A Multi-Echo Technique for Positive Contrast Detection of SPIO-labeled Cells at 9.4T

Introduction Therapeutic cell treatments have been applied to a large number of pathological diseases. Tracking the engraftment of cells is key to planning and assessing cell therapies. Migration dynamics and tissue integration are commonly assessed by locating iron-oxide labeled cells with T2* weighted MRI. Interpretation of the resulting signal voids can be challenging in preclinical scanners, especially in regions of magnetic field inhomogeneities or susceptibility. Although techniques exist to obtain positive contrast of iron-oxide labeled cells, such as Off-Resonance Imaging [1] and Inversion-Recovery with ON-Resonant Water Suppression [2], their sensitivity to magnetic field inhomogeneities deter application at high B0. We present here a multi-echo technique that exploits both the T1 and T2-relaxation effect of iron to achieve positive contrast of SPIO-labeled cells at 9.4T.