| Autor: |
Raabe, Nina, Forberich, Evelyn, Freund, Barbara, Bruns, Oliver T., Heine, Markus, Kaul, Michael G., Tromsdorf, Ulrich, Herich, Lena, Nielsen, Peter, Reimer, Rudolph, Hohenberg, Heinrich, Weller, Horst, Schumacher, U., Adam, Gerhard, Ittrich, Harald |
| Zdroj: |
Contrast Media & Molecular Imaging; Mar2015, Vol. 10 Issue 2, p153-162, 10p |
| Abstrakt: |
Accurate determination of tissue concentration of ultrasmall superparamagnetic iron oxide nanoparticles (USPIO) using T2* MR relaxometry is still challenging. We present a reliable quantification method for local USPIO amount with the estimation of the liver specific relaxivity r2* using monodisperse 59Fe-core-labeled USPIO (59FeUSPIO). Dynamic and relaxometric in vivo characteristics of unlabeled monodisperse USPIO were determined in MRI at 3 T. The in vivo MR studies were performed for liver tissue with 59FeUSPIO using iron dosages of 9 ( n = 3), 18 ( n = 2) and 27 ( n = 3) µmol Fe kg−1 body weight. The R2* of the liver before and after USPIO injection (∆ R2*) was measured and correlated with 59Fe activity measurements of excised organs by a whole body radioactivity counter (HAMCO) to define the dependency of ∆ R2* and 59FeUSPIO liver concentration and calculate the r2* of 59FeUSPIO for the liver. Ultrastructural analysis of liver uptake was performed by histology and transmission electron microscopy. ∆ R2* of the liver revealed a dosage-dependent accumulation of 59FeUSPIO with a percentage uptake of 70-88% of the injection dose. Hepatic ∆ R2* showed a dose-dependent linear correlation to 59FeUSPIO activity measurements ( r = 0.92) and an r2* in the liver of 481 ± 74.9 m m−1 s−1 in comparison to an in vitro r2* of 60.5 ± 3.3 m m−1 s−1. Our results indicate that core-labeled 59FeUSPIO can be used to quantify the local amount of USPIO and to estimate the liver-specific relaxivity r2*. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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