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Abstract #1518

Correcting for Off-Resonance Induced Degradation of Inversion Efficiency in Pseudo-Continuous ASL

Hesamoddin Jahanian1,2, Luis Hernandez-Garcia1,2, Douglas C. Noll1,2

1Functional MRI Laboratory, University of Michigan, Ann Arbor, MI, USA; 2Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA

Pseudo-continuous arterial spin labeing (pCASL) uses a long train of labeling pulses to provide multi-slice cerebral perfusion measurements while compensating for magnetization transfer effects without using additional hardware. Changes in local resonance frequency and field gradients, due to field inhomogenities, can compromise the tagging efficiency of pCASL, which causes loss in SNR and can lead to quantification error. Here we examine the efficacy of dynamically changing the residual gradient moment (h) to systematically compensate the unwanted changes in φ thus restoring the tagging efficiency of PCASL. The method is demonstrated using numerical simulation and In-vitro data.