Analysis of Systematic Errors on Estimated Parameters in q-Space MRI
Peeters F, Duprez T, Cosnard G
St-Luc University Hospital, UCL
We have investigated the effects of finite duration gradients on the estimated parameters in q-space MRI on the basis of a simple model: one dimensional restricted diffusion between planar boundaries. In this case the MR-signal could be calculated exactly. Different reconstruction schemes of the probability density function were considered: direct Fourier reconstruction together with a scaling and dilation correction and a Gram-Charlier expansion. Three characterizing parameters were analyzed: return-to-origin probability, standard deviation and kurtosis. It turns out that large systematic errors will result depending on the gradient timings. Moreover, the concept of an effective diffusion time seems not to work.