Fig. 4.
MRI-CEST imaging of tumor pH using exogenous DIACEST probes. Chemical structure of Iopamidol (a), pH dependence of the ratiometric values (b) calculated by ratioing the ST% contrast for the two amide groups (4.2 ppm and 5.5 ppm) and accuracy of the proposed method by comparing calculated vs. measured pH values (c) at 7 T. Adapted with permission by John Wiley and Sons from Magnetic Resonance in Medicine 2011, 65, 202–211. Representative T2w anatomical images of a TS/A mammary bearing tumor mouse with tumor ROI highlighted in green (d). Contrast ST% difference map calculated at 4.2 ppm (e) and 5.5 ppm (f) after Iopamidol i.v. injection (as ST% post–ST% pre injection) and corresponding calculated tumor pHe map over-imposed on the anatomical image (g)