Patent Document ID: 4532474
Application ID: 06530810
Patent Status: 1

Claim One:
1. A method of generating NMR image data using driven free precession and selective excitation for producing images having an increased data rate, comprising: (a) selectively exciting a planar slice within a sample at a flip angle which optimizes the NMR signal for some ratio of transverse to longitudinal relaxation times within said sample; (b) injecting a programmable amplitude imaging gradient along a first axis within said slice and injecting a dephasing gradient along a second axis within said slice and orthogonal to said first axis; (c) applying an alternatingly phased series of 180.degree. nonselective pulses to said sample at predetermined intervals to produce a corresponding series of spin echo signals in the intervals between said pulses, said intervals being significantly shorter than the transverse relaxation time in said sample; (d) restoratively injecting imaging and rephasing gradients, said gradients being injected along respective axes corresponding to, and configured to be the negative versions of, those gradients of step (b); and (e) said steps (a) selectively exciting, (b) injecting, (c) applying, and (d) restoratively injecting being done for each of a succession of projections, said programmable imaging gradient being distinct for each said succession of projections and said intervals containing a predetermined imaging gradient along a second axis within said slice and orthogonal to said first axis which is substantially constant for all of said succession of projections.