 |
    |
Group-Wise Cortical Correspondence via Sulcal Curve-Constrained Entropy Minimization
Ilwoo Lyu1, Sun Hyung Kim2, Joon-Kyung Seong4, Sang Wook Yoo5, Alan C. Evans6, Yundi Shi2, Mar Sanchez7, Marc Niethammer1,3, and Martin A. Styner1,2
1Dept. of Computer Science, University of North Carolina, Chapel Hill, NC, USA
ilwoolyu@cs.unc.edu
styner@cs.unc.edu
2Dept. of Psychiatry, University of North Carolina, Chapel Hill, NC, USA
3BRIC, University of North Carolina, Chapel Hill, NC, USA
4Dept. of Biomedical Engineering, Korea University, Seoul, South Korea
5Dept. of Computer Science, KAIST, Daejeon, South Korea
6Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
7Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
Abstract. We present a novel cortical correspondence method employing group-wise registration in a spherical parametrization space for the use in local cortical thickness analysis in human and non-human primate neuroimaging studies. The proposed method is unbiased registration that estimates a continuous smooth deformation field into an unbiased average space via sulcal curve-constrained entropy minimization using spherical harmonic decomposition of the spherical deformation field. We initialize a correspondence by our pair-wise method that establishes a surface correspondence with a prior template. Since this pair-wise correspondence is biased to the choice of a template, we further improve the correspondence by employing unbiased ensemble entropy minimization across all surfaces, which yields a deformation field onto the iteratively updated unbiased average. The specific entropy metric incorporates two terms: the first focused on optimizing the correspondence of automatically extracted sulcal landmarks and the second on that of sulcal depth maps. We also propose an encoding scheme for spherical deformation via spherical harmonics as well as a novel method to choose an optimal spherical polar coordinate system for the most efficient deformation field estimation. The experimental results show evidence that the proposed method improves the correspondence quality in non-human primate and human subjects as compared to the pair-wise method.
Keywords: Group-wise correspondence, Sulcal curves, Spherical harmonics, Entropy minimization, Cortical thickness
LNCS 7917, p. 364 ff.
lncs@springer.com
© Springer-Verlag Berlin Heidelberg 2013