Distribution of cardiac iron measured by magnetic resonance imaging (MRI)-R*2

Purpose

To assess regional iron distribution by magnetic resonance imaging (MRI)‐R₂* within the heart of patients with β‐thalassemia major (TM) and other iron overload diseases.

Materials and Methods

Breathhold electrocardiogram (ECG)‐gated MRI (1.5 T) of the heart was used for the measurement of transverse relaxation rates R₂* in 32 patients (11–79 years). In a mid‐papillary short‐axis slice divided into septal, anterior, lateral, and posterior quadrants, R₂* was analyzed from region of interest (ROI)‐based signal intensities from 12 echo times (TE = 1.3–26 msec). Typical boundary effects were evaluated in detail.

Results

The segmentation of the cardiac wall resulted in highly significant correlations of R₂* between septal and all other quadrants. In the patient group with R₂* < 50 s^?1 (normal), all quadrants show higher normalized median rates (126%–174%) than the septum (P < 10^?4), while this was relatively smaller in the group with septal R₂* > 50 s^?1. Typical boundary effects on segmental R₂* from blood, lung tissue, epicardial fat, and hepatic iron could not be easily separated from segmental iron distribution.

Conclusion

The measurement of MRI‐R2* in the interventricular septum is the least affected method by boundary effects to detect patients with iron overload at risk of developing heart failure. J. Magn. Reson. Imaging 2010;32:1104–1109. © 2010 Wiley‐Liss, Inc.