ODYSSÉE Lab.

GCM  Geodesic Connectivity Mapping
About / Introduction
What is the GCM Algorithm ?
In Short :
The GCM algorithm is "Fast Marching" based
Algorithm for computing
the anatomical connectivity in the brain.
The algorithm computes the anisotropic geodesic distance map, the
associated "gradients" and some connectivity measures with their
statistics along the geodesics.
Detailed description :
The GCM Library (Geodesic Connectivity
Mapping) is the C++ implementation of the GCM algorithm proposed by E.
Prados, C. Lenglet, J.P. Pons, Etal. in 2006 (see "Publications").
The GCM algorithm is a fast and robust algorithm for the computation of
anatomical connectivity in the brain. It
exploits the whole information provided by Diffusion Tensor Magnetic
Resonance Imaging (or DTI) and it is based on some models of the white
matter using
Riemannian geometry and the control theory. The GCM algorithm allows,
from a region of
interest, to compute the geodesic distance to any
other point and the associated optimal vector field. The latter can be
used to trace shortest paths coinciding with neural fiber bundles. The
GCM algorithm also allows to compute the degree of connectivity of the
region of
interest with the rest of the brain without the need of explicit
computation of the 3D geodesic curves.
This degree of connectivity is based on a general local connectivity
measure whose the algorithm computes the statistics along the optimal
paths (geodesics). All those quantities are computed simultaneously in
a process of
the type "Fast Marching". Apart from being extremely fast, this
algorithm has other advantages such as the strict
respect of the convoluted geometry of white matter, the fact that it is
parameterfree, and its robustness to noise. For some
theoretical/algoritmics/implementation details, some samples of results
and experimental validations, we refer to the associated publications
(see "Publications").
Keywords :
 Control Theory, Fast Marching Methods, Partial
Differential Equations (PDE),
 Anisotropic Distance Map, Anisotropic Geodesic Distances,
Riemanian Manifold,
 Brain Connectivity Mapping, White Matter Fibers, Diffusion
Tensor Images (DTI),
 Connectivity Measures, Statistics along the Geodesics,
 C++ source code.
Authors :
Christophe
Lenglet ,
JeanPhilipe Pons , Emmanuel Prados
License :
The GCM Library is distributed and governed by
an (LGPLlike) open source license: CeCILLC License. The
source code
has been registered to the APP
(French Agency for the Protection of
Programs) by the INRIA and UCLA.
