Characterizing White Matter Pathology with Quantitative Magnetization Transfer Imaging: Insight from a Four-Pool Model

Ives R. Levesque¹, G. Bruce Pike¹

Magnetization transfer is usually modeled using two proton pools. A model with four compartments is required to capture all of the commonly observed relaxation and cross-relaxation properties of human white matter; however, it is impractical for in vivo imaging. Simulations of magnetization transfer experiments were performed using variations on a basic four-model model of white matter, to investigate how these changes are reflected in the two-pool model of MT. We show that compartmental water exchange is negligible on an MT time-scale, and that estimation of the semi-solid-to-liquid pool ratio is robust, despite the presence of two liquid and semi-solid pools.