Transmission of Rotary Excitation enables Quantification of Oscillating nT-Fields using a Linear Calibration Model

Rotary excitation based MRI, which enables spatially resolved, non-invasive, direct detection of biomagnetic fields, complements the measurement range accessible via MEG since detection is independent of the distance to the body surface. We present an extension of the REX method towards quantitative imaging. A calibration function can be composed from REX data of two measurements of adjustable fields projected onto the tissue by the scanner’s gradient system. In subsequent measurements, the field strength can be inferred from the calibration model. First in vivo proof-of-concept measurements show that the calibration successfully eliminates influences of tissue properties and accurately quantifies oscillatory nT-fields.