Developing imidazoles as CEST MRI pH sensors

A series of intra‐molecular hydrogen bonded imidazoles and related heterocyclic compounds were screened for their N–H chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) contrast properties. Of the compounds, imidazole‐4,5‐dicarboxamides (I45DCs) were found to provide the strongest contrast, with the contrast produced at a large chemical shift from water (7.8 ppm) and strongly dependent on pH. We have tested several probes based on this scaffold, and demonstrated that these probes could be applied for in vivo detection of kidney pH after intravenous administration. Copyright © 2016 John Wiley & Sons, Ltd. We have designed MRI pH sensors using Imidazole‐4,5‐diamides (I45DCs) with large chemical shifts using the principles of IntraMolecular‐bond Shifted HYdrogens (IM‐SHY). These were found to provide significant CEST contrast with a large chemical shift from water (7.8 ppm) strongly dependent on pH and reference signal. Furthermore, we demonstrate that these probes could be applied for in vivo detection of kidney pH after intravenous administration.
Source: Contrast Media and Molecular Imaging - Category: Radiology Authors: Tags: Full paper Source Type: research