BACKGROUND
Prenatal alcohol exposure (PAE) occurs in ~10% of pregnancies in North America and can alter brain development. Prior research on brain morphology in children with PAE shows mixed findings for cortical thickness, and only a few studies have investigated more complex morphological features, showing decreased gyrification with PAE. Here, we use four anatomical measures to provide a comprehensive characterization of cortical morphology in youth with PAE compared to unexposed youth.
METHODS
T1-weighted Magnetic Resonance Imaging (MRI) was used to examine cortical morphology metrics in 163 scans from 121 youth (56 with PAE) aged 7-21 years. Each participant had between 1 and 3 scans. Images were processed to segment 98 cortical brain regions. Linear mixed-effects models were used to test the effects of PAE on cortical gyrification index, thickness, sulcal depth, and shape complexity index, as well as their relationships with age.
RESULTS
Individuals with PAE had significantly lower gyrification (β=-0.17, q = 0.028) and sulcal depth (β=-0.60, q = 0.013) in the right pars triangularis, lower shape complexity in the right occipital pole (β=-0.019, q = 0.012), and higher shape complexity in the right medial orbital gyrus (β=0.017, q = 0.012), compared to unexposed youth. PAE moderated the relationship between age and both gyrification and sulcal depth in several regions such that sulcal depth and gyrification decreased with age in the PAE group but slightly increased with age (or remained stable) in the unexposed group.
CONCLUSION
These findings build upon previous reports of structural and developmental differences in youth with PAE, suggesting that gyrification may be more sensitive to the effects of PAE than cortical thickness.
Chloe Scholten, Courtney P. Gilchrist, Bryce L. Geeraert et al.· Drug and Alcohol Dependence· 0 citations
Diffusion kurtosis imaging (DKI) is typically applied to white matter, but it may provide insight into age‐related microstructural changes in gray matter tissue like the hippocampus. The goal was to assess neurodevelopment and aging changes in hippocampal subfields using 1 mm isotropic DKI across the healthy lifespan (5–90 years). Multi‐shell, 1 mm3, diffusion imaging focused on the hippocampus, was acquired at 3 T in 363 healthy participants (5–90 years, 206 females). Automatic hippocampal subfield segmentation and unfolded maps were obtained using HippUnfold. Nonlinear lifespan trajectories, sex differences, and age‐corrected residual correlations with cognitive scores and other demographics were assessed for volume, mean diffusivity (MD), fractional anisotropy (FA), mean kurtosis (MK), and kurtosis FA (KFA). Whole hippocampus yielded distinct age trajectories for the volume, diffusion tensor, and diffusion kurtosis parameters: volume—quadratic fit (maximum ~35–42 years); MD—negative Gamma variate (minimum ~35 years); FA—positive Gamma variate fit (maximum ~25 years); MK—exponential fit (steep increase during development that plateaus after ~25 years); and KFA—negative linear across the lifespan. There were sex differences in age trajectories for volume and MK that were not evident with DTI metrics. Males exhibited larger volume and larger MK than females. The subfields showed similar age trajectories as whole hippocampus albeit with regional variations in the values. The subiculum showed dramatically higher MK after age 20, with males exhibiting higher values than females. MK residuals in whole hippocampus correlated positively with body mass index residuals in three age groups (young, middle age, and older). In conclusion, high‐resolution 1 mm isotropic DKI of hippocampus revealed linear and nonlinear patterns with development and aging over a wide age range of 5–90 years that differ from DTI. These results suggest that DKI can provide novel insight into age‐related microstructural changes at the sub‐hippocampal level.
P. Stack-Sanchez, Donald W. Gross, Ali R. Khan et al.· NMR in Biomedicine· 0 citations