Two-Step Strategy, FIB-4 Followed by Magnetic Resonance Elastography, for Detecting Advanced Fibrosis in NAFLD

Validation of AGA clinical care pathway and AASLD practice guidance for nonalcoholic fatty liver disease in a prospective cohort of patients with type 2 diabetes

BACKGROUND AND AIMS

Recently, the American Gastroenterological Association and the American Association for the Study of Liver Diseases developed clinical pathways to evaluate populations at high risk for NAFLD. We assessed the diagnostic performance of the new guidance in a well-phenotyped cohort of patients with Type 2 diabetes mellitus (T2DM).

APPROACH AND RESULTS

This prospective study enrolled patients age ≥50 years with T2DM. Participants underwent a standardized clinical research visit with MRI and ultrasound-based assessment of liver fat and stiffness and Enhanced Liver Fibrosis (ELF) testing. Of 417 participants (36% men) with T2DM with FIB-4 and MRE data, the prevalence of NAFLD was 64% and 12% had advanced fibrosis (MRE≥3.63 kPa). Applying the American Gastroenterological Association pathway of FIB-4 and vibration-controlled transient elastography, the false negative rate was 3.3% and 18% would qualify for specialty referral. Applying the FIB-4 + ELF American Association for the Study of Liver Diseases pathway, the false negative rate was 4.5%, but 50% would qualify for specialty referral. Applying higher ELF cut points improved the pathway, yielding a similar false negative rate of 4.9% but decreased specialty referral to 27%.

CONCLUSION

Validation of the American Gastroenterological Association clinical pathway in a prospectively recruited cohort with T2DM revealed a low false negative rate and avoided specialty referral in a large percentage of patients. The American Association for the Study of Liver Diseases pathway with FIB-4 + ELF resulted in a high rate of specialty referral, which improved with the utilization of higher ELF cut points and may serve as an alternative for primary care and endocrinology clinics without access to vibration-controlled transient elastography.

Effect of treatment periods on efficacy of glecaprevir and pibrentasvir in chronic hepatitis C: A nationwide, prospective, multicenter study

Background and aim

In patients with chronic hepatitis C, 8 weeks of glecaprevir and pibrentasvir (GLE/PIB) treatment for chronic hepatitis (non-cirrhosis) and 12 weeks for cirrhosis have been approved in Japan. However, whether 8 weeks of treatment for cirrhosis may reduce treatment efficacy has not been adequately investigated.

Methods

This prospective, nationwide, multicenter cohort study enrolled 1275 patients with chronic hepatitis C who received GLE/PIB therapy. The effect of liver fibrosis and treatment periods on the efficiency of GLE/PIB therapy was investigated. The primary endpoint was the sustained virological response (SVR) rate in patients with chronic hepatitis (non-cirrhosis) and cirrhosis. The association between treatment periods and liver fibrosis on the SVR after 12 weeks of treatment rate was investigated.

Results

The SVR rates in patients with chronic hepatitis with 8 weeks of treatment, chronic hepatitis with 12 weeks of treatment, cirrhosis with 8 weeks of treatment, and cirrhosis with 12 weeks of treatment were 98.9% (800/809), 100% (87/87), 100% (166/166), and 99.1% (211/213), respectively, and were was not different among these groups (P = 0.4).

Conclusion

GLE/PIB therapy for chronic hepatitis C had high efficacy regardless of liver fibrosis status and treatment periods. Periods of GLE/PIB therapy could be chosen with available modalities, and high SVR rates could be achieved regardless of the decision.

Magnetic resonance elastography for the prediction of hepatocellular carcinoma in chronic hepatitis B

Background and Aim

Magnetic resonance elastography (MRE) is used for the evaluation of liver fibrosis; however, it remains unclear whether MRE-based liver stiffness is associated with hepatocellular carcinoma (HCC) development, particularly in patients with chronic hepatitis B.

Methods

A total of 504 patients with chronic hepatitis B receiving MRE were enrolled. The primary endpoint was the association between MRE-based liver stiffness and HCC.

Results

In a cross-sectional analysis at the time of MRE measurement, the median (interquartile range) liver stiffness values in patients with presence or history of HCC and those without HCC were 3.68 (2.89-4.96) and 2.60 (2.22-3.45) kPa, respectively, and liver stiffness was significantly higher in patients with presence or history of HCC than in those without HCC (P < 0.001). In a longitudinal analysis of patients without HCC, the 1-, 3-, and 5-year cumulative incidence of HCC in patients with liver stiffness ≥3.6 kPa and those with liver stiffness <3.6 kPa were 3.8%, 7.0%, and 22.9%, and 0%, 0.9%, and 1.5%, respectively (P < 0.001). In the multivariable analysis, MRE-based liver stiffness (per 1 kPa) or liver stiffness ≥3.6 kPa was an independent factor for HCC development with an adjusted hazard ratio (aHR) of 1.61 (95% confidence interval [CI], 1.3-2.0) or aHR of 8.22 (95% CI, 2.1-31).

Conclusion

MRE-based liver stiffness is associated with HCC risk in patients with chronic hepatitis B and may be used for the early prediction of HCC development and determination of indications for treatment.

US-based Sequential Algorithm Integrating an AI Model for Advanced Liver Fibrosis Screening

Background Noninvasive tests can be used to screen patients with chronic liver disease for advanced liver fibrosis; however, the use of single tests may not be adequate. Purpose To construct sequential clinical algorithms that include a US deep learning (DL) model and compare their ability to predict advanced liver fibrosis with that of other noninvasive tests. Materials and Methods This retrospective study included adult patients with a history of chronic liver disease or unexplained abnormal liver function test results who underwent B-mode US of the liver between January 2014 and September 2022 at three health care facilities. A US-based DL network (FIB-Net) was trained on US images to predict whether the shear-wave elastography (SWE) value was 8.7 kPa or higher, indicative of advanced fibrosis. In the internal and external test sets, a two-step algorithm (Two-step#1) using the Fibrosis-4 Index (FIB-4) followed by FIB-Net and a three-step algorithm (Three-step#1) using FIB-4 followed by FIB-Net and SWE were used to simulate screening scenarios where liver stiffness measurements were not or were available, respectively. Measures of diagnostic accuracy were calculated using liver biopsy as the reference standard and compared between FIB-4, SWE, FIB-Net, and European Association for the Study of the Liver guidelines (ie, FIB-4 followed by SWE), along with sequential algorithms. Results The training, validation, and test data sets included 3067 (median age, 42 years [IQR, 33-53 years]; 2083 male), 1599 (median age, 41 years [IQR, 33-51 years]; 1124 male), and 1228 (median age, 44 years [IQR, 33-55 years]; 741 male) patients, respectively. FIB-Net obtained a noninferior specificity with a margin of 5% (P < .001) compared with SWE (80% vs 82%). The Two-step#1 algorithm showed higher specificity and positive predictive value (PPV) than FIB-4 (specificity, 79% vs 57%; PPV, 44% vs 32%) while reducing unnecessary referrals by 42%. The Three-step#1 algorithm had higher specificity and PPV compared with European Association for the Study of the Liver guidelines (specificity, 94% vs 88%; PPV, 73% vs 64%) while reducing unnecessary referrals by 35%. Conclusion A sequential algorithm combining FIB-4 and a US DL model showed higher diagnostic accuracy and improved referral management for all-cause advanced liver fibrosis compared with FIB-4 or the DL model alone. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Ghosh in this issue.

Transient Elastography Is the Best-Performing Non-Invasive Test of Liver Fibrosis in Obese Asian Patients with Non-Alcoholic Fatty Liver Disease: A Pilot, Cross-Sectional Study

Background and Objectives: The prevalence of NAFLD (non-alcoholic fatty liver disease) is increasing, and up to 64% of Asian patients with NAFLD are obese. Non-invasive tests (NITs) for the assessment of liver fibrosis are increasingly being used, but data on their performance in obese Asian patients are lacking. In this pilot cross-sectional study, we aim to compare the distribution of serum and radiological markers of fibrosis between obese Asian biopsy-proven NAFLD patients with and without fibrosis and estimate the diagnostic accuracies of these indices. Materials and Methods: Obese Asian patients with NAFLD and who had undergone a liver biopsy showing histological evidence of NAFLD were invited to participate. Liver fibrosis was assessed using laboratory (APRI, AAR, BARD, FIB4, NFS, and Asia-Pacific NAFLD advanced fibrosis score) and imaging modalities (TE: transient elastography, MRE: magnetic resonance elastography, and SWU: shear wave ultrasonography). Results: A total of 16 patients were included in the final analysis. On liver biopsy, nine patients (56.3%) had significant fibrosis (F2 or higher), and six of these patients had advanced fibrosis (F3 or higher). F4 fibrosis was present in one patient (6.3%). For the laboratory markers, we found that the BARD score correctly identified five out of six patients with advanced fibrosis (83.4%, p value 0.045). Among all the NITs studied, liver stiffness measured by TE had the highest accuracy of 87.5% in its established threshold of 8.5 kPa for the detection of advanced fibrosis. MRE also performed well (81.2% in 3.64 kPa). Conclusions: In conclusion, TE has performed well in the detection of advanced fibrosis in obese Asian patients with biopsy-proven NAFLD in our pilot study. Further large-scale definitive studies are needed to validate the results of our findings.

Advances in application of novel magnetic resonance imaging technologies in liver disease diagnosis

Liver disease is a major health concern globally, with high morbidity and mor-tality rates. Precise diagnosis and assessment are vital for guiding treatment approaches, predicting outcomes, and improving patient prognosis. Magnetic resonance imaging (MRI) is a non-invasive diagnostic technique that has been widely used for detecting liver disease. Recent advancements in MRI technology, such as diffusion weighted imaging, intravoxel incoherent motion, magnetic resonance elastography, chemical exchange saturation transfer, magnetic resonance spectroscopy, hyperpolarized MR, contrast-enhanced MRI, and ra-diomics, have significantly improved the accuracy and effectiveness of liver disease diagnosis. This review aims to discuss the progress in new MRI technologies for liver diagnosis. By summarizing current research findings, we aim to provide a comprehensive reference for researchers and clinicians to optimize the use of MRI in liver disease diagnosis and improve patient prognosis.

Screening for At-Risk Nonalcoholic Fatty Liver Disease in the Primary Care Setting

While nonalcoholic fatty liver disease is a leading cause of end-stage liver disease, most patients with nonalcoholic fatty liver disease do not develop cirrhosis and its complications. Therefore, risk stratification using inexpensive, noninvasive screening modalities is critical to avoid overdiagnosis and overtreatment of a large proportion of the population. In this review, we discuss the data supporting screening and current professional society recommendations on this topic. Screening for at-risk nonalcoholic fatty liver disease is recommended in patients with risk factors including diabetes, the metabolic syndrome, hepatic steatosis, and elevated aminotransferases. Screening typically consists of noninvasive testing using serum biomarkers followed by elastography using specialized imaging modalities. This sequential screening approach accurately identifies both high- and low-risk patients and is cost-effective when applied to at-risk populations. In conclusion, screening for advanced nonalcoholic fatty liver disease in the primary care setting is a crucial part of identifying high-risk patients who may benefit from aggressive intervention while avoiding overtreatment of patients at low risk of liver-related complications.

Non-invasive diagnosis and monitoring of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent form of chronic liver disease that poses challenges in diagnosis and risk stratification. Non-alcoholic steatohepatitis (NASH), the more progressive form of NAFLD, is particularly challenging to diagnose in the absence of histology. Liver biopsy is infrequently performed due to its invasive nature, potential for sampling error, and lack of inter-rater reliability. Non-invasive tests that can accurately identify patients with at-risk NASH (ie, individuals with biopsy-proven NASH with NAFLD activity score [NAS] ≥4 and fibrosis stage ≥2) are key tools to identify candidates for pharmacologic therapy in registrational trials for the treatment of NASH-related fibrosis. With emerging pharmacotherapy, non-invasive tests are required to track treatment response. Lastly, there is an unmet need for non-invasive tests to assess risk for clinical outcomes including progression to cirrhosis, hepatic decompensation, liver-related mortality, and overall mortality. In this Review we examine advances in non-invasive tests to diagnose and monitor NAFLD and NASH.

A practical use of noninvasive tests in clinical practice to identify high-risk patients with nonalcoholic steatohepatitis

BACKGROUND

Patients with nonalcoholic fatty liver disease (NAFLD) with type 2 diabetes (T2D) or other components of metabolic syndrome are at high risk for disease progression. We proposed an algorithm to identify high-risk NAFLD patients in clinical practice using noninvasive tests (NITs).

METHODS

Evidence about risk stratification of NAFLD using validated NITs was reviewed by a panel of NASH Experts. Using the most recent evidence regarding the performance of NITs and their application in clinical practice were used to develop an easy-to-use algorithm for risk stratification of NAFLD patients seen in primary care, endocrinology and gastroenterology practices.

RESULTS

The proposed algorithm uses a three-step process to identify NAFLD patients who are potentially at high risk for adverse outcomes. The first step is to use clinical data to identify most patients who are at risk for having potentially progressive NAFLD (e.g. having T2D or multiple components of metabolic syndrome). The second step is to calculate the FIB-4 score as a NIT that can further risk stratifying individuals who are at low risk for progressive liver disease and can be managed by their primary healthcare providers to manage their cardiometabolic comorbidities. The third step is to use second-line NITs (transient elastography or enhanced liver fibrosis tests) to identify those who at high risk for progressive liver disease and should be considered for specially care by providers with NASH expertise.

CONCLUSIONS

The use of this simple clinical algorithm can identify and assist in managing patients with NAFLD at high risk for adverse outcomes.

Head-to-head comparison between MEFIB, MAST, and FAST for detecting stage 2 fibrosis or higher among patients with NAFLD

BACKGROUND & AIMS

Patients with non-alcoholic fatty liver disease (NAFLD) and significant fibrosis (fibrosis stage ≥2) are candidates for pharmacological trials. The aim of this study was to perform a head-to-head comparison of the diagnostic test characteristics of three non-invasive stiffness-based models including MEFIB (magnetic resonance elastography [MRE] plus FIB-4), MAST (magnetic resonance imaging [MRI]-aspartate aminotransferase [AST]), and FAST (FibroScan-AST) for detecting significant fibrosis.

METHODS

This prospective study included 563 patients with biopsy-proven NAFLD undergoing contemporaneous MRE, MRI proton density fat fraction (MRI-PDFF) and FibroScan from two prospective cohorts derived from Southern California and Japan. Diagnostic performances of models were evaluated by area under the receiver-operating characteristic curve (AUC).

RESULTS

The mean age of the cohort was 56.5 years (51% were women). Significant fibrosis was observed in 51.2%. To detect significant fibrosis, MEFIB outperformed both MAST and FAST (both p <0.001); AUCs for MEFIB, MAST, and FAST were 0.901 (95% CI 0.875-0.928), 0.770 (95% CI 0.730-0.810), and 0.725 (95% CI 0.683-0.767), respectively. Using rule-in criteria, the positive predictive value of MEFIB (95.3%) was significantly higher than that of FAST (83.5%, p = 0.001) and numerically but not statistically greater than that of MAST (90.0%, p = 0.056). Notably, MEFIB's rule-in criteria covered more of the study population than MAST (34.1% vs. 26.6%; p = 0.006). Using rule-out criteria, the negative predictive value of MEFIB (90.1%) was significantly higher than that of either MAST (69.6%) or FAST (71.8%) (both p <0.001). Furthermore, to diagnose "at risk" non-alcoholic steatohepatitis defined as NAFLD activity score ≥4 and fibrosis stage ≥2, MEFIB outperformed both MAST and FAST (both p <0.05); AUCs for MEFIB, MAST, and FAST were 0.768 (95% CI 0.728-0.808), 0.719 (95% CI 0.671-0.766), and 0.687 (95% CI 0.640-0.733), respectively.

CONCLUSIONS

MEFIB was better than MAST and FAST for detection of significant fibrosis as well as "at risk" NASH. All three models provide utility for the risk stratification of NAFLD.

LAY SUMMARY

Non-alcoholic fatty liver disease (NAFLD) affects over 25% of the general population worldwide and is one of the main causes of chronic liver disease. Because so many individuals have NAFLD, it is not practical to perform liver biopsies to identify those with more severe disease who may require pharmacological interventions. Therefore, accurate non-invasive tests are crucial. Herein, we compared three such tests and found that a test called MEFIB was the best at detecting patients who might require treatment.

Noninvasive assessment of liver fibrosis and its clinical significance in nonalcoholic fatty liver disease

Liver fibrosis is the most important prognostic factor in patients with nonalcoholic fatty liver disease (NAFLD). Several noninvasive markers for fibrosis, including blood-based markers and imaging based-markers have been developed. Indirect fibrosis markers (e.g., fibrosis-4 index and NAFLD fibrosis score) consist of standard laboratory data and clinical parameters. Given its availability and high negative predictive value for advanced fibrosis, these markers are suitable for screening at primary care. Blood-based fibrogenesis markers (enhanced liver fibrosis and N-terminal propeptide of type 3 collagen), ultrasound-based modalities (vibration-controlled transient elastography, point shear wave elastography [SWE], and two-dimensional SWE), and magnetic resonance elastography have high diagnostic accuracy for liver fibrosis and are suitable for diagnosing liver fibrosis at secondary care centers. Sequential use of these markers can increase diagnostic accuracy and reduce health care costs. Furthermore, combining noninvasive makers may assist in identifying candidates for pharmacological trials and reducing screening failure. Emerging data suggest that these noninvasive markers are associated with liver-related events (hepatocellular carcinoma and decompensation) and mortality. Furthermore, delta change in noninvasive markers over time is also associated with time-course change in fibrosis, liver-related event risk, and mortality risk. However, the association between liver fibrosis and cardiovascular disease (CVD) risk is still controversial. CVD risk may decrease in patients with decompensated liver disease and noninvasive markers may be useful for assessing CVD risk in these patients. Therefore, noninvasive markers may be utilized as measures of fibrosis as well as real-time prognostic tools, in place of liver biopsy.

Impact of non-invasive biomarkers on hepatology practice: Past, present and future

Over the last two decades, there have been tremendous advances in the non-invasive diagnosis and risk stratification of chronic liver diseases (CLDs). Non-invasive approaches are based on the quantification of biomarkers in serum samples or on the measurement of liver stiffness, using either ultrasound- or magnetic resonance-based elastography techniques. The fibrosis-4 index (non-patented) and enhanced liver fibrosis test (patented) are the most widely adopted serum markers, whereas vibration-controlled transient elastography is the most widely adopted elastography technique. In this review, we discuss the role of non-invasive tests in the current era, as well as their accuracy and how their use in clinical practice has changed the practice of hepatology, including identification of early cirrhosis in patients with risk factors for CLD, diagnosis of portal hypertension, establishing prognosis in compensated cirrhosis, guiding antiviral treatment, and screening for fibrosis and cirrhosis in primary care.