MRI detects myocardial iron in the human heart

Abstract

Iron‐induced cardiac dysfunction is a leading cause of death in transfusion‐dependent anemia. MRI relaxation rates R₂(1/T₂) and R(1/T) accurately predict liver iron concentration, but their ability to predict cardiac iron has been challenged by some investigators. Studies in animal models support similar R₂ and R behavior with heart and liver iron, but human studies are lacking. To determine the relationship between MRI relaxivities and cardiac iron, regional variations in R₂ and R were compared with iron distribution in one freshly deceased, unfixed, iron‐loaded heart. R₂ and R were proportionally related to regional iron concentrations and highly concordant with one another within the interventricular septum. A comparison of postmortem and in vitro measurements supports the notion that cardiac R should be assessed in the septum rather than the whole heart. These data, along with measurements from controls, provide bounds on MRI‐iron calibration curves in human heart and further support the clinical use of cardiac MRI in iron‐overload syndromes. Magn Reson Med, 2006.