Triangular meshes comprising a 3D brain analytical polyhedral phantom used in 3D and 2D MRI simulations. The brain is oriented such that the x, y, z axes correspond to the right, anterior, superior anatomical axes. a) The outer cortical mesh with magnified inset illustrating triangles in the mesh, and b) inner cortical mesh with overlaid slab mesh used in 2D MRI simulation with finite slice thickness. Although not shown, the slice plane used to simulate idealized infinitesimally thin slice selection is centered in the slab mesh. c) The resulting 2D contours from the intersection of all meshes with the ideal slice plane. d) The resulting 3D sliced meshes from the intersection of all meshes with a 1mm thick slab mesh. The magnified inset illustrates triangles in the mesh.