Magnetic resonance spectroscopy and imaging

Abstract

In magnetic resonance spectroscopy or imaging, e.g. n.m.r. or e.s.r., a method of localizing the region of a sample from which a resonance signal is obtained by modulating the component M.sub.z of magnetization in the B.sub.o direction according to position in the sample. This is achieved by flipping the spins away from the B.sub.o direction, applying a gradient magnetic field so that they lose or gain phase according to their position, refocussing the effects of any resonance offsets including chemical shifts and subsequently returning them to the B.sub.o direction whereupon M.sub.z depends on the phase lost or gained and thus the position. This may be repeated, possibly with different gradient fields or different phase pulses, to further localize the region before a resonance signal is finally detected. The contribution to the resonance signal varies with M.sub.z and so is localized to regions of greater M.sub.z.

Dependencies are inferred from the claim text.