Evaluating pH in the Extracellular Tumor Microenvironment Using CEST MRI and Other Imaging Methods

Figure 8

¹H MR spectroscopic imaging of tumor pHe. (a) The ¹H spectrum from within a glioma showed the chemical shift of the IEPA H2 resonance (arrow), (b) which is correlated with pH as shown by an in vitro titration. (c) A parametric map of IEPA signal amplitudes showed accumulation of the agent in the glioma. (d) A parametric map of pHe was determined from the chemical shift of the IEPA H2 resonance and the correlation shown in (b). Reproduced with permission from [34].