Chemical-shift magnetic resonance imaging of two-line spectra by gradient reversal

A method of chemical-shift imaging is described using the invariance of chemical shifts to changes in magnetic field gradients used for frequency encoding of position in imaging. This enables separation of the effects on the observed signal of chemical shift from the effects of different positions along the imaging gradient when the signal is observed with different gradients. A simple implementation for a two-line spectrum is presented using signals observed with normal and reversed imaging gradients. This is used to create "fat" and "water" images of the thigh.