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Abstract #2197

On the Importance of T1 Estimation for SAGE Perfusion MRI Data

Alexander Brost1, Heiko Schmiedeskamp1, Matus Straka1, Jalal Andre2, Roland Bammer1

1Center for Quantitative Neuroimaging, Stanford University, Stanford, CA, United States; 2Department of Radiology, University of Washington, Seattle, WA, United States

The spin- and gradient-echo (SAGE) EPI sequence was developed to estimate cerebral blood flow (CBF) and cerebral blood volume (CBV). The main purpose of the sequence is to provide T1-independent perfusion-weighted imaging maps. Gadolinium-based contrast agents cause T1-shortening, in particular, when contrast agent leaks into the extravascular-extracellular space. Leakage correction using SAGE EPI requires a separately acquired pre-bolus T1 map. To estimate the effects of an incorrect T1 map, we simulated the effects using a pharmacokinetic model. Leakage correction could be applied to multi-echo data that lack a properly determined prebolus T1 map without significantly compromising CBV and MTT estimates.