Philip Lee1, Johannes Riegler2, Bingwen Zheng1, Anthony Price2, Mark F. Lythgoe2, Xavier Golay3
1Singapore Bioimaging Consortium, Biomedical Sciences Institute, Singapore, Singapore; 2Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom; 3Institute of Neurology, University College London, London, United Kingdom
Migration of super-paramagnetic labeled cells critically affects the success of therapeutic cell studies. Detection with T2* weighted MRI is normally implemented. But direct association of signal voids with SPIOs-labeled cells is erroneous, as they could originate from magnetic field inhomogeneities or partial volume effects. This study highlights the use of a multiple-echo ultra-short echo time (MUTE) sequence for positive contrast visualization of injected mononuclear cells. 5x105 and 2.5x105 of MNCs were directly injected into the left myocardium wall at the apex and mid-ventricle respectively and the heart was subsequently excised for MRI. Subtraction between the UTE (TE=0.208ms) and ECHO (TE=2.56ms) images exploited the transverse relaxation effect of iron, generating contrast-to-noise ratio of 19.6 and 22.7 respectively.