The SACT Template:A Human Brain Diffusion Tensor Template for School-age Children

School-age children are in a specific development stage corresponding to juvenility,when the white matter of the brain experiences ongoing maturation.Dffusion-weighted magnetic resonance imaging(DWI),especially diffusion tensor imaging(DTI),is extensively used to characterize the maturation by assessing white matter properties in vivo.In the analysis of DWI data,spatial normalization is crucial for conducting inter-subject analyses or linking the individual space with the reference space.Using tensor-based registration with an appropriate diffusion tensor template presents high accuracy regarding spatial normalization.However,there is a lack of a standardized diffusion tensor template dedicated to school-age children with ongoing brain development.Here,we established the school-age children diffusion tensor(SACT)template by optimizing tensor reorientation on high-quality DTI data from a large sample of cognitively normal participants aged 6-12 years.With an age-balanced design,the SACT template represented the entire age range well by showing high similarity to the age-specific templates.Compared with the tensor template of adults,the SACT template revealed significantly higher spatial normalization accuracy and inter-subject coherence upon evaluation of subjects in two different datasets of schoolage children.A practical application regarding the age associations with the normalized DTI-derived data was conducted to further compare the SACT template and the adult template.Although similar spatial patterns were found,the SACT template showed significant effects on the distributions of the statistical results,which may be related to the performance of spatial normalization.Looking forward,the SACT template could contribute to future studies of white matter development in both healthy and clinical populations.The SACT template is publicly available now(tp://igshare com/aricles/dataseu'SACT_.template/14071283).

The influence of the characteristics of a collection of particles on the scattered spectral density and its applications

The far-zone scattered spectral density of a light wave on the scattering from a collection of particles is investigated, and the relationship between the character of the collection and the distribution of the scattered spectral density is discussed. It is shown that both the number of particles and their locations in the collection play roles in the distribution of the far-zone scattered spectral density. This phenomenon may provide a potential method to reconstruct the structure character of a collection of particles from measurements of the far-zone scattered spectral density.