Gadoxetic Acid Uptake Rate as a Measure of Global and Regional Liver Function as Compared With Indocyanine Green Retention, Albumin-Bilirubin Score, and Portal Venous Perfusion.

PURPOSE

Global and regional liver function assessments are important for defining the magnitude and spatial distribution of dose to preserve functional liver parenchyma and reduce incidence of hepatotoxicity from radiation therapy for intrahepatic cancer treatment. This individualized liver function-guided radiation therapy strategy is critical for patients with heterogeneous and poor liver function, often observed in cirrhotic patients treated for hepatocellular carcinoma. This study aimed to validate as a measure of global and regional function through comparison with 2 well-regarded global function measures: indocyanine green retention (ICGR) and albumin-bilirubin (ALBI).

METHODS AND MATERIALS

Seventy-nine dynamic gadoxetic acid enhanced magnetic resonance imaging scans were acquired in 40 patients with hepatocellular carcinoma in institutional review board approved prospective protocols. Portal venous perfusion ( ) was quantified from gadoxetic acid enhanced magnetic resonance imaging using a dual-input 2-compartment model, and gadoxetic acid uptake rate ( was fitted using a linearized single-input 2-compartment model chosen for robust estimation. Four image-derived measures of global liver function were tested: (1) mean multiplied by liver volume ( ) (functional volume), (2) mean multiplied by blood distribution volume ( ) (3) mean and (4) liver volume ( ). The measure's correlation with corresponding ICGR and ALBI tests was assessed using linear regression. Voxel-wise similarity between and was compared using Spearman ranked correlation.

RESULTS

Significant correlations ( < .05) with ICGR and ALBI were found for and (in order of strength), but not for mean The mean ranked correlation coefficient between and maps was 0.09. and maps were predominantly mismatched in patients with poor liver function.

CONCLUSIONS

The metric combining function and liver volume ( ) was a stronger measure of global liver function compared with perfusion or liver volume alone, especially in patients with poor liver function. Gadoxetic acid uptake rate is promising for both global and regional liver function.