Iman Daryaei1,
Marty Pagel2
1Chemistry
and Biochemistry, University of Arizona, Tucson, AZ, United States; 2Biomedical
Engineering, University of Arizona, Tucson, AZ, United States
We have developed a MRI contrast agent that changes T2 relaxivity after treatment with nitric oxide. This change in T2 relaxation is attributed to a change in the chemical exchange rate of a proton on the agent, which changes T2 exchange relaxation. The T1 relaxivity does not change after treatment with nitric oxide, so that a ratio of T2- and T1-weighted images can detect nitric oxide in a concentration-independent manner. These results demonstrate that a new class of responsive MRI contrast agents can be developed by changing the chemical exchange rate of an agent and obtaining T2-weighted and T1-weighted images.