Study on the impact of the MR acquisition parameters over DTI scalars

Tractograpy reconstruction from DTI

A new article on the effect that Acquisition Parameters have on DTI has been published on the open-source journal PLOS One: "Impact of MR Acquisition Parameters on DTI Scalar Indexes: A Tractography Based Approach".

Purpose: The reproducibility of DTI scalar measures used on clinical studies is dubious at best. This scalar measures, such as Fractional Anisotropy (FA) or Mean Diffusivity (MD), are sensitive to the parameters of the MR acquisition (among many others sources of variation). This makes unreliable the quantitative comparison between clinical studies; and the posibility of use this measures as diagnostic biomarker.

This study presents an analysis on the impact of simultaneous changes in multiple parameters: number of gradient directions, b-value and voxel resolution. We employ a tractography-based approach, utilized by the significant number of clinical studies but not commonly studied.

Conclusions: Results from our experiments indicate that, while the number of gradient directions and the voxel resolution greatly affect the FA, AD and RD indexes, variations on the b-value specially affect the MD, but also AD and RD.

Therefore, no single scalar measure is robust to changes in all the considered acquisition parameters, although each of them is relatively insensitive to changes in some of the parameters.

Relevant differences were also found between the behavior of the two tractography algorithms.


DOI: 10.1371/journal.pone.0137905