High‐field diffusion MR histology: Image‐based correction of eddy‐current ghosts in diffusion‐weighted rapid acquisition with relaxation enhancement (DW‐RARE)

High‐resolution, diffusion‐weighted (DW) MR microscopy is gaining increasing acceptance as a nondestructive histological tool for the study of fixed tissue samples. Spin‐echo sequences are popular for high‐field diffusion imaging due to their high tolerance to B₀ field inhomogeneities. Volumetric DW rapid acquisition with relaxation enhancement (DW‐RARE) currently offers the best tradeoff between imaging efficiency and image quality, but is relatively sensitive to residual eddy‐current effects on the echo train phase, resulting in encoding direction‐dependent ghosting in the DW images. We introduce two efficient, image‐based phase corrections for ghost artifact reduction in DW‐RARE of fixed tissue samples, neither of which require navigator echo acquisition. Both methods rely on the phase difference in k‐space between the unweighted reference image and a given DW image and assume a constant, per‐echo phase error arising from residual eddy‐current effects in the absence of sample motion. Significant qualitative and quantitative ghost artifact reductions are demonstrated for individual DW and calculated diffusion tensor images. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.