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Abstract #2000

3D GRASE ASL Using a Modified Refocusing Pulse Phase Cycling Scheme Compatible with Vascular Crusher Gradients

David L. Thomas1, Enrico De Vita, 12, Xavier Golay1, Maria A. Fernandez-Seara3

1Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom; 2Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom; 3Center for Applied Medical Research, University of Navarra, Pamplona, Navarra, Spain

3D GRASE pCASL is a method for obtaining non-invasive perfusion maps of the brain with good SNR. A CPMG RF refocusing pulse phasing scheme is typically chosen for the 3D GRASE readout, to maximise robustness to B1 inhomogeneity. However, this method fails when vascular crusher gradients are implemented, due to violation of the CPMG condition. In this work, we implement an alternative refocusing pulse phasing scheme which is insensitive to the initial phase of the transverse magnetisation and still robust to B1 inhomogeneity, enabling use of vascular crusher gradients and improving the accuracy of perfusion quantification in 3D GRASE ASL.