Diffusion Direction Imaging: how to visualize white matter in the brain?

Diffusion MRI is more and more used for brain imaging, when it comes to diagnose stroke (or Cerabral Vascular Accident), brain tumors or multiple sclerosis.

From this image type, it's possible to perform tractography, meaning that we obtain a 3D reconstruction of the fibers into de brain volume. Nowadays, this method is used in clinical routine, the state-of-the art model being the so-called "DTI", for Diffusion Tensor Imaging. THis model nevertheless, is too sensitive to noise, and does not allow to detect crossing fibers.

The solution proposed here is a new model: DDI, for Diffusion Direction Imaging. THis method is more robust to noise, and is compatible with clinical constraints like limited calculation time for example. By using this model, you can deal with multiple fibers, crossing at the same voxel into the reconstructed volume.

This model is based on directionnal statistics, to compute only the needed parameters (fibers directions and anisotropy), and therefore reconstructing the diffusion profiles in each voxel.

The results already obtained had shown that we can efficiently distinguish between isotropes and anisotropes regions. They also showed an enhanced stability of estimations, and a superioraccuracy, whatever the noise level.