Barrera CA, et al. - In this retrospective analysis of 181 children with different ranges of iron overload, researchers assessed a biexponential R2* relaxometry model. Using two regions of interest (ROIs), they measured bi- and monoexponential R2* relaxometry in the liver applying a nonproprietary software: one encompassing the whole liver parenchyma (ROI-1) and the other only the periphery (ROI-2). A predominant biexponential behavior was defined as having residual ratio ≥1.5 and R2*fast ≥R2*slow. Based on liver iron concentration (LIC), participants were classified as stable (n = 23), mild (n = 58), moderate (n = 61), and severe (n = 39). The criteria for a predominant biexponential behavior was met by 37 subjects for ROI-1 and by 22 subjects for ROI-2. Compared with the other three LIC categories, biexponential model was more suitable for patients with severe iron overload for both ROIs.