Deformation based morphmetry and atlas based label segmentation: Application to serial mouse brain images

The aim of this paper is to investigate techniques that can identify and quantify longitudinal changes in vivo from magnetic resonance (MR) images of murine models of brain disease. Two different approaches have been compared. The first approach is a segmentation-based approach: Each subject at each time point is automatically segmented into a number of anatomical structures using atlas-based segmentation. This allows longitudinal analyses of group differences on a structure-by-structure basis. The second approach is a deformation-based approach: Longitudinal changes are quantified via registration of each subject´s follow-up images to that subject´s baseline image. Both approaches have been tested on two groups of mice: A transgenic model of Alzheimer´s disease and a wild-type background strain, using serial imaging performed over the age range from 6-14 months. We show that both approaches are able to identify longitudinal differences. However, atlas- based segmentation suffers from the inability to detect differences across populations and across time in regions which are much smaller than the anatomical regions. In contrast to this, the deformation-based approach can detect statistically significant differences in highly localized areas.