Xiujuan Geng1, Hong Gu1, Wang
  Zhan2, Wanyong Shin1, Yi-Ping Chao3, Norbert
  Schuff, Ching-Po Lin4, Yihong Yang1
1Neuroimaging, National Institute on
  Drug Abuse, NIH, Baltimore, MD, United States; 2Department of
  Radiology, University of California, San Francisco; 3Department of
  Electrical Engineering, National Taiwan University, Taiwan; 4Institute
  of Brain Science, National Yang-Ming University, Taiwan
We
  propose a novel diffeomorphic registration method for diffusion MRI data by
  mapping their orientation distribution functions (ODFs) represented with
  spherical harmonics (SHs). The registration is based on optimizing a
  diffeomorphic demons cost function. ODF reorientation is performed by
  rotating the SH coefficients to maintain the consistency with the local fiber
  orientations. Rotation on SH coefficients avoids the estimation of principle
  directions which has no analytical solution and is time consuming. The
  performance was tested using different SH orders. Results show that
  registration with higher orders improves the registration accuracy in terms
  of smaller similarity error and higher directional consistency.
Keywords