1Department of Radiology, University of Wisconsin, Madison, WI, United States, 2Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI, United States
Accurate MR-based attenuation correction (MRAC) is necessary to enable
quantitative PET imaging in PET/MR. Unfortunately, identification of bone via
MR methods is technically challenging due to its short T2*. Thus, ultrashort
time echo (UTE) techniques have been proposed. In this study, we explored rapid
multi-echo frequency encoded UTE and ramped hybrid encoding (RHE) for UTE-based
imaging schemes for MRAC with clinically feasible scan times (<35sec). By
using an IDEAL-based signal model for long T2* suppression, multi-echo hybrid
encoding UTE imaging performed better than frequency encoded UTE.
