Tissue Iron Distribution Assessed by MRI in Patients with Iron Loading Anemias

Area of Science:

• Biomedical Imaging
• Hematology
• Medical Physics

Background:

• Iron overload is a significant complication in various hematological disorders.
• Accurate assessment of tissue iron distribution is crucial for managing these conditions.
• Current methods like serum ferritin may not fully reflect tissue iron burden.

Purpose of the Study:

• To compare tissue proton transverse relaxation rates (R2) and cardiac R2* in patients with SCD, PNH, and NTDT against a control group.
• To identify specific iron distribution patterns across liver, spleen, bone marrow, and kidney in these patient cohorts.
• To evaluate the correlation between serum ferritin levels and tissue R2 values.

Main Methods:

• Utilized magnetic resonance imaging (MRI) to measure R2 values in bone marrow, spleen, liver, and kidney, and R2* in the heart.
• Compared these measurements between patient groups (SCD, PNH, NTDT) and healthy controls.
• Analyzed the relationship between serum ferritin and measured tissue R2 values.

Main Results:

• Patients with SCD, PNH, and NTDT showed increased liver and bone marrow R2 compared to controls.
• SCD and PNH patients exhibited increased spleen R2.
• Distinct iron loading patterns were observed: preferential liver loading in highly transfused SCD and PNH patients, spleen loading in low-transfused SCD, and reduced spleen loading in NTDT.
• Serum ferritin correlated moderately with tissue R2 in SCD and PNH but not in NTDT.

Conclusions:

• Simultaneous MRI-based R2 measurements effectively delineate tissue iron distribution patterns in hematological diseases.
• Tissue R2 is a more direct and accurate measure of iron loading than serum ferritin, particularly in NTDT.
• Understanding these biodistribution patterns aids in managing iron imbalance and its complications.