MRI of cells and mice at 1 and 7 Tesla with Gd-targeting agents: when the low field is better!
Article first published online: 29 NOV 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Contrast Media & Molecular Imaging
Volume 6, Issue 6, pages 421–425, November/December 2011
How to Cite
Geninatti-Crich, S., Szabo, I., Alberti, D., Longo, D. and Aime, S. (2011), MRI of cells and mice at 1 and 7 Tesla with Gd-targeting agents: when the low field is better!. Contrast Media Mol Imaging, 6: 421–425. doi: 10.1002/cmmi.436
- Issue published online: 29 NOV 2011
- Article first published online: 29 NOV 2011
- Manuscript Accepted: 10 JAN 2011
- Manuscript Revised: 16 DEC 2010
- Manuscript Received: 13 AUG 2010
- low field;
- Gd complexes;
- macromolecular imaging probes
Tumor cells were targeted with Gd-loaded/LDL (low density lipoproteins) adducts consisting of ca 300 Gd(III) amphiphilic complexes incorporated in the lipophilic LDL particles. The long reorientational time of the Gd(III) complex in the supramolecular adduct yielded a relaxivity peak at ca 1 T, whereas its relaxivity at 7 T was 5 times less. The field-dependent relaxivity markedly affected the signal enhancement attainable at the two magnetic fields. As tumor cells showed up-regulation of LDL transporters, B16 melanoma cells were labeled with the Gd-loaded/LDL adduct. Each cell contained ca 2 × 109 Gd atoms. Upon dispersion of 5000 labeled cells in 1 μl of agar, signal intensity (SI) enhancements of about 30 and 7% were observed at 1 and 7 T, respectively. The results obtained on cellular systems were confirmed in vivo upon the administration of Gd-loaded/LDL particles to C57 mice bearing a transplanted melanoma (B16) tumor. From the herein reported results, one may conclude that, for slowly moving Gd complexes, it is possible to obtain in vivo sensitivity enhancements at 1 T several times higher than that attained at high fields. Copyright © 2011 John Wiley & Sons, Ltd.