Comparative accuracy of endosonographic shear wave elastography and transcutaneous liver stiffness measurement: a pilot study

Mechanical rheological model on the assessment of elasticity and viscosity in tissue inflammation: A systematic review

Understanding the extent of inflammation is crucial for early disease detection, monitoring disease progression, and evaluating treatment responses. Over the past decade, researchers have demonstrated the need to understand the extent of inflammation through qualitative or quantitative characterization of tissue viscoelasticity using different techniques. In this scientific review, an examination of research on the association between elasticity and Viscosity in diseases, particularly as tissue inflammation progresses, is conducted. A review of utilizing mechanical rheological models to characterize quantitative viscoelastic parameters of normal and inflamed tissues is also undertaken. Based on inclusion and exclusion criteria, we identified 14 full-text studies suitable for review out of 290 articles published from January 2000 to January 2024. We used PRISMA guidelines for the systematic review. In the review, three studies demonstrated the criterion used by the researchers in identifying the best rheological model. Eleven studies showed the clinical application of the rheological model in quantifying the viscoelastic properties of normal and pathological tissue. The review quantified viscoelastic parameters for normal and pathological tissue across various soft tissues. It evaluated the effectiveness of each viscoelastic property in distinguishing between normal and pathological tissue stiffness. Furthermore, the review outlined additional viscoelastic-related parameters for researchers to consider in future stiffness classification studies.

Ultrasonographic Assessment of Tissue Stiffness: Recent Progress in Transient Elastography and Shear Wave Elastography in the Liver and Various Organs

Ultrasonography is a noninvasive and widely accessible modality in clinical practice. Recently, ultrasonography has been used to evaluate tissue stiffness; the two representative techniques are transient elastography (FibroScan®) and shear wave elastography. These modalities are now generally used for the assessment of liver fibrosis, the prediction of hepatocarcinogenesis, and determining prognosis. In addition, shear wave elastography is available, not only for the liver but also for various other organs, including the breast and brain. In the breast and brain, shear wave elastography distinguishes malignant lesions from benign ones. Moreover, shear wave elastography can be useful for differentiating between ischemic and hemorrhagic strokes. This review summarizes the recent progress in transient elastography and shear wave elastography of the liver and introduces the advantages of ultrasonographic assessment of tissue stiffness in various organs, including the breast, brain, kidney, heart, thyroid, pancreas, muscle, and bone.

Role of endoscopy in hepatology

The growing and evolving field of EUS and advanced hepatobiliary endoscopy has amplified traditional upper gastrointestinal endoscopy and unveiled novel options for remaining unsolved hepatobiliary issues, both diagnostically and therapeutically. This conceptually appealing and fascinating integration of endoscopy within the practice of hepatology is referred to as 'endo-hepatology'. Endo-hepatology focuses on the one hand on disorders of the liver parenchyma and liver vasculature and of the hepatobiliary tract on the other hand. Applications hanging under the umbrella of endohepatology involve amongst others EUS-guided liver biopsy, EUS-guided portal pressure measurement, EUS-guided portal venous blood sampling, EUS-guided coil & glue embolization of gastric varices and spontaneous portosystemic shunts as well as ERCP in the challenging context of (decompensated cirrhosis) and intraductal cholangioscopy for primary sclerosing cholangitis. Although endoscopic proficiency however does not necessarily equal in an actual straightforward end-solution for currently persisting (complex) hepatobiliary situations. Therefore, endohepatology continues to generate high-quality data to validate and standardize procedures against currently considered (best available) "golden standards" while continuing to search and trying to provide novel minimally invasive solutions for persisting hepatological stalemate situations. In the current review, we aim to critically appraise the status and potential future directions of endo-hepatology.

Endoscopic Ultrasound-based Shear Wave Elastography for Detection of Advanced Liver Disease

BACKGROUND AND AIMS

Endoscopic ultrasound shear wave elastography (EUS-SWE) is a novel modality for liver stiffness measurement. The aims of this study are to evaluate the performance and reliability of EUS-SWE for detecting advanced liver disease in a prospective cohort.

METHODS

EUS-SWE measurements were prospectively obtained from patients undergoing EUS between August 2020 and March 2023. Liver stiffness measurements were compared between patients with and without advanced liver disease (ALD), defined as stage ≥3, to determine diagnostic accuracy for advanced fibrosis and portal hypertension. Logistic regression was performed to identify variables that impact the reliability of EUS-SWE readings. Select patients underwent paired magnetic resonance elastography (MRE) for liver fibrosis correlation.

RESULTS

Patients with ALD demonstrated higher liver stiffness compared to healthy controls (left lobe: 17.6 vs. 12.7 kPa, P<0.001; median right lobe: 24.8 vs. 11.0 kPa, P<0.001). The area under the receiver operator characteristic (AUROC) for the detection of ALD was 0.73 and 0.80 for left and right lobe measurements, respectively. General anesthesia was associated with reliable EUS-SWE liver readings (odds ratio: 2.73, 95% CI: 1.07-7.39, P=0.040). Left lobe measurements correlated significantly with MRE with an increase of 0.11 kPa (95% CI: 0.05-0.17 kPA) for every 1 kPa increase on EUS-SWE. D.

CONCLUSIONS

SWE is a promising technology that can readily be incorporated into standard EUS examinations for the assessment of ALD.

Prevalence of Nonalcoholic Steatohepatitis and Associated Fibrosis Stages Among US Adults Using Imaging-Based vs Biomarker-Based Noninvasive Tests

Introduction: Nonalcoholic fatty liver disease (NAFLD) is believed to be the most common chronic liver disease worldwide. Therapies are under development for nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD, such that the prevalence of NASH with liver fibrosis, which is likely to require treatment, may be of interest to healthcare decision makers. Noninvasive tests are used in initial screening for NASH, as well as in observational studies of NASH prevalence. However, existing evidence does not address how estimated prevalence varies with different noninvasive tests. This analysis estimated the prevalence of NASH among US adults and assessed variation with different noninvasive tests. Methods: A cross-sectional analysis was conducted using the 2017-March 2020 National Health and Nutrition Examination Survey cycle. Participants with presumed NAFLD (steatosis and without alternative causes of liver disease) were identified, among whom NASH was predicted based on FAST score, Fibrosis-4 (FIB-4), and AST-to-Platelet Ratio Index (APRI) cutoffs across 11 scenarios. Among NASH participants, fibrosis stages were explored based on distribution across the spectrum of liver-stiffness measurements. Results: Among participants with complete data for the analysis (N=6969), prevalence of presumed NAFLD was 25.6%. Within presumed NAFLD, prediction of NASH using imaging-based NIT cutoffs yielded estimated prevalence of 1.3%-4.8% (3.3 million-12.2 million) based on FAST score cutoffs from 0.35-0.67. Using biomarker-based NIT cutoffs yielded estimated prevalence of 0.4%-12.3% (1.0 million-14.5 million) based on FIB-4 cutoffs from 0.90-2.67, and 0.1%-1.9% (0.2-5.0 million) based on APRI cutoffs from 0.50-1.50. Conclusion: Prevalence of NASH among US adults was estimated to range from 1.3% to 4.8% when predicted using imaging-based noninvasive test values for participants with presumed NAFLD, generally aligning with estimates in the literature of prevalence of biopsy-confirmed NASH. Use of biomarker-based noninvasive test values for prediction of NASH yielded a wider range of estimates with FIB-4, and a considerably lower range of estimates with APRI.

Endohepatology: The endoscopic armamentarium in the hand of the hepatologist

ABSTRACT

Recent advances in the field of hepatology include new and effective treatments for viral hepatitis. Further effort is now being directed to other disease entities, such as non-alcoholic fatty liver disease, with an increased need for assessment of liver function and histology. In fact, with the evolving nomenclature of fat-associated liver disease and the emergence of the term "metabolic-associated fatty liver disease" (MAFLD), new diagnostic challenges have emerged as patients with histologic absence of steatosis can still be classified under the umbrella of MAFLD. Currently, there is a growing number of endoscopic procedures that are pertinent to patients with liver disease. Indeed, interventional radiologists mostly perform interventional procedures such as percutaneous and intravascular procedures, whereas endoscopists focus on screening for and treatment of esophageal and gastric varices. EUS has proven to be of value in many areas within the realm of hepatology, including liver biopsy, assessment of liver fibrosis, measurement of portal pressure, managing variceal bleeding, and EUS-guided paracentesis. In this review article, we will address the endoscopic applications that are used to manage patients with chronic liver disease.

Endoscopic procedures in hepatology: Current trends and new developments

Gastrointestinal endoscopy has long been a reliable backbone in the diagnosis and management of hepatobilary disorders and their complications. However, with evolving non-invasive testing, personalised medicine has reframed the utility and necessity of endoscopic screening. Conversely, the growing interest and use of endoscopic ultrasound (EUS) and advanced endoscopy within gastrointestinal units has also opened novel diagnostic and therapeutic avenues for patients with various hepatobiliary diseases. The integration of "advanced endoscopy" within the practice of hepatology is nowadays referred to as "endo-hepatology". In essence, endo-hepatology consists of two pillars: one focusing primarily on disorders of the liver parenchyma, vascular disorders, and portal hypertension, which is mainly captured via EUS, while the other targets the hepatobiliary tract via endoscopic retrograde cholangiopancreatography and advanced imaging. Applications under the umbrella of endo-hepatology include, amongst others, EUS-guided liver biopsy, EUS-guided portal pressure gradient measurement, coil and glue embolisation of gastric varices as well as cholangioscopy. As such endo-hepatology could become an attractive concept wherein advanced endoscopy might reinforce the medical management of patients with hepatobiliary disorders and their complications after initial basic work-up. In this review, we discuss current trends and future developments within endo-hepatology and the remaining hurdles to overcome.

Distinct ways to perform a liver biopsy: The core technique setups and updated understanding of these modalities

There is dramatically increased incidence of several liver diseases worldwide; thus, an unmet need to diagnose and stage these pathological entities heralds the wide application of liver biopsy (LB) techniques. The ways of LB are versatile, including percutaneous LB, transjugular LB, and more recently an approach of minimal invasiveness, that is, EUS-guided LB (EUS-LB). In this review article, we come to the conclusion that EUS-LB may serve as a feasible, reliable, and safe alternative to percutaneous LB and transjugular LB in terms of improved diagnostic yield, excellent sampling performance, and controlled adverse events among patients with focal, infiltrative, and parenchymal liver diseases. Furthermore, extensive efforts have been made to optimize and refine several technical pillars within EUS-LB modality such as the selection of needle size/type, priming manner of biopsy needle, and choice of pass/actuation technique, all of which aim at obtaining better specimen quantity and quality. Another advantageous aspect and unique property pertinent to EUS-guided modality indicate that multiple screening, surveillance, and intervention procedures can be combined into one single endoscopic session. Accordingly, some pilot studies have clarified the clinical usefulness by integrating EUS-LB with simultaneous measurement of portal pressure gradient or examination of liver stiffness. However, more studies, in particular, randomized controlled trials or real-world evidence, are practically warranted to elucidate the validity and safety of EUS-LB as a regular/routine part of managing liver diseases.

Advances in Endohepatology

Over the past decade, the number of endoscopic procedures relevant to patients with liver disease not only increased but also altered and expanded in terms of indications and applications. "Endohepatology" refers to the integration of advanced endoscopy within the practice of hepatology with endoscopic ultrasound as one of the main pillars. Current applications under the umbrella of endohepatology focus on advanced diagnostics and oncological, vascular, and metabolic interventions. These involve, among others, endoscopic ultrasound (EUS)-guided liver biopsy, EUS-guided portal pressure gradient measurement, and EUS-guided coil and glue embolization of gastric varices. In addition to its conceptually attractive technical and innovative characteristics, endohepatology is also an appealing practical option for daily practice because it can be offered as a "one-stop clinic" intervention where comprehensive endoscopic diagnostic and/or therapeutic testing is performed in a single outpatient visit. In this review, we will discuss current trends and future developments within endohepatology and the remaining hurdles to overcome.

Endoscopic Advances in Hepatology

Endoscopy is and remains an indispensable tool in diagnosing and managing liver disease and its complications. Due to the progress in advanced endoscopy, endoscopy has become an alternative route for many surgical, percutaneous, and angiographic interventions, not only as a backup tool when conventional interventions fail but increasingly as a first-line choice. The term endo-hepatology refers to the integration of advanced endoscopy in the practice of hepatology. Endoscopy is key in the diagnosis and management of esophageal and gastric varices, portal hypertensive gastropathy, and gastric antral vascular ectasia. Endoscopic ultrasound (EUS) can be used for the evaluation of the liver parenchyma, liver lesions, and surrounding tissues and vessels, including targeted biopsy and complemented with new software functions. Moreover, EUS can guide portal pressure gradient measurement, and assess and help manage complications of portal hypertension. It is crucial that each present-day hepatologist is aware of the (rapidly increasing) full spectrum of diagnostic and therapeutic tools that exist within this field. In this comprehensive review, we would like to discuss the current endo-hepatology spectrum, as well as future directions for endoscopy in hepatology.