Validation of theoretical models of hyperpolarized gas diffusion MRI with finite element simulation in geometrical and realistic models of lung acinar airways from micro-CT

In this work, the stretched exponential (SEM) and cylindrical airway (CM) theoretical models for hyperpolarized gas diffusion MRI are validated with finite element (FE) simulations in two different acinar airway geometries. Simulations of ³He multiple b-value diffusion experiments were performed in a theoretical cylindrical acinar airway geometry and a micro-CT derived realistic acinus model. The simulated MRI diffusion signal was fitted to the CM and SEM. In FE simulations of both models, derived acinar airway parameters from CM and SEM demonstrated strong correlation and good agreement with the underlying model.