Abstract: A magnetic resonant image of an object is produced by subjecting the object to an initial slice selection to provide an active region and by subjecting the active region to a plurality of 180.degree. RF pulses and appropriate amplitude modulated x and y gradients.

Abstract: Zonal magnification of a selected area of an image produced by Echo Planar Imaging is acheived by taking images of a defined area in the presence of a selective 180.degree. R.F. control pulse so that subsequent processing produces a magnified image of the selected area with enhanced resolution.

Abstract: A nuclear magnetic resonance (NMR) method of producing a series of three or four dimensional spin parameter maps of a defined region, which spin parameter maps are displayable as a set of contiguous planar spin parameter maps with arbitrary orientation.

Abstract: Undesired signals are eliminated using a shaped RF pulse comprising a region of random frequency components and a region of zero components to effectively eliminate signals from areas volumes or frequency bands which are not required.

Abstract: A method of obtaining an NMR spectrum from a sample comprising the steps of: maintaining a static magnetic field along an axis which is homogeneous over at least a small volume constituting part of a sample applying a gradient to said magnetic field which varies in one direction orthogonal to said axis while applying an rf pulse to the sample to saturate all nuclei in the said volume except for a slab lying in a plane normal to the said one direction replacing the said gradient by a second gradient to said magnetic field which varies in a second direction orthogonal to said axis and said one direction while applying an rf pulse to the sample to saturate all nuclei in the said volume except for a slab lying in a plane normal to the said second direction, whereby nuclei in a narrow column extending parallel to the said axis have their spins left undisturbed replacing the second gradient by a third gradient to said static magnetic field which varies in a direction parallel to said axis while applying an rf pulse

Abstract: This invention provides methods of investigating a body by nuclear magnetic resonance. Nuclear magnetic resonance is preferentially excited in a slice of the body and the resulting free induction decay signals are detected in the presence of a magnetic field having first and second gradients (G.sub.y, G.sub.x).In one proposed method two experiments are performed in which the phase of the first gradient (G.sub.y) reversal is opposite, and the detected signals from the two experiments are edited to obtain a set of signals, for Fourier transformation, occurring when the first gradient has one sense. Two such sets may be obtained, one for each sense of the first gradient, and the data obtained after Fourier transformation re-ordered and added.In a second proposed method the second gradient (G.sub.x) is applied only when the first gradient (G.sub.

Abstract: A method of obtaining an NMR spectrum from a sample comprising the steps of: maintaining a static magnetic field along an axis which is homogeneous over at least a small volume constituting part of a sample applying a gradient to said magnetic field which varies in one direction orthogonal to said axis while applying an rf pulse to the sample to saturate all nuclei in the said volume except for a slab lying in a plane normal to the said one direction replacing the said gradient by a second gradient to said magnetic field which varies in a second direction orthogonal to said axis and said one direction while applying an rf pulse to the sample to saturate all nuclei in the said volume except for a slab lying in a plane normal to the said second direction, whereby nuclei in a narrow column extending parallel to the said axis have their spins left undisturbed replacing the second gradient by a third gradient to said static magnetic field which varies in a direction parallel to said axis while applying an rf pulse