Reducing motion artefacts in diffusion-weighted MRI of the brain: efficacyof navigator echo correction and pulse triggering

Diffusion-weighted MRI (DWI) is extremely sensitive to motion of the object being examined. Pulse triggering and navigator echo correction are methods for reducing motion artefacts which can be combined with conventional DWI sequences. Implementation of these methods in imaging sequences with a read out of one, three, or five echoes is presented and imaging results compared in a study of five healthy volunteers. As an objective measure for motion- induced image artefacts, the "artefacticity" of an image is defined. Pulse triggering and navigator echo correction significantly improve image qualit y and provide a technique for high-quality DWI on standard imagers without improved gradient hardware.