In vivo high-resolution 3D Overhauser-enhanced MRI in mice at 0.2 T
Version of Record online: 30 JAN 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Contrast Media & Molecular Imaging
Volume 7, Issue 1, pages 45–50, January/February 2012
How to Cite
Massot, P., Parzy, E., Pourtau, L., Mellet, P., Madelin, G., Marque, S., Franconi, J.-M. and Thiaudiere, E. (2012), In vivo high-resolution 3D Overhauser-enhanced MRI in mice at 0.2 T. Contrast Media Mol Imaging, 7: 45–50. doi: 10.1002/cmmi.464
- Issue online: 30 JAN 2012
- Version of Record online: 30 JAN 2012
- Manuscript Revised: 7 JUN 2011
- Manuscript Accepted: 7 JUN 2011
- Manuscript Received: 21 APR 2011
- Agence Nationale de la Recherche. Grant Number: Blanc_09_434420
- in vivo;
Overhauser-enhanced MRI (OMRI) offers the potentiality of detecting low-concentrated species generated by specific biological processes. However molecular imaging applications of OMRI need significant improvement in spatial localization. Here it is shown that 3D-OMRI of a free radical injected in tumor-bearing mice can be performed at high anatomical resolution at a constant field. A 30 mm cavity operating at 5.43 GHz was inserted in a C-shaped magnet for proton MRI at 0.194 T. Nude mice with or without brain-implanted C6 rat glioma were positioned in the cavity and injected with TOPCA (1-oxyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrole-3-carboxylic acid). OMRI was performed in 3D within several minutes in the brain region without high overheating of the animals. Voxel size was 0.5 × 0.5 × 1 mm3, providing good delineation of brain regions. Signal amplifications ranged from 2 in tumors to 10 in vessels several minutes after TOPCA injection. Time-course of signal enhancement could be measured by 2D OMRI at 15 s time intervals in a localized thin slice. The method opens the way for molecular imaging of biological activities able to generate OMRI-visible free radicals. Copyright © 2012 John Wiley & Sons, Ltd.