Adiabatically prepared spin-lock approach for T1ρ-based dynamic glucose enhanced MRI at ultrahigh fields

Purpose: Chemical exchange sensitive spin-lock and related techniques allow to observe the uptake of administered D-glucose in vivo. The exchange-weighting increases with the magnetic field strength, but inhomogeneities in the radiofrequency (RF) field at ultrahigh field whole-body scanners lead to artifacts in conventional spin-lock experiments. Thus, our aim was the development of an adiabatically prepared T_1ρ -based imaging sequence applicable to studies of glucose metabolism in tumor patients at ultrahigh field strengths.

Methods: An adiabatically prepared on-resonant spin-lock approach was realized at a 7 Tesla whole-body scanner and compared with conventional spin-lock. The insensitivity to RF field inhomogeneities as well as the chemical exchange sensitivity of the approach was investigated in simulations, model solutions and in the human brain.

Results: The suggested spin-lock approach was shown to be feasible for in vivo application at ultrahigh field whole-body scanners and showed substantially improved image quality compared with conventional spin-lock. The sensitivity of the presented method to glucose was verified in model solutions and a glucose contrast was observed in a glioblastoma patient after intravenous administration of glucose solution.

Conclusion: An adiabatically prepared spin-lock preparation was presented that enables a homogeneous and chemical exchange sensitive T_1ρ -based imaging at ultra-high field whole-body scanners, e.g., for T_1ρ -based dynamic glucose enhanced MRI. Magn Reson Med 78:215-225, 2017. © 2016 International Society for Magnetic Resonance in Medicine.