Hepatic iron overload in thalassemic patients: Proposal and validation of an MRI method of assessment

Background. A simple, accurate, reproducible and noninvasive method of body iron overload assessment would be of great clinical use. Objective. The purpose of the study was the implementation of a 0.5-T MRI method for liver iron overload measurement. Materials and methods. Thirty patients with thalassemia major took part in the study. Liver and paraspinal muscle signal intensity (SI) measurements were performed on T1-weighted images and normalized on a standard phantom, and a subjective hemochromatosis grading scale was made on both T1- and T2-weighted images. Serum ferritin levels and tissue iron from liver biopsy specimens were determined for comparison. Results. A close correlation was found between bioptic liver iron and both the liver-to-phantom SI ratio (r = -0.88) and the subjective grading scale (rho = 0.89). Serum ferritin correlated poorly with liver iron deposition, whether assessed by biopsy (r = 0.62) or MRI (r = -0.69). Conclusions. Both the subjective and the quantitative MRI methods proposed here are clinically valuable, with the former being adequate for a gross, the latter for an accurate estimation of tissue iron overload.