A review of responsive MRI contrast agents: 2005–2014

This review focuses on MRI contrast agents that are responsive to a change in a physiological biomarker. The response mechanisms are dependent on six physicochemical characteristics, including the accessibility of water to the agent, tumbling time, proton exchange rate, electron spin state, MR frequency or superparamagnetism of the agent. These characteristics can be affected by changes in concentrations or activities of enzymes, proteins, nucleic acids, metabolites, or metal ions, or changes in redox state, pH, temperature, or light. A total of 117 examples are presented, including ones that employ nuclei other than 1H, which attests to the creativity of multidisciplinary research efforts to develop responsive MRI contrast agents. Copyright © 2014 John Wiley & Sons, Ltd.
A total of 117 responsive MRI contrast agents were reported in 2005–2014 that can detect nine types of biomarkers. Each of these agents experiences a change in tumbling time; a change in aggregation state that changes superparamagnetism; a change in chemical exchange rate between the agent and water; a change in water accessibility; a change in ligand proximity; or a change in electronic state. This review describes the physicochemical characteristics and chemical structures for these responsive MRI contrast agents.

Source: Contrast Media and Molecular Imaging - September 1, 2014 Category: Radiology Authors: Dina V. Hingorani, Adam S. Bernstein, Mark D. Pagel Tags: Review Source Type: research