  Hippocampal atrophy in Alzheimer's disease (AD) is asymmetric and spatially
inhomogeneous. While extensive work has been done on volume and shape analysis
of atrophy of the hippocampus in AD, less attention has been given to
hippocampal asymmetry specifically. Previous studies of hippocampal asymmetry
are limited to global volume or shape measures, which don't localize shape
asymmetry at the point level. In this paper, we propose to quantify localized
shape asymmetry by optimizing point correspondences between left and right
hippocampi within a subject, while simultaneously favoring a compact
statistical shape model of the entire sample. To account for related variables
that have impact on AD and healthy subject differences, we build linear models
with other confounding factors. Our results on the OASIS3 dataset demonstrate
that compared to using volumetric information, shape asymmetry reveals
fine-grained, localized differences that indicate the hippocampal regions of
most significant shape asymmetry in AD patients.
