Liquid Like Solids: A promising, novel multicompartment diffusion MRI phantom material

Motivation: Traditional single-compartment phantoms lack control over pore size, are more indicative of water restriction, and have limited biological relevance. Goal(s): Evaluate liquid-like solids (LLS) as a potential dual-compartment phantom material for dMRI. Approach: LLS phantoms, prepared with different gel concentrations, were imaged with b=0-2500s/mm2 and the signal curves were compared with free water and silica gel, a restricted phantom material. Additionally, several frameworks were evaluated for multi-compartment dependence. Results: LLS phantoms show double-exponential DWI signal decay and gel concentration correspondence with dMRI-estimated volume fraction, with Gaussian and non-Gaussian frameworks showing measurable bias, supporting this material's utility in refining multicompartment models. Impact: Developing biologically relevant multicompartment materials as phantoms can support the advancement of dual tensor and compartment imaging models, allowing innovation and development in more sophisticated diffusion imaging techniques.