Correction of artifacts caused by maxwell terms in slice offset echo planar imaging

Method for correcting Maxwell term errors produced by imaging gradients in an NMR system during the acquisition of an NMR image slice using an echo-planar pulse sequence, the steps comprising:

• a) performing the echo planar pulse sequence by
• i) producing one or more RF pulses;
• ii) producing a readout gradient which alternates in polarity to produce a corresponding series of NMR gradient echo signals;
• iii) producing a phase-encoding gradient to individually spatial-encode the said name echo signals;
• iv) receiving each of said NMR echo signals;
• and
• v) storing the NMR echo signal;
• b) calculating a linear phase correction value .psi..sub.ro (z) in the readout direction for each image slice located at position z along a z axis;
• c) calculating a linear phase correction value .psi..sub.pe (z) in the phase-encoding direction for each image slice located at position z along the z axis;
• d) applying a linear phase correction .psi..sub.ro (z) to the stored NMR echo signals along the readout direction;
• e) applying a linear phase correction .psi..sub.pe (z) to the stored NMR echo signals along the phase-encoding direction;
• and
• f) reconstructing an image from the corrected NMR echo signals;
• and
• in which the value of the linear phase correction value .psi..sub.ro (z) is a function of the readout gradient amplitude and the value of the linear phase correction value .psi..sub.pe (z) is a function of both the readout gradient and phase-encoding gradient amplitudes.