Determination of liver-specific r2 * of a highly monodisperse USPIO by (59) Fe iron core-labeling in mice at 3 T MRI.
Contrast Media Mol Imaging
; 10(2): 153-62, 2015.
Article
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| MEDLINE
| ID: mdl-25078884
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 (59) Fe-core-labeled USPIO ((59) FeUSPIO). 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 (59) FeUSPIO 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 (59) Fe activity measurements of excised organs by a whole body radioactivity counter (HAMCO) to define the dependency of ∆R2 * and (59) FeUSPIO liver concentration and calculate the r2 * of (59) FeUSPIO 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 (59) FeUSPIO with a percentage uptake of 70-88% of the injection dose. Hepatic ∆R2 * showed a dose-dependent linear correlation to (59) FeUSPIO activity measurements (r = 0.92) and an r2 * in the liver of 481 ± 74.9 mm(-1) s(-1) in comparison to an in vitro r2 * of 60.5 ± 3.3 mm(-1) s(-1) . Our results indicate that core-labeled (59) FeUSPIO can be used to quantify the local amount of USPIO and to estimate the liver-specific relaxivity r2 *.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Imagen por Resonancia Magnética
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Compuestos Férricos
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Medios de Contraste
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Nanopartículas
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Marcaje Isotópico
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Hígado
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Contrast Media Mol Imaging
Asunto de la revista:
DIAGNOSTICO POR IMAGEM
Año:
2015
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Reino Unido