A stimulated echo artifact from slice interference in magnetic resonance imaging

When multiple slices are imaged with a short time between slice acquisitions, a disturbing line artifact along the direction of frequency encoding is often seen across the center of the images. The artifact consists of alternating bright and dark pixel intensities. In this paper, we show that the artifact is due to slice interference, and is caused by stimulated echoes that are produced in the regions of overlap between slices. A theoretical analysis of the formation of these stimulated echoes leads to ways of reducing the artifact, which are verified experimentally. The artifact can be suppressed most conveniently by extending the duration of the read gradient beyond the sampling window.