Ratiometric Magnetic Resonance Imaging: Contrast Agent Design Towards Better Specificity And Quantification

Magnetic Resonance Imaging (MRI) is a powerful imaging tool that combined with the use of contrast agents (CA) provides meaningful and crucial information both in the research and clinical settings. In recent years, strides have been taken towards the development of new CAs with enhanced capabilities (specificity, responsiveness, multimodality ...) to better diagnose and monitor physiological and pathological conditions in the body. Despite recent development, there are still challenges in the use of MRI to quantify specific functional or metabolic processes. The application of a ratiometric approach, in which images are acquired from the same sample using two different MR acquisitions, has potential to greatly improve the utility of MRI. In order to make this ratiometric approach work, a new generation of ratiometric probes are being developed which will be discussed in this review, classifying them based on the biological parameter under study as well as on the ratiometric analysis approach. Finally, the advantages and feasibility of using this methodology in a routine way will also be discussed. (C) 2021 Elsevier B.V. All rights reserved.