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Manganese‐enhanced magnetic resonance imaging (MEMRI) of rat brain after systemic administration of MnCl 2 : Changes in T 1 relaxation times during postnatal development
Author(s) -
de Sousa Paulo L.,
de Souza Sandra L.,
Silva Afonso C.,
de Souza Ricardo E.,
de Castro Raul Manhães
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20792
Subject(s) - olfactory bulb , manganese , cerebellum , magnetic resonance imaging , thalamus , cortex (anatomy) , medicine , chemistry , endocrinology , central nervous system , nuclear magnetic resonance , anesthesia , nuclear medicine , biology , neuroscience , physics , organic chemistry , radiology
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.