Non-contrast MR imaging of blood-brain barrier permeability to water at 5T: Improved reliability compared to 3T

Motivation: WEPCAST MRI was proposed for non-contrast assessment of BBB permeability, but is plagued by low SNR. Goal(s): This study aimed to examine the efficacy of WEPCAST at 5T for more reliable BBB evaluation. Approach: Labeling efficiency of ASL at 5T was estimated using phase-contrast MRI as normalization. Then, WEPCAST MRI was harmonized at 3T and 5T. The consistency of BBB permeability PS value at both fields and SNR were evaluated. Results: ASL labeling efficiency was 0.55±0.08 at 5T. A strong correlation was found between PS measured at 3T and 5T (R²=0.806). Both spatial and temporal SNRs at 5T were significantly higher than 3T. Impact: We proposed a WEPCAST imaging protocol at 5T that provided a superior performance in BBB assessment when compared to 3T, highlighting the potentials of 5T MRI in physiological imaging of the brain.