Geometric analysis of the b-dependent effects of Rician signal noise on diffusion tensor imaging estimates and determining an optimal b value

Paul A. Taylor, Bharat Biswal

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The optimal diffusion weighting (DW) factor, b, for use in diffusion tensor imaging (DTI) studies remains uncertain. In this study, the geometric relations of DW quantities are examined, in particular, the effects of Rician noise in the measured magnetic resonance signal. This geometric analysis is used to make theoretical predictions for selecting a b value to reduce the influence of noise. It is shown that the optimal b value for DTI studies in healthy human parenchyma is approximately b=1200 s mm-2, with a simple relation given as well for a given expected apparent diffusion coefficient. Monte-Carlo simulations on sets of realistic DTI measures are then performed, verifying the optimal DW for minimizing estimate errors. The effects of noise on various DTI parameters such as anisotropy indices (fractional anisotropy and scaled relative anisotropy), mean diffusivity, radial diffusivity, eigenvalues and the direction of the first eigenvector are investigated as well.

Original languageEnglish (US)
Pages (from-to)777-788
Number of pages12
JournalMagnetic Resonance Imaging
Volume29
Issue number6
DOIs
StatePublished - Jul 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging

Keywords

  • Diffusion tensor imaging (DTI)
  • MRI
  • Noise
  • Tensor estimation

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