The ghosting artifacts in echo-planar imaging can be greatly reduced by aligning the k-space coordinates between odd and even lines based on their relative time delay. However, we found this approach is limited in artifact reduction. Specifically, we found that the image still has prominent artifacts and high spatial frequency k-space coordinates for even and odd lines still differ from each other significantly after time delay correction. This result suggested the origin of the ghosting artifact is beyond the time delays between neighboring readouts. The image artifact, however, can be greatly reduced using trajectory correction.