Abstract #2630

Multiple Gradient- And Spin-Echo EPI Acquisition Technique with Z-Shimming to Compensate for Susceptibility-Induced Off-Resonance Effects

Heiko Schmiedeskamp¹, Matus Straka¹, Rexford David Newbould², Stefan Skare¹, Klaas P. Pruessmann³, Roland Bammer¹

¹Lucas Center, Department of Radiology, Stanford University, Stanford, CA, USA; ²GlaxoSmithKline, London, UK; ³Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

A combined gradient- and spin-echo EPI-based acquisition technique is presented for application in BOLD-fMRI and DSC-PWI. This technique includes additional z-shimming gradients prior to each EPI readout train to compensate for off-resonances in the brain, particularly in regions close to air-tissue interfaces, such as near the auditory canals and nasal cavities. Through root-sum-of-squares combination of multiple EPI trains, signal dropouts in the gradient-echo images could be remarkably reduced to a level similar to that of the spin-echo image acquired at the end of the pulse sequence.