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Abstract #4460

B1-Dependence of Single-Voxel MRS Sequences: STEAM, PRESS and MEGA-PRESS

Nicolaas AJ Puts1, 2, Michael Schr, 13, He Zhu1, 2, Peter B. Barker1, 2, Richard AE Edden1, 2

1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States; 2FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States; 3Philips Healthcare, Cleveland, OH, United States

In this abstract, we investigate the extent to which 3 single-voxel MRS sequences (STEAM, PRESS and MEGA-PRESS) are sensitive to miscalibration (or inhomogeneity) of the B1 field. Experimental results at 7T show that the actual B1 dependence is much worse than a naive model of sin dependence for excitation pulses and sin-squared for refocusing. For MEGA-PRESS, even a 20% drop in B1 can result in over 50% loss in signal.