Adding probabilistic fiber tracking

[SiemondeLange]

Currently, CATO only supports deterministic fiber tracking. While, deterministic tracking is widely used in the field of connectomics and has a high specificity (beneficial in connectome studies), there is a strong argument for providing probabilistic fiber tracking (PFT) to CATO.

PFT allows for the modelling of uncertainty in the estimated fiber pathways, providing a more detailed understanding of the underlying white matter connectivity. Moreover, PFT has been shown to have a greater sensitivity (and its specificity can be improved with streamline filtering methods).

The implementation of PFT in CATO could be approached in two possible ways. The first approach would be to integrate PFT directly into the fiber_reconstruction pipeline step, making the implementation as accessible to users as possible. Alternatively, PFT could be added as an add-on, providing more flexibility to use external software (e.g. MRtrix3) for the probabilistic fiber tracking.

As a first step, I suggest to make an inventory of possible PFT algorithms and implementations that we can use to decide on the specific PFT implementation in CATO.