HEMOCHROMATOSIS - DIAGNOSIS AND QUANTIFICATION OF LIVER IRON WITH GRADIENT-ECHO MR-IMAGING

PURPOSE: To assess the role of magnetic resonance (MR) imaging in dete ction and quantification of liver iron overload. MATERIALS AND METHODS : MR imaging at 0.5 T was prospectively performed on 77 patients (67 w ith liver iron overload and 10 without) who underwent a liver biopsy w ith biochemical determination of the liver iron concentration (LIC) (n ormal, <36 mu mol per gram of liver tissue [dry weight]). Ratios of si gnal intensities and liver T2 relaxation time were calculated from ima ges obtained with spin-echo and breath-hold gradient-echo (GRE) sequen ces. RESULTS: Liver-to-tissue signal intensity ratios were better corr elated with LIC than T2 relaxation time. Long-echo-time GRE sequences were the most sensitive for detection of slight overload. Thus, high s ensitivity (94%) and specificity (90%) were obtained with a liver-to-f at ratio threshold of 1. The quantification of iron with MR imaging wa s accurate when the LIC was 80-300 mu mol/g. For heavy overload, above 300 mu mol/g, quantification was impossible owing to complete signal loss. Pancreatic and splenic signal intensity were unchanged in most c ases. CONCLUSION: This method, which can be improved by using more sen sitive sequences with a high-field-strength system, should be competit ive with biopsy for the diagnosis of substantial liver iron overload.