Correction of Base-Line [Gd] Offsets Due to Effective Saturation Pulse Flip-Angle Variations in 3T Liver DCE-MRI

Andrew Brian Gill^1,2, Andrew N. Priest², Richard T. Black¹, David J. Bowden², Martin J. Graves², David J. Lomas²

[Gd] base-line discrepancies in liver DCE-MRI data have been recorded when using a dual acquisition, saturation-prepared fast gradient echo sequence at 3T, recording images in two separate slice orientations in each heartbeat. Pre-contrast discrepancies in [Gd] are thought to be due to flip-angle variation in the saturation pulses. A theoretical correction is derived to estimate the flip-angle at each region of interest and hence determine the true [Gd] curve. Volunteer data has been analysed using a dual-input pharmacokinetic model. Results show correction of the base-line discrepancy, consistent values for pharmacokinetic indices and improved values for the tissue arrival times.