Correlation study between MR quantitative cardiac iron accumulated and serum ferritin, liver iron concentration in patients with .BETA.-thalassemia major

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Objective Using MRI-T2 * method to quantify the cardiac iron overload in patients with β-thalassemia major and to evaluate the correlation between cardiac T2 * values and serum ferritin (SF),liver iron concentration(LIC).Methods Fifty-eight over 10 years old transfusion-dependent patients with β-thalassemia major were underwent MRI heart measurement to obtain T2 * values.Spearman rank correlation was used to analyze the relationship between cardiac T2*,SF,and LIC.Patients were divided into two groups based on standard setting (SF ＞2500 μg/L or LIC ＞ 15 mg/g of dry tissue).Differences of cardiac T2 * values between two groups were evaluated by Wilcoxon rank sum test with cardiac T2 * ＜ 20 ms as diagnosis standard.The sensibilities and specificities of prediction for cardiac iron deposition with the index of SF ＞ 2500 μg/L or LIC ＞ 15 mg/g dry tissue were calculated,and receiver operating characteristic (ROC) curve analysis was performed.Results The range (median) of cardiac T2 * values,SF and LIC in 58 patients were 4.7-51.1 ms (14.0 ms),1345-23 640 μg/L (5741 μg/L),9.0-＞43.0 mg/g dry tissue (41.4 mg/g),respectively.There was no linear correlation between cardiac T2 * values and SF (r =-0.240,P =0.070).Cardiac T2 * values and LIC was weakly correlated (r =-0.420,P =0.002).The range (median) of cardiac T2 * values was 6.1-47.6 ms (23.7 ms) in 7 patients of SF ≤ 2500 μg/L group.The range (median) of cardiac T2 * values was 4.7-51.1 ms(13.5 ms) in 51 patients of SF ＞2500 μg/L group.There was no statistically significant difference between two groups (Z =-0.489,P =0.625).The range (median) of cardiac T2 * values was 24.4-51.1 ms (44.8 ms) in 5 patients of the LIC ≤15 mg/g dry tissue group.The range (median) of cardiac T2 * values was 4.7-45.5 ms (13.2 ms) in 53 patients of HIC ＞ 15 mg/g dry tissue group.There was significant difference between T2 * values of the two groups(Z =-2.895,P =0.004).To predict cardiac iron deposition,the sensibilities and specificities were 90.9％ (30/33) and 16.0％ (4/25) for the index of SF ＞2500 μg/L,100.0％ (33/33) and 20.0％(5/25) for LIC ＞ 15 mg/g dry tissue respectively.The areas under the ROC curve were 0.652 with the index of SF and 0.775 with the index of LIC.Conclusions MRI-T2 * method can directly quantify the cardiac iron overload in patients with β-thalassemia major.There is no linear correlation between cardiac T2 * values and SF.Cardiac T2 * values and LIC is weakly correlated.Using SF or LIC as an indirect index to predict cardiac iron deposition is not reliable in clinical. Key words: Thalassemia; Iron metabolism disorders; Magnetic resonance imaging; Heart