Comprehensive approach for correction of motion and distortion in diffusion‐weighted MRI

TLDR

Patient motion and eddy‑current induced distortion cause artifacts in diffusion‑weighted MRI parameter maps. The study proposes a comprehensive method to correct spatial misalignment of diffusion‑weighted images acquired with varying gradient strengths and orientations. The method employs a mutual‑information based registration with a spatial transformation model that simultaneously corrects eddy‑current distortion, rigid body motion, and signal amplitude, and recalculates b‑matrices, allowing fast, accurate alignment to a template. Qualitative and quantitative analyses demonstrate significant improvement in diffusion tensor imaging data from the human brain. Published in Magn Reson Med 51:103–114 (2004) by Wiley‑Liss, Inc.

Abstract

Abstract Patient motion and image distortion induced by eddy currents cause artifacts in maps of diffusion parameters computed from diffusion‐weighted (DW) images. A novel and comprehensive approach to correct for spatial misalignment of DW imaging (DWI) volumes acquired with different strengths and orientations of the diffusion sensitizing gradients is presented. This approach uses a mutual information‐based registration technique and a spatial transformation model containing parameters that correct for eddy current‐induced image distortion and rigid body motion in three dimensions. All parameters are optimized simultaneously for an accurate and fast solution to the registration problem. The images can also be registered to a normalized template with a single interpolation step without additional computational cost. Following registration, the signal amplitude of each DWI volume is corrected to account for size variations of the object produced by the distortion correction, and the b‐ matrices are properly recalculated to account for any rotation applied during registration. Both qualitative and quantitative results show that this approach produces a significant improvement of diffusion tensor imaging (DTI) data acquired in the human brain. Magn Reson Med 51:103–114, 2004. Published 2003 Wiley‐Liss, Inc.