Journal of Isfahan Medical School

Journal of Isfahan Medical School

Phantom-Based Validation of a T2∗ MRI Relaxometry Protocol for the Clinical Assessment and Classification of Iron Overload in Thalassemia Major Patients

Document Type : Original Article (s)

Authors
Farzaneh Ghorbani 1
Bahareh Shahraki 2
Pegah Lotfi 3
Mohammad Ghorbani 4
Zahra Badiee 5
Alireza Montazerabadi 6
1 Assistant Professor of Medical Physics, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
2 MSc in Medical Imaging Technology, Department of Radiology, Imam Ali Ibn Abi Talib Hospital, Zahedan University of Medical Sciences, Zahedan, Iran
3 PhD Student in Medical Physics, Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
4 Assistant Professor of Laboratory Hematology and Blood Banking, Department of Pathology, School of Medicine, Social Development and Health Promotion Research Center, Gonabad University of Medical Sciences, Gonabad, Iran
5 Associate Professor of Pediatric Hematology and Oncology, Department of Hematology and Oncology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
6 Associate Professor of Medical Physics, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
10.48305/jims.v44.i865.0898
Abstract
Background: Accurate hepatic iron overload assessment in thalassemia major patients is critical for optimal clinical management. While T_2^* based MRI relaxometry is the standard noninvasive reference for tissue iron quantification, T_2^* values vary with scanner, imaging protocol, and analysis method, potentially causing clinical misclassification. This study evaluated the necessity of quality control and site-specific correction coefficients.
Methods: In this retrospective, observational, 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 applying correction coefficients (non-modified) and patients were classified into five clinical severity groups based on T_2^* 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 T_2^* values and actual iron concentration. Patient datasets were then reanalyzed by applying these coefficients (QC-modified), and classifications were updated accordingly.
Findings: Applying the center-specific correction coefficients significantly altered clinical iron-overload categorization in 31.6% of patients. Without corrections, iron levels tended to be overestimated in the Zahedan center and underestimated in the Mashhad center. The phantom study confirmed a very strong correlation between T_2^* values and true iron concentration (R2 ≈ 0.98), confirming the accuracy of the calibration method.
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 diagnostic errors in thalassemia patients. Implementing scanner-specific analysis improves iron burden estimation and facilitates more precise clinical decisions regarding transfusion and chelation therapy.

Highlights

Farzaneh Ghorbani: Google Scholar , PubMed

Alireza Montazerabadi: Google Scholar , PubMed

Keywords
Thalassemia
Magnetic Resonance Relaxometry
Iron Overload
Calibration
Quantitative Imaging Biomarkers
Subjects
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Journal of Isfahan Medical School
Volume 44, Issue 865
1st Week, August
July and August 2026
Pages 898-907

  • Receive Date 20 May 2026
  • Accept Date 11 July 2026