Exploring the potential utilities of 99mTc-labeled RBC-equilibrium radionuclide angiocardiography in transfusion-dependent β-thalassemia major patients.

Abstract

99mTc-labeled RBC-equilibrium radionuclide angiocardiography (ERNA) is done in transfusion-dependent beta-thalassemia major (β-TM) patients routinely for cardiac dysfunction. This prospective study aimed at evaluating the potential of ERNA in demonstrating the bone marrow hyperplasia as an adjunct biomarker for monitoring the adequacy of blood transfusions in transfusion-dependent β-TM patients. One hundred and twenty-six patients of β-TM (study group) and 30 nonthalassemic patients (control) underwent ERNA study with an additional whole-body imaging. We quantitated the normalized bone marrow tracer uptake (due to marrow hyperplasia) and hepatic tracer uptake (indicator of hepatic perfusion) in both the groups on whole-body imaging. Liver and myocardial iron deposition were evaluated with T2* MRI in the thalassemic group. β-TM group showed significantly increased mean normalized marrow count (MN) compared to the control group (P < 0.001) reflecting peripheral marrow hyperplasia (indirect marker for blood transfusion inadequacy). The hematological parameters in the study group showed a negative correlation with MN, without such correlation in the control group. The study group showed greater derangement in hepatic perfusion with significantly less mean normalized hepatic tracer uptake (HN) compared to the control group. Hepatic iron deposition (evaluated with T2* MRI) also showed a negative correlation with hepatic perfusion parameter (HN) assessed by ERNA, though myocardial iron deposition did not show any significant correlation with cardiac systolic/diastolic parameters evaluated by ERNA in the study group. ERNA study with these novel parameters (MN and HN) may have the potential to assess peripheral marrow hyperplasia and derangement in hepatic perfusion in transfusion-dependent β-TM.