Abstract #0775

Narayana P, Kramer L, Ewing-Cobbs L, Fletcher J, Hasan K, Gupta R, Ahn C

The contributors to human in vivo tissue diffusion anisotropy remain to be unresolved even for the simplest white matter structure such as the corpus callousm (CC) which is known to have heterogeneous axonal density and myelination levels. DTI literature on gender based differences in ansiotropy are llargely inconsistent. In this report, we use the transverse and longitudinal eigenvalues on the seven segments of the corpora callosa of 16 males and 16 age-matched females and show that subtle microstructural differences in the water molecular diffusion in large myelinated fibers can be detected using optimized entire brain DTI at high SNR and using the principal eigenvalues as a more specific morphological index.