1. Delphine Ribes (Internship UNC 2005/2006) Guido Gerig
Cortical Thickness Analysis
Delphine Ribes
(Internship UNC 2005/2006)
Guido Gerig

2. Grey Matter exterior boundary
Project
Measure Cortical Thickness by using the Danielsson Distance Transform ?
White matter Boundary
Grey Matter exterior boundary ?
Cortical Thickness ?

3. Just another cortical thickness method …
Given imperfect, somewhat noisy tissue images
Perfect, topologically correct surface cannot be obtained
Not necessary to inflate cortex
Display on wm and gm surfaces
Separate measure of thickness inside folds and on outer cortex
Choice: “Engineering method” based on Euclidean distance transform
Good enough to collect statistics across cortical areas, not precise measurements at each voxel

4. Danielsson Distance Map
Cortical Thickness
Pipeline :
Danielsson Distance Map
Brain Seg Image
Vector Map
Distance Maps White and Grey

5. Grey Matter exterior boundary
Distance Maps White and Grey
Grey Matter exterior boundary
White matter Boundary
Vector Map
Problem :
Each grey matter voxel points to white matter surface
Gray matter surface in folds is not known
Solution :
At each wm surface point, choose the grey matter voxel distance with maximum distance
Method : Maximum Operator
=> For each white Matter point, find the furthest grey Matter point

10. Summary: Procedure
Distance gray matter surface to white matter boundary
Tissue Segmentation
Cortical thickness for full brain and for individual lobes
Lobe Parcellation

11. Status Tool fully written in ITK
Toolkit available on UNC website and compiled on UNC dashboard
Visualization with NA-MIC MeshVisu (Oguz)
Comprehensive manual, very easy to use
Might go very well with EMS (needs tissue segmentation and parcellation)