Assessment of cardiac iron by MRI susceptometry and R2*in patients with thalassemia

A magnetic resonance imaging cardiac magnetic susceptometry (MRI-CS) technique for assessing cardiac tissue iron concentration based on phase mapping was developed. Normal control subjects (n=9) and thalassemia patients (n=13) receiving long-term blood transfusion therapy underwent MRI-CS and MRI measurements of the cardiac relaxation rate R2*. Using MRI-CS, subepicardium and subendocardium iron concentrations were quantified exploiting the hemosiderin/ferritin iron specific magnetic susceptibility. The average of subepicardium and subendocardium iron concentrations and R2* of the septum were found to be strongly correlated (r=0.96, P<.0001), and linear regression analysis yielded CIC (mu g Fe/g(wet tissue))=(6.4 +/- 0.4). R2* (septum) (s(-1)) - (120 +/- 40). The results demonstrated that septal R2* indeed measures cardiac iron level. (C) 2010 Elsevier Inc. All rights reserved.