Patent ID: 6975117

Claim:
A magnet assembly for use in magnetic resonance imaging, comprising: a ferromagnetic frame; first means for generating magnetic flux magnetically coupled to the ferromagnetic frame; two opposed ferromagnetic poles magnetically coupled to the ferromagnetic frame, wherein the poles extend from the respective pole supports and are spaced apart from each other to form a gap region therebetween for receiving at least a portion of a subject and for scanning a first portion of the subject at a first resolution; second means for generating a gradient magnetic field in the gap region; and third means for changing magnetic flux in a portion of the gap region such that, during scanning, a first, constant magnetic flux density is provided across the portion of the gap region and a second, different magnetic flux density is provided across the remainder of the gap region, for scanning one or more portions of the subject at one or more resolutions different than the first resolution, the third means being separate from the second means.