Prospectively Motion Compensated Amide Proton Transfer MRI for Body Oncology

Jochen Keupp¹, Guang Jia², Ivan E. Dimitrov³, Silke Hey⁴, Michael V. Knopp²

Endogenous contrast of exchangeable amide protons of intra-cellular proteins and peptides (amide proton transfer, APT) has been developed sucessfully and applied for first cinical studies in oncology applications. The work up to now has been mostly focused on the brain, with some extensions to e.g. prostate and breast APT. The organs addressed so far are not subject to respiratory motion. Body oncology applications in e.g. liver and kidney are challenging for APT, because the time scale of RF saturation needed for sensitive APT MRI (about 2s) is of the same order as typical respiratory intervals. A basic respiratory triggered saturation transfer technique was previously developed for contrast agent studies in human kidneys. In the current work, this approach was extended for improved stability of the contrast with varying respiratory cycles, scan time efficiency and SAR management. The novel technique was successfully tested in human volunteers with a focus on APT contrast in liver and kidney.