Evaluating Exchange Processes in the Human Brain: Magnetization Transfer Vs Adiabatic Rotating Frame Relaxation Methods

Silvia Mangia¹, Michael Garwood¹, Steen Moeller¹, Dennis Sorce¹, Kamil Ugurbil¹, Shalom Michaeli¹

In the present work we investigate the different sensitivity to exchange processes generated at 4T by a variety of preparation pulses. To this aim, we quantitatively analyzed images from the human brain acquired by preparing magnetization with an off-resonance hard pulse, to exploit the so-called magnetization-transfer effect, or by preparing magnetization with a series of adiabatic pulses with different modulation functions, to exploit adiabatic rotating frame relaxation mechanisms. Results demonstrate that the two approaches are sensitive to completely different regimes of exchange, thus providing complimentary information to characterize the tissue.