Assessment of Liver Fibrosis Stage Using Integrative Analysis of Hepatic Heterogeneity and Nodularity in Routine MRI with FIB-4 Index as Reference Standard

Non-invasive imaging biomarkers in chronic liver disease

Chronic liver disease (CLD) is a global and worldwide clinical challenge, considering that different underlying liver entities can lead to hepatic dysfunction. In the past, blood tests and clinical evaluation were the main noninvasive tools used to detect, diagnose and follow-up patients with CLD; in case of clinical suspicion of CLD or unclear diagnosis, liver biopsy has been considered as the reference standard to rule out different chronic liver conditions. Nowadays, noninvasive tests have gained a central role in the clinical pathway. Particularly, liver stiffness measurement (LSM) and cross-sectional imaging techniques can provide transversal information to clinicians, helping them to correctly manage, treat and follow patients during time. Cross-sectional imaging techniques, namely computed tomography (CT) and magnetic resonance imaging (MRI), have plenty of potential. Both techniques allow to compute the liver surface nodularity (LSN), associated with CLDs and risk of decompensation. MRI can also help quantify fatty liver infiltration, mainly with the proton density fat fraction (PDFF) sequences, and detect and quantify fibrosis, especially thanks to elastography (MRE). Advanced techniques, such as intravoxel incoherent motion (IVIM), T1- and T2- mapping are promising tools for detecting fibrosis deposition. Furthermore, the injection of hepatobiliary contrast agents has gained an important role not only in liver lesion characterization but also in assessing liver function, especially in CLDs. Finally, the broad development of radiomics signatures, applied to CT and MR, can be considered the next future approach to CLDs. The aim of this review is to provide a comprehensive overview of the current advancements and applications of both invasive and noninvasive imaging techniques in the evaluation and management of CLD.

Development and validation of a potential biomarker to improve the assessment of liver fibrosis progression in patients with chronic hepatitis B

We aimed to develop and validate a novel combined score to improve the assessment of liver fibrosis progression in patients with chronic hepatitis B (CHB). In this study, a total of 331 CHB patients from three cohorts who underwent liver biopsy were enrolled, and the Scheuer system was used for liver fibrosis classification. The combined score was derived by principal component analysis of key differentially expressed genes. For significant liver fibrosis (≥S2), the areas under the receiver operating characteristics curves (AUROCs) of the combined score were 0.838, 0.842, and 0.881 in the three cohorts, respectively. And for advanced liver fibrosis (≥S3), the AUROCs were 0.794, 0.801, and 0.901, respectively. Compared with the results of AUROCs for aspartate aminotransferase≥to≥platelet ratio (APRI) and fibrosis index based on four factors (FIB-4) in the validation cohorts, better clinical diagnostic value for assessing the progression of liver fibrosis was found in the combined score. Additionally, univariate ordered logistic regression analysis indicated that the combined score could serve as a more superior and stable risk factor than APRI and FIB-4 in the assessment of liver fibrosis. For CHB patients with normal alanine aminotransferase (ALT), our results further emphasized the diagnostic value of the combined score for significant fibrosis (≥S2) and advanced fibrosis (≥S3). Moreover, it was found that patients with the high combined score, who were associated with the advanced fibrosis stage, had higher levels of drug sensitivity and immune checkpoint expression. In conclusion, the novel combined score could serve as a potential biomarker and contribute to improving the assessment of fibrosis stage in CHB patients.

Regional Analysis of Liver Surface Nodularity in a Single Axial MR Image for Staging Liver Fibrosis

BACKGROUND

The assessment of liver surface nodularity (LSN) for staging hepatic fibrosis is restricted in clinical practice because it requires customized software and time-consuming procedures. A simplified method to estimate LSN score may be useful in the clinic.

PURPOSE

To evaluate the regional analysis of LSN and processing time in a single axial liver MR image for staging liver fibrosis.

STUDY TYPE

Retrospective.

POPULATION

A total of 210 subjects, a multicenter study.

FIELD STRENGTH/SEQUENCE

A 3 T/noncontrast gradient echo T1WI.

ASSESSMENT

Subjects were divided into five fibrosis groups (F₀  = 29; F₁  = 20; F₂  = 32; F₃  = 50; F₄  = 79) based on the METAVIR fibrosis scoring system. The mean LSN (on three slices) and regional LSN (on one slice) measurements, and the processing times, are compared. The regional LSN scores in five regions-of-interests (ROI_1-5 ) were analyzed in a single axial MRI at the level of the hilum by two independent observers.

STATISTICAL TESTS

Regional variations in LSN scores were compared using ANOVA with Tukey test. Agreement between the mean and regional LSN measurements was evaluated using Pearson correlation coefficients (r) and Bland-Altman plots. The diagnostic performance of mean and regional LSN scores according to fibrosis stage was evaluated with the AUROC. A P value < 0.05 was considered statistically significant.

RESULTS

Total processing time for a regional LSN measurement (3.6 min) was 75.5% less than that for mean LSN measurement (14.7 min). Mean LSN scores and all five regional LSN scores showed significant differences between fibrosis groups. Among regional LSN scores, ROI₅ showed the highest AUROC (0.871 at cut-off 1.12) for discriminating F_0-2 vs. F_3-4 and the best correlation with mean LSN score (r = 0.800, -0.07 limit of agreement).

CONCLUSION

Quantitative regional LSN measurement in a single axial MR image reduces processing time. Regional ROI₅ LSN score might be useful for clinical decision-making and for distinguishing the difference between early fibrosis (F_0-2 ) and advanced fibrosis (F_3-4 ) in the liver.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.