Prospectively Motion Compensated Amide Proton Transfer MRI for Body Oncology

Purpose In recent years, saturation transfer (ST) MRI techniques based on endogenous contrast of exchangeable amide protons of intracellular proteins and peptides (amide proton transfer, APT) have been developed successfully and applied in first clinical studies for oncology and neurology applications. The work has been mostly focused on applications in the brain, with recent extensions to e.g. prostate and breast. 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 ST technique was previously researched 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 tested in human volunteers with a focus on APT contrast in liver and kidney.