Method of construction of a MRI-based tabular database of 3D stereotaxic co-ordinates for individual structures in the basal ganglia of Macaca mulatta.

Primate models are commonly used in Parkinson's disease research to study stereotaxic strategies that demand accurate localization of the structures in basal ganglia. We demonstrate a method to construct an extensive tabular database of 3D stereotaxic co-ordinates of various basal ganglia structures from high-quality magnetic resonance (MR) images of 47 adult female 3-5 kg rhesus monkeys. For each animal, the structures in the basal ganglia were traced as they appeared on the axial MR images. Their maximal outlines were projected in the axial plane to create a stack of images and X, Y, Z co-ordinates were calculated for margins of each structure. These co-ordinates and the outlines of the individual nuclei help delineate a "common area," which was further narrowed down to a point that represents the 'most reliable target point' (MRTP) in subthalamic nucleus, globus pallidum, caudate and putamen on both sides. Common area and MRTP represent the region that can most definitely be associated with a structure and hence the most definite target for a given structure. The goal of this study is to demonstrate the method of construction, discuss the feasibility and usefulness of such a tabular database that could potentially add to accuracy of localization while using atlas-based stereotaxy. Though use of MRI remains a standard practice and advances in imaging have made targeting for functional surgery more accurate, in developing countries that implies prohibitive costs per procedure. Population based human databases similar to the monkey database described here, when used along with less expensive imaging modalities can reduce the costs considerably as well as add to the accuracy of targeting.