Diagnosis and management of transfusion iron overload: the role of imaging

Abstract

The characterization of iron stores is important to prevent and treat iron overload. Serum markers such as ferritin, serum iron, iron binding capacity, transferrin saturation, and nontransferrin-bound iron can be used to follow trends in iron status; however, variability in these markers limits predictive power for any given individual. Liver iron represents the best single marker of total iron balance. Measures of liver iron include biopsy, superconducting quantum interference device, computer tomography, and magnetic resonance imaging (MRI). MRI is the most accurate and widely available noninvasive tool to assess liver iron. The main advantages of MRI include a low-rate of variability between measurements and the ability to assess iron loading in endocrine tissues, the heart and the liver. This manuscript describes the principles, validation, and clinical utility of MRI for tissue iron estimation.

Figure 1

The relationship between R2 on the right side of the liver and needle biopsy iron concentrations [18]. This research was originally published in Blood. St Pierre TG, et al. Noninvasive measurement and imaging of liver iron concentrations using proton magnetic resonance. Blood 2005;105:855–861. © the American Society of Hematology. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Figure 2

Iron trajectories of two patients. Scattergram demonstrating cardiac iron versus liver iron (HIC) in two patients who developed cardiac iron loading despite having apparently adequate iron chelation [17]. Figure adapted from Wood JC. Magnetic resonance imaging measurement of iron overload. Curr Opin Hematol 2007; 14:183–190 with permission from Lippincott Williams and Wilkins.