Assisted labeling techniques for the human brain cortex

With the improvements in techniques for generating surface models from magnetic resonance (MR) images, it has recently become feasible to study the morphological characteristics of the human brain cortex in vivo. Studies of the entire surface are important for measuring global features, but analysis of specific cortical regions of interest provides a more detailed understanding of structure. We have previously developed a method for automatically segmenting regions of interest from the cortical surface using a watershed transform. Each segmented region corresponds to a cortical sulcus and is thus termed a "sulcal region". In this work, we describe three important augmentations of this methodology. First, we describe a user interface that allows for the efficient labeling of the segmented sulcal regions called the Interactive Program for Sulcal Labeling (IPSL). Two additional augmentations of the methodology allow for even finer division of regions on the cortex. Both employ the fast marching technique to track curves of interest on the cortical surface. These curves are then used to separate segmented regions. Validation experiments indicate that the proposed methodology gives highly repeatable results.