R2*-MRI versus HIC. Agreement among the 3 reviewers was very high (ICC = 0.98); therefore, only data for reviewer 1 are illustrated. (A) Plot of R2*-MRI measurements versus HIC values obtained by liver biopsy with linear regression lines and 95% prediction limits. The intercept was −454.85 (P = .31), the slope was 28.02 (P < .001), and R² was 0.72. The correlation coefficient for R2*-MRI and HIC was 0.98 (P < .001). (B) Standard Bland-Altman plot^6,7  shows the difference versus the average of HIC (R2*) and HIC (biopsy), that is, (HIC [R2*] − HIC [biopsy]) versus (HIC [R2*] + HIC [biopsy])/2. The solid line represents the mean difference between HIC (R2*) and HIC (biopsy); dashed lines, upper and lower 95% limits of agreement between the 2 measurements. (C) R2*-MRI versus HIC regression line overlaid with regression lines from 2 other published methods of R2*-MRI showing that the Wood et al³  regression line falls well within our 95% predicted interval across the entire range of values, but the regression line from Anderson et al¹  (extrapolated from a published log-transformed plot) has a substantially lower slope, probably reflecting differences in instrumentation and biopsy iron quantification technique.