Iron overload in thalassemia: comparative analysis of magnetic resonance imaging, serum ferritin and iron content of the liver.

Abstract

Iron overload in patients with thalassemia is a common feature which requires continuous chelation therapy and monitoring. Serum ferritin determination is widely accepted as a simple method for following iron load in patients with primary hemochromatosis; however, several reports on thalassemic patients emphasize that ferritinemia is not accurate and that other methods such as direct measurement of iron in the liver (HIC) and magnetic resonance imaging (MRI) are more precise. In order to contribute to the general understanding of iron load in thalassemia we used liver MRI to study 33 thalassemic patients, most of whom were also evaluated for iron content by liver biopsy. The data were then compared with serum ferritin levels. Ferritin levels ranged between 276 and 8031 ng/mL, and liver iron content ranged from 1.6 to 31.0 mg/g dry weight; grade III or IV liver siderosis was recorded in 23/33 patients, just as 23/33 patients were found to have severe or very severe siderosis at MRI. Significant correlations with ferritin levels were recorded between grade IV and grades III, II and I (p < 0.01, p = 0.02, and p = 0.03, respectively). Ferritinemia also showed significant linearity with liver iron content (r = 0.603, p = 0.001). No significant differences of levels were recorded, however, between patients found to have severe and those with mild iron load at MRI (p = 0.073). Our study shows that serum ferritin levels exhibit a tendency to be significantly correlated with the true status of hemochromatosis in thalassemic patients; however, the discrepancies recorded in several patients and the scarce or total lack of correlation with MRI suggest exploring other approaches to this problem in order to make proper decisions about therapy.