Construction of a 3D probabilistic atlas of human cortical structures
Source: NeuroImage
2008 Feb;39(3):1064-1080.
Author: Shattuck DW, Mirza M, Adisetiyo V, Hojatkashani C, Salamon G, Narr KL, Poldrack RA, Bilder RM & Toga AW PubMed ID: 18037310
Abstract:
We describe the construction of a digital brain atlas composed of data
from manually delineated MRI data. A total of 56 structures were
labeled in MRI of 40 healthy, normal volunteers. This labeling was
performed according to a set of protocols developed for this project.
Pairs of raters were assigned to each structure and trained on the
protocol for that structure. Each rater pair was tested for concordance
on 6 of the 40 brains; once they had achieved reliability standards,
they divided the task of delineating the remaining 34 brains. The data
were then spatially normalized to well-known templates using 3
popular algorithms: AIR5.2.5’s nonlinear warp (Woods et al., 1998)
paired with the ICBM452 Warp 5 atlas (Rex et al., 2003), FSL’s
FLIRT (Smith et al., 2004) was paired with its own template, a skullstripped
version of the ICBM152 T1 average; and SPM5’s unified
segmentation method (Ashburner and Friston, 2005) was paired with
its canonical brain, the whole head ICBM152 T1 average. We thus
produced 3 variants of our atlas, where each was constructed from 40
representative samples of a data processing stream that one might use
for analysis. For each normalization algorithm, the individual
structure delineations were then resampled according to the computed
transformations. We next computed averages at each voxel location to
estimate the probability of that voxel belonging to each of the 56
structures. Each version of the atlas contains, for every voxel,
probability densities for each region, thus providing a resource for
automated probabilistic labeling of external data types registered into
standard spaces; we also computed average intensity images and
tissue density maps based on the three methods and target spaces.
These atlases will serve as a resource for diverse applications including
meta-analysis of functional and structural imaging data and other
bioinformatics applications where display of arbitrary labels in
probabilistically defined anatomic space will facilitate both knowledge-based development and visualization of findings from multiple
disciplines.