Liposome Encapsulated Manganese Chloride as a Liver Specific Contrast Agent for Magnetic Resonance Imaging

A study was undertaken to examine the possibility of using a liposome encapsulated paramagnetic ion (Mn$\sp{2+}$) as a contrast agent for magnetic resonance imaging (MRI) of the liver. Previous work with liposomes had shown that liposomes were concentrated in the liver after intravenous injection. Uptake of the vesicles into tumors was shown to be negligible. This suggested the possibility that the differences in uptake of the Mn$\sp{2+}$ in liposomes between liver and tumor might provide a means of highlighting tumors using MRI. Electron spin resonance (ESR) and proton nuclear magnetic resonance (NMR) relaxation were used in experiments to study the blood clearance, liver uptake and vesicle break down. The results showed that the Mn$\sp{2+}$ must be released from the vesicle and transferred to some extent to hepatocytes in order to bring about effective relaxation enhancement in liver tissue. After study of several different liposome preparations, it was found that vesicles composed of phosphatidylcholine, phosphatidylserine and cholesterol brought about the most rapid reduction in liver relaxation times. This vesicle preparation was injected intravenously into Fisher 344 rats with implanted liver tumors. The vesicles caused a marked reduction in the relaxation times of liver tissue, but little change in the relaxation times of the tumor. Magnetic resonance images obtained at 0.5 Tesla showed a large increase in the signal intensity in the liver and little change in the tumor. The results of this investigation showed the effectiveness of encapsulated Mn$\sp{2+}$ as an MRI contrast agent for liver metastases.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Niesman, Michael Ross

Contributors dc:contributor

• Magin, Richard

• Biology, General
• Chemistry, Pharmaceutical

Language dc:language

eng

Identifier

(UMI)AAI8823215

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/77687