Harmonization of quantitative liver function evaluation using gadoxetate disodium-enhanced magnetic resonance imaging

This study aimed to develop a clinically applicable harmonization method for the hepatocellular uptake index (HUI), a quantitative liver function index, using gadoxetate disodium-enhanced (EOB)-MRI, to ensure consistency across diverse MR systems.

This retrospective study, approved by our institutional review board, included consecutive patients who underwent three-dimensional gradient-echo T1-weighted EOB-MRI, HUI measurements, indocyanine green disappearance rate (ICG-PDR), and albumin-bilirubin linear predictor (ALBI-LP) between April 2011 and June 2024. Six different MR systems were used for HUI measurements. A harmonization method using ALBI-LP was developed and validated for estimating liver reserves corresponding to ICG-PDR through statistical analysis of residuals.

A total of 498 patients (mean age, 68.0 years ± 11.6; 320 men) were evaluated. A statistically significant linear correlation was observed between HUI, ICG-PDR, and ALBI-LP in each MR system, leading to the determination of conversion factors for HUI harmonization. The harmonizing equation, harmonized HUI (h-HUI) = HUI･(Slope2'/-1.425)･0.955, was derived, with Slope2' representing the regression slope between HUI and ALBI-LP for each MR system. The standard deviation of the estimation error for ICG-PDR was significantly smaller using h-HUI by ALBI-LP (0.051, [0.048-0.054]) compared to non-harmonized HUI (0.060, [0.056-0.063]) or ALBI-LP (0.060, [0.057-0.064]), and equivalent to h-HUI by ICG-PDR (0.051, [0.045, 0.055]).

The HUI harmonized by the ALBI-LP is a clinically applicable method for ensuring the comparability of MR devices in quantitative liver reserve prediction using gadoxetate disodium-enhanced MR imaging.

Question The accurate prediction of quantitative liver function by hepatocyte-specific contrast-enhanced MRI necessitates the harmonization of MR systems. However, no established method has yet been identified. Findings In quantitative hepatic function assessment, albumin-bilirubin linear predictor can be employed to achieve harmonization between MR systems equivalent to the indocyanine green clearance test. Clinical relevance Quantitative liver function, as measured by the indocyanine green clearance test, can be accurately estimated using the hepatocellular uptake index, harmonized with the albumin-bilirubin linear predictor, across diverse MR systems.