Manganese-enhanced magnetic resonance imaging (MEMRI) of rat brain after systemic administration of MnCl2: Changes in T1 relaxation times during postnatal development

✍ Scribed by Paulo L. de Sousa; Sandra L. de Souza; Afonso C. Silva; Ricardo E. de Souza; Raul Manhães de Castro

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 755 KB
• Volume: 25
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.20792

✦ Synopsis

Abstract

Purpose

To measure regional T~1~ changes in the postnatal rat brain following systemic administration of the contrast agent manganese chloride (MnCl~2~).

Materials and Methods

MnCl~2~ (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 T~1~ values.

Results

In the brains of animals who did not receive the contrast agent (control group), we observed a consistent age‐dependent decrease in T~1~ values. In the brains of manganese‐infused animals (manganese group), however, T~1~ values were significantly lower than in the control group, indicating the uptake of manganese, but no dependence of T~1~ on age was found.

Conclusion

Our T~1~ measurements indicate that the relative Mn^2+^ 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.