| Abstract: The automated extraction of the cerebrospinal fluid-tissue
boundary, particularly around the ventricular surface, from serial
structural MRI of the brain acquired in imaging studies of aging and
dementia is a challenging segmentation problem because of the common
occurrence of peri-ventricular lesions which locally alter the appearance
of white matter. We examine a level set approach which evolves a 4D
description of the ventricular surface over time. This has the advantage
of allowing constraints on the contour in the temporal direction,
improving the consistency of the extracted object over time. A short
review of the level set methods used in image segmentation is given. We
then follow the approach proposed by Chan and Vese which is based on the
Mumford and Shah model and implemented using the Osher and Sethian level
set method. We have extended this to the 4D case to propagate a 4D
contour toward the tissue boundaries through the evolution of a 5D
implicit function. This model is then adapted to allow intensity
contrast changes between time frames in the MRI sequence. Results on time
sequences of 3D brain MR images are presented and discussed. |
