Manganese-enhanced magnetic resonance imaging (MEMRI) of rat brain after systemic administration of MnCl2: Changes in T1 relaxation times during postnatal development
Article first published online: 15 DEC 2006
Copyright © 2006 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging
Volume 25, Issue 1, pages 32–38, January 2007
How to Cite
de Sousa, P. L., de Souza, S. L., Silva, A. C., de Souza, R. E. and de Castro, R. M. (2007), Manganese-enhanced magnetic resonance imaging (MEMRI) of rat brain after systemic administration of MnCl2: Changes in T1 relaxation times during postnatal development. J. Magn. Reson. Imaging, 25: 32–38. doi: 10.1002/jmri.20792
- Issue published online: 21 DEC 2006
- Article first published online: 15 DEC 2006
- Manuscript Accepted: 31 AUG 2006
- Manuscript Received: 5 DEC 2005
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil. Grant Number: DCR grant 304137/2003-0
- Le Studium (Agency for research and international hosting associate researchers in “Région Centre”), Orléans, France
- NINDS Intramural Research Program
- contrast agent;
- brain development;
- blood–brain barrier;
- T1 relaxation time
To measure regional T1 changes in the postnatal rat brain following systemic administration of the contrast agent manganese chloride (MnCl2).
Materials and Methods
MnCl2 (120 mM) was administered intravenously (i.v.) at 1.25 mL/hour to a dose of 175 mg/kg body weight. MRI experiments were performed on anaesthetized animals (32 male Wistar rats, postnatal days (PDs) 11, 16, 21, and 31) at 2.0 T. Regions of interest (ROIs) were drawn in sagittal slices and placed over five brain regions: olfactory bulb, cerebellum, cortex, thalamus, and hypothalamus. The signal intensities of each ROI were measured and fitted to a three-parameter function to estimate T1 values.
In the brains of animals who did not receive the contrast agent (control group), we observed a consistent age-dependent decrease in T1 values. In the brains of manganese-infused animals (manganese group), however, T1 values were significantly lower than in the control group, indicating the uptake of manganese, but no dependence of T1 on age was found.
Our T1 measurements indicate that the relative Mn2+ concentrations are higher in neonates and decrease with brain development. An estimate of the relative cortical concentration of manganese shows a two-fold drop from PD 11 to PD 31. J. Magn. Reson. Imaging 2007. © 2006 Wiley-Liss, Inc.