Change in Blood-brain Barrier Permeability with Age – Comparing a Physiologically Informed Biophysical Model with a Triexponential Decay Model

With age the integrity of blood-brain barrier (BBB) slowly deteriorates. Multi-TE ASL, being a water-based MRI method, offers detection of subtle changes in the BBB by probing T2 relaxation. In this study, we evaluated the sensitivity of multi-TE ASL method in detecting changes in the BBB occurring due to age using two models; a physiologically informed biophysical (PIB) model by estimating exchange time and a simpler tri-exponential decay (TD) model by determining the rate of change of tissue fraction. We found that both models were able to detect age-based changes in BBB. Moreover, PIB model showed higher robustness.