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In vivo serial evaluation of superparamagnetic iron‐oxide labeled stem cells by off‐resonance positive contrast
Author(s) -
Suzuki Yoriyasu,
Cunningham Charle H.,
Noguchi Kenichiro,
Chen Ian Y.,
Weissman Irving L.,
Yeung Alan C.,
Robbins Robert C.,
Yang Phillip C.
Publication year - 2008
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21816
Subject(s) - viability assay , transplantation , stem cell , magnetic resonance imaging , in vivo , luciferase , bioluminescence imaging , contrast (vision) , transfection , embryonic stem cell , nuclear magnetic resonance , chemistry , microbiology and biotechnology , cell , biology , medicine , gene , biochemistry , radiology , physics , optics
MRI is emerging as a diagnostic modality to track iron‐oxide‐labeled stem cells. This study investigates whether an off‐resonance (OR) pulse sequence designed to generate positive contrast at 1.5T can assess the location, quantity, and viability of delivered stem cells in vivo. Using mouse embryonic stem cell transfected with luciferase reporter gene ( luc ‐mESC), multimodality validation of OR signal was conducted to determine whether engraftment parameters of superparamagnetic iron‐oxide labeled luc ‐mESC (SPIO‐ luc ‐mESC) could be determined after cell transplantation into the mouse hindlimb. A significant increase in signal‐ and contrast‐to‐noise of the SPIO‐ luc ‐mESC was achieved with the OR technique when compared to a gradient recalled echo (GRE) sequence. A significant correlation between the quantity of SPIO‐ luc ‐mESC and OR signal was observed immediately after transplantation (R 2 = 0.74, P < 0.05). The assessment of transplanted cell viability by bioluminescence imaging (BLI) showed a significant increase of luciferase activities by day 16, while the MRI signal showed no difference. No significant correlation between BLI and MRI signals of cell viability was observed. In conclusion, using an OR sequence the precise localization and quantitation of SPIO‐labeled stem cells in both space and time were possible. However, the OR sequence did not allow evaluation of cell viability. Magn Reson Med 60:1269–1275, 2008. © 2008 Wiley‐Liss, Inc.