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.
Misra et al. (Tue,) studied this question.