Effect of Spatial Distribution of Magnetic Dipoles on Lamor Frequency Distribution and MRI Signal Decay - A Numerical Approach Under Static Dephasing Conditions
Pintaske J, Mueller-Bierl B, Schick F
University Hospital Tuebingen
Cells loaded with superparamagnetic iron oxide (SPIO) cause relatively strong magnetic field distortions, implying that field superposition effects of neighboring cells have to accounted for. We treat SPIO loaded cells as magnetic dipoles in a homogeneous magnetic field and compute the static 3D frequency distribution and related signal decay for various spatial dipole distributions. We demonstrate that non-monoexponential signal decay can result directly from magnetic field inhomogeneities. Our results provide deeper understanding of how the spatial distribution of SPIO loaded cells affects the MR signal formation and have to be considered for the in-vivo quantification of SPIO-loaded cells.