Macromolecular proton fraction mapping in magnetic resonance imaging: physicochemical principles and biomedical applications

Fast mapping of the macromolecular proton fraction (MPF) is a recently developed method based on the magnetization transfer effect, which is caused by the incoherent exchange of magnetic energy between water and macromolecules in biological objects. A fundamental distinctive feature of MPF as a biophysical parameter is its sensitivity and specificity to myelin in the nervous tissue. Important advantages of the MPF mapping method include insensitivity to the magnetic field, high reproducibility of results, and the absence of the influence of paramagnetic ions. This review presents the mathematical and physicochemical basics of MPF mapping and outlines the state-of-the-art biomedical applications of the method.