Functional liver imaging score derived from hepatobiliary-specific contrast-enhanced MRI: a study on agreement and correlation.

purposeTo investigate inter-and intra-observer agreement of Functional Liver Imaging Score (FLIS) in different populations, hepatobiliary phase (HBP), and radiologists, while analyzing the correlation between FLIS and liver function.

methodsA single-center retrospective study analyzed 203 patients from 2017 to 2021. Inter-observer and intra-observer consistency was assessed by the Intraclass Correlation Coefficient (ICC) by means of Spearman correlation analysis, evaluating the correlation between FLIS and Child-Turcotte-Pugh (CTP) score, as well as the relevant laboratory data. The discriminatory efficacy of FLIS for different stages of CLD and CTP grades was assessed by the receiver operating characteristic curve.

resultsIn all 203 patients, inter-observer ICC range was 0.885 to 0.954, and intra-observer ICC range was 0.946 to 0.985 among different radiologists. Inter-observer ICC range was 0.908 to 0.985, and intra-observer ICC range was 0.924 to 0.991 at different HBP time points. Inter-observer ICC range was 0.89 to 1, and intra-observer ICC range was 0.943 to 1 in different populations. The correlation coefficients between FLIS and albumin, total bilirubin, international normalized ratio, prothrombin time, and CTP scores were 0.617, -0.651, -0.706, -0.724, and -0.818. FLIS had good diagnostic efficacy in differentiating different stages of CLD and CTP grades; the area under the curve was 0.708, 0.752, 0.871, and 0.908.

conclusionsFLIS had a good intra-observer and inter-observer agreement among different populations, HBP and radiologists. FLIS showed a good correlation with CTP grades and laboratory data. FLIS can be used as one of the imaging assessment tools to distinguish different stages of CLD and CTP grades. CRITICAL RELEVANCE STATEMENT: FLIS showed significant correlations with prothrombin time, international normalized ratio, serum albumin, total bilirubin, and CTP score, and distinguished different stages of CLD and CTP grades, which positioned it as a non-invasive imaging tool for liver function assessment. KEY POINTS: High reliability: FLIS demonstrates excellent inter- and intra-observer agreement among different radiologists, hepatobiliary phase (10-25 min), and populations (healthy subjects, CLD, cirrhosis). Strong correlation with liver function: FLIS significantly correlates with liver function markers: albumin, total bilirubin, international normalized ratio, prothrombin time, and CTP scores. Diagnostic efficacy: differentiates CLD stages and CTP grades, highest accuracy for distinguishing advanced cirrhosis. CLINICAL UTILITY: FLIS serves as a robust and non-invasive imaging tool for assessing liver function and stratifying disease severity in CLD and cirrhosis.