Towards the Contrast Mechanism of Chemical Exchange Saturation Transfer (CEST) in Tumors at 9.4T

Junzhong Xu¹, Zhongliang Zu¹, Jingping Xie¹, Daniel F. Gochberg¹, John C. Gore¹

To investigate whether the APT contrast in vivo reflects real differences in protein concentrations between tumors and normal tissues, we correlated APT contrast with multiple other MR parameters and protein concentration in 9L gliomas and normal tissues. R1 and PSR confirm that the total macromolecular content relevant for affecting water relaxation is lower in tumors, whereas APT and R2 detect other variations in composition that cause an increased contribution from exchanging protons. In additional, nuclear Overhauser effects (NOE) were also investigated which may provide a new imaging parameter to detect cancer, and the underlying biophysical mechanism is under investigation.