Background: Accurate hepatic iron overload assessment in thalassemia major is critical for clinical management. While T2* based MRI relaxometry is the noninvasive reference for iron quantification, T2* values vary with scanner and protocol, potentially causing misclassification. This study evaluated the necessity of site-specific correction coefficients.
Methods: In this two-center study, hepatic iron concentration was quantified in 79 patients with β-thalassemia major from Mashhad and Zahedan using MRI Relaxometry. Initially, images were analyzed without correction (non modified) and patients were classified into five clinical severity groups based on T2* values. For quantitative validation, a phantom containing defined iron concentrations was imaged at both centers, and site-specific correction coefficients were derived from the relationship between phantom T2* and actual iron concentration. Patient datasets were then reanalyzed applying these coefficients (QC modified), and classifications were updated accordingly.
Findings: Applying the center-specific correction significantly altered iron-overload categorization in 31.6% of patients. Without corrections, iron levels tended to be overestimated in the Zahedan center and underestimated in Mashhad. The phantom study confirmed a strong correlation between T2* and true iron concentration (R2≈0.98) validating the calibration process.
Conclusion: The findings highlight that phantom-based calibration and scanner-specific analysis play a pivotal role in enhancing the quantitative accuracy of MRI Relaxometry and preventing misclassification in thalassemia patients. Implementing site specific analysis improves iron burden estimation and facilitates more precise clinical decisions regarding transfusion and chelation therapy.