Correction for distortion of echo‐planar images used to calculate the apparent diffusion coefficient

Abstract An algorithm for correcting the distortions that occur in diffusion‐weighted echo‐planar images due to the strong diffusion‐sensitizing gradients is presented. The dominant distortions may be considered to be only changes of scale coupled with a shear and linear translation in the phase‐encoding direction. It is then possible to correct for them by using an algorithm in which each line of the image in the phase‐encoding direction is considered in turn, with only one parameter (the scale) to be found by searching.