method for simultaneous measurement of nmr signals, particularly for the determination of flussgeschwindigkeiten in magnetic resonance imaging using multiple slice fourier flow (= muff) method

摘要

In a method for the simultaneous measurement of spin resonance signals, in particular NMR signals, from layers located at different depths in a test volume, simultaneous excitation of the different layers is effected by a multiple-component rf excitation pulse Pn, consisting of n individual components Pm with the frequencies omega m, which act selectively on defined layers m of the test volume, in the presence of a layer-selective gradient, the individual components Pm having a phase displacement phi m which is varied from one sequence to the next by successive addition of a constant phase increment DELTA phi m modulo 360 fixed individually for each individual component Pm. If phase coding is effected according to the "Fast Fourier Flow Technique" with the aid of a bipolar gradient pulse, then the flow velocity of a medium moving through the test volume can be measured directly in a multi-dimensional Fourier transformation experiment, simultaneous for several flow cross-sections, in a single recording cycle.