Comparison of fractional and geodesic anisotropy in diffusion tensor images of 90 monozygotic and dizygotic twins

We used diffusion tensor magnetic resonance imaging (DTI) to reveal the extent of genetic effects on brain fiber microstructure, based on tensor-derived measures, in 22 pairs of monozygotic (MZ) twins and 23 pairs of dizygotic (DZ) twins (90 scans). After Log-Euclidean denoising to remove rank-deficient tensors, DTI volumes were fluidly registered by high-dimensional mapping of co-registered MP-RAGE scans to a geometricallycentered mean neuroanatomical template. After tensor reorientation using the strain of the 3D fluid transformation, we computed two widely-used scalar measures of fiber integrity: the fractional anisotropy (FA), and geodesic anisotropy (GA), which measures the geodesic distance between tensors in the symmetric positive-definite tensor manifold. Spatial maps of intraclass correlations (r) between MZ and DZ twins were compared to compute maps of Falconer's heritability statistics, i.e. the proportion of population variance explainable by genetic differences among...

• Type: Conference
• Year: 2008
• Where: ISBI
• Authors: Agatha D. Lee, Natasha Lepore, Marina Barysheva, Yi-Yu Chou, Caroline A. Brun, Sarah K. Madsen, Katie McMahon, Greig I. de Zubicaray, Matthew Meredith, Margaret J. Wright, Arthur W. Toga, Paul M. Thompson
• Keywords: ISBI 2008, Medical Imaging, Positive-definite Tensor Manifold, Tensor Magnetic Resonance, Widely-used Scalar Measures