ObjectiveTo investigate the feasibility and accuracy of quantifying liver iron concentration (LIC) in patients with thalassemia (TM) using 1.5T and 3T T2*MRI.Methods1.5T MRI T2*values were measured in 391 TM patients from three medical centers: the T2*values of the test group were combined with the LIC (LICF) provided by FerriScan to construct the curve equation. In addition, the liver 3T MRI liver T2*data of 55 TM patients were measured as the 3T group: the curve equation of 3T T2*value and LICFwas constructed.ResultsBased on the test group LICF(0.6–43 mg/g dw) and the corresponding 1.5T T2*value, the equation was LICF= 37.393T2*∧(−1.22) (R2= 0.971;P< 0.001). There was no significant difference between LICe − 1.5Tand LICFin each validation group (Z= −1.269, −0.977, −1.197;P= 0.204, 0.328, 0.231). There was significant consistency (Kendall'sW= 0.991, 0.985, 0.980; allP< 0.001) and high correlation (rs= 0.983, 0.971, 0.960; allP< 0.001) between the two methods. There was no significant difference between the clinical grading results of LICe − 1.5Tand LICFin each validation group (χ2= 3.0, 4.0, 2.0;P= 0.083, 0.135, 0.157), and there was significant consistency between the clinical grading results (Kappa's K = 0.943, 0.891, 0.953;P< 0.001). There was no statistical correlation between the LICF(≥14 mg/g dw) and the 3T T2*value of severe iron overload (P= 0.085). The LICF(2–14 mg/g dw) in mild and moderate iron overload was significantly correlated with the corresponding T2*value (rs= −0.940;P< 0.001). The curve equation constructed from LICFand corresponding 3T T2*values in this range is LICF= 18.463T2*∧(−1.142)(R2= 0.889;P< 0.001). There was no significant difference between LICFand LICe − 3Tin the mild to moderate range (Z = −0.523;P= 0.601), and there was a significant correlation (rs= 0.940;P< 0.001) and significant consistency (Kendall'sW= 0.970;P= 0.008) between them. LICe − 3Thad high diagnostic efficiency in the diagnosis of severe, moderate, and mild liver iron overload (specificity = 1.000, 0.909; sensitivity = 0.972, 1.000).ConclusionThe liver iron concentration can be accurately quantified based on the 1.5T T2*value of the liver and the specific LIC-T2*curve equation. 3T T2*technology can accurately quantify mild-to-moderate LIC, but it is not recommended to use 3T T2*technology to quantify higher iron concentrations.