A method for correcting MR data elements acquired in the presence of an imperfectly linear gradient field, each element comprising nominal first and second quadrature components. The quadrature components are multiplied by an artifact correction factor to provide respective first and second quantities. A Gradwarp geometric correction operation is applied to respective quantities to provide a corrected first and second quadrature component, corresponding to each data element. For a given data element, the arctangent function is applied to the result obtained by dividing the first corrected component by the second corrected component to provide a corrected phase component for use in forming an image.