1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Skope Magnetic Resonance Technologies, Zurich, Switzerland; 3Division of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
Background phase errors of various spatial and temporal orders limit the accuracy of phase-contrast magnetic resonance imaging. Current calibration techniques can compensate for them almost completely; however, they require the MR system to be temporally stable. In the present work we analyze the stability of background phase errors under thermal changes of the gradient system as it may occur for scans of long duration and high duty-cycle. Measurement of the gradient impulse response function shows a shift in frequency of the oscillatory field fluctuations with increasing temperature which results in a change of 0th and 1st order field offsets.