
A new method of magnetic resonance (MR) angiog‐raphy is presented that produces signal from flowing spins and suppresses that from stationary spins by means of a flow excitation pulse sequence consisting of adiabatic 90° and 180° radio‐frequency (RF) pulses interleaved with flow‐dephasing gradient lobes. Stationary spins are refocused along the z axis, while flowing spins are dephased by the gradient lobes and generate a transverse component that can be measured directly to produce the angio‐gram. Adiabatic RF pulses and unipolar gradient lobes give the pulse sequence a high degree of immunity to RF and magnetic field inhomogeneity. The pulse sequence can be successfully applied with a transmit/receive surface coil. The disadvantage of adiabatic RF pulses is that their long duration makes it difficult to suppress the signal of stationary spins with short T2.