MKI67 and glioma: This is an hypothesis strengthened by the potential sensitivity of APT-weighted CEST to protein build-up during cell proliferation, as for instance shown by Togao et al.[8] and Jiang et al.[23, 24] in a correlation between MTRasym and the Ki-67 labelling index, a histopathological marker of cell proliferation, in patients with low- and high-grade glioma.