Abstract: A device and method for rapidly performing automatic magnet shimming using algebraic techniques, based on field maps computed by phase measurement within Carr-Purcell echo sequences. The correction computation for determining shim currents is carried out by a linear programming algorithm which compensates field inhomogeneities within the sample by a linear combination of all the shims. The procedure is non-iterative, thus avoiding instability problems and improving speed performance.

Abstract: A system for imaging P-31 spectra from different slices through a living body specimen positioned in the bore of the hollow main field magnet of an NMR spectrometer, consisting of applying a timed series of different discrete different-amplitude magnetic field gradient pulses to the specimen, whereby to generate time-spaced echo signals from respective points along the specimen while timed RF resonance excitation pulses are applied to the specimen. The echo signals are used to derive respective chemical shift spectra from the points, each spectrum containing information showing the in vivo metabolic state at one of the points. The various spectra can be simultaneously displayed to enable concurrent slice-by-slice interpretation of the metabolic information. The gradient pulses are derived from coils mounted inside the main field magnet arranged to generate a magnetic field vector traversing the specimen. The gradient coils are energized by using a suitably programmed computer.