Separation of SPIO and Air Bubbles for Molecular Imaging

Tian Liu^1,2, Richard Wong^1,2, Pascal Spincemaille², Yi Wang^1,2

Dark T2* contrast of SPIO has been widely used in cell tracking in molecular MRI, but this negative contrast may be indistinguishable from the one generated by air bubbles that are commonly observed in gel phantoms due to their porous nature. In this study, we propose to distinguish air bubble from SPIO labeled cells by quantifying the magnetization at two different field strengths, 1.5T and 3T, using the fact that SPIO magnetization is typically saturated at field > 1T while the magnetization of air increases linearly with field strength.