Quantification of liver iron overload among pediatric patients with magnetic resonance imaging: current state of the art.

Secondary iron overload in pediatric oncology patients is related to excessive iron accumulation in the liver, with subsequent cirrhosis and dangerous complications affecting numerous other organs. Liver iron concentration (LIC) correlates linearly with the total body iron stores; therefore, the quantification of hepatic iron is of major research interest. Although liver biopsy has been considered the gold standard for identifying iron overload, magnetic resonance imaging (MRI) is a non-invasive and highly accurate alternative method for the assessment of hemochromatosis. Our intention is to present a brief description of MRI-based procedures and a comparison of selected methods. Briefly, among the available methods, the liver-to-muscle signal intensity is accessible and easy to apply; however, it assumes that muscle is pathology-free, which may not always be true. Transverse relaxometry is a valid method and allows for the identification of a low iron burden. However, this technique is unfortunately prone to motion artifacts and provides inconsistent results in cases of heavy iron overload. Finally, quantitative susceptibility mapping (QSM) is a notable procedure considered to be of significant interest for the future. The exact correlation between QSM and LIC, as measured by liver biopsy has yet to be established.