Validation of R2* magnetic resonance imaging for quantifying secondary iron overload in pediatric patients.

Purpose: Non-invasive assessment of iron deposition is the standard of care for guiding chelation therapy in patients with iron overload. Several magnetic resonance imaging (MRI)-based techniques have been developed. This study compares the MRI-based R2* method with the standard R2-based method for quantifying iron levels in the liver and heart in children and young adults with secondary iron overload.

Methods: A single-center prospective study was conducted over 2.5 years involving 14 patients aged 4-22 years with secondary iron overload. These patients underwent 40 MRI scans using both R2 and R2* methods at same time. A total of 36 scans were analyzed, comparing the two methods using linear regression analysis and Bland-Altman plots.

Results: The study shows a significant correlation between liver iron concentration measurements obtained using the R2* method and those obtained using the R2-based method (adjusted R² = 0.77128). The agreement was even stronger for R2* values in the cardiac septum (adjusted R² = 0.93483).

Conclusion: The R2* method for assessing iron deposition in the liver and cardiac septum is comparable to the R2-based method and is suitable for clinical use. However, due to slight differences in measurements between the two techniques, it is advisable to consistently use one method for monitoring treatment in each patient. Further research is needed to refine the calibration equations.

Clinical significance: This study highlights the MRI-based R2* method as a reliable, non-invasive, and cost-effective alternative to the R2-based method for monitoring iron overload in pediatric patients, with no additional costs for institutions or third parties.