Influence of fat droplet size on liver R2* relaxometry by Monte Carlo simulation and phantom studies

Motivation: Liver fat (hepatic steatosis) can confound R2*-based iron quantification in chemical shift encoded MRI, while the size of fat droplets may also affect liver R2*. However, it is infeasible to experimentally investigate the influence of fat droplet size in vivo on liver R2* due to tissue complexity. Goal(s): To investigate the influence of fat droplet size on liver R2* at both 1.5T and 3.0T. Approach: Monte Carlo simulation and phantom studies. Results: Liver R2* demonstrates a positive linear relationship with proton density fat fraction and remains relatively unaffected by fat droplet size. Impact: These findings may benefit phantom design and understanding of the underlying mechanisms of R2* characteristics in the presence of hepatic steatosis.