Brain morphometrics correlations with age among 352 subjects imaged with both 3T and 7T MRI: 7T improves statistical power

Motivation: Differences in statistical power between 3T and 7T MRI when assessing brain morphometrics correlation with age have not been robustly investigated. Goal(s): We aimed to showcase the effect size difference using a large number of paired 3T and 7T scans. Approach: We evaluated the correlation between age and brain volumes and cortical thicknesses from 352 healthy volunteers using FreeSurfer using two covariate normalization methods. Results: 7T MRI showed an overall stronger correlation between morphometrics and age and a larger number of significantly correlated brain volumes and cortical thicknesses. Sample size requirements were also reduced at 7T for comparable statistical power. Impact: With the same acquisition time, scanning at 7T would require less subjects to reach the same statistical power, allowing studies to acquire additional sequences and save costs. 7T could be advantageous when investigating brain regions that require large sample size.