Relationship between MR Phase & Tissue Microstructure

Saba El-Hilo¹, Stella Atkins, Alexander Rauscher²

Multiple Sclerosis (MS) lesions in the human brain can be identified in MR phase images as regions with increased MR resonance frequency with respect to their surroundings. In this work we investigate the relationship between changes in tissue architecture (from anisotropic to isotropic) and MR frequency shifts using numerical simulations. Moreover, we compare the results with data acquired in 20 subjects with MS. The numerical simulations resulted in an exponential decrease in MR signal phase. A decrease in phase after a lesion appears is also observed in the data which supports the validity of the simulated model.