The property of GVF makes it a suitable choice for our cortical surface refinement. 3 shows the result of the final deformed surface on our sample data set using GVF based deformable surface. A cross section of the initial and final deformable surface overlaid on top of the MRI image is shown in Fig. 4. Final GVF deformable surface. Cross section of the initial and final deformable surface overlaid on top of the MRI image.
Initial surface is plotted as blue and final surface is plotted as red.
Once the cortex has been extracted, differential geometric quantities may be computed. Differential geometry provides a natural mathematical framework to study the cortical surface geometry. Among many geometric quantities defined for the surface, curvature information is the most valuable since it quantifies the structure of the sulci and gyri, thus providing the basis for scientific and comparative studies. 5 shows two views of the mean curvature, plotted on the extracted cortical surface of our sample data set. Red in the mean curvature figure stands for positive mean curvature values, green stands for zero, and blue stands for negative mean curvature values.