Nuclear magnetic resonance spatial mapping

Abstract

A method for obtaining a spatial mapping using nuclear magnetic resonance. A sample is subjected to time dependent magnetic gradient fields having linear components in the X and Y directions, normalized so that the time dependency is eliminated in the vicinity of a line X.sub.0,X.sub.0,Z. A time independent gradient field is applied along this line. An initial RF pulse is applied to rotate the magnetization 180 degrees. This is followed by a 90 degree pulse and then a series of 180 degree pulses. It has been determined experimentally that the relaxation times T.sub.1 and T.sub.2 for ischemic muscle tissue are longer than T.sub.1 and T.sub.2 for normal tissue. The above-described pulse pattern enhances the differentiation between the ischemic and normal tissue, and can provide useful data in applications wherein data can only be acquired during a short period of time. The differentiation between the relaxation times in ischemic versus normal tissue increase throughout the period during which measurement is taken, or until the signals become so weak as to indistinguishable from the background noise. The value for the magnetization along the line X.sub.0, Y.sub.0 , Z thus obtained is Fourier transformed to yield a measure of the magnetization (and therefore the degree of ischemia) as a function of Z along the line X.sub.0, Y.sub.0 Z.