Using 1H MRS imaging to detect ISUCA, we were able to measure pHe from multiple voxels in HCT116 colorectal tumour xenografts in mice bearing a tumour model in which all cells expressed CAIX (CA9 tumours) and also size-matched empty vector (EV) tumours that expressed lower levels of CAIX only in hypoxic areas (note that we use CAIX for the carbonic anhydrase IX enzyme, CA9 for the corresponding gene and CA9 for the HCT116 tumour line that constitutively expresses the enzyme). Here, CA9 is linked to colorectal neoplasm.