Midsagittal surface measurement of the head: an assessment of craniofacial asymmetry

Left/right craniofacial asymmetry is typically measured by comparing distances between standard anatomical landmarks. However, these measurements are of limited use for visualizing and quantifying the asymmetry at non-landmark locations. This work presents a method for calculating, measuring and visualizing the planar deviation of the midsagittal surface for the purpose of craniofacial dysmorphology assessment, pre-operative corrective surgery planning, and post-operative evaluation. A set of midsagittal landmarks are used to define a reference midsagittal plane and to define a non-planar surface that passes through the landmarks. The surface is modeled as a thin-plate spline that can be visualized in 3D using a virtual reality markup language browser and it can be fused with the original volume rendered CT data using VoxelViewTM.