Comparison of T1 sensitivity to ferumoxytol at 0.55T versus 3T: a preclinical cardiac MRI study

Motivation: Ferumoxytol-enhanced cardiac MRI has potential to detect ischemia by enabling more accurate and sensitive assessment of changes in myocardial blood volume. However, in-vivo comparison of ferumoxytol behavior at different field strengths is lacking. Goal(s): To compare the myocardial and blood T1 sensitivity to ferumoxytol and T1 map quality between 0.55T and 3T. Approach: We analyzed and compared a) relative myocardial and blood T1 changes with different ferumoxytol doses, b) artifact severity at two field strengths Results: 0.55T demonstrated 2.5-fold greater myocardial T1 sensitivity to ferumoxytol compared to 3T, with significantly reduced susceptibility artifacts. Impact: The increased ferumoxytol sensitivity at 0.55T enables potential dose reduction while maintaining diagnostic quality, offering a more robust platform for MBV assessment. This could particularly benefit stress/rest T1 reactivity measurements where detecting subtle MBV changes is crucial.