On the Nature of Phase Contrast in Multiple Sclerosis Lesions

Dmitriy A. Yablonskiy¹, Jie Luo¹, Aditi Iyer¹, Alexander L. Sukstanskii¹, Anne H. Cross²

Phase images obtained by gradient echo MRI provide image contrast in multiple sclerosis distinct from T1W and T2W images. Herein we examine phase contrast in MS based on the Generalized Lorentzian Approach that relates MR signal phase to tissue microarchitechture. Our theory and experimental data show that the phase contrast can appear almost abruptly at the onset of a lesion. Also, contrary to common sense anticipation that phase contrast should grow with MS lesion progression (as it happens for other contrast mechanisms), we demonstrate that it can actually disappear as the tissue destruction progresses toward black hole phase.