Hepatic Iron Overload in Transfusion Dependent Chronic Hemolytic Anemic Patients: Where Does MRI R2* Relaxometry Stand?

Abstract

Background: Hepatic iron overload in pediatric population with repeated blood transfusion is an important morbidity warranting the evolution of a noninvasive method of liver iron quantification. MR T2*/R2* relaxometry technique has shown promising results in this domain. Aim of Study:To show the value of MR T2*/R2* relaxometry technique, in assessment of hepatic iron overload in a sample pediatric patient population at our hospital on repeated blood transfusions therapy for thalassemia and sickle cell anemia.Patients and Methods: A total of 44 patients, mean age 11.14±3.38 (range: 6-17 years old) patients with thalassemia and sickle cell anemia who had received more than 20 blood transfusions and on chelation therapy at the time of the examination, underwent MRI T2*/R2* relaxometry study. The corresponding iron overload was calculated for each patient, then correlation between R2* and serum ferritin level was done by using Pearson's correlation coefficient.Results: Serum ferritin levels ranged between 56.7 and 11524ng/mL (mean 3605.8ng/mL). R2* values ranged between 77.1 and 11426Hz (mean 2361Hz). Based on the calculated Liver Iron Concentrations (LIC) values which ranged between 0.47 and 42.55mg/g (mean 11.38mg/g) 9 patients (20.45%) showed normal hepatic iron load, 10 patients (22.73%) showed mild iron overload, 13 patients (29.55%) showed moderate overload and 12 patients (27.27%) showed severe overload. The correlation between R2* and serum ferritin was a weak positive one with a Pearson's coefficient of 0.49 (p=0.000645). The correlation between LIC and serum ferritin was a moderate positive one with a Pearson's correlation of 0.5 ( p=0.000494). Conclusion:Quantification of liver iron deposition in children with chronic hemolytic anemia receiving multiple blood transfusions is empirical for chelation therapy monitoring. R2* relaxometry shows promising results as an effective quantitative tool for estimation of hepatic iron overload when compared to serum ferritin levels, therefore providing a safer alternative in contrast to tissue biopsy.