Work

Optimising oscillating waveform-shape for pore size sensitivity in diffusion-weighted MR

Year: 2013

Type: article

Abstract: Optimising the shape of a generalised gradient waveform (GEN) in diffusion-weighted MR has been shown to, in theory, greatly increase sensitivity to pore size. The broad class of optimised shapes takes simple oscillatory forms. To speed up convergence of the optimisation, improve computation times and make the waveforms more practical, here we explore various oscillatory waveforms constructed from trapezoidal and sinusoidal shapes and compare their performance with the optimised GEN waveform. The oscillating waveforms are optimised to maximise sensitivity to parameters, such as axon radius, intra-cellular volume fraction and diffusion constants, of a simple white matter model. Simulation experiments find that all oscillating waveforms we tried perform significantly better than the original generalised waveform due to the improved convergence of the optimisation. Differences among the oscillating shapes however are very small and although a truncated sinusoidal waveform consistently gives the lowest cost function, no significant difference in the estimated model parameters was found. Therefore the simplest choice, i.e. the trapezoidal parametrisation, seems sufficient for most practical purposes.

Source: Microporous and Mesoporous Materials

DOI: 10.1016/j.micromeso.2013.03.004

Authors: Ivana Drobnjak, Gastao Cruz, Daniel C. Alexander

Institution: University College London

Language: English

Topic: Advanced Neuroimaging Techniques and Applications

Subfield: Radiology, Nuclear Medicine and Imaging

Field: Medicine

Domain: Health Sciences

Open Access status: hybrid

Estimated APC paid: $1,654

Funder: Engineering and Physical Sciences Research Council