Rotational Dynamics and Proton Relaxation of MRI Paramagnetic Contrast Agents

Rotational dynamics play an important role in determining the relaxation characteristics of paramagnetic contrast agents (PCA's) used in magnetic resonance imaging. In this work, a methodology employing continuous wave electron paramagnetic resonance spectroscopy has been developed and established to probe the rotational dynamics of model contrast agents. Rotational dynamics of model contrast agents have been determined, not only in an aqueous environment, where the agents tumble isotropically, but also in highly viscous environments (mirroring those that can be found within the body), where the agents undergo anisotropic motion. These results have been extended to study the rotational dynamics of PCA's covalently linked to dendrimers, non-covalently linked to human serum albumin, and taken up within rat hepatocytes. Dendrimeric contrast agents also tumble anisotropically. On the other hand, a two population model must be used to describe the rotational dynamics of contrast agents in a human serum albumin solution or a rat hepatocyte suspension. Proton relaxation of model agents, which utilized nuclear magnetic relaxation dispersion (NMRD), have also been studied for agents in these environments. Combining the results from the motional studies with careful analyses of the NMRD profiles, this work affirmed and established and significance of second-sphere relaxation as well as the physical models for proton relaxation of the model contrast agents in the environments studied. From these analyses, useful information has been extracted about the proton relaxation of the model agents that can be and have been used to effect rational design of paramagnetic contrast agents in the future.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Chen, John Wen-Yueh

Contributors dc:contributor

• Belford, R.L.
• Clarkson, Robert B.

• Biophysics, Medical

Language dc:language

eng

Identifier

(MiAaPQ)AAI9812551

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/84375