@MASTERSTHESIS\{IMM2007-05354,
    author       = "S. Lanche",
    title        = "Point-Wise Quantification of Craniofacial Asymmetry",
    year         = "2007",
    keywords     = "Asymmetry, craniofacial anomalies, treatment evaluation, population study, statistical modelling, principal component analysis, image registration, thin-plate splines, {B-}splines",
    school       = "Informatics and Mathematical Modelling, Technical University of Denmark, {DTU}",
    address      = "Richard Petersens Plads, Building 321, {DK-}2800 Kgs. Lyngby",
    type         = "",
    note         = "Supervised by Associate Professor Rasmus Larsen (IMM), Research Engineer Tron A. Darvann (3D-Lab), and PhD Student Hildur Olafsdottir (IMM).",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/5354-full.html",
    abstract     = "This thesis presents a methodology of point-wise quantification of craniofacial asymmetry. The asymmetry was computed using two similar methods involving comparison of the right and left sides of the skull.

The new method of asymmetry quantification was applied to two types of craniofacial data: surface scans of infants with deformational plagiocephaly, and micro {CT} scans of mice with Crouzon syndrome. The asymmetry was quantified and spatially localized. In the first case, a statistical model, created by performing a principal component analysis, was used to assess treatment outcomes. In the second case, the asymmetry quantiiation permitted population classification by comparing the average asymmetry of the Crouzon mice to the one of a control group.

The proposed methods require establishment of full correspondence between left and right sides of the skull. This was achieved by deforming a perfectly symmetric subject (where each point on the left side had a known corresponding point on the other side) to assume {''}perfectly{''} the shape/image of a subject. The procedure combined global (afine) and local (thin-plate splines or {B-}splines) transformations.

Qualitative and quantitative validations of the presented methods were carried out on the presented methods. Expert measurements and an alternative {''}naive{''} method were seen to confirm the ability of our methods to localize and quantify the cranial asymmetry. Furthermore, the statistical model was checked using visual assessment."
}