Methods for validating the anatomical trajectory of reconstructed fibre tracts in diffusion magnetic resonance fibre tractography

Abstract

The introduction of diffusion tensor imaging fifteen years ago revolutionised the way of studying white matter disorders through the means of diffusion magnetic resonance fibre tractography. It remains the only method available to date to non-invasively study white matter architecture in-vivo. However, there are a number of limitations and pitfalls associated with this technique that calls to question the validity of fibre tractography. In particular the lack of a genuine gold standard prohibits quantitative analysis on the performance of fibre tractography algorithms. It is therefore of great importance for proper validation of fibre tractography to establish robust methods that may serve as a gold standard. In this review, several classical and contemporary methods used to study white matter architecture are discussed that can be used to validate the anatomical trajectory of white matter bundles in the brain derived by fibre tractography with high precision. It emphasises the need for true three-dimensional acquisition of ground truth data at high resolution from realistic specimen in order to accurately resolve the correct trajectory of white matter tracts in the presence of crossing fibres.