Plot of transverse relaxivity R2^* (1/T2^*) versus biopsied hepatic iron concentration (HIC) in 21 patients (23 biopsies). R2^* has units of hertz and HIC has units of milligram per gram dry weight of liver. R value was 0.97, and dashed lines indicate 95% prediction intervals for the regression. Average R2^* value for 13 healthy controls is shown for comparison ○, plotted using an HIC value estimated from normative data (no biopsy). Repeat MRI and biopsy examinations as well as control data were excluded from statistical calculations.