Elastography Assessment of Liver Fibrosis: Society of Radiologists in Ultrasound Consensus Conference Statement

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.

Metabolic-Dysfunction-Associated Steatotic Liver Disease (MASLD) after Liver Transplantation: A Narrative Review of an Emerging Issue

The development of steatotic liver disease after liver transplant (LT) is widely described, and epidemiological data have revealed an increased incidence in recent times. Its evolution runs from simple steatosis to steatohepatitis and, in a small proportion of patients, to significant fibrosis and cirrhosis. Apparently, post-LT steatotic disease has no impact on the recipient's overall survival; however, a higher cardiovascular and malignancy burden has been reported. Many donors' and recipients' risk factors have been associated with this occurrence, although the recipient-related ones seem of greater impact. Particularly, pre- and post-LT metabolic alterations are strictly associated with steatotic graft disease, sharing common pathophysiologic mechanisms that converge on insulin resistance. Other relevant risk factors include genetic variants, sex, age, baseline liver diseases, and immunosuppressive drugs. Diagnostic evaluation relies on liver biopsy, although non-invasive methods are being increasingly used to detect and monitor both steatosis and fibrosis stages. Management requires a multifaceted approach focusing on lifestyle modifications, the optimization of immunosuppressive therapy, and the management of metabolic complications. This review aims to synthesize the current knowledge of post-LT steatotic liver disease, focusing on the recent definition of metabolic-dysfunction-associated steatotic liver disease (MASLD) and its metabolic and multisystemic concerns.

Determining the ideal measurement site and respiratory condition for liver transient elastography: toward clinical practice standardization

OBJECTIVES

Liver transient elastography (TE) has been endorsed by the WHO as the first-line diagnostic tool for liver diseases. Although unreliable and invalid results caused by intercostal space (ICS)-associated factors (including excessive subcutaneous fat and a narrow ICS relative to the transducer size) and operator inexperience are not uncommon, no standard guidelines for ideal probe placement are currently available. Herein, we conducted a prospective observational study to identify an ideal measurement site and respiratory condition for TE by characterizing anatomical and biomechanical properties of the ICSs using ultrasound B-mode and elasticity imaging.

METHODS

Intercostal ultrasound was performed pointwise at four specific sites in 59 patients to simultaneously measure the width, stiffness, and skin‒liver capsule distance (SCD) of the ICSs over the liver, under end-inspiratory and end-expiratory conditions. Intersections between the 8th ICS and anterior axillary line, the 7th ICS and anterior axillary line, the 8th ICS and mid-axillary line, and the 7th ICS and mid-axillary line were defined as Sites 1 to 4, respectively.

RESULTS

Results indicated that Sites 2 and 3 presented greater intercostal width; Sites 3 and 4 displayed lower intercostal stiffness; Sites 2 and 3 exhibited a shorter SCD. The ICSs were significantly wider and stiffer at end-inspiration. Additionally, the liver was more easily visualized at Sites 1 and 3.

CONCLUSION

We recommend Site 3 for TE probe placement owing to its greater width, lower stiffness, and smaller abdominal wall thickness. Performing TE at end-inspiration is preferred to minimize transducer-rib interferences. This study paves the way toward a standardized TE examination procedure.

CRITICAL RELEVANCE STATEMENT

A standardized measurement protocol for WHO-recommended liver TE was first established to improve the success and efficiency of the examination procedure.

KEY POINTS

WHO-recommended TE is unreliable or fails due to intercostal space-related factors. The 8th intercostal space on the mid-axillary line and end-inspiration are recommended. This standardized protocol aids in handling challenging cases and simplifies operational procedures.

Association of Diabetic Retinopathy with Midlife Hepatic Steatosis Diagnosed by Elastography and Hepatic Steatosis Index in Type 2 Diabetes in an Indian Population

Aims: People with type 2 diabetes mellitus are at increased risk of developing hepatic steatosis. We determined the prevalence of hepatic steatosis in middle-aged patients with and without diabetic retinopathy (DR) in an Indian population. We feel this information is critical, with trends of increasing chronic liver disease-related mortality at younger ages. Method: Institution-based analytical cross-sectional study with 114 middle-aged type 2 diabetes patients; 57 in each group with <15 years of duration of DM and without excessive drinking. Hepatic steatosis was determined by the hepatic steatosis index (HSI), hepatic ultrasonography (USG), and elastography. Result: The HSI in DR (37.9 ± 3.9) was more (P = 0.012) than in without diabetic retinopathy (NODR) (36.3 ± 3.3). There was no difference between two groups in liver span (P = 0.829) or in the prevalence of fatty liver (P = 0.562) as determined by conventional USG. Elastography value (kPa) was more (P = 0.001) in DR (6.51 ± 1.85) than in NODR (5.14 ± 1.60). On elastography, 50.9% in DR had a likelihood ratio (Metavir score for a stiffness value) for stage 2 Metavir score. In DR, 11.8% of those missed by USG had a likelihood ratio for ≥ stage 2 Metavir score on elastography. The presence of DR was independently correlated with kPa value (P < 0.001). Conclusion: A significantly higher prevalence of hepatic steatosis was observed in DR in this population. DR can be a useful biomarker for early hepatic screening in midlife, particularly with hepatic elastography, so that timely diagnosis of hepatic steatosis can be made.

Prospective evaluation of liver shearwave elastography measurements with 3 different technologies and same day liver biopsy in patients with chronic liver disease

BACKGROUND

Most ultrasound-based methods for assessing liver fibrosis still need further validation with liver biopsy used as gold standard to assess their accuracy.

AIMS

To assess accuracy of three shear wave elastography (SWE) methods: 1) Philips Elast Point Quantification (ElastPQTM), 2) Siemens Virtual TouchTM Quantification (VTQ) acoustic radiation force impulse (ARFI), and 3) transient elastography (TE) measured by Echosens FibroscanTM.

METHODS

160 patients underwent liver stiffness measurements (LSM) with three SWE methods immediately prior to liver biopsy.

RESULTS

The number of LSM required for reliable studies could be reduced to 6 for ElastPQ and to 7 for VTQ from standard recommendations of 10. Significant fibrosis and interquartile range/median (IQR/M)> 30 were independent predictors for lower reliability for detection of liver fibrosis. Ordinal logistic regression corrected for age showed that there was a significant interaction between steatosis (p = 0.008) and lobular inflammation (p = 0.04) and VTQ (ARFI) and between lobular inflammation and TE (p = 0.006).

CONCLUSIONS

We showed variations in SWE measurements using different ARFI technologies. TE and ElastPQ achieved good diagnostic performance, whereas VTQ showed lower diagnostic accuracy. The number of measurements required for reliable studies can be reduced to 6 for ElastPQ and to 7 for VTQ, which have important clinical implications.

Dual elastography to discriminate adjacent stages of fibrosis and inflammation in chronic hepatitis B: A prospective multicenter study

BACKGROUND AND AIMS

To evaluate the diagnostic performance of dual elastography (dual-elasto) in continuous differentiation of liver fibrosis and inflammation in a large prospective cohort of patients with chronic HBV.

APPROACH AND RESULTS

Adults with positive HBsAg for at least 6 months were recruited from 12 medical centers. Participants underwent dual-elasto evaluations. Biopsy was performed 3 days after dual-elasto examination. Four logistic regression models were trained and strung together into series models. Decision trees based on the series models were performed to achieve continuous differentiation of liver fibrosis and inflammation. The influence of inflammation on the fibrosis stage was also evaluated. A total of 560 patients were included in the training set and 240 in the validation set. Areas under the receiver operating characteristic curve of the series model were 0.82, 0.86, 0.93, and 0.96 to predict ≥F1, ≥F2, ≥F3, and F4 in the validation set, which were significantly higher than those of serum markers and shear wave elastography (all p < 0.05), except for the ≥ F1 levels ( p = 0.09). The AUCs of the series model were 0.93, 0.86, 0.95, and 0.84 to predict inflammation stages ≥G1, ≥G2, ≥G3, and G4, respectively. Decision trees realized 5 continuous classifications of fibrosis and inflammation. Inflammation could enhance the mild fibrosis stage classification while showing limited influences on severe fibrosis or cirrhosis diagnosis.

CONCLUSIONS

Dual-elasto demonstrated high performance in the continuous discrimination of fibrosis and inflammation in patients with HBV and could be used to diagnose mild fibrosis without the influence of inflammation.

Palm-Sized Wireless Transient Elastography System with Real-Time B-Mode Ultrasound Imaging Guidance: Toward Point-of-Care Liver Fibrosis Assessment

Transient elastography (TE), recommended by the WHO, is an established method for characterizing liver fibrosis via liver stiffness measurement (LSM). However, technical barriers remain towards point-of-care application, as conventional TE requires wired connections, possesses a bulky size, and lacks adequate imaging guidance for precise liver localization. In this work, we report the design, phantom validation, and clinical evaluation of a palm-sized TE system that enables simultaneous B-mode imaging and LSM. The performance of this system was validated experimentally using tissue-equivalent reference phantoms (1.45-75 kPa). Comparative studies against other liver elastography techniques, including conventional TE and two-dimensional shear wave elastography (2D-SWE), were performed to evaluate its reliability and validity in adults with various chronic liver diseases. Intra- and inter-operator reliability of LSM were established by an elastography expert and a novice. A good agreement was observed between the Young's modulus reported by the phantom manufacturer and this system (bias: 1.1-8.6%). Among 121 patients, liver stiffness measured by this system and conventional TE were highly correlated (r = 0.975) and strongly agreed with each other (mean difference: -0.77 kPa). Inter-correlation of this system with conventional TE and 2D-SWE was observed. Excellent-to-good operator reliability was demonstrated in 60 patients (ICCs: 0.824-0.913). We demonstrated the feasibility of employing a fully integrated phased array probe for reliable and valid LSM, guided by real-time B-mode imaging of liver anatomy. This system represents the first technical advancement toward point-of-care liver fibrosis assessment. Its small footprint, along with B-mode guidance capability, improves examination efficiency and scales up screening for liver fibrosis.

Imaging of Fontan-Associated Liver Disease

ABSTRACT

The Fontan procedure is the definitive treatment for patients with single-ventricle physiology. Surgical advances have led to a growing number of patients surviving into adulthood. Fontan-associated liver disease (FALD) encompasses a spectrum of pathologic liver changes that occur secondary to altered physiology including congestion, fibrosis, and the development of liver masses. Assessment of FALD is difficult and relies on using imaging alongside of clinical, laboratory, and pathology information. Ultrasound, computed tomography, and magnetic resonance imaging are capable of demonstrating physiologic and hepatic parenchymal abnormalities commonly seen in FALD. Several novel imaging techniques including magnetic resonance elastography are under study for use as biomarkers for FALD progression. Imaging has a central role in detection and characterization of liver masses as benign or malignant. Benign FNH-like masses are commonly encountered; however, these can display atypical features and be mistaken for hepatocellular carcinoma (HCC). Fontan patients are at elevated risk for HCC, which is a feared complication and has a poor prognosis in this population. While imaging screening for HCC is widely advocated, no consensus has been reached regarding an optimal surveillance regimen.

Association between infrapatellar fat pad ultrasound elasticity and anterior knee pain in patients with knee osteoarthritis

This study investigates whether infrapatellar fat pad (IPFP) elasticity is associated with anterior knee pain in patients with knee osteoarthritis (KOA). The IPFP elasticity of 97 patients with KOA (Kellgren and Lawrence [KL] grades of the femorotibial and patellofemoral joints ≥ 2 and ≤ 2, respectively), aged 46-86 years, was evaluated via shear wave speed using ultrasound elastography. The patients were divided into two groups according to the presence or absence of anterior knee pain. Univariate analyses were used to compare patient age, sex, femorotibial KL grade, magnetic resonance imaging findings (Hoffa, effusion synovitis, bone marrow lesion scores, and IPFP size), and IPFP elasticity between the groups. Multivariate logistic regression analyses were subsequently performed using selected explanatory variables. IPFP elasticity was found to be associated with anterior knee pain in the univariate (p = 0.007) and multivariate (odds ratio: 61.12, 95% CI 1.95-1920.66; p = 0.019) analyses. Anterior knee pain is strongly associated with stiffer IPFPs regardless of the femorotibial KL grade, suggesting that ultrasound elastography is useful for the diagnosis of painful IPFP in patients with KOA.

THE ROLE OF ELASTOGRAPHY IN CLINICALLY SIGNIFICANT PORTAL HYPERTENSION

• In compensated cirrhosis, using non-invasive methods would exempt the patient from the need of an endoscopy. • The Baveno VII presented the "rule of 5" for Vibration-Controlled Transient Elastography; liver stiffness measurement ≤15 kPa and platelets >150.000/mm3 exclude clinically significant portal hypertension (CSPH), while when ≥25 kPa is highly suggestive of CSPH. • Spleen stiffness measurement has been proposed as a more specific technique to predict the presence of CSPH. • Elastography has gained prestige in the non-invasive evaluation of patients with advanced chronic liver disease by allowing prophylactic measures to be taken when suggesting the presence of CSPH. This is a narrative review that aims to discuss the importance of elastographic methods in the evaluation of clinically significant portal hypertension (CSPH) in cirrhotic patients, where the authors propose an algorithm for evaluating these patients. In compensated advanced chronic liver disease, the goal is to prevent the development of CSPH and, in those already with CSPH, prevent the appearance of gastroesophageal varices (GEV) and other complications of portal hypertension. In compensated cirrhosis, the prevalence of GEV is 30-40%, of which 10-20% are at risk of bleeding. Therefore, using non-invasive methods would exempt the patient from the need of an endoscopy. Hepatic Elastography is a non-invasive, safe, reproducible method, available through many techniques: Vibration-Controlled Transient Elastography (VCTE), Shear Wave Elastography (SWE) and Magnetic Resonance Elastography (MRE). The Baveno VII presented the "rule of 5" for VCTE: liver stiffness measurement (LSM) ≤15 kPa and platelets >150.000/mm3 exclude CSPH, while an LSM ≥25 kPa is highly suggestive of CSPH. Also, the "rule of 4" for SWE has been proposed: patients with ≥17 kPa could be considered as having CSPH. At last, spleen stiffness measurement (SSM) has been proposed as a more specific technique to predict the presence of CSPH. In conclusion, elastography has gained prestige in the non-invasive evaluation of patients with advanced chronic liver disease by allowing prophylactic measures to be taken when suggesting the presence of CSPH.

Imaging of fibrogenesis in the liver by [18F]TZ-Z09591, an Affibody molecule targeting platelet derived growth factor receptor β

BACKGROUND

Platelet-derived growth factor receptor beta (PDGFRβ) is a receptor overexpressed on activated hepatic stellate cells (aHSCs). Positron emission tomography (PET) imaging of PDGFRβ could potentially allow the quantification of fibrogenesis in fibrotic livers. This study aims to evaluate a fluorine-18 radiolabeled Affibody molecule ([18F]TZ-Z09591) as a PET tracer for imaging liver fibrogenesis.

RESULTS

In vitro specificity studies demonstrated that the trans-Cyclooctenes (TCO) conjugated Z09591 Affibody molecule had a picomolar affinity for human PDGFRβ. Biodistribution performed on healthy rats showed rapid clearance of [18F]TZ-Z09591 through the kidneys and low liver background uptake. Autoradiography (ARG) studies on fibrotic livers from mice or humans correlated with histopathology results. Ex vivo biodistribution and ARG revealed that [18F]TZ-Z09591 binding in the liver was increased in fibrotic livers (p = 0.02) and corresponded to binding in fibrotic scars.

CONCLUSIONS

Our study highlights [18F]TZ-Z09591 as a specific tracer for fibrogenic cells in the fibrotic liver, thus offering the potential to assess fibrogenesis clearly.

Non-alcoholic fatty liver disease and diabetic retinopathy: Is there an association?

Background

Studies have not proven whether an association exists between diabetic retinopathy (DR) and non-alcoholic fatty liver disease (NAFLD). The reports from various parts of the world have not used uniform criteria, and hence, results are inconclusive. Both DR and NAFLD are common conditions encountered in primary care.

Methods

A total of 130 patients with type 2 diabetes from the medical wards of a tertiary care hospital were enrolled. After documentation of clinical and biochemical data, they underwent ultrasonography (USG) of the abdomen and fibroscan grading of liver. Retinopathy was assessed and classified as per the Early Treatment Diabetic Retinopathy Study.

Results

The mean age of the patients included in the study was 46.5+/-8.8 with 55% of the participants being male and 45% female. The mean HbA1c was 7.168+/2.4. The association between DR and hepatic fibrosis was assessed by fibroscan (p 0.003) and USG (p 0.001) and was significant on univariate analysis. Multivariate analysis did not confirm this. There was no association between increasing grades of either condition. Although fibroscan and USG significantly concorded in diagnosing NAFLD, fibroscan diagnosed more cases as compared to USG (83 vs 73).

Conclusion

Larger studies should be conducted to conclusively determine the association in order to investigate pathogenetic factors and treatment strategies.

Shear wave elastography of the ulnar collateral ligament in division IA pitchers across a competitive collegiate season

Background

The ulnar collateral ligament (UCL) is a commonly injured elbow stabilizer during throwing. Shear wave elastography (SWE) is a technique that may reveal structural changes in the UCL that are indicative of ligament health and injury risk. The purpose of this study was to assess preseason and inseason shear wave velocity (SWV) in the UCL of collegiate pitchers and to asses repeatability of this measurement technique in healthy volunteers.

Methods

Seventeen collegiate baseball pitchers and 11 sex-matched volunteers were recruited. Two-dimensional SWE of the UCL was performed by a single radiologist. In pitchers, SWV was measured at the proximal, midsubstance, and distal UCL for dominant and nondominant elbows preseason, midseason, and postseason, and Kerlan-Jobe Orthopaedic Clinic (KJOC) Shoulder and Elbow questionnaire scores were recorded. In volunteers, SWV was measured at UCL midsubstance in dominant elbows at 3 separate occasions over 1 week. An independent samples t-test was used to compare preseason midsubstance measures between pitchers and the healthy volunteers. A mixed-model analysis of covariance (covaried on preseason measures) was used to compare SWV measures at the preseason, midseason, and postseason time points. A similar generalized linear model for nonparametric data was used to compare KJOC scores. Type-I error was set at P < .05.

Results

Mean preseason midsubstance dominant arm UCL SWV did not significantly differ between the pitchers (5.40 ± 1.65 m/s) compared to the healthy volunteers (4.35 ± 1.45 m/s). For inseason measures among the pitchers, a decrease in midsubstance (-1.17 ± 0.99 m/s, P = .021) and proximal (-1.55 ± 0.91 m/s, P = .001) SWV was observed at midseason compared to preseason. The proximal measure was also observed to be significantly lower than the nondominant arm (-1.97 ± 0.95 m/s, P < .001). Proximal SWV remained reduced relative to the preseason and the postseason mark (-1.13 ± 0.91 m/s, P = .015). KJOC scores decreased at midseason compared to preseason (P = .003) but then increased to a similar preseason value at the postseason measurement (preseason = 92 ± 3, midseason = 87 ± 3, postseason = 91 ± 3). The repeatability coefficient of SWE in the volunteer cohort was 1.98 m/s.

Conclusion

Decreased SWV in the proximal and midsubstance of the dominant arm UCL at midseason suggests structural changes indicative of increasing laxity or 'softening' of the UCL. Associated decline in KJOC scores suggests that these changes are associated with functional decline. Future studies with more frequent sampling would be invaluable to further explore this observation and its significance for predicting and managing UCL injury risk.

Usefulness of two-dimensional shear wave elastography in the assessment of non-alcoholic fatty liver disease in children and adolescents

Two-dimensional shear wave elastography (2D-SWE) evaluates liver stiffness using a non-invasive method, but studies in the paediatric population are rare. This study evaluated the role of 2D-SWE in the diagnosis and severity of paediatric non-alcoholic fatty liver disease (NAFLD). In total, 131 patients with NAFLD and 25 healthy controls were enrolled in this study. The diagnosis and severity of NAFLD were initially assessed using the ultrasound fatty liver index (US-FLI), and all participants underwent 2D-SWE. US-FLI semi-quantitatively measures the severity of NAFLD on a scale of 2-8. The assessment of liver stiffness measurement (LSM) by 2D-SWE is presented in kilopascals (kPa). The NAFLD group was characterised by significantly higher LSM (4.40 ± 0.90 kPa) than the control group (3.76 ± 0.28 kPa) (P < 0.001). 2D-SWE significantly correlated with age, height, weight, body mass index, glucose, aspartate aminotransferase, alanine aminotransferase, high-density lipoprotein cholesterol, US-FLI, and triglyceride-glucose index (P < 0.001). In the receiver operating characteristic curve analysis, the area under the curve of LSM for predicting US-FLI ≥ 2 and ≥ 6 was 0.784 (P < 0.001) and 0.819 (P < 0.001), respectively. In conclusion, we suggest that 2D-SWE can be used as a non-invasive diagnostic tool for diagnosing and assessing the severity of paediatric NAFLD.

Liver Ultrasound Elastography in Non-Alcoholic Fatty Liver Disease: A State-of-the-Art Summary

Non-alcoholic fatty liver disease (NAFLD) is a chronic disease which is currently the most common hepatic disorder affecting up to 38% of the general population with differences according to age, country, ethnicity and sex. Both genetic and acquired risk factors such as a high-calorie diet or high intake of saturated fats have been associated with obesity, diabetes and, finally, NAFLD. A liver biopsy has always been considered essential for the diagnosis of NAFLD; however, due to several limitations such as the potential occurrence of major complications, sampling variability and the poor repeatability in clinical practice, it is considered an imperfect option for the evaluation of liver fibrosis over time. For these reasons, a non-invasive assessment by serum biomarkers and the quantification of liver stiffness is becoming the new frontier in the management of patients with NAFLD and liver fibrosis. We present a state-of-the-art summary addressing the methods for the non-invasive evaluation of liver fibrosis in NAFLD patients, particularly the ultrasound-based techniques (transient elastography, ARFI techniques and strain elastography) and their optimal cut-off values for the staging of liver fibrosis.

Performance of two-dimensional shear wave elastography and transient elastography compared to liver biopsy for staging of liver fibrosis

BACKGROUND

Staging of liver fibrosis traditionally relied on liver histology; however, transient elastography (TE) and more recently two-dimensional shear wave elastography (2D-SWE) evolved to noninvasive alternatives. Hence, we evaluated the diagnostic accuracy of 2D-SWE assessed by the Canon Aplio i800 ultrasound system using liver biopsy as reference and compared the performance to TE.

METHODS

In total, 108 adult patients with chronic liver disease undergoing liver biopsy, 2D-SWE and TE were enrolled prospectively at the University Hospital Zurich. Diagnostic accuracies were evaluated using the area under the receiver operating characteristic (AUROC) analysis, and optimal cut-off values by Youden's index.

RESULTS

Diagnostic accuracy of 2D-SWE was good for significant (≥F2; AUROC 85.2%, 95% confidence interval (95%CI):76.2-91.2%) as well as severe fibrosis (≥F3; AUROC 86.8%, 95%CI: 78.1-92.4%) and excellent for cirrhosis (AUROC 95.6%, 95%CI: 89.9-98.1%), compared to histology. TE performed equally well (significant fibrosis: 87.5%, 95%CI: 77.7-93.3%; severe fibrosis: 89.7%, 95%CI: 82.0-94.3%; cirrhosis: 96%, 95%CI: 90.4-98.4%), and accuracy was not statistically different to 2D-SWE. 2D-SWE optimal cut-off values were 6.5, 9.8 and 13.1 kPa for significant fibrosis, severe fibrosis and cirrhosis, respectively.

CONCLUSIONS

Performance of 2D-SWE was good to excellent and well comparable with TE, supporting the application of this 2D-SWE system in the diagnostic workup of chronic liver disease.

How to Identify Advanced Fibrosis in Adult Patients with Non-Alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH) Using Ultrasound Elastography-A Review of the Literature and Proposed Multistep Approach

Non-alcoholic fatty liver disease (NAFLD), and its progressive form, non-alcoholic steatohepatitis (NASH), represent, nowadays, real challenges for the healthcare system. Liver fibrosis is the most important prognostic factor for NAFLD, and advanced fibrosis is associated with higher liver-related mortality rates. Therefore, the key issues in NAFLD are the differentiation of NASH from simple steatosis and identification of advanced hepatic fibrosis. We critically reviewed the ultrasound (US) elastography techniques for the quantitative characterization of fibrosis, steatosis, and inflammation in NAFLD and NASH, with a specific focus on how to differentiate advanced fibrosis in adult patients. Vibration-controlled transient elastography (VCTE) is still the most utilized and validated elastography method for liver fibrosis assessment. The recently developed point shear wave elastography (pSWE) and two-dimensional shear wave elastography (2D-SWE) techniques that use multiparametric approaches could bring essential improvements to diagnosis and risk stratification.

Chronic Hepatitis B Virus: What an Internist Needs to Know

Chronic hepatitis B virus (HBV) infection is a bloodborne infection which affects approximately 1.6 million persons in the U.S. and 292 million persons worldwide and is associated with significant morbidity and mortality due to cirrhosis and hepatocellular carcinoma. HBV disproportionately affects foreign-persons from endemic regions such as sub-Saharan Africa and the Asian-Pacific region. Chronic HBV is diagnosed with positive HBsAg and detectable HBV DNA. Patients with immunoactive disease (elevated HBV DNA and serum ALT) may require antiviral therapy with peg-interferon or oral nucleos(t)ide analogues which suppress viral replication, and are associated with a decreased risk for liver events.

Validation of a screening algorithm for hepatic fibrosis by Doppler ultrasound and elastography in a general population

BACKGROUND

Early detection can prevent the initial stages of fibrosis from progressing to cirrhosis.

PURPOSE

To evaluate an algorithm combining three echographic indicators and elastographic measurements to screen for hepatic fibrosis in an unselected population.

MATERIAL AND METHODS

From May 2017 to June 2018, all patients with no history and no known chronic liver disease who were referred for an ultrasound (US) were prospectively included in eight hospitals. The indicators being sought were liver surface irregularity, demodulation of hepatic veins, and spleen length >110 mm. Patients presenting at least one of these underwent elastography measurements with virtual touch quantification (VTQ) or supersonic shear imaging (SSI). If elastography was positive, patients were referred to hepatologist for fibrosis evaluation. Reference standard was obtained by FibroMeter^VCTE or biopsy. A FibroMeter^VCTE result >0.384 indicated a "necessary referral" to a hepatologist.

RESULTS

Of the 1501 patients included, 504 (33.6%) were positive for at least one US indicator. All of them underwent US elastography, with 85 being positive. Of the patients, 58 (3.6%) had a consultation with a liver specialist: 21 had positive FibroMeter^VCTE and nine had an indication of biopsy for suspicion of fibrosis. This screening algorithm made it possible to diagnose 1.6% of patients in our population with unknown fibrosis. Of the patients, 50% referred to the liver specialist were "necessary referrals."

CONCLUSION

Our study suggests that three simple US indicators with no systematic elastographic measurement could be applied in day-to-day practice to look for hepatic fibrosis in an unsuspected population allowing relevant referrals to a hepatologist.

Quantitative Assessment of Liver Impairment in Chronic Viral Hepatitis with [99mTc]Tc-Mebrofenin: A Noninvasive Attempt to Stage Viral Hepatitis-Associated Liver Fibrosis

Background and objectives—Chronic viral hepatitis B and C infections are one of the leading causes of chronic liver impairment, resulting in liver fibrosis and liver cirrhosis. An early diagnosis with accurate liver fibrosis staging leads to a proper diagnosis, thus tailoring correct treatment. Both invasive and noninvasive techniques are used in the diagnosis and staging of chronic liver impairment. Those techniques include liver biopsy, multiple serological markers (as either single tests or combined panels), and imaging examinations, such as ultrasound or magnetic resonance elastography. Nuclear medicine probes may also be employed in staging liver fibrosis, although the literature scarcely reports this. The purpose of our study was to investigate whether a dynamic liver scintigraphy with [^99mTc]Tc-mebrofenin has any value in staging or grading chronic liver damage. Materials and Methods—We prospectively enrolled patients with chronic viral hepatitis B and C infection referred for liver biopsy. All patient underwent dynamic liver scintigraphy with 99mTc-mebrofenin prior to liver biopsy. Dynamic liver scintigraphy was performed immediately after intravenous tracer injection for 30 min scanning time. Multiple scintigraphy parameters were calculated (whole liver lobe and focal area time to peak (TTP), 30 min to peak ratio (30/peak), whole lobe and focal area slope index in 350 s (slope_350). Liver biopsy took place shortly after imaging. Results—We found that many dynamic scintigraphic parameters are positively or negatively associated with different stages of liver fibrosis. The main parameters that showed most value are the ratio between 30 min and the peak of the dynamic curve (30/peak_dex (ratio)), and liver clearance corrected for body surface area and liver area (LCL_m²_dm² (%/min/m²/dm²)). Conclusions—Our present study proves that conducting dynamic liver scintigraphies with [^99mTc]Tc-mebrofenin has potential value in staging liver fibrosis. The benefits of this method, including whole liver imaging and direct imaging of the liver function, provide an advantage over presently used quantitative imaging modalities.

Evaluating short-term outcomes of the value of sound touch elastography (STE) following the treatment for Budd-Chiari syndrome (BCS): a case series study

AIM

To investigate the value of sound touch elastography (STE) in the evaluation of short-term therapeutic effect of Budd-Chiari syndrome (BCS) by measuring liver stiffness (LS), and in addition, to analyse the relationships between liver function, pressure gradient of the hepatic veins, and LS.

MATERIALS AND METHODS

A case series study was conducted at Affiliated Hospital of Xuzhou Medical University from August 2020 to December 2020. Patients diagnosed with BCS were recruited prospectively and grouped according to Child-Pugh grade before endovascular therapy. LS was measured using STE before and after therapy. Comparisons between the LS and hepatic venous pressure gradient (HVPG) changes of patients were tested with paired sample t-tests.

RESULTS

A total of 46 patients (23 males and 23 females) were included in this study. According to the Child-Pugh scoring criteria, 24 patients were classified as grade A, 16 as grade B, and 6 as grade C. LS was significantly different between the three groups (F = 127.01, p<0.001). Post-treatment LS was significantly lower than pre-treatment (p<0.001). The mean HVPG before treatment was 13.02 ± 3.82 mmHg and decreased after intervention (p<0.001).

CONCLUSION

The STE is a potential tool for evaluating short-term therapeutic effect of BCS patients.

Value of shear-wave elastography and cerebral-placental-uterine ratio in women diagnosed with preeclampsia and fetal growth restriction in prediction of adverse perinatal outcomes

PURPOSE

The aim of this study was to measure placental stiffness with shear-wave elastography technique and to evaluate the relationship with cerebral-placental-uterine ratio (CPUR) and adverse perinatal outcomes in patient groups diagnosed with preeclampsia (PE) and fetal growth restriction (FGR) in the second and third trimesters compared to the control group.

MATERIALS AND METHODS

This prospective cross-sectional study was conducted at our hospital between March 2019 and March 2020. The study groups were divided into three groups: PE, FGR, and low risk pregnancy (LRP) group. The study population had singleton pregnancies and the placental site was at the anterior wall. Both shear-wave elasticity (SWE) and shear-wave velocity (SWV) were measured in the placenta during pregnancy. CPUR was calculated for each group.

RESULTS

A total of 147 patients were included in this study. The mean SWE (kilopascals) values in the PE group were significantly higher than in the FGR and controls (difference of means = 3.67, 9.45; 95% CI (1.23-6.1, 7-11.8); p < .05), respectively. The mean SWV values were significantly higher in PE and FGR groups than controls (p < .05). CPUR showed correlation with central maternal surface of placenta (p: .02, r: -0.184), central fetal surface of placenta (p < .001, r: -0.288), peripheral maternal surface of placenta (p: .002, r: -0.252), and peripheral fetal surface of placenta SWE values (p: .03, r: -0.181). NICU admission was correlated with central fetal surface of placenta SWE values (p: .002, r: 0.258).

CONCLUSION

In conclusion, we demonstrated increased placental stiffness in both the PE and the FGR group. Also, this difference was found to be more prominent in preeclampsia. This technique seems useful for assessment of placental function and may strengthen the utility of Doppler parameters for predicting adverse perinatal outcomes in high-risk pregnancies.

Comparing shear wave elastography with liver biopsy in the assessment of liver fibrosis at King Hussein Medical Center

Background and study aims

The aim of this prospective study is to compare the sensitivity and specificity of the liver shear wave elastography to the golden standard liver biopsy in staging liver fibrosis.

Patients and methods

Ninety-five patients were included in this study. These patients were sent for liver biopsy as a possible living liver donor or because of different pathologies including viral and autoimmune hepatitis and congenital liver diseases. A shear wave elastography and US-guided liver biopsy were done at the same setting by one experienced radiologist. One experienced histopathologist, blinded to SWE results, read the specimens.

Results

We included 95 patients in the study with a mean age of 30 years (range 3–65 years). We had 15/95 (16%) patients with hepatitis B/C, 61/95 (64%) patients with another liver disease, and 19/95 (20%) were donors. The mean of liver stiffness measured by elastography in patients was 6.5±0.19 kPa. The mean liver stiffness measured by elastography in patients with F0–F1 fibrosis was 5.39 ± 0.62 kPa, F2 was 7.32 ± 0.41, at stage F3 was 8.46 ± 0.33, and in the F4 stage, it was 11.42 ± 2.8 kPa. We found a significant difference in the mean level of liver stiffness in different degrees of fibrosis (p = 0.0001).

Conclusion

The shear wave elastography could be used to assess liver fibrosis regardless of the cause.

Doppler hemodynamic liver index and hepatic elastic modulus: Advanced ultrasonographic techniques for non-invasive prediction of esophageal varices in cirrhosis

PURPOSE

Currently esophagoscopy is the gold standard for assessment of esophageal varices in cirrhosis. Predicting the presence of esophageal varices, varices needing treatment (VNT) and variceal grade by advanced ultrasonographic techniques using a combination of Doppler hemodynamic liver index (HDLI) (quantifying portal hypertension) and hepatic elastic modulus (quantifying hepatic fibrosis) would be a cost-effective and non-invasive alternative to routine endoscopy.

METHODS

Our cross-sectional study consisted of cirrhotic patients diagnosed using clinical features and laboratory parameters. Portal venous Doppler and liver sonoelastography were performed in selected subjects for obtaining measurements of HDLI (portal vein diameter/mean velocity) and hepatic elastic modulus respectively. Within 3 days of ultrasound, the subjects underwent upper GI endoscopy for assessment of presence, VNT and grade (F1, F2, F3) of varices. Subjects were divided into two groups (without and with varices) and data analyzed using XLSTAT.

RESULTS

A total of 60 subjects (26 without and 34 with varices) were evaluated. Mean Doppler HDLI of subjects with varices was significantly higher (0.72 vs. 0.59, p < 0.0001) with progressive increase in values with variceal grade, being highest in grade-F3 (mean 0.77). Likewise, mean hepatic elastic modulus was also higher in subjects with varices (28.9 vs. 12.6 kPa, p < 0.0001) and showed progressive increase with grade (51.1 kPa for F3). For predicting presence of varices, maximum accuracy of elastic modulus was at cut-off of 14.5 kPa (sensitivity, specificity 83% and 84.6%) and Doppler HDLI was at 0.66 (66% and 92.3%). Good inter-rater agreement was present (κ 0.66).

CONCLUSION

Combination of Doppler HDLI and hepatic elastic modulus is an excellent non-invasive method for predicting the presence, VNT, and variceal grade and may obviate need for routine endoscopic screening in cirrhosis.

Evaluation of a Whole-Liver Dixon-Based MRI Approach for Quantification of Liver Fat in Patients with Type 2 Diabetes Treated with Two Isocaloric Different Diets

Dixon-based methods for the detection of fatty liver have the advantage of being non-invasive, easy to perform and analyze, and to provide a whole-liver coverage during the acquisition. The aim of the study was to assess the feasibility of a whole-liver Dixon-based approach for liver fat quantification in type 2 diabetes (T2D) patients who underwent two different isocaloric dietary treatments: a diet rich in monosaturated fatty acids (MUFA) and a multifactorial diet. Thirty-nine T2D patients were randomly assigned to MUFA diet (n = 21) and multifactorial diet (n = 18). The mean values of the proton density fat fraction (PDFF) over the whole liver and over the ROI corresponding to that chosen for MRS were compared to MRS-PDFF using Spearman’s correlation (ρ). Before–after changes in percentage of liver volume corresponding to MRI-PDFF above thresholds associated with hepatic steatosis (LV%TH, with TH = 5.56%, 7.97% and 8.8%) were considered to assess the proposed approach and compared between diets using Wilcoxon rank-sum test. Statistical significance set at p < 0.05. A strong linear relationship was found between MRS-PDFF and MRI-PDFFs (ρ = 0.85, p < 0.0001). Changes in LV%TH% were significantly higher (p < 0.05) in the multifactorial diet than in MUFA diet (25% vs. 9%, 35% vs. 12%, and 38% vs. 13% decrease, respectively, for TH = 5.56%, 7.97%, and 8.8%) and this was reproducible compared to results obtained using the standard liver fat analysis. A volumetric approach based on Dixon method could be an effective, non-invasive technique that could be used for the quantitative analysis of hepatic steatosis in T2D patients.

Triglyceride Glucose-Waist Circumference Is Superior to the Homeostasis Model Assessment of Insulin Resistance in Identifying Nonalcoholic Fatty Liver Disease in Healthy Subjects

The triglyceride glucose (TyG) index has been suggested as a marker for insulin resistance; however, few studies have investigated the clinical implications of markers that combine obesity markers with the TyG index. This study aimed to investigate the associations between non-alcoholic fatty liver disease (NAFLD) and TyG-related markers in healthy subjects in Korea. We enrolled 21,001 asymptomatic participants who underwent hepatic ultrasonography. The homeostasis model assessment of insulin resistance (HOMA-IR), TyG index, TyG-body mass index, and TyG-waist circumference (WC) were subsequently analyzed. NAFLD was diagnosed using hepatic ultrasonography. A multiple logistic regression analysis was performed to evaluate the associations between the quartiles of each parameter and the risk of NAFLD. The increase in the NAFLD risk was most evident when the TyG-WC quartiles were applied; the multivariate-adjusted odds ratios for NAFLD were 4.72 (3.65–6.10), 13.28 (10.23–17.24), and 41.57 (31.66–54.59) in the 2nd, 3rd, and 4th TyG-WC quartiles, respectively, when compared with the lowest quartile. The predictability of the TyG-WC for NAFLD was better than that of the HOMA-IR using the area under the curve. The TyG-WC index was superior to the HOMA-IR for identifying NAFLD in healthy Korean adults, especially in the non-obese population.

Steatosis grading consistency between controlled attenuation parameter and MRI-PDFF in monitoring metabolic associated fatty liver disease

Background

The consistency in steatosis grading between magnetic resonance imaging-based proton density fat fraction (MRI-PDFF) and controlled attenuation parameter (CAP) before and after treatment remains unclear. This study aimed to compare the diagnostic accuracy of steatosis grading between MRI-PDFF and CAP using liver biopsy as standard and to evaluate the value of monitoring changes in steatosis grading with CAP during follow-up utilizing MRI-PDFF as a reference.

Methods

Consecutive patients from a biopsy cohort and a randomized controlled trial were included in this study and classified into 3 groups (the biopsy, orlistat treatment, and routine treatment subgroups). Hepatic steatosis was measured via MRI-PDFF and CAP at baseline and at the 6th month; the accuracy and cutoffs were assessed in the liver biopsy cohort at baseline.

Results

A total of 209 consecutive patients were enrolled. MRI-PDFF and CAP showed comparable diagnostic accuracy for detecting pathological steatosis [⩾S1, area under the receiver operating characteristic curve (AUC) = 0.984 and 0.972, respectively]; in contrast, CAP presented significantly lower AUCs in grades S2-3 and S3 (0.820 and 0.815, respectively). The CAP values correlated well with the MRI-PDFF values at baseline and at the 6th month (r = 0.809 and 0.762, respectively, both p < 0.001), whereas a moderate correlation in their changes (r = 0.612 and 0.524 for moderate-severe and mild steatosis, respectively; both p < 0.001) was observed. The AUC of CAP change was obtained to predict MRI-PDFF changes of ⩾5% and ⩾10% (0.685 and 0.704, p < 0.001 and p = 0.001, respectively). The diagnostic agreement of steatosis grade changes between MRI-PDFF and CAP was weak (κ = 0.181, p = 0.001).

Conclusions

CAP has decreased value for the initial screening of moderate-severe steatosis and is limited in monitoring changes in steatosis during treatment. The confirmation of steatosis grading with MRI-PDFF remains necessary.

Liver stiffness measured with two-dimensional shear wave elastography comparable to histopathology falls dominantly on the severe liver fibrosis

BACKGROUND

Two-dimensional shear-wave elastography (2D-SWE) has been used for years for liver assessment of patients with chronic hepatitis B (CHB), but its effectiveness remains unclear in different populations and using different ultrasound systems.

OBJECTIVE

This study investigated the effectiveness of 2D-SWE in evaluating liver fibrosis in patients with CHB.

METHODS

A prospective investigation was conducted after approval by the institutional ethics committee, with 116 out of 133 patients with CHB referred for liver biopsy included and 50 patients with healthy livers selected as controls. Assessment with 2D-SWE of liver stiffness measurement (LSM) was compared with histopathological results. Cutoff values for LSM were set to determine the degree of fibrosis, and area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity were calculated.

RESULTS

The optimal LSM cutoff for differentiating healthy livers from livers with CHB and any liver fibrosis was 6.485 kPa, with an AUROC of 0.927, sensitivity of 94%, and specificity of 19.8%. The optimal LSM cutoff values for F1, F2, F3, and F4 were 6.19 kPa, 6.485 kPa, 7.46 kPa, and 9.62 kPa, respectively, with corresponding AUROCs of 0.516, 0.625, 0.779, and 0.881, respectively. Comparisons of AUROCs between F1 and F3, F1 and F4, F2 and F3, and F2 and F4 were all significantly different (P = 0.0001, P <  0.0001, P = 0.0139, and P = 0.0003, respectively); comparisons of AUROCs between F1 and F2 and between F3 and F4 were not significantly different (P = 0.1232 and P = 0.2462, respectively). Comparisons of LSMs between healthy livers and F0 and between healthy livers and a combination of F0 and F1 were significantly different (P = 0.002 and P = 0.001, respectively). Comparisons of LSMs between F1 and F2 and between F3 and F4 were not significantly different (P = 0.233 and P = 0.072, respectively). Other comparisons between fibrosis score groups were significantly different (F1 and F3, P = 0.003; F1 and F4, P = 0.007; F2 and F3, P = 0.013; F2 and F4, P = 0.015).

CONCLUSION

2D-SWE using a specific diagnostic ultrasound system is effective for the assessment of severe liver fibrosis and cirrhosis, but is limited in diagnosing mild liver fibrosis.

Quantitative Ultrasound Elastography Methods in Focal Liver Lesions Including Hepatocellular Carcinoma: From Diagnosis to Prognosis

ABSTRACT

The ability of ultrasound elastography to diagnose focal liver lesions and determine their prognoses including hepatocellular carcinoma (HCC) is unclear. At present, radiofrequency ablation and liver resection are the most common treatments for HCC. However, the survival rate remains disappointing because of recurrences and postoperative liver failure, necessitating the development of noninvasive approaches. There is currently no systematic definition of an elastic technique for measuring liver stiffness to predict the recurrence of HCC after radiofrequency ablation and postoperative liver failure. In this review, recent advances in ultrasound elastography for the diagnosis and prognosis of focal liver lesions are discussed including HCC.

Improving Linkage to Care of Hepatitis C: Clinical Validation of GeneXpert® HCV Viral Load Point-of-Care Assay in Indonesia

Hepatitis C virus (HCV) infection large-scale diagnosis and treatment are hampered by lack of a simple, rapid, and reliable point-of-care (POC) test, which poses a challenge for the elimination of hepatitis C as a public health problem. This study aimed to evaluate Cepheid Xpert^® HCV Viral Load performance in comparison with the Roche Cobas^® TaqMan^® HCV Test using serum samples of HCV-infected patients in Indonesia. Viral load quantification was performed on 243 anti-HCV positive patients’ samples using both Xpert HCV VL and Roche HCV tests, followed by HCV genotyping by reverse hybridization. Strength of the relationship between the assays was measured by Pearson correlation coefficient, while level of agreement was analyzed by Deming regression and Bland–Altman plot analysis using log₁₀-transformed viral load values. Quantifiable viral load was detected in 180/243 (74.1%), with Xpert HCV VL sensitivity of 100% (95% CI 0.98, 1.00) and specificity of 98.4% (95% CI 0.91, 0.99) based on the Roche HCV test, while HCV genotypes were determined in 172/180 (95.6%) samples. There was a good correlation between both assays (r = 0.97, P < 0.001), overall and per genotype, with good concordance by Deming regression and a mean difference of −0.25 log₁₀ IU/mL (95% CI −0.33, −0.18) by Bland–Altman plot analysis. Xpert HCV VL test was demonstrated as a POC platform with good performance for HCV diagnosis and treatment decision that would be beneficial for decentralized services in resource-limited areas. HCV testing sites, alongside additional GeneXpert modular systems distributed toward the fight against COVID-19, could ensure some continuity, once this pandemic is controlled.

Diagnostic Performance of Shear Wave Elastography in the Noninvasive Evaluation of Liver Inflammation of Chronic Hepatitis B Patients

ABSTRACT

In the current study, we sought to delineate the elastographic characteristics and further compare the diagnostic performance of various shear wave elastography modalities in hepatitis B virus patients whose liver fibrosis stage was less than F2 by liver biopsy. We retrospectively studied the clinical and imaging data of chronic hepatitis B virus patients who underwent liver biopsy at our hospital between January 2017 and October 2017. Totally, 102 patients were eligible for the study. The mean Young modulus of sound touch elastography (STE) and sound touch quantify (STQ) gradually increased as inflammation grade of the liver rose from G0 to G3. Spearman rank correlation analysis revealed that the mean Young modulus of STE and STQ significantly correlated with hepatic inflammation grade (r = 0.341, P < 0.05). The area under the receiver operating characteristic curve (AUC) was the highest for the mean Young modulus of STE (AUC = 0.740; P = 0.015) followed by that of STQ (AUC = 0.684; P = 0.063) for G ≥ 2 hepatic inflammation and the AUC was the highest for the mean Young modulus of STE (AUC = 0.920; P = 0.000) followed by that of STQ (AUC = 0.910; P = 0.000) for G ≥ 3 hepatic inflammation. The current study demonstrated that the mean Young modulus of STE and STQ could serve as a useful diagnostic marker for hepatic inflammation of hepatitis B virus patients with no apparent liver fibrosis.

Elastography for Pediatric Chronic Liver Disease: A Review and Expert Opinion

In adults with chronic liver diseases, ultrasound and magnetic resonance shear wave elastography (SWE) can replace liver biopsy in several clinical scenarios. Several guidelines on the use of ultrasound SWE for the adult population have been published. However, the number of publications in the pediatric population is limited, and available guidelines on SWE do not specifically address pediatric chronic liver diseases. In this article, we review the literature on the use of SWE for pediatric chronic liver diseases and provide expert opinion on how to use SWE, both ultrasound and magnetic resonance techniques, in the pediatric population.

What's New in Hepatic Steatosis

Hepatic steatosis can lead to liver cancer, cirrhosis, and portal hypertension. There are two main types, non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease. The detection and quantification of hepatic steatosis with lifestyle changes can slow the evolution from NAFLD to steatohepatitis. Currently, the gold standard for the quantification of fat in the liver is biopsy, has some limitations. Hepatic steatosis is frequently detected during cross sectional imaging. Ultrasound (US), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI) provide noninvasive assessment of liver parenchyma and can detect fat infiltration in the liver. However, the non-invasive quantification of hepatic steatosis by imaging has been challenging. Recent MRI techniques show great promise in the detection and quantification of liver fat. The aim of this article is to review the utilization of non-invasive imaging modalities for the detection and quantification of hepatic steatosis, to evaluate their advantages and limitations.

Spleen elastography in patients with Systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune inflammatory connective tissue disease. It is characterized by varying degrees of fibrosis of the skin and internal organs. Tissue fibrosis is the final phase of a complex biological process of immune activation and vascular damage. The spleen is one of the organs thought to be involved in a systemic fibrosing process. Yet, there is a lack of research that provides evidence about splenic involvement in patients with SSc through objective instrumental techniques. Ultrasound elastography is a modern method which detects changes in the stiffness and elasticity of different organs. To assess the elasticity and stiffness of the spleen in healthy subjects and patients with SSc, the study included 34 patients with SSc and 35 healthy volunteers. Point SWE spleen elastography was performed on all participants in the two study groups through an Esaote MyLab 9 eXP with a C1-8 iQ appleprobe transducer. The mean age in the SSc patient group was 47.35 ± 11.48 years vs. 46.20 ± 14.55 years in the healthy controls, with no significant age difference, p = 0.717. The mean Body Mass Index (BMI) in the SSc patient group was 22.42 ± 2.12 kg/m² vs. 24.23 ± 4.29 kg/m² in the healthy control group with no significant difference, p = 0.410. Among the SSc patients, 18(53%) were with dcSSc and 16 (47%) with lcSSc. The mean disease duration was 59 ± 28 months, ranging between 18 and 118 months. Spleen stiffness median was significantly higher in the SSc patient group (3.19 m/s) in comparison with the healthy controls (2.40 m/s), p < 0.001. Spleen size was normally distributed and did not differ significantly between the SSc patients (105.84 ± 7.87 mm) and the healthy controls (104.16 ± 8.99 mm), p = 0.410. A significantly higher mean of spleen stiffness was observed in the dcSSc patients (3.38 ± 0.20 m/s) in comparison with the lcSSc group (2.81 ± 0.38 m/s), p < 0.001. Spleen size did not show a significant association with the type of SSc. Spleen size in the dcSSc subgroup had a mean value of 103.45 ± 5.56 mm vs. 108.51 ± 9.30 in the lcSSc subgroup, p = 0.071. pSWE is an objective, reliable, and easy-to-implement method for detecting early fibrous changes in the spleen in patients with SSc. A good approach in patients with SSc could be the search for similar processes in other internal organs, such as the liver and thyroid gland.

Ultrasound-based liver elastography: current results and future perspectives

Chronic liver disease affects 185 million population worldwide. It encompasses a heterogenous disease spectrum, but all can lead to the development of liver fibrosis. The degree of liver fibrosis is not only a prognosticator, but has also been used to guide the treatment strategy and to evaluate treatment response. Traditionally, staging of liver fibrosis is determined on histological analysis using samples obtained from an invasive liver biopsy. Ultrasound-based liver elastography is a non-invasive method of assessing diffuse liver disease in patients with known chronic liver disease. The use of liver elastography has led to a significant reduction in the number of liver biopsies performed to assess the severity of liver fibrosis and a liver biopsy is now reserved for only select sub-groups of patients. The aim of this review article is to discuss the key findings and current evidence for ultrasound-based elastography in diffuse liver disease as well as the technical challenges and to evaluate the potential research direction.

A New Visual Transient Elastography Technique for Grading Liver Fibrosis in Patients With Chronic Hepatitis B

ABSTRACT

Liver fibrosis is evaluated to assess the prognosis and guide the treatment of chronic hepatitis B (CHB). To compare the efficiency of 2 transient elastography techniques for grading liver fibrosis in CHB: visual transient elastography (ViTE) with real-time image guidance and FibroScan (FS) with no image guidance. All of the CHB patients in this study underwent both FS and ViTE examinations. The final diagnosis was based on the histological findings of a liver biopsy. According to the severity of liver fibrosis (based on the Scheuer criteria), the area under the receiver operating characteristic curve values for diagnostic efficiency were calculated for the 2 elastography techniques. This study enrolled 227 patients (79 [39.1%] women; mean age, 45.8 ± 16.8 years). The ViTE and FS liver elasticity measurements were highly correlated with liver fibrosis stage (r = 0.852 and r = 0.813, respectively). The area under the receiver operating characteristic curve value was larger for ViTE compared with FS, with respect to differentiating liver fibrosis stage, but not significantly (P > 0.05). The ViTE and FS can be used to detect and stage liver fibrosis. ViTE, easier and quicker to perform with superior interoperator reproducibility, is a stable and reliable elastography technique that benefits from real-time visual guidance.

Reliability of acoustic radiation force impulse shear wave elastography in the evaluation of liver stiffness in morbidly obese patients

PURPOSE

To evaluate technical and patient-related factors that can affect the reliability of acoustic radiation force impulse shear wave elastography (ARFI-SWE) in morbidly obese patients.

METHODS

A prospective single-center study was performed on 41 patients (32 females, 78%) presenting for preoperative evaluation for bariatric surgery. ARFI-SWE was performed using a 6 to 1.5 MHz curved (6C1) transducer. Hepatic steatosis was mild, moderate, severe, and absent in 24.4%, 12.2%, 43.9%, and 19.5% of patients, respectively. Interquartile range/median (IQR/M) ranged from 0.05 to 2.07 (0.78 ± 0.56 m/s). Twenty patients (48.7%) had reliable measurements (IQR/M < 0.3). Shear wave velocity (SWV) values were >1.34 m/s (clinically significant fibrosis) in 25 of 41 patients (61%) and >2.2 m/s (advanced fibrosis) in 19 patients (46%).

RESULTS

Median SWV was correlated with body mass index (BMI; correlation coefficient [CC] = .37; 95% CI, 0.07-0.61; P-value = .03) and skin-to-liver capsule distance (SLD) (CC = .38; 95% CI, 0.09-0.62; P-value = .01). IQR/M was higher in patients with BMI > 40 (0.24 ± 0.11 vs 0.39 ± 0.25, P-value = .031) and SLD > 3 cm (0.46 ± 0.27 vs 0.23 ± 0.08, P-value = .001), and there was higher number of unreliable examinations among patient with SLD > 3 cm (16/23 vs 5/18, P-value = .01).

CONCLUSION

ARFI-SWE is technically more challenging among patients with higher BMI and SLD, resulting in a higher number of unreliable studies, which highlights the need for further advancement of ARFI technology.

Evaluation of spleen stiffness in healthy volunteers using point shear wave elastography

INTRODUCTION AND OBJECTIVES

This study aims to measure the values of spleen stiffness (SS) in healthy subjects, the inter-operator agreement in SS measurement, and to detect statistically significant correlations between SS and age, sex, weight, BMI, portal vein dynamics and splenic dimensions.

MATERIALS AND METHODS

The study included 100 healthy volunteers who had no substantial alcohol intake (<30g/daily for man, <20g/daily women), were negative on hepatitis B, hepatitis C, HIV blood serology, and had any history of lymphoproliferative disorders. Abdominal ultrasound, liver and spleen elastography were performed on each patient to search for focal splenic lesions, bile tract or portal vein dilatation, moderate/severe liver steatosis, and to measure liver and spleen stiffness.

RESULTS

The mean value was 18.14 (±3.08) kPa. In the group of men (n=49), the mean was 17.73 (±2.91) kPa, whereas in the group of women (n=51) it was 16.72 (±3.32) kPa. Statistical analyses showed no correlation between spleen stiffness and sex, age, weight, and BMI. Regarding their splenoportal axis, statistically significant differences in SS were found in the means of the two subgroups of subjects stratified by their portal flow velocity (p=0.003) and spleen area (p<0.001). Spearman's rank showed a weak association between SS and portal flow velocty (r=0.271) and splenic area (r=-0.237). ICC showed excellent (0.96) inter-operator agreement and Bland-Altman plot demonstrated no systematic over/under-estimation of spleen stiffness values.

CONCLUSIONS

Our results may serve as a reference point in the evaluation of SS especially in patients affected by advanced liver disease.

The use of elastography in placental research - A literature review

INTRODUCTION

Ultrasound elastography is a technique used to quantify biomechanical changes that occur in parenchymal tissue with disease. Recent research has applied the technique to the placenta in order to investigate changes associated with uteroplacental dysfunction. We performed a literature review to summarise the current available information regarding this novel technique.

METHODS

Pubmed, CINAHL and Embase were searched using the terms "placenta", "ultrasound" and "elastography". Only full text studies written in English and limited to placental sonoelastography were included.

RESULTS

Twenty-eight studies met the inclusion criteria and were included in this review. Publications were divided into in vivo and ex vivo groups, and further categorised into four subgroups: normal pregnancy, pregnancy-induced hypertension and pre-eclampsia, fetal growth restriction and other pregnancy complications.

CONCLUSION

Ultrasound elastography can quantitatively assess biomechanical properties of the placenta in conditions where placental function is compromised.

Organ Stiffness in the Work-Up of Myelofibrosis and Philadelphia-Negative Chronic Myeloproliferative Neoplasms

To define the role of spleen stiffness (SS) and liver stiffness (LS) in myelofibrosis and other Philadelphia (Ph)-negative myeloproliferative neoplasms (MPNs), we studied, by ultrasonography (US) and elastography (ES), 70 consecutive patients with myelofibrosis (MF) (no.43), essential thrombocythemia (ET) (no.10), and polycythemia vera (PV) (no.17). Overall, the median SS was not different between patients with MF and PV (p = 0.9); however, both MF and PV groups had significantly higher SS than the ET group (p = 0.011 and p = 0.035, respectively) and healthy controls (p < 0.0001 and p = 0.002, respectively). In patients with MF, SS values above 40 kPa were significantly associated with worse progression-free survival (PFS) (p = 0.012; HR = 3.2). SS also correlated with the extension of bone marrow fibrosis (BMF) (p < 0.0001). SS was higher in advanced fibrotic stages MF-2, MF-3 (W.H.O. criteria) than in pre-fibrotic/early fibrotic stages (MF-0, MF-1) (p < 0.0001) and PFS was significantly different in the two cohorts, with values of 63% and 85%, respectively (p = 0.038; HR = 2.61). LS significantly differed between the patient cohort with MF and healthy controls (p = 0.001), but not between the patient cohorts with ET and PV and healthy controls (p = 0.999 and p = 0.101, respectively). We can conclude that organ stiffness adds valuable information to the clinical work-up of MPNs and could be employed to define patients at a higher risk of progression.

[18F]-Alfatide PET imaging of integrin αvβ3 for the non-invasive quantification of liver fibrosis

BACKGROUND & AIMS

The vitronectin receptor integrin αvβ3 drives fibrogenic activation of hepatic stellate cells (HSCs). Molecular imaging targeting the integrin αvβ3 could provide a non-invasive method for evaluating the expression and the function of the integrin αvβ3 on activated HSCs (aHSCs) in the injured liver. In this study, we sought to compare differences in the uptake of [18F]-Alfatide between normal and injured liver to evaluate its utility for assessment of hepatic fibrogenesis.

METHODS

PET with [18F]-Alfatide, non-enhanced CT, histopathology, immunofluorescence staining, immunoblotting and gene analysis were performed to evaluate and quantify hepatic integrin αvβ3 levels and liver fibrosis progression in mouse models of fibrosis (carbon tetrachloride [CCl4] and bile duct ligation [BDL]). The liver AUC divided by the blood AUC over 30 min was used as an integrin αvβ3-PET index to quantify fibrosis progression. Ex vivo analysis of frozen liver tissue from patients with fibrosis and cirrhosis verified the animal findings.

RESULTS

Fibrotic mouse livers showed enhanced [18F]-Alfatide uptake and retention compared to control livers. The radiotracer was demonstrated to bind specifically with integrin αvβ3, which is mainly expressed on aHSCs. Autoradiography and histopathology confirmed the PET imaging results. Further, the mRNA and protein level of integrin αvβ3 and its signaling complex were higher in CCl4 and BDL models than controls. The results obtained from analyses on human fibrotic liver sections supported the animal findings.

CONCLUSIONS

Imaging hepatic integrin αvβ3 with PET and [18F]-Alfatide offers a potential non-invasive method for monitoring the progression of liver fibrosis.

LAY SUMMARY

Integrin αvβ3 expression on activated hepatic stellate cells (aHSCs) is associated with HSC proliferation during hepatic fibrogenesis. Herein, we show that a radioactive tracer, [18F]-Alfatide, binds to integrin αvβ3 with high affinity and specificity. [18F]-Alfatide could thus be used as a non-invasive imaging biomarker to track hepatic fibrosis progression.

Ultrasound liver elastography beyond liver fibrosis assessment

Several guidelines have indicated that liver stiffness (LS) assessed by means of shear wave elastography (SWE) can safely replace liver biopsy in several clinical scenarios, particularly in patients with chronic viral hepatitis. However, an increase of LS may be due to some other clinical conditions not related to fibrosis, such as liver inflammation, acute hepatitis, obstructive cholestasis, liver congestion, infiltrative liver diseases. This review analyzes the role that SWE can play in cases of liver congestion due to right-sided heart failure, congenital heart diseases or valvular diseases. In patients with heart failure LS seems directly influenced by central venous pressure and can be used as a prognostic marker to predict cardiac events. The potential role of LS in evaluating liver disease beyond the stage of liver fibrosis has been investigated also in the hepatic sinusoidal obstruction syndrome (SOS) and in the Budd-Chiari syndrome. In the hepatic SOS, an increase of LS is observed some days before the clinical manifestations; therefore, it could allow an early diagnosis to timely start an effective treatment. Moreover, it has been reported that patients that were successfully treated showed a LS decrease, that reached pre-transplantation value within two to four weeks. It has been reported that, in patients with Budd-Chiari syndrome, LS values can be used to monitor short and long-term outcome after angioplasty.

Update to the Society of Radiologists in Ultrasound Liver Elastography Consensus Statement

This multidisciplinary update of the Society of Radiologists in Ultrasound consensus statement on liver elastography incorporates the large volume of new information available in the literature since the initial publication. The recommended procedure for acquiring stiffness measurements is reviewed. There has been substantial improvement in the acoustic radiation force impulse (ARFI) technology-most notably the addition of a quality assessment of the shear wave propagation. Due to the efforts of the Quantitative Imaging Biomarkers Alliance, or QIBA, the variability of liver stiffness measurements between systems had decreased. There are now effective treatments for hepatitis B and hepatitis C, and follow-up after effective treatment should be based on the use of the delta change of the value obtained at viral eradication or suppression. Because the detection of compensated advanced chronic liver disease (cACLD) is very important, the new guidelines are made based on the probability of cACLD for given stiffness values. The panel recommends a vendor-neutral rule of four for interpretation for ARFI techniques. This new method simplifies interpretation of liver stiffness results and is more clinically relevant.

Can Accurate Shear Wave Velocities Be Obtained in Kidneys?

OBJECTIVES

There are conflicting results in the literature on the use of shear wave elastography of the kidney parenchyma to determine whether renal stiffness values are related to a disease process. This study was conducted to evaluate the raw data from 3 ultrasound systems and determine whether adequate displacement curves are obtained to accurately estimate shear wave speeds.

METHODS

Shear wave elastography was performed on 5 healthy volunteers with 3 ultrasound systems. The raw data were collected and evaluated for the shear wave propagation quality to determine whether accurate estimates of renal shear wave speeds could be determined.

RESULTS

Results from the 3 machines demonstrate that accurate shear wave displacement curves are not obtained with renal elastography on existing systems (as of June 2018). One vendor has recently released software that appears to acquire accurate shear wave displacements.

CONCLUSIONS

Elastographic studies performed on the kidney to date are likely to be inaccurate. A new algorithm that appears to acquire accurate shear wave displacements in the kidney has been developed. Additional studies are needed to confirm that the new algorithm provides accurate clinical results. This study demonstrates that although the system provides a shear wave speed, it is important to confirm the accuracy of that number by evaluating the raw data.

Feasibility and reproducibility of shear wave elastography in pediatric cranial ultrasound

BACKGROUND

Head ultrasound (US) is commonly used to evaluate the neonatal brain but may be limited by its lack of sensitivity and specificity. Ultrasound shear wave elastography (SWE) might provide additional information to conventional gray-scale imaging.

OBJECTIVE

To assess whether SWE of brain parenchyma can be (1) successfully performed at a large academic medical center where US technologists perform the majority of examinations and (2) used to detect intracranial pathology.

MATERIALS AND METHODS

Pediatric patients undergoing head ultrasound underwent simultaneous SWE examination. We included normal examinations (n=70) and those with intracranial pathology (n=8) for analysis. We analyzed inter-reader variability and examination success rates and assessed the stiffness of white matter and deep gray nuclei in normal and pathological states across multiple gestational age groups.

RESULTS

Average gestational age of the term, pre-term and extreme pre-term groups were 38.4±1.2 weeks, 29.0±3.7 weeks and 28.3±3.1 weeks, respectively. Overall examination success rate was 79.5%. We observed a decrease in the SWE examination time from the first month (5.9±3.7 min) to the second month (4.1±1.7 min; P=0.01). Forty-one repeat examinations were performed on 14 children by different technologists, with an intraclass correlation coefficient (ICC) of 0.91. Mean stiffness in the periventricular white matter was lower than in the deep gray nuclei in all gestational age groups: term group (1.3 m/s vs. 1.5 m/s, P<0.001), pre-term (1.3 m/s vs. 1.4 m/s P=0.12), and extremely preterm group (1.2 m/s vs. 1.4 m/s, P=0.001). Mean stiffness for the deep gray nuclei differed between the term (1.5±0.3 m/s) and pre-term (1.4±0.2 m/s) groups (P<0.01). No significant differences in white matter stiffness were seen in relation to gestational age. Infants with large intraparenchymal hemorrhage had increased white matter stiffness (1.3±0.1 m/s) and deep gray nuclei stiffness (1.6±0.2 m/s) compared to full-term infants with normal head ultrasounds. These differences approached statistical significance with P=0.09 and P=0.06, respectively.

CONCLUSION

We demonstrated that SWE performed by pediatric sonography technologists is reproducible. We found differences in stiffness between deep gray nuclei and periventricular white matter across multiple age groups.

Ultrasound elastography in patients with fatty liver disease

Hepatic steatosis, or fatty liver disease, occurs due to the accumulation of lipids in hepatocytes. When it becomes chronic, lobular inflammation develops and the disease can evolve to hepatic fibrosis, liver cirrhosis, or hepatocellular carcinoma. Early diagnosis is desirable because patients diagnosed in the early stage of the disease respond better to treatment. In the early stages of fatty liver disease, the physical examination is often unremarkable. Fatty liver disease and hepatic fibrosis can be diagnosed and monitored through laboratory tests, imaging, and biopsy. Among the imaging methods, ultrasound stands out as an effective means of diagnosing and following patients with liver disease. Ultrasound used in conjunction with elastography (ultrasound elastography) has recently shown great utility in the follow-up of such patients. Ultrasound elastography studies the degree of deformation (stiffness) of an organ or lesion, so that when there is hardening, fibrosis, or cirrhosis of the liver, those alterations are well demonstrated. In this review article, we discuss the application of the different types of ultrasound elastography for liver studies: transient elastography, point shear wave elastography, and two-dimensional shear wave elastography. Although magnetic resonance elastography may also be used in the analysis of liver fibrosis, it will not be addressed in this article.

Impact of respiratory motion on liver stiffness measurements according to different shear wave elastography techniques and region of interest methods: a phantom study

Purpose

This study quantified the impact of respiratory motion on liver stiffness measurements according to different shear wave elastography (SWE) techniques and region of interest (ROI) methods, using liver fibrosis phantoms.

Methods

Three operators measured stiffness values in four phantoms with different stiffness on a moving platform with two SWE techniques (point-SWE [pSWE] and 2-dimensional SWE [2D-SWE]), three types of motion (static mode and moving mode at low and high speeds), and four ROI methods in 2D-SWE (circle, point, box, and multiple). The circular ROI method was used to compare the two SWE techniques. The occurrence of technical failure and unreliable measurements, stiffness values, and measurement time were evaluated.

Results

Technical failure was observed only in moving mode for pSWE and 2D-SWE (n=1 for both). Unreliable measurements were also only observed in moving mode and were significantly less common in 2D-SWE (n=1) than in pSWE (n=12) (P<0.001). No statistically significant differences in the technical failure rate or stiffness values were noted between the static and moving modes for both SWE techniques. The technical failure and unreliable measurement rates were not significantly different among the ROI methods for 2D-SWE. Stiffness values did not differ significantly according to the ROI method used in any moving mode. However, the multiple ROI method had significantly shorter measurement times than the circular ROI method for all moving modes.

Conclusion

2D-SWE may be preferable for evaluating liver fibrosis in patients with poor breath-hold. Furthermore, 2D-SWE with multiple ROIs enables rapid measurements, without affecting liver stiffness values.