Fig. 2

Metabolic profiles of in vitro cell extracts. a Exemplary CEST-MRI-derived MTR_asym spectra of 4T1 (yellow), 67NR (purple) or T-cell (green) extracts. b-d Quantitative MTR_asym for Glc-, 2 ppm- and APT-weighted CEST contrast of the different cell extracts. Extracts of highly malignant 4T1 breast cancer cells demonstrated higher Glc- and APT-weighted and lower 2 ppm-weighted CEST contrast compared to low malignant 67NR cell extracts. T-cell extracts showed higher CEST contrast at all three examined frequency offsets. e–g Metabolite concentrations (glucose (Glc), creatine (Cr), amide protons (APT)) quantified by ¹H-NMR spectroscopy, with similar metabolic differences between the cell lines than observed with CEST-MRI. Each dot represents one sample, with horizontal lines indicating minimum, mean and maximum values of each respective group. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001