Assessment of Iron Overload in Pediatric Patients with Thalassemia Major During One Year Follow-up After Hematopoietic Stem Cell Transplantation Using T2* MRI Technique

Background: Iron overload especially in heart and liver cause serious complications for patients with thalassemia major (TM) including cardiomyopathy which is the main cause of death in TM patients. Using non-invasive methods for follow-up, MRI based methods like T2* MRI technique has been recently much more considered. This study investigates the changes in iron overload in TM patients before and after hematopoietic stem cell transplantation (HSCT) using T2* MRI technique.

Methods: Patients with TM who were candidate for HSCT enrolled. Cardiac and hepatic T2* values were measured three times during the treatment; one before HSCT, one six months later and the other one 12 months after HSCT. These values were compared to each other to determine how degree of iron overload changes during one year follow-up

Results: Twenty-eight patients including 19 boys and 9 girls with mean age 7.27years (range: 3.5-13) were included. The mean± SD for cardiac T2* values before and after HSCT (6 and 12 months) were 19.00±7.13, 18.77±8.25 and 21.72±7.80 respectively. These numbers for hepatic T2* values were 5.11±4.03, 3.83±2.48 and 3.56±2.69 respectively. While the differences between cardiac T2* values during one year follow-up after HSCT were not statistically significant (p-value=0.19), hepatic T2* values have decreased significantly (p-value=0.001) meaning that although cardiac iron overload has not changed dramatically, hepatic iron overload is getting worse even one year after HSCT.

Conclusion: Using T2* MRI for measuring iron overload in TM patients shows that despite of receiving chelation therapy or phlebotomy after HSCT, hepatic iron overload is still getting worse  in TM patients whereas cardiac iron overload is the same as before transplantation. It seems that for better understanding of liver iron overload, follow-up should be continued for years later.