Vincent J. Schmithorst1, 2, Luis Hernandez-Garcia3, Jennifer Vannest2, Akila Rajagopal2, Gregory Lee2, Scott Holland2
1Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States; 2Radiology, Children's Hospital Medical Center, Cincinnati, OH, United States; 3Functional MRI Laboratory, University of Michigan, Ann Arbor, MI, United States
The optimal approach for simultaneous ASL/BOLD imaging covering the whole brain is unknown. Via simulations, we compared relative ASL and BOLD CNR obtained using three possible acquisition strategies. Optimal performance was obtained using a dual-excitation approach, in which images with a short TE for ASL contrast are obtained immediately after the ASL tagging pulse; afterwards, images with a longer TE for BOLD contrast are acquired. Compared to a dual-echo acquisition, the dual-excitation strategy with optimized excitation flip angles provided a near 70% increase in ASL CNR for later-acquired slices, with only a 1% reduction in BOLD CNR.