Direct Detection of Peak-like Magnetic Field Fluctuations using Rotary Excitation (REX) based MRI

With spin-locking, the resonance of the spin system can be shifted adjustably to the low frequency range for detection of biomagnetic field oscillations. In this study, we demonstrate that spin-locking is also sensitive to peak-like magnetic field fluctuations with broader spectral width. Simulations and measurements demonstrate that, in addition to the application of imaging neural oscillations, the spatially resolved detection of biomagnetic peaks is possible. Initial results show a high agreement between simulations and experiments and mark a first step towards spin-lock based diagnostics of biomagnetic activity, e.g. imaging of the cardiac conduction system.