Prediction of iron-induced MRI relaxation by Monte Carlo modeling
Ghugre N, Wood J
Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California
MRI is becoming increasingly important in non-invasive quantification of iron-loaded tissue but the underlying biophysics remains poorly characterized. There is indication that unlike the case of free ferritin, susceptibility-based diffusional losses dominate over the contribution of contact mechanisms in vivo as a result of ferritin aggregation and sequestration. To examine the potential role of iron fluctuations at the lysosomal scale(~0.4 &[micro]m radius), we employed a Monte Carlo model to simulate the effect of particle size and aggregation on iron-induced MRI signal relaxation and compared this with human liver tissue relaxometry; our model predictions suggest that mesoscopic relaxation dominates microscopic effects.