Comparing Isotropic and Anisotropic Smoothing for Voxel-Based DTI Analyses: A Simulation Study

Wim Van Hecke, Alexander Leemans, Steve De Backer, Ben Jeurissen, Paul M. Parizel, Jan Sijbers

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77 Citations (Scopus)


Voxel-based analysis (VBA) methods are increasingly being used to compare diffusion tensor image (DTI) properties across different populations of subjects. Although VBA has many advantages, its results are highly dependent on several parameter settings, such as those from the coregistration technique applied to align the data, the smoothing kernel, the statistics, and the post-hoc analyses. In particular, to increase the signal-to-noise ratio and to mitigate the adverse effect of residual image mis-alignments, DTI data are often smoothed before VBA with an isotropic Gaussian kernel with a full width half maximum up to 16 x 16 x 16 mm(3). However, using isotropic smoothing kernels can significantly partial volume or voxel averaging artifacts, adversely affecting the true diffusion properties of the underlying fiber tissue. In this work, we compared VBA results between the isotropic and an anisotropic Gaussian filtering method using a Simulated framework. Our results clearly demonstrate an increased sensitivity and specificity of detecting a predefined simulated pathology when the anisotropic smoothing kernel was used. Hum Brain Mapp 31:98-114, 2010. (C) 2009 Wiley-Liss, Inc.

Original languageEnglish
Pages (from-to)98-114
Number of pages17
JournalHuman Brain Mapping
Issue number1
Publication statusPublished - Jan 2010
Externally publishedYes

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