Fast Bound Pool Fraction Imaging of the In Vivo Rat Brain: Assocation with Myelin Content & Validation in the C6 Glioma Model

Hunter R. Underhill¹, Robert C. Rostomily¹, Andrei M. Mikheev¹, Chun Yuan¹, Vasily L. Yarnykh¹

Cross-relaxation imaging is a quantitative MRI technique that measures the kinetic parameters of magnetization transfer between protons bound to water and protons bound to macromolecules (i.e. bound pool fraction, f). A new time-efficient approach for solely capturing the in vivo whole-brain parametric map of f was proposed, validated with histology, and used to estimate myelin density in the normal rat brain on a 3.0 T clinical scanner. In both whole-brain f maps and myelin density maps, replacement of normal gray matter and white matter by proliferating and invading tumor cells was readily identified in vivo and confirmed with histology.