Quantitative computed tomography assessment of transfusional iron overload

Area of Science:

• Radiology
• Medical Imaging
• Biomedical Engineering

Background:

• Quantitative computed tomography (QCT) has been explored for liver iron quantification for over three decades.
• Clinical validation of QCT for liver iron concentration (LIC) remains limited.
• Transfusional siderosis necessitates accurate monitoring of iron overload.

Purpose of the Study:

• To compare liver attenuation measurements from QCT with magnetic resonance imaging (MRI)-derived LIC estimates.
• To assess the clinical utility of QCT for quantifying liver iron in patients with transfusional siderosis.

Main Methods:

• A cohort of 37 patients with transfusional siderosis underwent both QCT and MRI for LIC monitoring.
• QCT and MRI measurements were performed within a 6-year period, with a mean time difference of 14 days.
• Liver attenuation values from QCT were correlated with MRI-derived LIC.

Main Results:

• A linear relationship was observed between liver attenuation and LIC for values outside the normal range (r(2) = 0.94).
• Intersubject variability in intrinsic liver attenuation limited QCT's ability to quantify LIC below 8 mg/g dry weight.
• QCT and MRI demonstrated equivalent accuracy for LIC around 22 mg/g dry weight, with QCT outperforming MRI at higher LIC levels.

Conclusions:

• QCT is not suitable for monitoring patients with well-controlled iron levels due to measurement uncertainty.
• QCT presents a cost-effective, available, and high-throughput alternative for liver iron quantification in moderate to severe cases, particularly where MRI resources are scarce.