Frequency Correction for MR Spectroscopy in the Human Breast At 7 Tesla with External Field Monitoring

Bart Lowie van de Bank¹, Vincent Oltman Boer¹, Mariska P. Luttje¹, Jannie Petra Wijnen¹, Gerard van Vliet¹, J. M. Hoogduin¹, Peter R. Luijten¹, Dennis W. Klomp¹

Variations in the frequency of the main magnetic field hamper applications in MR imaging and spectroscopy. We demonstrate the feasibility of real time observation of B0 fluctuations in the human breast with a field probe at a 7T MR system. In addition, we demonstrate that direct observation of field distortions may substantially improve frequency correction, compared to the indirect calibration method based on respiratory belt synchronization. The field probes can be used to accurately and directly measure dynamic frequency offsets caused by breathing.