Method in the form of a pulse sequence for fast calculation of images of the fat and water distribution in an examination subject on the basis of nuclear magnetic resonance

Claim 1

A pulse sequence for operating a nuclear magnetic resonance tomography apparatus comprising the steps of: charging an examination subject with a first RF pulse which is selective with respect to a first spectral component of a spectrum of the examination subject; activating a dephasing gradient in a first direction; charging said examination subject with a second RF pulse which is selective with respect to a second spectral component of said spectrum of said examination subject; generating at least one phase-coding gradient in at least a first or a second direction, and generating a dephasing gradient in a third direction; generating a first read-out gradient in said third direction in a direction opposite to the dephasing gradient and reading out a first signal with respect to said second spectral component under said first read-out gradient; generating a second read-out gradient in said third direction and reading out a second signal with respect to said first spectral component under said second read-out gradient; generating gradients for re-phasing nuclear spins in all of said first, second and third directions; repeating the above steps a selected number of times with a step-by-step variation of each phase-coding gradient having a repetition time which is shorter than the transverse relaxation time of the nuclear spins and obtaining a sample of each of said first and second signals for each repetition; entering said samples of said first and second signals respectively into first and second matrices; and conducting a Fourier transformation of the data contained in each of said first and second matrices to obtain respective projections of the nuclear spin density distributions of said first and second spectral components.