Drobnjak, I; Cruz, G; Alexander, DC; (2013) Optimising oscillating waveform-shape for pore size sensitivity in diffusion-weighted MR. Microporous and Mesoporous Materials , 178 11 - 14. 10.1016/j.micromeso.2013.03.004.

Preview

PDF 1-s2.0-S1387181113001224-main.pdf Download (641kB)

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.

Download activity - last month

Export as CSVXMLJSON

Download activity - last 12 months

Export as XMLCSVJSON

Downloads by country - last 12 months

Export as JSONCSVXML

Archive Staff Only

View Item