TRACTOTRON: HOW DOES IT WORK?

In Summary

Tractotron is a software using FMRIB software library (FSL) as well as recently published white matter tract atlases (Rojkova et al., BSF 2015) in the MNI152 referential to determine the pattern of disconnection induced by a lesion at the individual level. For a given lesion, Tractotron provides a probability and proportion of disconnection for almost all known tracts (Foulon et al. 2018). Results are exported as an excel file ready to be analysed with any statistical software distribution. The probability corresponds to the lesioned voxel with the highest % value. The proportion corresponds to the number of damaged voxels in the tract divided by the total volume of the tract. Dimensional statistics can be run on the proportion of disconnection. However we advise for group comparisons when using the probability of disconnection mainly because probability and severity are unrelated. Patients with a probability of disconnection >50% (0.5) are usually considered as disconnected. Above a probability of disconnection of 50% a patient is more likely to be disconnected than not being disconnected.

Figure 1: Tractotron step by step

*probability.xls is the chance to have fibers disconnected in the tract.

proportion.xls is the proportion of overlap between the lesion’s volume and the tract’s volume.

PAPER METHOD SECTION (feel free to edit or copy and paste)

We mapped the lesion from each patient onto tractography reconstructions of white matter pathways obtained from a group of healthy controls (Rojkova et al., BSF 2015). We quantified the severity of the disconnection by measuring the probability of the tract to be disconnected (Thiebaut de Schotten et al. 2014) using Tractotron software as part of the BCBtoolkit (Foulon et al. 2018; http://www.toolkit.bcblab.com).