Liver Radioembolization: Predicting Lung Shunt Fraction with Contrast-Enhanced CT, Eliminating the Need for 99mTc-MAA

Area of Science:

• Radiology
• Nuclear Medicine
• Oncology

Background:

• Accurate Lung Shunt Fraction (LSF) estimation is crucial for Yttrium-90 (90Y) radioembolization to prevent lung damage.
• Current LSF assessment using 99m Tc macroaggregated albumin (99m Tc-MAA) is invasive, complex, and costly.

Purpose of the Study:

• To investigate Contrast-Enhanced Computed Tomography (CECT) as a non-invasive method for estimating LSF.
• To develop and validate a novel CECT-based metric for LSF estimation.

Main Methods:

• A retrospective analysis of 30 liver cancer patients undergoing 4-phase liver CECT and 99m Tc-MAA imaging was performed.
• A novel metric was developed using CECT arterial and portal phases to quantify hypervascular volumes.
• The hypervascular-to-perfused volume ratio from CECT was correlated with LSF values obtained from 99m Tc-MAA imaging.

Main Results:

• A strong correlation (R²=0.95) was found between the CECT-derived hypervascular-to-perfused volume ratio and LSF.
• The strongest correlation was achieved when hypervascular volume was corrected by hypoxic volume and normalized by perfused volume.
• The CECT-based LSF estimation showed a 1-sigma uncertainty of 3%.

Conclusions:

• CECT-based LSF estimation presents a viable, non-invasive alternative to 99m Tc-MAA imaging for 90Y radioembolization planning.
• Further prospective studies are needed to validate this approach in larger patient cohorts.