Mathematical/computational challenges in creating deformable and
probabilistic atlases of the human brain
Source: Human Brain Mapping
2000 Feb;9(2):81-92.
Author: Thompson PM, Woods RP, Mega MS, Toga AW. PubMed ID: 10680765
Abstract:
Striking variations in brain structure, especially in the gyral
patterns of the human cortex, present fundamental challenges in human
brain mapping. Probabilistic brain atlases, which encode information on
structural and functional variability in large human populations, are
powerful research tools with broad applications. Knowledge-based imaging
algorithms can also leverage atlased information on anatomic variation.
Applications include automated image labeling, pathology detection in
individuals or groups, and investigating how regional anatomy is altered
in disease, and with age, gender, handedness and other clinical or
genetic factors. In this report, we illustrate some of the mathematical
challenges involved in constructing population- based brain atlases. A
disease-specific atlas is constructed to represent the human brain in
Alzheimer's disease (AD). Specialized strategies are developed for
population-based averaging of anatomy. Sets of high-dimensional elastic
mappings, based on the principles of continuum mechanics, reconfigure
the anatomy of a large number of subjects in an anatomic image database.
These mappings generate a local encoding of anatomic variability and are
used to create a crisp anatomical image template with highly resolved
structures in their mean spatial location. Specialized approaches are
also developed to average cortical topography. Since cortical patterns
are altered in a variety of diseases, gyral pattern matching is used to
encode the magnitude and principal directions of local cortical
variation. In the resulting cortical templates, subtle features emerge.
Regional asymmetries appear that are not apparent in individual
anatomies. Population-based maps of cortical variation reveal a mosaic
of variability patterns that segregate sharply according to functional
specialization and cytoarchitectonic boundaries