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Keywords:

  • MEMRI;
  • manganese;
  • pancreas;
  • non CNS organs;
  • MP-RAGE

Abstract

Manganese-enhanced magnetic resonance imaging (MEMRI) is a novel imaging technique capable of monitoring calcium influx, in vivo. Manganese (Mn2+) ions, similar to calcium ions (Ca2+), are taken up by activated cells where their paramagnetic properties afford signal enhancement in T1-weighted MRI methodologies. In this study we have assessed Mn2+ distribution in mice using magnetization-prepared rapid gradient echo (MP-RAGE) based MRI, by measuring changes in T1–effective relaxation times (T1-eff), effective R1-relaxation rates (R1-eff) and signal intensity (SI) profiles over time. The manganese concentration in the tissue was also determined using inductively coupled plasma atomic emission spectrometry (ICP-AES). Our results show a strong positive correlation between infused dose of MnCl2 and the tissue manganese concentration. Furthermore, we demonstrate a linear relationship between R1-eff and tissue manganese concentration and tissue-specific Mn2+ distribution in murine tissues following dose-dependent Mn2+ administration. This data provides an optimized MnCl2 dose regimen for an MP-RAGE based sequence protocol for specific target organs and presents a potential 3D MRI technique for in vivo imaging of Ca2+ entry during Ca2+-dependent processes in a wide range of tissues. Copyright © 2010 John Wiley & Sons, Ltd.