Meeting Banner
Abstract #1893

Optimising Time-Varying Gradient Orientation for Microstructure Sensitivity in Diffusion-Weighted MR

Ivana Drobnjak1, Daniel C. Alexander1

1Center for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom

We explore whether variable, rather than fixed, orientation of diffusion-gradients improves sensitivity to coherently oriented pore size. We optimise the shape and orientation of the gradient waveform to minimise the expected variance of parameter estimates of a simple white-matter model. Results suggest that: varying orientation in a plane perpendicular to the cylinders does not increase sensitivity to model parameters; variation in a parallel plane increases sensitivity significantly because it improves the diffusion constant estimates; similar improvement in estimates can be achieved without optimising orientation, but by having one measurement in the parallel and the others in the perpendicular direction.

Abstract PDF Poster PDF

Keywords

accommodate accuracy achievable achieved adapt advantage aligned allowing almost arise axis axon axons bars better black bound calculation central class closely closer coherently college combinations comp comparing complex component computing consistency constant constraints cylinders described despite diameter diffusion discus done double equally error estimating explain extended features find finds fixed fluctuates form formation free frequencies function future gain giving global grad gradient gradients hand hindered improves inclusion info intend intrinsic intro investigate like magnitude make marked matrix maxim measuring minim model much noticed objective offer optimal optimizations optimized oration orientation oriented orthogonal ostensibly output para parallel particular pore pores posterior preference previous priori procession progresses protocols prove pulse pulsed radius reflection reported rest rule sample satisfied science sensitivity separate shape significantly slew spaced square straight strength stronger structure suggesting system systems take tends tissue tool true typical unlikely variable variation varies varying vector wave waveform waves weeps whether white wider zero