Andreas Stadlbauer PhD, Presenter: Nothing to Disclose

Erich Kurt Salomonowitz MD, Abstract Co-Author: Nothing to Disclose

Katja Pinker MD, Abstract Co-Author: Research funded, Bracco Group

Klaus M. Friedrich MD, Abstract Co-Author: Nothing to Disclose

Ulf Baumhackl, Abstract Co-Author: Nothing to Disclose

To quantify differences in age-related changes of diffusivity and fiber parameters in the three major white matter structures and in total brain fibers.

Diffusion tensor imaging (DTI) data with an isotropic voxel size of 1.9mm3 were acquired at 3T from 38 healthy volunteers with an age range of 18–88 years. Fractional anisotropy (FA), mean diffusivity (MD), eigenvalues (λ1, λ2, and λ3), number of fibers (NoF), and mean NoF/voxel (FpV) were calculated for segmented association, callosal, and projection fibers as well as whole brain fibers using quantitative fiber tracking.

For all three fiber structures and total brain fibers NoF and FpV showed a strong to moderate negative correlation in dependence of age with a P<0.001, except for FpV of projection fibers, where the correlation was found to be not significant. NoF decrease significant stronger (P=0.043) and FpV significant weaker (P=0.005) in projection fibers compared to total fibers. For FA we found a strongest decline for association and no significant changes for projection fibers. These differences in correlation between association and projection fibers were significant (P=0.002). The strongest relative changes per decade for FpV (-4.7%) and FA (-1.13%) showed association, and for NoF (-10.4%) callosal fibers.

Changes in the fiber connectivity of the human brain due to normal aging are not uniform in the three major fiber structures, but pronounced for fiber structures including frontal fibers.

These results are relevant for the differentiation between age-related degradation and pathologic changes (e.g. dementia) of white matter brain structures.

Stadlbauer, A, Salomonowitz, E, Pinker, K, Friedrich, K, Baumhackl, U, Diffusion Tensor Imaging and Quantitative Fiber Tracking to Assess Age-related Degradation in the Central Nervous System.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4435118.html