Fig. 5
In vivo CEST-MRI of ICI-treated 4T1 tumors and respective ex vivo analysis. a Exemplary T2-weighted images with pixelwise MTRasym maps for ∆Glc-, APT- or 2 ppm-weighted CEST contrast of ICI-treated 4T1 tumors on day six and day nine compared to untreated controls. b-g Boxplots showing quantified MTRasym for ∆Glc-, APT- and 2 ppm-weighted CEST contrast of whole tumors, with the horizontal line indicating the mean, and boxes representing the 10th and 90th percentile. After ICI treatment, ∆Glc-weighted CEST contrast decreased, while APT- and 2 ppm-weighted CEST contrast increased after treatment on day six (b–d) and day nine (e–g). *p < 0.05. h Exemplary sections of 4T1 tumors after 4-channel staining of GLUT1 (red), GLUT3 (turquoise), CD3 (green) and nuclei (blue) with correlating merged images. ICI-treated tumors showed increased CD3 expression. GLUT1 expression decreased after treatment, while expression of GLUT3 was approximately constant. Scale bars indicate 100 µm. i Exemplary images of MALDI-2-MS with corresponding H&E stainings showing reduced intratumoral glucose accumulation after ICI therapy on both day 6 and day 9. Tumor contours are marked with dashed red lines