FAST METHOD AND DEVICE FOR DETERMINING AN NMR DISTRIBUTION IN A REGION OF A BODY

摘要

29 "Fast method and device for determining an NMR distribution in a region of a body". The invention relates to the determination of an NMR distribution in which an alternating gradient field is applied while sampling the NMR signal (FID signal, nuclear spin echo signal). The frequency of the alternating gradient field is comparatively low (order of magnitude of 100 Hz) and this field has from a few to some tens of cycles in each measurement period. While an FID signal is being sampled the image frequency field matrix is scanned using a zig-zag (oscillating) line pattern during each line of which data is provided for elements in from a few to some tens of rows in the image frequency matrix. By applying preparation gradient fields, the image frequency matrix can be filled by means of successive zig-zag line patterns which have been shifted with respect to one another and which thus enable a uniform sampling density to be provided in the image frequency space. The filling of the image frequency matrix with signal samples is thus speeded up by a factor of a few to some tens of times by the invention, the energy required for controlling the gradient field coils being substantially reduced at the same time.