Quantitative description of radiofrequency (RF) power‐based ratiometric chemical exchange saturation transfer (CEST) pH imaging

摘要: Chemical exchange saturation transfer (CEST) MRI holds great promise for imaging pH. However, routine CEST measurement varies not only with pH-dependent chemical rate but also agent concentration, providing pH-weighted information. Conventional ratiometric normalizes the confounding concentration factor by analyzing relative effect from different exchangeable groups, requiring agents multiple chemically distinguishable labile proton sites. Recently, an RF power-based approach has been developed concentration-independent pH using a single group. To facilitate quantification and optimization of new analysis, we quantitated ratio (rCESTR) derived its signal-to-noise contrast-to-noise ratio. Using creatine as representative containing site, our study demonstrated that optimized analysis provides good sensitivity. We showed rCESTR follows base-catalyzed relationship independent concentration. The accuracy was within 0.15–0.20 unit. Furthermore, absolute can be obtained proposed analysis. summarize, pH-sensitive complements conventional groups-based