Full Paper

Cross-subject comparison of principal diffusion direction maps

  1. Armin Schwartzman1,*,
  2. Robert F. Dougherty2,
  3. Jonathan E. Taylor1

Article first published online: 19 MAY 2005

DOI: 10.1002/mrm.20503

Issue

Magnetic Resonance in Medicine

Magnetic Resonance in Medicine

Volume 53, Issue 6, pages 1423–1431, June 2005

Additional Information

How to Cite

Schwartzman, A., Dougherty, R. F. and Taylor, J. E. (2005), Cross-subject comparison of principal diffusion direction maps. Magnetic Resonance in Medicine, 53: 1423–1431. doi: 10.1002/mrm.20503

Author Information

  1. 1

    Department of Statistics, Stanford University, Stanford, California, USA

  2. 2

    Department of Psychology, Stanford University, Stanford, California, USA

*390 Serra Mall, Stanford, CA 94305, U.S.A.

Publication History

  1. Issue published online: 19 MAY 2005
  2. Article first published online: 19 MAY 2005
  3. Manuscript Revised: 11 JAN 2005
  4. Manuscript Accepted: 11 JAN 2005
  5. Manuscript Received: 30 JUN 2004

Funded by

  • William R. and Sara Hart Kimball Stanford Graduate Fellowship
  • Schwab Foundation for Learning
  • NIH. Grant Number: EY015000
  • NSF. Grant Number: DMS-0405970

SEARCH

SEARCH BY CITATION

ARTICLE TOOLS

View Full Article (HTML) Get PDF (428K)

Keywords:

  • diffusion tensor imaging;
  • principal diffusion direction;
  • directional statistics;
  • false discovery rate;
  • multiple subjects

Abstract

Diffusion tensor imaging (DTI) data differ fundamentally from most brain imaging data in that values at each voxel are not scalars but 3 × 3 positive definite matrices also called diffusion tensors. Frequently, investigators simplify the data analysis by reducing the tensor to a scalar, such as fractional anisotropy (FA). New statistical methods are needed for analyzing vector and tensor valued imaging data. A statistical model is proposed for the principal eigenvector of the diffusion tensor based on the bipolar Watson distribution. Methods are presented for computing mean direction and dispersion of a sample of directions and for testing whether two samples of directions (e.g., same voxel across two groups of subjects) have the same mean. False discovery rate theory is used to identify voxels for which the two-sample test is significant. These methods are illustrated in a DTI data set collected to study reading ability. It is shown that comparison of directions reveals differences in gross anatomic structure that are invisible to FA. Magn Reson Med 53:1423–1431, 2005. © 2005 Wiley-Liss, Inc.

View Full Article (HTML) Get PDF (428K)