Water only sequence: an accurate method to estimate hepatic siderosis in patients with thalassemia major and intermedia

Abstract

Background: Thalassemia is a common hemoglobinopathy in our region. Iron overload is a major complication of thalassemia, and an accurate quantification of iron deposition is the mainstay of treatment planning. The liver is the main organ for storage of iron, and quantification of hepatic siderosis is a reliable estimation of total iron overload. Objectives: The aim of this study was to determine the accuracy of chemical shift sequences (CSS), especially a water only sequence (WOS), to estimate hepatic siderosis in thalassemia patients. Patients and Methods: During a seven-month period, from May to December 2016, one hundred and two known cases of thalassemia major and intermedia underwent liver MRI. The liver iron concentration was estimated using T2* MR relaxometry. The iron signal percentage and fraction were calculated using chemical shift sequences and correlated with estimated liver iron concentration (LIC). Results: The correlation coefficient of in-phase and opposed-phase sequences was 0.566 in estimating hepatic siderosis, which was improved by employing water only sequence (0.640). The sensitivity, specificity and positive predictive value were 90.5%, 94.4% and 98.7% for the in-phase and opposed-phase sequences and 82.1%, 94.4% and 98.6% for the water only sequence, respectively. Conclusion: Chemical shift sequences, including a water only sequence, are accurate for the assessment of hepatic siderosis. Water only sequences can effectively minimize the confounding effect of fatty liver.