An Optimal, Routinely Applicable Multi-Echo Gradient Echo (mGRE) Data Acquisition Scheme for QQ-based Oxygen Extraction Fraction (OEF) Mapping

Motivation: Oxygen extraction fraction (OEF) is an essential biomarker for assessing brain tissue viability in neurologic disorders. A novel OEF mapping technique, QQ, has demonstrated clinical potential as it utilizes a single, routine sequence available on all MRI scanners: multi-echo gradient echo (mGRE). However, mGRE data acquisition for maximizing QQ's accuracy remains understudied. Goal(s): To propose an optimal, readily applicable mGRE data acquisition scheme for QQ. Approach: Using mGRE, we tested different numbers of evenly spaced echoes (4 to 13 echoes), with fixed first and last echo time (3 and 40 ms). Results: mGRE with 10 echoes provided maximum OEF accuracy in simulations. Impact: The proposed sampling scheme requires no additional modifications to the routine mGRE sequence, it can be therefore readily applied in clinical settings, enhancing the detection of lesion abnormalities.