Abstract: A method of a device for determining the spectral distribution of a nuclear magnetization in a limited volume, wherein each sequence of r.f. and gradient excitation comprises a sub-sequence which dephases the nuclear magnetization everywhere outside a defined layer. This sub-sequence is followed by three r.f. pulses, the first two of which are layer-selective. These three r.f. pulses excite the nuclear magnetization in an area of intersection between said layer and two layers which extend perpendicularly to one another and to said layer. In order to suppress undesirable FID signals and to enhance the spectrum, phase cycling is performed.

Abstract: The invention relates to an NMR tomography apparatus which, in addition to coil systems for generating a magnetic field which varies linearly in space, bar at least one further coil system for generating a magnetic field which varies non-linearly in space so that a locally non-constant gradient of the magnetic field is obtained. The variation of the spatial resolution is thus the same as that of the gradient of the magnetic field.