Method and apparatus for correcting spatial distortion in magnetic resonance images due to magnetic field inhomogeneity including inhomogeneity due to susceptibility variations

Apparatus for use in correcting spatial distortion in magnetic resonance images due to magnetic field inhomogeneity including inhomogeneity due to susceptibility variations in a object being imaged comprising

• a) means for establishing a magnetic field (B.sub.0) through said object along an axis in a three axis coordinate system;
• b) means for applying first RF pulses to said object and a first magnetic gradient along a first axis;
• c) means for applying first magnetic gradients along at least one axis in a plurality of first read-out sequences,
• d) means for detecting a plurality of magnetic resonance signals in response to said plurality of first read-out sequences;
• e) means for processing said plurality of first magnetic resonance signals to obtain a first complex image in an image plane;
• f) means for applying second RF pulses to said object and a second magnetic gradient along said first axis;
• g) means for applying second magnetic gradients along said at least one axis in a plurality of second read-out sequences;
• h) means for detecting a plurality of second magnetic resonance signals in response to said plurality of second read-out sequences;
• i) means for processing said plurality of second magnetic resonance signals to obtain a second complex image in said image plane;
• j) means for obtaining a position-error profile for pixels from said complex images;
• and
• k) means for shifting the location of pixels in the image plane using said position-error profile of said pixels.