Imaging of callosal microstructures
is of importance to understand its functional and anatomical connectivity to the
projected cortical areas across two hemispheres. In this work, we tested our
hypothesis that the parametric T1 measure could be sensitive to the corpus
callosum (CC) microstructure and the fiber size within CC, and it may reflect
the underlying functionality. In comparison with histology reports, our T1
maps indicate high inhomogeneity in CC and a positive trend between the T1
value and CC fiber size. In addition, diffusion tractograpy analysis shows that
regional differentiation of CC T1 value or fiber size is indicative
of unique connection to the cortical areas with distinct brain function. We
found that the large callosal fibers likely connect to sensory and visual cortices;
in contrast, small callosal fibers connect higher functional brain regions. The
overall results show the new utility of parametric T1
imaging for quantitatively assessment of the fiber microstructure of human
corpus callosum and its connections to functionally relevant cortices. This
imaging approach could provide a robust and useful tool for detection of fiber
abnormality in the human white matter and dysfunction.
