Motivation: Iron particle sizes can influence microscopic magnetic field heterogeneities, affecting R2* decay. Goal(s): To investigate the impact of iron particle size on R2* and fat fraction (FF) estimations for coexisting hepatic iron overload and steatosis. Approach: Impact of iron particle sizes (0.38, 0.52, and 0.71 μm) was analyzed using Monte Carlo simulations and fat-iron phantoms with varying iron content and FF. Three-way ANOVA assessed the impact of iron particle size on R2* and FF estimations. Results: R2* and FF estimations are affected by iron particle size, with smaller particles causing higher R2* values and increased FF estimation bias. Impact: In the concomitant presence of fat and iron, the size of iron particles can affect the accuracy of fat fraction and R2* estimations, and hence may cause bias in the assessment of hepatic iron overload and steatosis using MRI.
Shrestha et al. (Tue,) studied this question.