Eddy‐current compensated diffusion weighting with a single refocusing RF pulse

A modification of the Stejskal‐Tanner diffusion‐weighting preparation with a single refocusing RF pulse is presented which involves three gradient lobes that can be adjusted to null eddy currents with any given decay rate to reduce geometric distortions in diffusion‐weighted echo‐planar imaging (EPI). It has a very similar compensation performance as the commonly used double‐spin‐echo preparation but (i) is less sensitive to flip angle imperfections, e.g. along the slice profile, and B₁ inhomogeneities and (ii) can yield shorter echo times for moderate b values, notably for longer echo trains as required for higher spatial resolution. It therefore can provide an increased signal‐to‐noise ratio as is simulated numerically and demonstrated experimentally in water phantoms and the human brain for standard EPI (2.0 × 2.0 mm²) and high‐resolution EPI of inner field‐of‐views using 2D‐selective RF excitations (0.5 × 1.0 mm²). Thus, the presented preparation may help to overcome current limitations of diffusion‐weighted EPI, in particular at high static magnetic fields. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.