The human brain undergoes significant changes in the first few years after birth, but knowledge about this
critical period of development is quite limited. Previous neuroimaging studies have been mostly focused on
morphometric measures such as volume and shape, although tissue property measures related to the degree of
myelination and axon density could also add valuable information to our understanding of brain maturation.
Our goal is to complement brain growth analysis via morphometry with the study of longitudinal tissue property
changes as reflected in patterns observed in multi-modal structural MRI and DTI. Our preliminary study includes
eight healthy pediatric subjects with repeated scans at the age of two weeks, one year, and two years with T1,
T2, PD, and DT MRI. Analysis is driven by the registration of multiple modalities and time points within and
between subjects into a common coordinate frame, followed by image intensity normalization. Quantitative
tractography with diffusion and structural image parameters serves for multi-variate tissue analysis. Different
patterns of rapid changes were observed in the corpus callosum and the posterior and anterior internal capsule,
structures known for distinctly different myelination growth. There are significant differences in central versus
peripheral white matter. We demonstrate that the combined longitudinal analysis of structural and diffusion
MRI proves superior to individual modalities and might provide a better understanding of the trajectory of early neurodevelopment.