Infant brain images

Mapping cortical hemispheric asymmetries in infants would increase our understanding of the origins and developmental trajectories of hemispheric asymmetries. We analyze longitudinal cortical hemispheric asymmetries in 73 healthy subjects at birth, 1, and 2 years of age using surface-based morphometry of magnetic resonance images with a specific focus on the vertex position, sulcal depth, mean curvature, and local surface area. Prominent cortical asymmetries are found around the peri-Sylvian region and superior temporal sulcus (STS) at birth that evolve modestly from birth to 2 years of age. Sexual dimorphisms of cortical asymmetries are present at birth, with males having the larger magnitudes and sizes of the clusters of asymmetries than females that persist from birth to 2 years of age. The left supramarginal gyrus (SMG) is significantly posterior to the right SMG, and the maximum position difference increases from 10.2 mm for males (6.9 mm for females) at birth to 12.0 mm for males (8.4 mm for females) by 2 years of age. The right STS and parieto-occipital sulcus are significantly larger and deeper than those in the left hemisphere, and the left planum temporale is significantly larger and deeper than that in the right hemisphere at all 3 ages. Our results indicate that early hemispheric structural asymmetries are inherent and gender related.

Quantitative measurement of dynamic cortex development during early postnatal stages is of great importance to understand early cortical structural and functional development. Conventional methods usually independently reconstruct cortical surfaces of longitudinal images from the same infant, which often generates longitudinallyinconsistent cortical surfaces and leads to inconsistence in cortex development measurement. This paper aims to address this problem by presenting a method to reconstruct consistent cortical surfaces from longitudinal brain MR images in the first-year infants for accurate and consistent measurement of dynamic cortex development. Specifically, longitudinal development of the inner cortical surface is first modeled by a deformable sheet with elasto-plasticity property to establish longitudinally smooth correspondences of inner cortical surfaces. Then, the modeled longitudinal inner cortical surfaces are jointly deformed to locate inner and outer cortical surfaces with a spatial-temporal deformable surface. The method has been applied on 10 infants, each with 5 or 6 scans acquired at every 3 months from birth. Experimental results show that our method can accurately and consistently reconstruct dynamic cortical surfaces from longitudinal infant images, with the average surface distance as low as 0.2mm. By using our method, we can quantitatively characterize longitudinally dynamic cortical thickness development in the first-year infants. Index Terms—infant longitudinal cortical surfaces, infant cortical thickness development 1.