Diagnostic accuracy of controlled attenuation parameter measured by transient elastography for the non-invasive assessment of liver steatosis: a prospective study

Comparative study of ultrasound attenuation analysis and controlled attenuation parameter in the diagnosis and grading of liver steatosis in non-alcoholic fatty liver disease patients

PURPOSE

To assess the diagnostic performance of Ultrasound Attenuation Analysis (USAT) in the diagnosis and grading of hepatic steatosis in patients with non-alcoholic fatty liver disease (NAFLD) using Controlled Attenuation Parameters (CAP) as a reference.

MATERIALS AND METHODS

From February 13, 2023, to September 26, 2023, participants underwent CAP and USAT examinations on the same day. We used manufacturer-recommended CAP thresholds to categorize the stages of hepatic steatosis: stage 1 (mild) - 240 dB/m, stage 2 (moderate) - 265 dB/m, stage 3 (severe) - 295 dB/m. Receiver Operating Characteristic curves were employed to evaluate the diagnostic accuracy of USAT and determine the thresholds for different levels of hepatic steatosis.

RESULTS

Using CAP as the reference, we observed that the average USAT value increased with the severity of hepatic steatosis, and the differences in USAT values among the different hepatic steatosis groups were statistically significant (p < 0.05). There was a strong positive correlation between USAT and CAP (r = 0.674, p < 0.0001). When using CAP as the reference, the optimal cut-off values for diagnosing and predicting different levels of hepatic steatosis with USAT were as follows: the cut-off value for excluding the presence of hepatic steatosis was 0.54 dB/cm/MHz (AUC 0.96); for mild hepatic steatosis, it was 0.59 dB/cm/MHz (AUC 0.86); for moderate hepatic steatosis, it was 0.73 dB/cm/MHz (AUC 0.81); and for severe hepatic steatosis, it was 0.87 dB/cm/MHz (AUC 0.87).

CONCLUSION

USAT exhibits strong diagnostic performance for hepatic steatosis and shows a high correlation with CAP values.

Intact ketogenesis predicted reduced risk of moderate-severe metabolic-associated fatty liver disease assessed by liver transient elastography in newly diagnosed type 2 diabetes

Aim

Hepatic ketogenesis is a key metabolic pathway that regulates energy homeostasis. Some related controversies exist regarding the pathogenesis of metabolic-associated fatty liver disease (MAFLD). We aimed to investigate whether intact ketogenic capacity could reduce the risk of MAFLD based on transient electrography (TE) in patients with newly diagnosed type 2 diabetes (T2D).

Methods

A total of 361 subjects with newly diagnosed T2D were recruited and classified into two groups based on the median serum β-hydroxybutyrate (βHB) level, referred to as the intact and impaired ketogenesis groups. The glucometabolic relevance of ketogenic capacity and associations of the baseline serum β-HB and MAFLD assessed with TE were investigated.

Results

Compared to the impaired ketogenesis group, the intact ketogenesis group showed better insulin sensitivity, lower serum triglyceride levels, and higher glycated hemoglobin levels. The controlled attenuation parameter (CAP) was lower in the intact ketogenesis group without statistical significance (289.7 ± 52.1 vs. 294.5 ± 43.6; p=0.342) but the prevalence of moderate-severe steatosis defined by CAP ≥260 dB/m was significantly lower in the intact group. Moreover, intact ketogenesis was significantly associated with a lower risk of moderate-severe MAFLD after adjusting for potential confounders (adjusted odds ratio 0.55, 95% confidence interval 0.30-0.98; p=0.044).

Conclusion

In drug-naïve, newly diagnosed T2D patients, intact ketogenesis predicted a lower risk of moderate-severe MAFLD assessed by TE.

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.

Association between Sarcopenic Obesity Status and Nonalcoholic Fatty Liver Disease and Fibrosis

Background/Aims

There are no data regarding the association between sarcopenic obesity status and nonalcoholic fatty liver disease (NAFLD) and NAFLD-associated liver fibrosis. Therefore, we aimed to investigate the relationship between sarcopenic obesity status (sarcopenia only, obesity only, and sarcopenic obesity) and NAFLD and liver fibrosis in Korean adults.

Methods

In total, 2,191 subjects completed a health checkup program, including abdominal ultrasonography and FibroScan. Subjects were classified into the following four categories: optimal body composition (nonobese and nonsarcopenic), sarcopenia only (nonobese), obesity only (nonsarcopenic), and sarcopenic obesity. Sarcopenic obesity was stratified by the skeletal muscle mass index and body fat using bioelectrical impedance analysis. NAFLD was diagnosed by ultrasonography, and liver fibrosis was assessed using transient elastography in subjects with NAFLD.

Results

The prevalence of NAFLD and liver fibrosis significantly increased according to the sarcopenic obesity status. In the logistic regression analysis, after adjusting for multiple risk factors, the odds ratio (OR) for the risk of NAFLD was largest in the sarcopenic obesity group (OR, 3.68; 95% confidence interval [CI], 2.94 to 4.60), followed by the obesity only (OR, 2.25; 95% CI, 1.67 to 3.03) and sarcopenia only (OR, 1.92; 95% CI, 1.30 to 2.84) groups, when compared with the optimal group. Additionally, liver fibrosis was independently associated with sarcopenic obesity status (OR 4.69, 95% CI 1.95 to 11.29; OR 4.17, 95% CI 1.56 to 11.17; OR 3.80, 95% CI 0.86 to 16.75, respectively).

Conclusions

These results demonstrated that sarcopenic obesity was independently associated with NAFLD and liver fibrosis and increased the risk of NAFLD and liver fibrosis more than obesity or sarcopenia alone.

Ultrasound-Based Quantification of Fibrosis and Steatosis with a New Software Considering Transient Elastography as Reference in Patients with Chronic Liver Diseases

The goal of this study was to evaluate the performance of two new ultrasound-based techniques (ShearWave PLUS elastography [2-D-SWE PLUS], SSp PLUS Imaging [SSp PLUS]) implemented on the Aixplorer Mach 30 ultrasound system (Supersonic Imagine, Aix-en-Provence, France) for the non-invasive assessment of liver steatosis and fibrosis, using transient elastography (TE) with the controlled attenuation parameter (CAP) as reference. This monocentric cross-sectional study included 133 consecutive adult patients with chronic hepatopathies. Liver stiffness and steatosis were evaluated in the same session using the techniques mentioned above. An excellent correlation was observed between liver stiffness measurements obtained with 2-D-SWE PLUS and TE (r = 0.92, p < 0.0001). The best cutoff value of 2-D-SWE PLUS for predicting F≥2 was 6.8 kPa; for F≥3, 8.4 kPa; and for F4, 11 kPa. With respect to steatosis evaluation, a strong negative correlation between CAP and SSp PLUS values (r = -0.70, p < 0.0001) was obtained. The best SSp PLUS cutoff value for predicting steatosis was 1537 m/s.

Conventional ultrasound for diagnosis of hepatic steatosis is better than believed

BACKGROUND

Hepatic steatosis is a condition frequently encountered in clinical practice, with potential progression towards fibrosis, cirrhosis, and hepatocellular carcinoma. Detection and staging of hepatic steatosis are of most importance in nonalcoholic fatty liver disease (NAFLD), a disease with a high prevalence of more than 1 billion individuals affected. Ultrasound (US) is one of the most used noninvasive imaging techniques used in the diagnosis of hepatic steatosis. Detection of hepatic steatosis with US relies on several conventional US parameters, which will be described. US is the first-choice imaging in adults at risk for hepatic steatosis. The use of some scoring systems may add additional accuracy especially in assessing the severity of hepatic steatosis.

SUMMARY

In the presented paper, we discuss screening and risk stratification, ultrasound features for diagnosing hepatic steatosis, B-mode criteria, focal fatty patterns and Doppler features of the hepatic vessels, and the value of the different US signs for the diagnosis of liver steatosis including classifying the severity of steatosis using different US scores. Limitations of conventional B-mode and Doppler features in the evaluation of hepatic steatosis are also discussed, including those in grading and assessing the complications of steatosis, namely fibrosis and nonalcoholic steatohepatitis.

KEY MESSAGES

Ultrasound is the first-line imaging examination for the screening and follow-up of patients with liver steatosis. The use of some scoring systems may add additional accuracy in assessing the severity of steatosis. Conventional B-mode and Doppler ultrasound have limitations in grading and assessing the complications of steatosis.

Quantification of Liver Fibrosis, Steatosis, and Viscosity Using Multiparametric Ultrasound in Patients with Non-Alcoholic Liver Disease: A "Real-Life" Cohort Study

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. This study aimed to evaluate the performance of four ultrasound-based techniques for the non-invasive multiparametric (MPUS) assessment of liver fibrosis (LF), steatosis (HS), and inflammation in patients with NAFLD. We included 215 consecutive adult patients with NAFLD (mean age: 54.9 ± 11.7; 54.5% were male), in whom LF, HS, and viscosity were evaluated in the same session using four new ultrasound-based techniques embedded on the Aixplorer MACH 30 system: ShearWave Elastography (2D-SWE.PLUS), Sound Speed Plane-wave UltraSound (SSp.PLUS), Attenuation Plane-wave UltraSound (Att.PLUS), and Viscosity Plane-wave UltraSound (Vi.PLUS). Transient Elastography (TE) with Controlled Attenuation Parameter (CAP) (FibroScan) were considered as control. All elastographic measurements were performed according to guidelines. Valid liver stiffness measurements (LSM) were obtained in 98.6% of patients by TE, in 95.8% of patients by 2D-SWE.PLUS/Vi.PLUS, and in 98.1% of patients by Att.PLUS/SSp.PLUS, respectively. Therefore, 204 subjects were included in the final analysis. A strong correlation between LSMs by 2D-SWE.PLUS and TE (r = 0.89) was found. The best 2D-SWE.PLUS cut-off value for the presence of significant fibrosis (F ≥ 2) was 7 kPa. Regarding steatosis, SSp.PLUS correlated better than Att.PLUS with CAP values: (r = −0.74) vs. (r = 0.45). The best SSp.PLUS cut-off value for predicting the presence of significant steatosis was 1524 m/s. The multivariate regression analysis showed that Vi.PLUS values were associated with BMI and LSM by 2D-SWE.PLUS. In conclusion, MPUS was useful for assessing fibrosis, steatosis, and inflammation in a single examination in patients with NAFLD.

Changing Trends in Liver Transplantation: Challenges and Solutions

Despite improvements in postliver transplant outcomes through refinements in perioperative management and surgical techniques, several changing trends in liver transplantation have presented challenges. Mortality on the waitlist remains high. In the United States, Europe, and the United Kingdom, there is an increasing need for liver transplantation, primarily as a result of increased incidence of nonalcoholic steatohepatitis-related cirrhosis and cancer indications. Meanwhile, donor suitability has decreased, as donors are often older and have more comorbidities. Despite a mismatch between organ need and availability, many organs are discarded. Notwithstanding this, many solutions have been developed to overcome these challenges. Innovative techniques in allograft preservation, viability assessment, and reconditioning have allowed the use of suboptimal organs with adequate results. Refinements in surgical procedures, including live donor liver transplantations, have increased the organ pool and are decreasing the time and mortality on the waitlist. Despite many challenges, a similar number of solutions and prospects are on the horizon. This review seeks to explore the changing trends and challenges in liver transplantation and highlight possible solutions and future directions.

Controlled Attenuation Parameter for Quantification of Steatosis: Which Cut-Offs to Use?

Chronic liver diseases (CLDs) are a public health problem, even if frequently they are underdiagnosed. Hepatic steatosis (HS), encountered not only in nonalcoholic fatty liver disease (NAFLD) but also in chronic viral hepatitis, alcoholic liver disease, etc., plays an important role in fibrosis progression, regardless of CLD etiology; thus, detection and quantification of HS are imperative. Controlled attenuation parameter (CAP) feature, implemented in the FibroScan® device, measures the attenuation of the US beam as it passes through the liver. It is a noninvasive technique, feasible and well accepted by patients, with lower costs than other diagnostic techniques, with acceptable accuracy for HS quantification. Multiple studies have been published regarding CAP performance to quantify steatosis, but due to the heterogeneity of CLD etiologies, of steatosis prevalence, etc., it had widely variable calculated cut-off values, which in turn limited the day-to-day utility of CAP measurements in clinical practice. This paper reviews published studies trying to suggest cut-off values usable in clinical practice.

Quantitative assessment of liver steatosis using ultrasound controlled attenuation parameter (Echosens)

Controlled attenuation parameter (CAP) is the algorithm available on the FibroScan system (Echosens, France) for quantification of liver steatosis. It assesses the ultrasound beam attenuation, which is directly related to liver fat content. The inter-observer reproducibility of the technique is high, with a reported concordance correlation coefficient of 0.82. Specific quality criteria for CAP measurements are not clearly defined yet, and there are conflicting results in the literature. Using liver biopsy as the reference standard, several studies have assessed the CAP performance in grading liver steatosis, and have reported that values are not affected by liver fibrosis. The cutoff for detection of liver steatosis reported in the literature ranges from 222 decibels per meter (dB/m) in a cohort of patients with chronic hepatitis C to 294 dB/m in a meta-analysis of nonalcoholic fatty liver disease (NAFLD) patients. CAP has been used as a tool to noninvasively evaluate the prevalence of NAFLD in groups at risk or in the general population; however, it should be underscored that different CAP cutoffs for steatosis detection (S > 0) were used in different studies, and this limits the robustness of the findings. CAP, alone or combined with other noninvasive indices or biomarkers, has been proposed as a tool for assessing nonalcoholic steatohepatitis or as a noninvasive predictor of prognosis in patients with chronic liver disease. CAP is easy to perform and has become a point-of-care technique. However, there is a large overlap of values between consecutive grades of liver steatosis, and cutoffs are not clearly defined.

The Role of Elastography in Non-Alcoholic Fatty Liver Disease

The most common liver disease in developing countries is non-alcoholic fatty liver disease (NAFLD). This involves the abnormal accumulation of lipids in the liver, the pathogenesis of the disease being related to dyslipidemia, obesity, insulin resistance and type 2 diabetes. Most often, the diagnosis of NAFLD is incidental, when performing routine blood tests or when performing a transabdominal ultrasound. The NAFLD spectrum ranges from simple forms of hepatic steatosis to the most advanced form of the disease, steatohepatitis (NASH), which in evolution can cause inflammation, fibrosis, cirrhosis of the liver and even liver cancer. For the evaluation of the prognosis and the clinical evolution, the most important parameter to define is the degree of liver fibrosis. Currently, the gold standard remains the liver biopsy, the differentiation between NAFLD and NASH being made only on the basis of histological analysis. However, liver biopsy is an invasive procedure, with numerous risks such as bleeding, lesions of the other organs and complications related to anesthesia, which significantly reduces its widespread use. Moreover, the risk of a false negative result and the increased costs of the procedure further limits its use in current practice. For this reason, non-invasive methods of evaluating the degree of liver fibrosis have gained ground in recent years. Imaging techniques such as elastography have shown promising results in evaluating and staging NAFLD. The aim of this article is to review the current status of the non-invasive tests for the assessment of NAFLD with a focus on the ultrasound-based elastography techniques.

Hepatocellular Carcinoma and Non-Alcoholic Fatty Liver Disease: A Step Forward for Better Evaluation Using Ultrasound Elastography

Simple Summary

Non-alcoholic fatty liver disease (NAFLD) attracts a lot of attention, due to the increasing prevalence and progression to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Consequently, new non-invasive, cost-effective diagnostic methods are needed. This review aims to explore the diagnostic performance of ultrasound (US) elastography in NAFLD and NAFLD-related HCC, adding a new dimension to the conventional US examination—the liver stiffness quantification. The vibration controlled transient elastography (VCTE), and 2D-Shear wave elastography (2D-SWE) are effective in staging liver fibrosis in NAFLD. VCTE presents the upside of assessing steatosis through the controlled attenuation parameter. Hereby, we critically reviewed the elastography techniques for the quantitative characterization of focal liver lesions (FLLs), focusing on HCC: Point shear wave elastography and 2D-SWE. 2D-SWE presents a great potential to differentiate malignant from benign FLLs, guiding the clinician towards the next diagnostic steps. As a disease-specific surveillance tool, US elastography presents prognostic capability, improving the NAFLD-related HCC monitoring.

Abstract

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) in the general population prompts for a quick response from physicians. As NAFLD can progress to liver fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC), new non-invasive, rapid, cost-effective diagnostic methods are needed. In this review, we explore the diagnostic performance of ultrasound elastography for non-invasive assessment of NAFLD and NAFLD-related HCC. Elastography provides a new dimension to the conventional ultrasound examination, by adding the liver stiffness quantification in the diagnostic algorithm. Whilst the most efficient elastographic techniques in staging liver fibrosis in NAFLD are vibration controlled transient elastography (VCTE) and 2D-Shear wave elastography (2D-SWE), VCTE presents the upside of assessing steatosis through the controlled attenuation parameter (CAP). Hereby, we have also critically reviewed the most important elastographic techniques for the quantitative characterization of focal liver lesions (FLLs), focusing on HCC: Point shear wave elastography (pSWE) and 2D-SWE. As our paper shows, elastography should not be considered as a substitute for FLL biopsy because of the stiffness values overlap. Furthermore, by using non-invasive, disease-specific surveillance tools, such as US elastography, a subset of the non-cirrhotic NAFLD patients at risk for developing HCC can be detected early, leading to a better outcome. A recent ultrasomics study exemplified the wide potential of 2D-SWE to differentiate benign FLLs from malignant ones, guiding the clinician towards the next steps of diagnosis and contributing to better long-term disease surveillance.

Serum visfatin level as a noninvasive marker for nonalcoholic fatty liver disease in children and adolescents with obesity: relation to transient elastography with controlled attenuation parameter

BACKGROUND

Obesity is associated with an increased risk of nonalcoholic fatty liver disease (NAFLD). Visfatin is an adipokine produced by visceral fat tissue and liver cells. Transient elastography with controlled attenuation parameter (CAP) noninvasively assesses liver fibrosis and steatosis.

AIM

To measure visfatin level in 80 children and adolescents with obesity as a potential biomarker for NAFLD and assess its relation to transient elastography.

METHODS

Abdominal ultrasound, liver stiffness and CAP measurements were performed for all patients. Fasting lipid profile, fasting blood glucose, insulin level, liver and kidney functions, coagulation profile and serum visfatin levels were assessed.

RESULTS

Among patients with obesity, 31 (38.8%) had NAFLD and 16 (20%) patients had elevated alanine aminotransferase (ALT), while 9 (11.2%) had both NAFLD and elevated ALT. Transient elastography showed that 12.5% had fibrosis stage F1, 2.5% had F2 and another 2.5% had F3 while none had F4. Using CAP, 23.8, 13.8 and 17.5% had S1, S2 and S3, respectively. Serum visfatin levels were significantly elevated in all patients compared with nonobese controls. Higher visfatin levels were found among patients with dyslipidemia, NAFLD, elevated ALT and steatosis defined by CAP. Serum visfatin was related to the degree of fibrosis and steatosis. Visfatin cutoff value 18 ng/mL could significantly detect the presence of NAFLD with 83.9% sensitivity and 81.4% specificity. Serum visfatin was positively correlated to BMI, waist circumference, waist/hip ratio, ALT, total cholesterol, liver stiffness and CAP.

CONCLUSIONS

Visfatin could be a promising serum biomarker for monitoring liver disease among pediatric patients with obesity.

Screening for Liver Fibrosis and Steatosis in a Large Cohort of Patients with Type 2 Diabetes Using Vibration Controlled Transient Elastography and Controlled Attenuation Parameter in a Single-Center Real-Life Experience

BACKGROUND

Type 2 diabetes mellitus (T2DM), obesity, hyperlipidemia, and hypertension are considered risk factors for developing non-alcoholic fatty liver disease (NAFLD). This study aims to assess steatosis and fibrosis severity in a cohort of T2DM patients, using vibration controlled transient elastography (VCTE) and controlled attenuation parameter (CAP).

MATERIAL AND METHOD

We performed a prospective study in which, in each patient, we aimed for 10 valid CAP and liver stiffness measurements (LSM). To discriminate between fibrosis stages, we used the following VCTE cut-offs: F ≥ 2-8.2 kPa, F ≥ 3-9.7 kPa, and F4 - 13.6 kPa. To discriminate between steatosis stages, we used the following CAP cut-offs: S1 (mild) - 274 dB/m, S2 (moderate) - 290dB/m, S3 (severe) - 302dB/m.

RESULTS

During the study period, we screened 776 patients; 60.3% had severe steatosis, while 19.4% had advanced fibrosis. Female gender, BMI, waist circumference, elevated levels of AST, total cholesterol, triglycerides, blood glucose, and high LSM were associated with severe steatosis (all p-value < 0.05). BMI, waist circumference, elevated levels of AST, HbA1c, and CAP were associated with advanced fibrosis (all p-values < 0.05).

CONCLUSION

Higher BMI (obesity) comprises a higher risk of developing severe steatosis and fibrosis. Individualized screening strategies should be established for NAFLD according to different BMI.

Transient elastography for assessment of fibrosis and steatosis of liver grafts from brain-death donors

BACKGROUND

An objective and accurate evaluation of liver grafts is required to improve the prognosis of liver transplant recipients and to increase the number of available liver grafts.

AIM

To compare outcomes using FibroScan with that of pathology in liver grafts from brain-dead donors (DBD).

METHODS

Liver grafts from 52 DBD were examined using ultrasound (US), FibroScan before liver transplantation (LT). Blood tested before LT and a biopsy was performed pre- or intra-operation to determine pathology. The diagnostic accuracy of the FibroScan results was compared with the pathology results, which is the gold standard for evaluating liver grafts. The donors enrolled were grouped by the stage of liver fibrosis (F0-F4) and steatosis (S0-S3), based on Kleiner's scoring system of nonalcoholic fatty liver disease, respectively.

RESULTS

The liver stiffness (LS) value in group F1 was significantly increased compared with group F0 (8.74±1.32kPa and 5.93±1.64kPa, respectively, P<0.01). The LS value had a significant positive correlation with the liver graft fibrosis stage (r=0.73, P<0.01). The area under receiver operating characteristic curves (AUROC) for F1 stage fibrosis was 0.93 (P<0.01). Significant differences in the controlled attenuation parameter (CAP) were found among groups S0, S1, and S2 (173.30±38.36dB/m, 230.29±23.27dB/m, 250.00±57.01dB/m, respectively; F=12.41, P<0.01). The CAP was associated with the liver graft steatosis stage (r=0.64, P<0.01). The AUROC for S1 and S2 stage steatosis in liver grafts was 0.89 (P=0.002) and 0.83 (P=0.007), respectively.

CONCLUSIONS

Transient elastography quantifies fibrosis and steatosis in liver grafts from 52 DBD with a high diagnostic accuracy and provides further imaging evidence for use in assessing liver grafts.

Ultrasound-based techniques for the diagnosis of liver steatosis

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of diffuse liver disease. An accurate estimate of the fat in the liver is important in the diagnostic work-up of patients with NAFLD because the degree of liver steatosis is linked to the metabolic syndrome and the cardiovascular risk. Ultrasound (US) B-mode imaging allows to subjectively estimate the fatty infiltration in the liver; however, it has a low performance for the detection of mild steatosis. Quantitative US is based on the analysis of the radiofrequency echoes detected by an US system, and it allows to calculate a backscatter coefficient or an attenuation coefficient or the sound speed. The estimation of the backscatter coefficient is rather cumbersome and requires the use of a phantom for addressing all sources of variability. Controlled attenuation parameter (CAP) available on the FibroScan^® system (Echosens, France) measures the attenuation of the US beam. CAP is accurate in grading fatty infiltration-even though there is an overlap between consecutive grade of liver steatosis-and the values are not influenced by liver fibrosis. Several US manufacturers are developing or have already developed software for quantifying the attenuation of the US beam. Preliminary results show that proprietary technologies implemented in US systems seem more accurate than CAP for grading liver steatosis. Another available method for quantifying liver steatosis is based on the computation of the sound speed and the initial results appear promising.

New diagnostic technique to evaluate hepatic steatosis using the attenuation coefficient on ultrasound B mode

Purpose

We have developed a diagnostic technique to evaluate hepatic steatosis using the attenuation coefficient (ATT) in ultrasound B mode imaging. A controlled attenuation parameter (CAP) by vibration-controlled transient elastography (VCTE) has also been used to evaluate hepatic steatosis. As that method uses ultrasound A mode, visualizing the liver in real time is difficult. We designed this clinical study to evaluate the diagnostic advantage of our technique using ATT compared to CAP.

Materials and methods

The study group included 94 patients with chronic liver disease who had undergone both ATT and CAP assessment at the time of liver biopsy. The M-probe and XL-probe were used for CAP measurement. Data for ATT and CAP were compared as a function of the steatosis grade.

Results

The area under the receiver operating characteristic curve (AUC-ROCs) for ATT and PAC as a function of the steatosis grade were as follows: grade 1, 0.74 and 0.81; grade 2, 0.80 and 0.85; and grade 3, 0.96 and 0.98, respectively.

Conclusion

The accuracy of steatosis grade diagnosis using ATT was the same as that using CAP, with no significant differences and with the added advantage of B mode ultrasound being more convenient and rapid, compared to A mode ultrasound, particularly for patients with subcutaneous fat thickness ≥2 cm.

Quantitative Hepatic Fat Quantification in Non-alcoholic Fatty Liver Disease Using Ultrasound-Based Techniques: A Review of Literature and Their Diagnostic Performance

Non-alcoholic fatty liver disease is a condition that is characterized by the presence of >5% fat in the liver and affects more than one billion people worldwide. If adequate and early precautions are not taken, non-alcoholic fatty liver disease can progress to cirrhosis and death. The current reference standard for detecting hepatic steatosis is a liver biopsy. However, because of the potential morbidity associated with liver biopsies, non-invasive imaging biomarkers have been extensively investigated. Magnetic resonance imaging-based methods have proven accuracy in quantifying liver steatosis; however, these techniques are costly and have limited availability. Ultrasound-based quantitative imaging techniques are increasingly utilized because of their widespread availability, ease of use and relative cost-effectiveness. Several ultrasound-based liver fat quantification techniques have been investigated, including techniques that measure changes in the acoustic properties of the liver caused by the presence of fat. In this review, we focus on quantitative ultrasound approaches and their diagnostic performance in the realm of non-alcoholic fatty liver disease.

NON-INVASIVE ASSESSMENT OF LIVER STEATOSIS AND FIBROSIS USING TRANSIENT ELASTOGRAPHY AND CONTROLLED ATTENUATION PARAMETER IN TYPE 2 DIABETES PATIENTS

CONTEXT

Nonalcoholic fatty liver disease is common in type 2 diabetes mellitus patients, being difficult to diagnose.

OBJECTIVE

To find a correlation between elastographic parameters and lab results, for facilitating the diagnosis of nonalcoholic fatty liver disease.

DESIGN

This is a cross sectional study, conducted at the Departments of Diabetes, Nutrition and Metabolic Diseases, and Gastroenterology and Hepatology, of the Clinical Emergency Hospital "Pius Brinzeu" Timisoara.

SUBJECTS AND METHODS

We included 190 type 2 diabetes mellitus patients, collected data regarding medical history, clinical and biological features and applied the Alcohol Use Disorders Identification Test. We excluded patients with other causes of liver disease. Liver steatosis and fibrosis were evaluated through transient elastography, yielding two parameters: liver stiffness as an indicator of liver fibrosis stage, expressed in kPa, and liver steatosis stage, assessed by controlled attenuation parameter, expressed in dB/m. Data were analyzed using SPSS 15.

RESULTS

The analyzed group comprised 113 patients. Elastographic measurements showed that 93.8% of the patients had steatosis (controlled attenuation parameter ≥232.5 dB/m) and 70.8% severe steatosis (controlled attenuation parameter ≥290 dB/m). Severe steatosis was more common in women (75.7%) than in men (68.1%) (p<0.0001). From the patients with steatosis, 47.2% had liver stiffness values suggestive for fibrosis and 19.8% for cirrhosis. Most patients with steatosis and severe fibrosis were obese (66.7%). Triglycerides/HDLc ratio >4 correlated with hepatic steatosis (p=0.04), being more common in patients with severe fibrosis/cirrhosis (58.3%) than in those with absent or mild fibrosis (36.2%).

CONCLUSIONS

Our study found a clear correlation between type 2 diabetes mellitus and the presence of liver steatosis. It correlates with body mass index, waist circumference (in men) and triglycerides/HDLc ratio. Controlled attenuation parameter is a useful noninvasive method for detection and quantification of liver steatosis.

Effect of Meal Ingestion on Liver Stiffness and Controlled Attenuation Parameter

Background and Aims

Despite the increasing use of noninvasive methods for the assessment of liver fibrosis and steatosis, the effect of fasting and food intake on these parameters is not yet clear. Our aims were to evaluate the effect of food intake on liver stiffness (LS) (measured by transient elastography) and controlled attenuation parameter (CAP) in patients with different degrees of liver disease and healthy volunteers, and secondarily, to assess possible factors associated with variations of LS and CAP.

Methods

We performed a prospective single-center study including patients with liver disease and healthy volunteers. LS and CAP were evaluated using FibroScan® (Echosens, Paris, France), before (fasting ≥8 h) and 30 min after intake of a standardized breakfast. We used common cutoffs for LS: > 7 kPa for significant fibrosis (F2 to F4) and > 11 to 14 kPa (mean 12.5 kPa) for cirrhosis.

Results

Fifty-nine (72%) patients with liver disease and 22 (28%) healthy volunteers were included. LS significantly increased 30 min after food intake (pre-meal 6.1 kPa [IQR: 4.7-9.8] vs. after-meal 6.8 kPa [IQR: 5.5-10.6]; p < 0.001). This difference was only significant in patients with chronic liver disease (p = 0.02) and not in healthy volunteers (p = 0.106). CAP values did not increase significantly after food intake. Gender, body mass index, mass of body fat, lean body mass, and percent of body fat were not related with significant variations of LS and CAP values after meal intake.

Conclusions

Significant variations of LS were observed after ingestion of a standard meal, which may have consequences for patient management. CAP values were not significantly affected by food intake. Therefore, we consider that before the isolated evaluation of CAP, it is not necessary to perform any fasting period.

Individual patient data meta-analysis of controlled attenuation parameter (CAP) technology for assessing steatosis

BACKGROUND & AIMS

The prevalence of fatty liver underscores the need for non-invasive characterization of steatosis, such as the ultrasound based controlled attenuation parameter (CAP). Despite good diagnostic accuracy, clinical use of CAP is limited due to uncertainty regarding optimal cut-offs and the influence of covariates. We therefore conducted an individual patient data meta-analysis.

METHODS

A review of the literature identified studies containing histology verified CAP data (M probe, vibration controlled transient elastography with FibroScan®) for grading of steatosis (S0-S3). Receiver operating characteristic analysis after correcting for center effects was used as well as mixed models to test the impact of covariates on CAP. The primary outcome was establishing CAP cut-offs for distinguishing steatosis grades.

RESULTS

Data from 19/21 eligible papers were provided, comprising 3830/3968 (97%) of patients. Considering data overlap and exclusion criteria, 2735 patients were included in the final analysis (37% hepatitis B, 36% hepatitis C, 20% NAFLD/NASH, 7% other). Steatosis distribution was 51%/27%/16%/6% for S0/S1/S2/S3. CAP values in dB/m (95% CI) were influenced by several covariates with an estimated shift of 10 (4.5-17) for NAFLD/NASH patients, 10 (3.5-16) for diabetics and 4.4 (3.8-5.0) per BMI unit. Areas under the curves were 0.823 (0.809-0.837) and 0.865 (0.850-0.880) respectively. Optimal cut-offs were 248 (237-261) and 268 (257-284) for those above S0 and S1 respectively.

CONCLUSIONS

CAP provides a standardized non-invasive measure of hepatic steatosis. Prevalence, etiology, diabetes, and BMI deserve consideration when interpreting CAP. Longitudinal data are needed to demonstrate how CAP relates to clinical outcomes.

LAY SUMMARY

There is an increase in fatty liver for patients with chronic liver disease, linked to the epidemic of the obesity. Invasive liver biopsies are considered the best means of diagnosing fatty liver. The ultrasound based controlled attenuation parameter (CAP) can be used instead, but factors such as the underlying disease, BMI and diabetes must be taken into account. Registration: Prospero CRD42015027238.

Controlled attenuation parameter using the FibroScan® XL probe for quantification of hepatic steatosis for non-alcoholic fatty liver disease in an Asian population

BACKGROUND

The FibroScan® XL probe reduces failure of liver stiffness measurement (LSM) and unreliable results in obese patients.

OBJECTIVE

The objective of this article is to evaluate the accuracy of controlled attenuation parameter (CAP) obtained using the XL probe for the estimation of hepatic steatosis in patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

Adult NAFLD patients with a liver biopsy within six months were included and were examined with the FibroScan® M and XL probes. Histopathological findings were reported according to the Non-Alcoholic Steatohepatitis Clinical Research Network Scoring System. Participants who did not have fatty liver on ultrasonography were recruited as controls.

RESULTS

A total of 57 NAFLD patients and 22 controls were included. The mean age of the NAFLD patients and controls was 50.1 ± 10.4 years and 20.2 ± 1.3 years, respectively (p = 0.000). The mean body mass index was 30.2 ± 5.0 kg per m2 and 20.5 ± 2.4 kg per m2, respectively (p = 0.000). The distribution of steatosis grades were: S0, 29%; S1, 17%; S2, 35%; S3, 19%. The AUROC for estimation of steatosis grade ≥ S1, S2 and S3 was 0.94, 0.80 and 0.69, respectively, using the M probe, and 0.97, 0.81 and 0.67, respectively, using the XL probe.

CONCLUSION

CAP obtained using the XL probe had similar accuracy as the M probe for the estimation of hepatic steatosis in NAFLD patients.

Lobeglitazone, a Novel Thiazolidinedione, Improves Non-Alcoholic Fatty Liver Disease in Type 2 Diabetes: Its Efficacy and Predictive Factors Related to Responsiveness

Despite the rapidly increasing prevalence of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes (T2D), few treatment modalities are currently available. We investigated the hepatic effects of the novel thiazolidinedione (TZDs), lobeglitazone (Duvie) in T2D patients with NAFLD. We recruited drug-naïve or metformin-treated T2D patients with NAFLD to conduct a multicenter, prospective, open-label, exploratory clinical trial. Transient liver elastography (Fibroscan®; Echosens, Paris, France) with controlled attenuation parameter (CAP) was used to non-invasively quantify hepatic fat contents. Fifty patients with CAP values above 250 dB/m were treated once daily with 0.5 mg lobeglitazone for 24 weeks. The primary endpoint was a decline in CAP values, and secondary endpoints included changes in components of glycemic, lipid, and liver profiles. Lobeglitazone-treated patients showed significantly decreased CAP values (313.4 dB/m at baseline vs. 297.8 dB/m at 24 weeks; P = 0.016), regardless of glycemic control. Lobeglitazone improved HbA(1C) values (7.41% [57.5 mM] vs. 6.56% [48.2 mM]; P < 0.001), as well as the lipid and liver profiles of the treated patients. Moreover, multivariable linear regression analysis showed that hepatic fat reduction by lobeglitazone was independently associated with baseline values of CAP, liver stiffness, and liver enzymes, and metformin use. Lobeglitazone treatment reduced intrahepatic fat content, as assessed by transient liver elastography, and improved glycemic, liver, and lipid profiles in T2D patients with NAFLD. Further randomized controlled trials using liver histology as an end point are necessary to evaluate the efficacy of lobeglitazone for NAFLD treatment.

Diagnostic Accuracy of Controlled Attenuation Parameter for Detecting Hepatic Steatosis in Patients with Chronic Liver Disease

Introduction

Controlled attenuation parameter (CAP), measured by transient elastography, has been suggested as a noninvasive method for the detection and quantification of steatosis. We aimed to assess the accuracy of CAP to detect steatosis in patients with chronic liver disease (CLD) compared with liver histology and to evaluate factors that correlate with the CAP value.

Methods

Patients with CLD who underwent liver biopsy and simultaneous CAP determination were consecutively enrolled. CAP was measured using the M probe of FibroScan® (Echosens, Paris, France). Histologically, steatosis was categorized as absent (S0: <5%), mild (S1: 5-33%), moderate (S2: 34-66%) and severe (S3: >66% of all hepatocytes).

Results

We analyzed 159 patients with CLD (61% men, mean age 47.9 ± 12.9 years). We found a positive correlation between CAP and steatosis in histology (r_s = 0.869, p < 0.001), arterial hypertension (r_s = 0.222, p = 0.005), type 2 diabetes mellitus (r_s = 0.279, p < 0.001), body mass index (BMI; r_s = 0.533, p < 0.001), total cholesterol (r_s = 0.442, p < 0.001), triglycerides (r_s = 0.272, p = 0.001), and non-alcoholic fatty liver disease (NAFLD; r_s = 0.588, p < 0.001). In the multivariate analysis, BMI >25 (odds ratio [OR] 48.4, 95% confidence interval [CI] 23.78-72.95, p < 0.001), serum total cholesterol (OR 3.803, 95% CI 2.203-13.889, p = 0.008), and NAFLD etiology (OR 40.8, 95% CI 15.01-66.66, p = 0.002) were independently associated with higher CAP values. We did not find any significant correlation between CAP and the grade of necroinflammatory activity (r_s = 0.063, p = 0.808) or fibrosis (r_s = 0.071, p = 0.713) in histology and with alanine aminotransferase (r_s = 0.190, p = 0.356) or aspartate aminotransferase (r_s = 0.117, p = 0.142). Optimal CAP cutoff values for detecting steatosis ≥S1, ≥S2, and ≥S3 were 206.5, 232.5, and 282.5 dB/m, respectively. CAP performance was 0.822, 0.956, and 0.976 for diagnosing steatosis ≥S1, ≥S2, and ≥S3, respectively.

Conclusions

CAP had an excellent diagnostic accuracy for the detection of steatosis in diverse CLD patients. A CAP value cutoff of <282.5 dB/m excludes severe steatosis ≥S3 with an accuracy of 98%.

Transient elastography (FibroScan®) with controlled attenuation parameter in the assessment of liver steatosis and fibrosis in patients with nonalcoholic fatty liver disease - Where do we stand?

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Currently, the routinely used modalities are unable to adequately determine the levels of steatosis and fibrosis (laboratory tests and ultrasonography) or cannot be applied as a screening procedure (liver biopsy). Among the non-invasive tests, transient elastography (FibroScan^®, TE) with controlled attenuation parameter (CAP) has demonstrated good accuracy in quantifying the levels of liver steatosis and fibrosis in patients with NAFLD, the factors associated with the diagnosis and NAFLD progression. The method is fast, reliable and reproducible, with good intra- and interobserver levels of agreement, thus allowing for population-wide screening and disease follow-up. The initial inability of the procedure to accurately determine fibrosis and steatosis in obese patients has been addressed with the development of the obese-specific XL probe. TE with CAP is a viable alternative to ultrasonography, both as an initial assessment and during follow-up of patients with NAFLD. Its ability to exclude patients with advanced fibrosis may be used to identify low-risk NAFLD patients in whom liver biopsy is not needed, therefore reducing the risk of complications and the financial costs.

Discrimination of Nonalcoholic Steatohepatitis Using Transient Elastography in Patients with Nonalcoholic Fatty Liver Disease

Background/aims

The accuracy of noninvasive markers to discriminate nonalcoholic steatohepatitis (NASH) is unsatisfactory. We investigated whether transient elastography (TE) could discriminate patients with NASH from those with nonalcoholic fatty liver disease (NAFLD).

Methods

The patients suspected of NAFLD who underwent liver biopsy and concomitant TE were recruited from five tertiary centers between November 2011 and December 2013.

Results

The study population (n = 183) exhibited a mean age of 40.6 years and male predominance (n = 111, 60.7%). Of the study participants, 89 (48.6%) had non-NASH and 94 (51.4%) had NASH. The controlled attenuation parameter (CAP) and liver stiffness (LS) were significantly correlated with the degrees of steatosis (r = 0.656, P<0.001) and fibrosis (r = 0.714, P<0.001), respectively. The optimal cut-off values for steatosis were 247 dB/m for S1, 280 dB/m for S2, and 300 dB/m for S3. Based on the independent predictors derived from multivariate analysis [P = 0.044, odds ratio (OR) 4.133, 95% confidence interval (CI) 1.037–16.470 for CAP>250 dB/m; P = 0.013, OR 3.399, 95% CI 1.295–8.291 for LS>7.0 kPa; and P<0.001, OR 7.557, 95% CI 2.997–19.059 for Alanine aminotransferase>60 IU/L], we developed a novel CLA model for discriminating patients with NASH. The CLA model showed good discriminatory capability, with an area under the receiver operating characteristic curve (AUROC) of 0.812 (95% CI 0.724–0.880). To assess discriminatory power, the AUROCs, as determined by the bootstrap method, remained largely unchanged between iterations, with an average value of 0.833 (95% CI 0.740–0.893).

Conclusion

This novel TE-based CLA model showed acceptable accuracy in discriminating NASH from simple steatosis. However, further studies are required for external validation.

[A new non-invasive method for assessing steatosis in chronic liver diseases]

AIM

To assess the diagnostic accuracy of the controlled attenuation parameter (CAP) to determine the grade of hepatic steatosis (HS) in patients with chronic liver diseases (CLD) of different etiologies and to compare the obtained results with morphological findings.

MATERIALS AND METHODS

A total of 45 patients (18 men and 27 women) aged 25 to 73 years with CLD were examined. All the patients underwent liver puncture biopsy for assessing the HS index and fibrosis stage, as well as determination of hepatic elasticity (F, kPa) for estimating the stage of fibrosis and the grade of HS by CAP (S, dB/m) using a FibroScan device. When assessing HS, the CAP values of <229, 230-249, 250-276, and more than 277 dB/m correspond to HS grade 0 (S0), S1, S2, and S3, respectively. This is a pilot study in Russia.

RESULTS

CAP is a rather high effective method in determining the absence of steatosis (S0) (the area under the receiver operating characteristics curve (AUROC) was 0.78) and severe steatosis (S3) (AUROC 0.90). AUROC was 0.64 and 0.59 for HS S1 and S2, which is regarded as satisfactory and poor

RESULTS

respectively. Only 3 out of the 45 patients had HS, as evidenced by morphological examination; and the results of CAP showed another result; all the other cases had a HS grade corresponding to S1. In the entire cohort of the examinees, the sensitivity, specificity, and accuracy of CAP was 86, 69.5, and 78%, respectively; AUROC was 0.77 (95% CI, 0.6587-0.9006; p=0.40).

CONCLUSION

CAP is a promising method for the rapid and non-invasive diagnosis of HS in patients with CLD. At the same time, our findings show that it is necessary to clarify the quantitative indicators of the compliance of CAP and morphological evaluation of HS.

Noninvasive assessment of alcoholic liver disease using unidimensional transient elastography (Fibroscan®)

Unidimensional transient elastography (TE) is a noninvasive technique, which has been increasingly used in the assessment of diffuse liver diseases. This paper focuses on reviewing the existing data on the use of TE in the diagnosis of fibrosis and in monitoring disease progression in alcoholic liver disease, on the factors that may influence the result of fibrosis prediction, and last but not least, on its potential use in assessing the steatosis degree. Therefore, this field is far from being exhausted and deserves more attention. Further studies are required, on large groups of biopsied patients, in order to find answers to all the remaining questions in this field.