Patent ID: 6025716
Filing Date: 2000-02-15
Classification: G01R

Abstract:
A method for operating a magnetic resonance imaging apparatus comprising the steps of:(a) emitting a plurality of successive excitation pulses and in each of said pulses exciting respective atomic nuclei participating in at least two different chemical bonds in an examination volume, said atomic nuclei which are excited by each of said pulses exhibiting at least two different resonant frequencies due to said participation in at least two different chemical bonds;(b) between two successive excitation pulses, emitting a pre-phasing pulse and emitting a readout gradient consisting of readout pulses of alternating operational signs, and acquiring a gradient echo signal of a first type under one of said gradient pulses having a first operational sign, and obtaining a gradient echo signal of a second type under one of said gradient pulses having a second operation sign;(c) selecting respective echo times of the gradient echo signal of the first type and the gradient echo signal of the second type so that, within each voxel, a shift of the resonant frequencies in the gradient echo signal of the first type, due to a first type of chemical bond, produces a signal enhancement, and a shift of the resonant frequencies in the gradient echo signal of the second type, due to a second chemical bond, produces signal attenuation; and(d) from said gradient echo signals of the first type and of the second type, obtaining raw data for two respectively different images of said imaging volume.