Utility of controlled attenuation parameter measurement for assessing liver steatosis in Japanese patients with chronic liver diseases

High-density lipoproteins and non-alcoholic fatty liver disease

Background and aims

Non-alcoholic fatty liver disease (NAFLD), a high incidence liver pathology, is associated with a ∼1.5-fold higher cardiovascular disease risk. This phenomenon is generally attributed to the NAFLD-associated increase in circulating levels of pro-atherogenic apolipoprotein B100-containing small dense low-density lipoprotein and plasma hypertriglyceridemia. However, also a significant reduction in cholesterol transported by anti-atherogenic high-density lipoproteins (HDL) is frequently observed in subjects suffering from NAFLD as compared to unaffected people. In this review, we summarize data regarding the relationship between NAFLD and plasma HDL-cholesterol levels, with a special focus on highlighting potential causality between the NAFLD pathology and changes in HDL metabolism.

Methods and results

Publications in PUBMED describing the relationship between HDL levels and NAFLD susceptibility and/or disease severity, either in human clinical settings or genetically-modified mouse models, were critically reviewed for subsequent inclusion in this manuscript. Furthermore, relevant literature describing effects on lipid loading in cultured hepatocytes of models with genetic alterations related to HDL metabolism have been summarized.

Conclusions

Although in vitro observations suggest causality between HDL formation by hepatocytes and protection against NAFLD-like lipid accumulation, current literature remains inconclusive on whether relative HDL deficiency is actually driving the development of fatty liver disease in humans. In light of the current obesity pandemic and the associated marked rise in NAFLD incidence, it is of clear scientific and societal interest to gain further insight into the relationship between HDL-cholesterol levels and fatty liver development to potentially uncover the therapeutic potential of pharmacological HDL level and/or function modulation.

Imaging of Castleman Disease

Castleman disease (CD) is a group of rare and complex lymphoproliferative disorders that can manifest in two general forms: unicentric CD (UCD) and multicentric CD (MCD). These two forms differ in clinical manifestation, imaging appearances, treatment options, and prognosis. UCD typically manifests as a solitary enlarging mass that is discovered incidentally or after development of compression-type symptoms. MCD usually manifests acutely with systemic symptoms including fever and weight loss. As a whole, CD involves lymph nodes throughout the chest, neck, abdomen, pelvis, and axilla and can have a wide variety of imaging appearances. Most commonly, lymph nodes or masses in UCD occur in the chest, classically with well-defined borders, hyperenhancement, and possible characteristic patterns of calcification and/or feeding vessels. Lymph nodes affected by MCD, while also hyperenhancing, tend to involve multiple nodal chains and manifest alongside anasarca or hepatosplenomegaly. The polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) subtype of MCD may demonstrate lytic or sclerotic osseous lesions in addition to features typical of MCD. Since a diagnosis of CD based solely on imaging findings is often not possible, pathologic confirmation with core needle biopsy and/or surgical excision is necessary. Nevertheless, imaging plays a crucial role in supporting the diagnosis of CD, guiding appropriate regions for biopsy, and excluding other potential causes or mimics of disease. CT is frequently the initial imaging technique used in evaluating potential CD. MRI and PET play important roles in thoroughly evaluating the disease and determining its extent, especially the MCD form. Complete surgical excision is typically curative for UCD. MCD usually requires systemic therapy. ^©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

The Accuracy of Ultrasound Controlled Attenuation Parameter in Diagnosing Hepatic Fat Content

Purpose

The Controlled Attenuation Parameter (CAP score) is based on ultrasonic properties of retropropagated radiofrequency signals acquired by Fibroscan^TM (Echosens, Paris, France). Since ultrasound propagation is influenced by the presence of fat, CAP score was developed to quantify steatosis. The aim of this study was to delineate the accuracy of CAP in diagnosing hepatic steatosis, compared to the gold standard of liver biopsy.

Patients and Methods

A total of 150 patients underwent same-day liver biopsy and measurement of hepatic steatosis with Fibroscan. Only examinations with 10 satisfactory measurements, and an inter-quartile range of less than 30% of the median liver stiffness values were included for data analysis. Histological staging was then correlated with median values and Spearman correlation calculated. P values of <0.05 were considered statistically significant.

Results

For diagnosis of hepatic steatosis (HS), CAP could predict the steatosis S2 with AUROC 0.815 (95% CI 0.741-0.889), sensitivity (0.81) and specificity (0.73) when the optimal cut-off value was set at 288 dB/m. CAP detected histological grade S3 with AUROC 0.735 (95% CI 0.618-0.851), sensitivity (0.71) and specificity (0.74), with a cut-off value of 330 dB/m. The AUROC for steatosis grade S1 was 0.741 (95% CI 0.650-0.824), with a cut-off value of 263 dB/m with sensitivity 0.75 and specificity 0.70. Univariate analysis showed a correlation between CAP and diabetes (p 0.048).

Conclusion

The performance of CAP to diagnose steatosis severity decreases as steatosis progresses. CAP is associated with diabetes but not other clinical factors and parameters of the metabolic syndrome.

Serum Cardiotrophin-1 Concentration Is Negatively Associated with Controlled Attenuation Parameters in Subjects with Non-Alcoholic Fatty Liver Disease

Background: Since non-alcoholic fatty liver disease (NAFLD) is highly associated with obesity, cardiovascular disease, and diabetes, biomarkers for the diagnosis of NAFLD have become an important issue. Although cardiotrophin-1 (CT-1) has a protective effect on the liver in NAFLD animal models, the serum levels of CT-1 in human subjects with NAFLD were still unknown. Objective: The present study aimed to investigate the relationship between the circulating concentration of CT-1 and the severity of hepatic steatosis graded by the value of the controlled attenuation parameter (CAP) in humans. Design and Methods: The study was designed as a cross-sectional study, and a total of 182 subjects were enrolled. Hepatic steatosis measurement was carried out with a Firoscan® device and recorded by CAP. The enrolled study subjects were categorized into CAP < 238 dB/m, 238 ≤ CAP ≤ 259 dB/m, 260 ≤ CAP ≤ 290 dB/m, and CAP > 290 dB/m. Serum CT-1 concentrations were determined by enzyme-linked immunosorbent assay. The association between the serum CT-1 concentration and NAFLD was examined by multivariate linear regression analysis. Results: Body mass index, percentage of body fat, systolic and diastolic blood pressure, alanine aminotransferase (ALT), cholesterol, triglyceride, hemoglobin A1c and homeostatic model assessment for insulin resistance (HOMA-IR) were significantly increased in groups with higher CAP value, whereas high-density lipoprotein cholesterol was significantly decreased. In addition, serum CT-1 concentrations were significantly decreased in subjects with higher CAP values. In multivariate linear regression models, including age, sex, body fat percentage, CAP, high sensitivity- C reactive protein, uric acid, creatinine, ALT, total cholesterol, and HOMA-IR, only age, CAP and uric acid independently associated with CT-1 levels. Moreover, having NAFLD was independently associated with CT-1 after adjustment for sex, obesity and type 2 diabetes. Conclusions: Serum CT-1 concentrations are decreased in subjects with NAFLD and negatively associated with CAP.

The Effect of Walking Combined with Neuromuscular Electrical Stimulation on Liver Stiffness and Insulin Resistance in Patients with Non-alcoholic Fatty Liver Disease: An Exploratory Randomized Controlled Trial

Increased liver stiffness and insulin resistance are important therapeutic targets in patients with nonalcoholic fatty liver disease (NAFLD). A hybrid training system (HTS) has been developed which combines application of electrical stimulation and volitional contractions. We compared the effect of walking exercise (5.6 km/h) both with and without simultaneous HTS on liver stiffness and insulin resistance. In a single-blind, controlled trial, 32 subjects with NAFLD were randomized to 12 weeks of triweekly 30 minute walking exercise with either HTS (HTS group) or without HTS (control group). Transient elastography for the assessment of liver stiffness, body weight, visceral fat, the homeostasis model assessment of insulin resistance, fasting blood glucose, serum aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transpeptidase were evaluated. Data were evaluated using the linear model after adjusting the baseline value. In the subjects with BMI of 27 kg/m² or more, the decrement of transient elastography in the HTS group was significantly larger than in the control group (mean ± standard error: Δ2.13 ± 0.64 kPa vs. Δ-0.67 ± 0.42 kPa, p=0.0009). There were no significant differences between groups in other endpoints. These results showed that simultaneously combining electrical stimulation with walking exercise could potentially improve liver stiffness in people who have NAFLD. In fact, because the exercise effect was increased by HTS without increasing the walking speed, this HTS could be especially useful for obese or overweight subjects, in whom NAFLD and joint problems often coexist. However, its effects on insulin resistance and body composition were not clear.

Quantitative Evaluation of Hepatic Steatosis Using Advanced Imaging Techniques: Focusing on New Quantitative Ultrasound Techniques

Nonalcoholic fatty liver disease, characterized by excessive accumulation of fat in the liver, is the most common chronic liver disease worldwide. The current standard for the detection of hepatic steatosis is liver biopsy; however, it is limited by invasiveness and sampling errors. Accordingly, MR spectroscopy and proton density fat fraction obtained with MRI have been accepted as non-invasive modalities for quantifying hepatic steatosis. Recently, various quantitative ultrasonography techniques have been developed and validated for the quantification of hepatic steatosis. These techniques measure various acoustic parameters, including attenuation coefficient, backscatter coefficient and speckle statistics, speed of sound, and shear wave elastography metrics. In this article, we introduce several representative quantitative ultrasonography techniques and their diagnostic value for the detection of hepatic steatosis.

The liver steatosis severity and lipid characteristics in primary biliary cholangitis

Background

Patients with primary biliary cholangitis (PBC) often have comorbid dyslipidemia, and determining the degree of hepatic steatosis can help predict the risk of cardiovascular events in PBC patients. The aim of our study was to analyze the characteristics of lipid distribution and the degree of hepatic steatosis in PBC.

Methods

We retrospectively analyzed 479 cases of PBC, chronic hepatitis B (CHB), chronic hepatitis C (CHC), non-alcoholic fatty liver disease (NAFLD), and healthy subjects (Normal) diagnosed by liver biopsy or definitive clinical diagnosis. Controlled attenuation parameter (CAP) values were applied to assess the degree of steatosis of the liver, and lipid levels were also compared in the five cohorts.

Results

We found that among the five groups of subjects, the PBC group had the lowest CAP values (P < 0.001), and the high-density lipoprotein cholesterol (HDL-C) level in the PBC group was higher than normal, CHC and CHB group (P = 0.004, P = 0.033, P < 0.001, respectively).In the multivariate linear analysis, only BMI (β = 1.280, P = 0.028), ALP (β = − 0.064, P = 0.012), TBA (β = − 0.126, P = 0.020), TG (β = 12.520, P = 0.000), HDL-C (β = − 11.338, P = 0.001) and LDL-C (β = 7.012, P = 0.002) were independent predictors of CAP.

Conclusions

Among PBC, CHB, CHC, NAFLD and healthy subjects, PBC had the lowest degree of hepatic steatosis and higher HDL-C levels, all of which were found to be protective factors against atherosclerosis and cardiovascular risk and would provide a valuable reference for the risk of developing cardiovascular events in PBC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01974-4.

Estimation of Liver Fat by FibroScan in Patients With Nonalcoholic Fatty Liver Disease

Background

Assessment of nonalcoholic fatty liver disease (NAFLD) includes estimation of liver fat (steatosis). Controlled attenuation parameter (CAP) value obtained by FibroScan^® (Echosens, Paris, France) is an alternative to liver biopsy for diagnosing and estimating steatosis (S). This study aimed to estimate the liver fat by CAP in NAFLD patients.

Methods

An observational cross-sectional study was conducted at the Liver Unit of Bir Hospital, from January 2021 to May 2021 after ethical clearance from the Institutional Review Board of the National Academy of Medical Sciences. A convenient sampling method was used. Data were analyzed with descriptive and inferential statistics involving bivariate and multivariate analysis.

Results

A total of 127 NAFLD patients were enrolled. The mean (±SD) CAP value was 271.53 (±50.69) dB/m. Total cholesterol, triglyceride, and body mass index (BMI) correlated positively (p<0.05) while systolic blood pressure correlated negatively with CAP value (p=0.031). On multivariate analysis, patients with BMI ≥25 kg/m² were found 3.7 times more likely to have CAP ≥291 dB/m (S3, severe steatosis) than those with BMI <25 kg/m² (p=0.048, 95% CI 1.01, 13.50). The mean (±SD) CAP values were 276.19 (±49.93) and 246.60 (±48.50) dB/m among those with BMI ≥25 kg/m² and <25 kg/m², respectively (p=0.016, using independent t-test). CAP steatosis grading correlated positively with both the ultrasound grading (p<0.001) and fibrosis grading by liver stiffness measurement (p=0.004). 

Conclusion

In this observational cross-sectional study of NAFLD patients, the mean (±SD) CAP value was 271.53 (±50.69) dB/m, which corresponds to moderate steatosis (S2). Obese NAFLD patients with ≥25 kg/m² were 3.7 times more likely to have severe steatosis (S3) than nonobese NAFLD patients with BMI <25 kg/m².

Assessment of Hepatic Steatosis in Patients with Chronic Hepatitis B Using Fibroscan and its Relation to Insulin Resistance

Background & Aim:

Simple hepatic steatosis is a benign condition, but it may cause serious liver damage as it may lead to steatohepatitis, fibrosis and cirrhosis. The Controlled Attenuation Parameter (CAP) of fibroscan assesses hepatic steatosis. The aim of this work was to assess hepatic steatosis in patients with chronic hepatitis B infection using FibroScan and to detect its relation to insulin resistance.

Methods:

Seventy-seven patients with chronic HBV were enrolled in this study. Body mass index, complete lipid profile, fasting insulin, HOMA-IR, pelviabdominal ultrasound and fibroscan were assessed in all patients.

Results:

According to the presence of significant steatosis, seventy-seven patients enrolled in this study were divided into different groups, such as group I 47 patients (61.04%) with CHB virus infection with non-significant steatosis and group II 30 patients (38.96%) with CHB infection with significant steatosis. There was a statistically significant increase in fasting insulin and HOMA-IR in group II (p-value <0.001). CAP results ranged from 100-396 db/m with no significant difference in liver stiffness measurements in two studied groups (P value= 0.886). There was a significant positive correlation between the degree of hepatic steatosis measured by fibroscan and fasting insulin blood level, HOMA-IR, serum cholesterol and LDL. At cutoff > 222 db/m steatosis measured by fibroscan had a sensitivity of 63.33% and specificity of 82.35% for the detection of insulin resistance.

Conclusion:

In CHB infected patients, steatosis measurement by fibroscan was a strong predictor of Insulin Resistance (IR) and vice versa.

The clinical usefulness of elastography in the evaluation of nonalcoholic fatty liver disease patients: A biopsy-controlled study

BACKGROUND

We aimed at determination of the usefulness of elastography [acoustic radiation force impulse (ARFI) and FibroScan] for evaluation of nonalcoholic fatty liver disease (NAFLD) patients.

PATIENTS AND METHODS

A prospective cross-sectional study included 60 biopsy-proven NAFLD patients (mean age: 45 years) was carried out. All patients were subjected to lab works, liver biopsy, and measurement of liver stiffness by ARFI and FibroScan and steatosis by controlled attenuation parameter (CAP). CAP measurements were adjusted for the presence of NAFLD and presence or absence of diabetes and according to BMI.

RESULTS

Linear regression analysis showed that CAP is an independent predictor for significant hepatic steatosis (P<0.001). No significant difference was found in diagnostic accuracy between adjusted and nonadjusted CAP values for diagnosis of mild (>S1) or significant (>S2) hepatic steatosis (P=0.17 and 0.29 respectively). The median ARFI velocities for F1, F2, F3, and F4 were 0.92, 1.08, 1.07, and 2.58 m/s, respectively. Although there was an overall significant increase in ARFI values across the fibrosis grades (P<0.04), the difference in ARFI values was only significant between fibrosis grades F1 and F4 (P=0.02).

CONCLUSION

Elastography is a promising noninvasive tool for diagnosis and grading of hepatic steatosis and fibrosis in patients with NAFLD/nonalcoholic steatohepatitis with good sensitivity and specificity, especially in moderate to marked grades.

Practical Use of Transient Elastography in Screening for Nonalcoholic Steatohepatitis in a Japanese Population

Background and Aims: Fatty infiltration of liver may induce insulin resistance (IR), and a proportion of patients with nonalcoholic fatty liver disease (NAFLD) is diagnosed with nonalcoholic steatohepatitis. Transient elastography is gaining popularity as a means of non-invasively determining both liver stiffness (fibrosis level) and degree of fatty infiltration, expressed as controlled attenuation parameter (CAP) value. Methods: The aims of this study were to investigate the association between IR and level of fatty liver, and to identify the group at a greater risk of nonalcoholic steatohepatitis using transient elastography and other noninvasive fibrosis markers. A total of 169 patients without chronic hepatitis B and C were analyzed. Results: The CAP value was significantly associated with IR (HOMA-IR ≥2.5; AUROC = 0.81), and the optimal cut-off to discriminate IR was 264 dB/m. The liver stiffness measurement and aspartate aminotransferase-to-platelet ratio index values were significantly higher for CAP ≥264 than in CAP <264. The 9 patients among the overall 169 patients (5.3%) and among the 102 NAFLD patients (8.8%) who showed ≥264 dB and ≥7.0 kPa in transient elastography could represent good candidates for liver biopsy. Conclusions: Evaluation of NAFLD based on CAP values was useful in diagnosing IR. About 9% of NAFLD patients in a Japanese outpatient clinic with a few metabolic complications might be considered good candidates for liver biopsy to confirm nonalcoholic steatohepatitis.

High Fib4 index in patients with suspected NASH is associated with elevation of chymase-dependent angiotensin II-forming activity in circulating mononuclear leucocytes

Fatal hepatic disease is closely related to non-alcoholic fatty liver disease, especially non-alcoholic steatohepatitis (NASH). NASH is associated with cardiovascular events because it develops on the background of lifestyle-related diseases. Chymase-dependent angiotensin II-forming activity (dAIIFA) in circulating mononuclear leucocytes (CML) is a marker of local angiotensin II production and inflammation. This study investigated the association between CML chymase dAIIFA and NASH. Cardiovascular outpatients were recruited and the Fib4 index (F4I) was calculated. Patients with an F4I > 2.67 were classified into the high F4I group and these patients were strongly suspected to have NASH, while patients with an F4I < 1.30 were classified into the low F4I group. Patient background factors were compared between these groups. CML chymase dAIIFA was measured by ELISA using Nma/Dnp-modified angiotensin I. Among 499 patients, 16% were classified into the high F4I group. Compared with the low F4I group, the high F4I group had a significantly higher age, pancytopenia, more frequent diabetes mellitus, lower diastolic blood pressure, lower estimated glomerular filtration rate, higher brain natriuretic peptide, lower plasma aldosterone concentration, higher total AIIFA, higher CML chymase dAIIFA, and higher pulse wave velocity. Contrary to expectations, the body mass index, triglycerides, and low-density lipoprotein cholesterol were relatively low in the high F4I group. Many cardiovascular outpatients have a high F4I and can probably be categorized as NASH. The high F4I patients had few features of metabolic syndrome and were suspected to have elevated tissue chymase dAIIFA contributing to inflammation in the liver as well as in cardiovascular organs.

Controlled Attenuation Parameter for Assessment of Hepatic Steatosis in Indian Patients

BACKGROUND/AIMS

The gold standard method for measurement of hepatic steatosis is liver histology. Controlled Attenuation Parameter (CAP) can measure hepatic steatosis non-invasively. We aimed to assess the accuracy of CAP for detection of hepatic steatosis.

METHODS

A total of 462 patients (May 2012-January 2017)-89 non-alcoholic fatty liver disease, 182 chronic hepatitis B, 88 chronic hepatitis C and 103 patients with other etiologies who underwent simultaneous liver biopsy and CAP estimation using Transient Elastography (TE) were included. Steatosis was graded as S0: steatosis in 0-5% of hepatocytes, S1: 6-33%, S2: 34-66% and S3: 67-100%. Receiver Operating Characteristic (ROC) curves were plotted to evaluate the accuracy of CAP in detecting hepatic steatosis. Predictors of CAP were assessed by multivariate linear regression model.

RESULTS

The mean age ± SD was 33.8 ± 11.6 years; 296 (64.1%) were males. On liver histology, steatosis grades S0, S1, S2 and S3 were seen in 331 (71.6%), 74 (16.0%), 39 (8.4%) and 18 (3.9%), respectively. The median CAP (IQR) values for S0, S1, S2, and S3 steatosis were 206 (176-252) dB/m, 295 (257-331) dB/m, 320 (296-356) dB/m, and 349 (306-363) dB/m, respectively. For estimation of ≥S1, ≥S2, and ≥S3 using CAP, AUROC were 0.879, 0.893, and 0.883, respectively. In multivariate analysis, only BMI (OR 1.18; CI, 1.11-1.26, P < 0.001) and grade of hepatic steatosis (grade 1, OR, 3.94; 95% CI, 1.58-9.84, P = 0.003; grade 2, OR 42.04; 95% CI, 4.97-355.31, P = 0.001 and grade 3, OR 35.83; 95% CI 4.31-297.61, P = 0.001) independently predicted CAP.

CONCLUSIONS

CAP detects hepatic steatosis with good accuracy in Indian patients with various etiologies.

Predictors of treatment efficacy and liver stiffness changes following therapy with Sofosbuvir plus Ribavirin in patients infected with HCV genotype 2

While the combination therapy of ribavirin (RBV) and sofosbuvir (SOF) is effective in genotype 2 HCV infection, the predictors of treatment efficacy and posttreatment changes in α-fetoprotein (AFP) and liver stiffness (markers of hepatocellular carcinoma), remain unclear. In this study, 302 patients with chronic HCV genotype 2 infection were treated with SOF (400 mg) plus RBV (400-1000 mg; based on body weight) for 12 weeks. We evaluated the efficacy and safety of treatment, as well as measured serum AFP, liver stiffness, and controlled attenuation parameter (CAP, a surrogate marker of steatosis) at baseline and within 48 weeks of treatment completion. The intention-to-treat analysis showed a sustained virological response (SVR) rate of 95.7%. None of the patients discontinued treatment due to side effects. Multivariate analysis identified pretreatment (no treatment with interferon), level of AFP (AFP; <10 μg/L), and RBV/body weight (BW) ratio (≥9.0 mg/kg) as independent predictors of SVR. The SVR rate in patients with two predictors of poor response (AFP ≥10 μg/L and RBV/BW ratio <9.0 mg/kg) was significantly lower than in other patients. In the SVR group, posttreatment AFP level and liver stiffness were significantly lower than at baseline. CAP tended to be higher after treatment than at baseline in all patients. SOF plus RBV combination therapy achieved a high SVR rate and was safe in HCV genotype 2 infected patients. Treatment reduced AFP levels and improved liver stiffness, but increased CAP.

A prospective comparative assessment of the accuracy of the FibroScan in evaluating liver steatosis

Background/aims

Recent studies have demonstrated the utility of the FibroScan^® device in diagnosing liver steatosis, but its usefulness has not been thoroughly appraised. We investigated the usefulness of the controlled attenuation parameter (CAP) in detecting and quantifying liver steatosis.

Methods

A prospective analysis was applied to 79 chronic liver disease patients who underwent a liver biopsy, a FibroScan investigation, ultrasonography, and hepatic steatosis index (HSI). The presence and degree of steatosis as measured by the FibroScan device, ultrasonography and HSI were compared with the results for the liver biopsy tissue.

Results

There was substantial concordance between the liver biopsy results and the CAP as evaluated by the kappa (κ) index test for detecting liver steatosis (κ_CAP = 0.77, P<0.001; κ_{ultrasonography} = 0.60, P<0.001; κ_HSI = 0.47, P<0.001). The areas under the receiver operating characteristic curve (AUROCs) of the CAP, ultrasonography, and HSI were 0.899 [95% confidence interval (CI) = 0.826–0.972)], 0.859 (95% CI = 0.779–0.939), and 0.766 (95% CI = 0.655–0.877), respectively. The optimal CAP cutoff value for differentiating between normal and hepatic steatosis was 247 dB/m, which produced sensitivity and specificity values of 91.9% and 85.7%, respectively, as well as a positive predictive value of 85.0% and a negative predictive value of 92.3%.

Conclusion

The CAP produces results that are highly concordant with those of a liver biopsy in detecting steatosis. Therefore, the CAP is a noninvasive and reliable tool for evaluating liver steatosis, even in the early stages.

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.

Multimaterial Decomposition Algorithm for the Quantification of Liver Fat Content by Using Fast-Kilovolt-Peak Switching Dual-Energy CT: Clinical Evaluation

Purpose To assess the clinical accuracy and reproducibility of liver fat quantification with the multimaterial decomposition (MMD) algorithm, comparing the performance of MMD with that of magnetic resonance (MR) spectroscopy by using liver biopsy as the reference standard. Materials and Methods This prospective study was approved by the institutional ethics committee, and patients provided written informed consent. Thirty-three patients suspected of having hepatic steatosis underwent non-contrast material-enhanced and triple-phase dynamic contrast-enhanced dual-energy computed tomography (CT) (80 and 140 kVp) and single-voxel proton MR spectroscopy within 30 days before liver biopsy. Percentage fat volume fraction (FVF) images were generated by using the MMD algorithm on dual-energy CT data to measure hepatic fat content. FVFs determined by using dual-energy CT and percentage fat fractions (FFs) determined by using MR spectroscopy were compared with histologic steatosis grade (0-3, as defined by the nonalcoholic fatty liver disease activity score system) by using Jonckheere-Terpstra trend tests and were compared with each other by using Bland-Altman analysis. Real non-contrast-enhanced FVFs were compared with triple-phase contrast-enhanced FVFs to determine the reproducibility of MMD by using Bland-Altman analyses. Results Both dual-energy CT FVF and MR spectroscopy FF increased with increasing histologic steatosis grade (trend test, P < .001 for each). The Bland-Altman plot of dual-energy CT FVF and MR spectroscopy FF revealed a proportional bias, as indicated by the significant positive slope of the line regressing the difference on the average (P < .001). The 95% limits of agreement for the differences between real non-contrast-enhanced and contrast-enhanced FVFs were not greater than about 2%. Conclusion The MMD algorithm quantifying hepatic fat in dual-energy CT images is accurate and reproducible across imaging phases. ^© RSNA, 2017 Online supplemental material is available for this article.

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.

A noninvasive diagnostic model to assess nonalcoholic hepatic steatosis in patients with chronic hepatitis B

OBJECTIVE

The objective of this study was to develop a noninvasive diagnostic test for nonalcoholic hepatic steatosis in patients with chronic hepatitis B (CHB) by using routinely available clinical markers.

METHODS

A retrospective study of patients with CHB, with or without hepatic steatosis (fatty change) who were diagnosed with controlled attenuation parameter (CAP) measured by transient elastography were included. Patient information was analyzed on lifestyle; laboratory tests, including serum lipid levels; blood pressure; blood uric acid; and medical history of type 2 diabetes mellitus (T2DM).

RESULTS

A total of 1312 patients were included in the study; 618 patients had confirmed hepatic steatosis. The CAP levels were significantly correlated with patient height (p < 0.001), weight (p < 0.001), waistline measurement (p < 0.001), hipline measurement (p < 0.001), and diastolic blood pressure (DBP) (p < 0.001). Multivariate logistic regression analysis resulted in the development of an equation for the diagnostic of simple steatosis: the fatty liver (FL) test. The area under the receiver operating characteristic (AUROC) curve of the FL test was 0.79 (p < 0.001) in the training group and 0.82 in the validation group. When the FL test was >-0.425, the sensitivity, specificity, positive likelihood ratio (LR) and negative LR were 74.72%, 72.12%, 2.68, and 0.35 respectively. The average FL test result was -0.54 ± 1.26 in patients with CHB without hypertension, and 0.42 ± 1.35, 1.12 ± 1.65, and 1.98 ± 1.22 in patients with hypertension grade 1, 2, and 3, respectively (p < 0.001).

CONCLUSION

This study has demonstrated a noninvasive test for hepatic steatosis in patients with CHB.

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.

Non-invasive diagnosis of hepatic steatosis

Non-invasive diagnosis and quantification of hepatic steatosis rely on two different but complementary approaches: biomarkers or imaging techniques, either ultrasound-based such as liver ultrasonography and controlled attenuation parameter (CAP), or computed tomography (CT) and magnetic resonance imaging (MRI). Scores for the detection of steatosis have not gained much popularity in clinical practice so far. CAP, using the M probe, is the most promising technique but needs to be implemented with the XL probe and compared to ultrasound that, despite its limitations, remains the most widely used method. CT, owing to its low sensitivity and the fact that it involves a potential radiation hazard, is inappropriate. Finally, proton density fat fraction measurement by MRI is currently the most accurate and sensitive imaging method, simpler and more practical than magnetic resonance spectroscopy, but restricted, up to now, just to research and clinical trials.

Controlled attenuation parameter is correlated with actual hepatic fat content in patients with non-alcoholic fatty liver disease with none-to-mild obesity and liver fibrosis

AIM

Non-invasive steatosis-quantifying methods are required for non-alcoholic fatty liver disease (NAFLD) patients in order to monitor disease severity and assess therapeutic efficacy. Controlled attenuation parameter (CAP) evaluated with vibration-controlled transient elastography can predict the presence of steatosis, but its application to absolute hepatic fat quantitation remains unclear. The aim of this st\udy was to examine whether CAP is correlated with real hepatic fat content in NAFLD patients.

METHODS

Eighty-two NAFLD patients who had undergone percutaneous liver biopsy were enrolled. CAP was measured using FibroScan(®) just before liver biopsy. The percentage of fat droplet area to hepatocyte area in biopsied specimen was determined morphometrically using computerized optical image analyzing system. The correlation between CAP and liver histology was examined.

RESULTS

CAP showed an excellent correlation with actual liver fat percentage in the NAFLD patients with body mass index (BMI) of less than 28 kg/m(2) (r = 0.579, P < 0.0001), especially less than 25 kg/m(2) (r = 0.708, P < 0.01), but the meaningful correlation disappeared in the patients with BMI of 28 kg/m(2) or more. In the patients with BMI of less than 28 kg/m(2) , CAP quantitativeness was affected by the presence of stage 2-4 fibrosis, but not the presence of hepatocyte ballooning and severity of lobular inflammation.

CONCLUSION

CAP may be a promising tool for quantifying hepatic fat content in NAFLD patients with none-to-mild obesity and liver fibrosis. Further improvement of CAP performance is needed for the NAFLD patients with BMI of more than 28 kg/m(2) or significant hepatic fibrosis.

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.

Controlled attenuation parameter for the detection of hepatic steatosis in patients with chronic hepatitis B

BACKGROUND

Controlled attenuation parameter (CAP) is a non-invasive method for diagnosing liver steatosis based on vibration-controlled transient elastography. The primary objective of this study was to assess CAP performance and determine the cut-off values for the diagnosis of hepatic steatosis in patients with chronic hepatitis B (CHB) using liver biopsy as a gold standard. The second objective was to apply the cut-off values found in the first cohort to a larger cohort to compare the performance of CAP and ultrasonography.

METHODS

Overall, 189 patients with CHB who underwent liver biopsy and CAP detection and 1707 patients with CHB and CAP who underwent abdominal ultrasonography were prospectively enrolled. The performance of CAP for evaluating hepatic steatosis compared with liver biopsy was calculated using the area under the receiver operating characteristic curve (AUROC).

RESULTS

In the 189 patients who underwent liver biopsy, the cut-offs for the CAP with steatosis S ≥ 1, S ≥ 2 and S ≥ 3 were 222 dB/m, 247 dB/m and 274 dB/m, respectively, and the AUROC were 0.88 (95% confidence interval [CI] = 0.82-0.95), 0.92 (95% CI = 0.87-0.97) and 0.94 (95% CI = 0.90-0.99), respectively. After applying the cut-offs above to the 1707 patients, it was found that CAP had a good concordance with abdominal ultrasonography with steatosis grade > S2. On multivariate analysis, body mass index (p < 0.001), triglyceride level (p < 0.001) and fasting glucose level (p = 0.001) were independent risk factors of CAP.

CONCLUSIONS

CAP had high diagnostic performance for evaluating hepatic steatosis in patients with CHB and had a good concordance with abdominal ultrasonography.

The common PNPLA3 variant p.I148M is associated with liver fat contents as quantified by controlled attenuation parameter (CAP)

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is becoming the most prevalent liver disorder. The PNPLA3 (adiponutrin) variant p.I148M has been identified as common genetic modifier of NAFLD. Our aim was to assess the relationships between genetic risk and non-invasively measured liver fat content.

METHODS

Hepatic steatosis was quantified by transient elastography, using the controlled attenuation parameter (CAP) in 174 patients with chronic liver diseases (50% women, age 18-77 years). In addition, a cohort of 174 gender-matched healthy controls (50% women, age 32-77 years) was recruited. The PNPLA3 mutation as well as the novel NAFLD-predisposing genetic variant (TM6SF2 p.E167K) were genotyped with allele-specific probes.

RESULTS

The PNPLA3 genotype correlated significantly (P = 0.001) with hepatic CAP measurements. The p.148M risk allele increased the odds of developing liver steatosis (OR = 2.39, P = 0.023). In multivariate models, BMI and PNPLA3 mutation were both independently associated with CAP values (P < 0.001 and P = 0.007, respectively). Carriers of the TM6SF2 risk allele presented with increased aminotransferase activities (ALT: P = 0.007, AST: P = 0.004), but the presence of this variant did not affect CAP values.

CONCLUSIONS

The PNPLA3 p.I148M variant represents the most important prosteatotic genetic risk factor. NAFLD carriers of this variant should be followed up carefully, with elastography and CAP being ideally suited for this purpose.

Value of controlled attenuation parameter in diagnosing nonalcoholic fatty liver disease

AIM: To assess the value of controlled attenuation parameter (CAP) in diagnosing nonalcoholic fatty liver disease (NAFLD).

METHODS: From January 2012 to March 2015, 146 NAFLD patients diagnosed by biopsy were enrolled in this study. CAP measurement was conducted by Fibroscan in all patients. The relationships between CAP and body mass index (BMI), aspartate transaminase (ALT), blood lipids and hepatic steatosis were analyzed, and the area under the receiver operating characteristic curve (AUC) was used to determine the diagnostic accuracy of CAP for NAFLD.

RESULTS: A total of 146 patients were recruited, including 58 patients with NAFLD alone and 88 patients with NAFLD and chronic hepatitis B (CHB). CAP was found to be positively correlated with BMI (r = 0.54, P < 0.05) and hepatic steatosis (r = 0.848, P < 0.05), while there was no relationship between CAP and ALT, AST, blood lipid, liver inflammation grade or fibrosis stage. The cut-offs for the CAP values in patients with hepatic steatosis vs mild steatosis, mild steatosis vs moderate steatosis, moderate steatosis vs severe steatosis were 252.50 dB/m, 281.50 dB/m, and 326.50 dB/m, respectively, with AUROC of 0.818, 0.917 and 0.789, respectively.

CONCLUSION: Controlled attenuation parameter appears to be a promising tool for diagnosing NAFLD.

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.

Role of ultrasound in the diagnosis and treatment of nonalcoholic fatty liver disease and its complications

We review the role of liver ultrasonography (US) and related techniques as non-invasive tools in predicting metabolic derangements, liver histology, portal hypertension and cardiovascular risk as well as allowing early diagnosis and management of hepatocellular carcinoma in patients with nonalcoholic fatty liver disease. In this setting, US detects fatty changes as low as ≥20% and hepatic steatosis identified ultrasonographically, in its turn, closely mirrors coronary and carotid atherosclerosis burden. Semi-quantitative US indices (to exclude nonalcoholic steatohepatitis) and sonoelastography (to quantify fibrosis) help in predicting liver histology and selecting patients to submit to liver biopsy. Surveillance for hepatocellular carcinoma conducted through biannual US is mandatory and US has a role in guiding locoregional treatment and in evaluating the efficacy of treatment. High-intensity focused ultrasound can be delivered with precision resulting in coagulative necrosis of hepatocellular carcinoma without puncturing the liver. Costs and inconveniences have so far hampered its diffusion.

Usefulness of liver test and controlled attenuation parameter in detection of nonalcoholic fatty liver disease in patients with chronic renal failure and coronary heart disease

BACKGROUND

In recent years, nonalcoholic fatty liver disease (NAFLD) was recognized as an important factor in chronic kidney disease (CKD) pathogenesis. The concentrations of serum aminotransferases in both chronic dialysis and chronic renal failure (CRF) patients most commonly fall within the lower end of the range of normal values. The aim of the present study was to investigate the usefulness of four liver tests and four biological scores in detection of NAFLD in comparison with transient elastography (TE) findings in different groups of patients.

METHODS

The study was cross-sectional analysis collected data from a single tertiary care center. Of 202 patents there were 52 patients with CKD, 50 patients with end-stage renal disease (ESRD) treated with haemodialysis (HD), 50 renal transplant recipients (RTRs) and 50 patients with proven coronary heart disease (CHD). Fifty sex- and age-matched individuals without NAFLD and with normal liver and kidney function tests served as controls. With the help of TE (FibroScan®, Echosense SA, Paris, France), liver stiffness was selected as the parameter to quantify liver fibrosis and Controlled Attenuation Parameter (CAP) was used to detect and quantify liver steatosis.

RESULTS

According to the CAP findings 76.9 %CKD patients, 82 %HD patients, 74 %RTRs and 69.1 % CHD patients had CAP > 238 dB.m(-1) and thus by definition NAFLD. We have found that ALT, AST and GGT levels were positively correlated with CAP values while ALT and AST showed positive correlation with liver stiffness acquired with TE only in CHD patients. According to TE findings APRI (AUC 0.796) and FIB-4 (AUC 0.790) scores were correlated with the presence of fibrosis, while HIS score was correlated with the presence of steatosis (AUC 0.867) only in CHD patients.

CONCLUSION

Liver tests and biological scores are not useful for NAFLD detection in CRF patients. TE with CAP provides the opportunity of noninvasive screening for NAFLD as well as liver fibrosis in patients with CRF.

Non-invasive assessment of liver steatosis in non-alcoholic fatty liver disease

AIM

The diagnosis of non-alcoholic fatty liver disease (NAFLD) is based on the histological findings. Further, there may be interobserver differences. Liver to spleen (L/S) ratio on computed tomography (CT) is employed to detect or even quantify the fat content of the liver. The objective of this study was to accurately diagnose fatty liver by evaluating the relationship between L/S ratio and histological findings.

METHODS

Sixty-seven biopsy-proven NAFLD patients were enrolled. L/S ratio on CT was calculated. The area of steatosis in liver specimens was measured by BIOREVO BZ-9000 microscope, and the percentage of steatosis was calculated using Dynamic cell count BZ-H1C software.

RESULTS

Steatotic grade assessed by pathologist was significantly correlated with the percentage of steatosis and L/S ratio. Factors associated with steatosis were L/S ratio, aspartate aminotransferase and Homeostasis Model of Assessment - Insulin Resistance as determined by multivariate analysis. L/S ratios were: S0, 1.16 ± 0.20 (mean ± standard deviation); S1, 0.88 ± 0.28; S2, 0.76 ± 0.20; and S3, 0.40 ± 0.18, respectively. The optimal cut-off value of L/S ratio to exclude steatosis was 1.1, and the area under the receiver-operator curve for the diagnosis of steatosis was 0.886.

CONCLUSION

Our study suggests that while 0% of steatosis showed 1.296 L/S ratio, the cut-off value of L/S ratio would be 1.1 at least to exclude clinically important liver steatosis.

Controlled attenuation parameter for the detection and quantification of hepatic steatosis in nonalcoholic fatty liver disease

BACKGROUND AND AIM

Controlled attenuation parameter (CAP) has been suggested as a noninvasive method for detection and quantification of hepatic steatosis. We aim to study the diagnostic performance of CAP in nonalcoholic fatty liver disease (NAFLD) patients.

METHODS

Transient elastography was performed in consecutive NAFLD patients undergoing liver biopsy and non-NAFLD controls. The accuracy of CAP for the detection and quantification of hepatic steatosis was assessed based on histological findings according to the Nonalcoholic Steatohepatitis Clinical Research Network Scoring System.

RESULTS

Data for 101 NAFLD patients (mean age 50.3 ± 11.3 years old, 51.5% male) and 60 non-NAFLD controls were analyzed. CAP was associated with steatosis grade (odds ratio [OR] = 29.16, P < 0.001), body mass index (BMI; OR = 4.34, P < 0.001) and serum triglyceride (OR = 13.59, P = 0.037) on multivariate analysis. The median CAP for steatosis grades S0, S1, S2, and S3 were 184 dB/m, 305 dB/m, 320 dB/m, and 324 dB/m, respectively. The areas under receiver operating characteristics curves (AUROC) for estimation of steatosis grades ≥ S1, S2, and S3 were 0.97, 0.86, and 0.75, respectively. The optimal CAP cutoffs for estimation of steatosis grades ≥ S1, S2, and S3 were 263 dB/m, 281 dB/m, and 283 dB/m, respectively. Among non-obese patients, the AUROC for estimation of steatosis grades ≥ S1 and S2 were 0.99 and 0.99, respectively. Among obese patients, the AUROC for estimation of steatosis grades ≥ S1, S2, and S3 were 0.92, 0.64, and 0.58, respectively.

CONCLUSIONS

CAP is excellent for the detection of significant hepatic steatosis. However, its accuracy is impaired by an increased BMI, and it is less accurate to distinguish between the different grades of hepatic steatosis.

Controlled attenuation parameter for the detection of steatosis severity in chronic liver disease: a meta-analysis of diagnostic accuracy

BACKGROUND AND AIM

Controlled attenuation parameter (CAP) is a novel ultrasound-based elastography method for detection of steatosis severity. This meta-analysis aimed to assess the performance of CAP.

METHODS

PubMed, the Cochrane Library, and the Web of Knowledge were searched to find studies, published in English, relating to accuracy evaluations of CAP for detecting stage 1 (S1), stage 2 (S2), or stage 3 (S3) hepatic steatosis which was diagnosed by liver biopsy. Sensitivities, specificities, and hierarchical summary receiver operating characteristic (HSROC) curves were used to examine CAP performance. The clinical utility of CAP was also evaluated.

RESULTS

Nine studies, with 11 cohorts were analyzed. The summary sensitivities and specificities values were 0.78 (95% confidence interval [CI], 0.69-0.84) and 0.79 (95% CI, 0.68-0.86) for ≥ S1, 0.85 (95% CI, 0.74-0.92) and 0.79 (95% CI, 0.71-0.85) for ≥ S2, and 0.83 (95% CI, 0.76-0.89) and 0.79 (95% CI, 0.68-0.87) for ≥ S3. The HSROCs were 0.85 (95% CI, 0.81-88) for ≥ S1, 0.88 (95% CI, 0.85-0.91) for ≥ S2, and 0.87 (95% CI, 0.84-0.90) for ≥ S3. Following a "positive" measurement (over the threshold value) for ≥ S1, ≥ S2, and ≥ S3, the corresponding post-test probabilities for the presence of steatosis (pretest probability was 50%) were 78%, 80% and 80%, respectively; if the values were below these thresholds ("negative" results), the post-test probabilities were 22%, 16%, and 17%, respectively.

CONCLUSIONS

CAP has good sensitivity and specificity for detecting hepatic steatosis; however, based on a meta-analysis, CAP was limited in their accuracy of steatosis, which precluded widespread use in clinical practice.

Controlled attenuation parameter for non-invasive assessment of hepatic steatosis in Chinese patients

AIM: To evaluate the performance of a novel non-invasive controlled attenuation parameter (CAP) to assess liver steatosis.

METHODS: This was a multi-center prospective cohort study. Consecutive patients (aged ≥ 18 years) who had undergone percutaneous liver biopsy and CAP measurement were recruited from three Chinese liver centers. Steatosis was categorized as S0: < 5%; S1: 5%-33%; S2: 34%-66%; or S3: ≥ 67%, according to the nonalcoholic fatty liver disease (NAFLD) activity score. The FibroScan^® 502 equipped with the M probe (Echosens, Paris, France) was used to capture both CAP and liver stiffness measurement values simultaneously. Receiver operating characteristic curves were plotted, and the areas under the curves were calculated to determine the diagnostic efficacy. The accuracy of the CAP values at the optimal thresholds was defined by maximizing the sum of sensitivity and specificity (maximum Youden index).

RESULTS: A total of 152 patients were recruited, including 52 (34.2%) patients with NAFLD and 100 (65.8%) with chronic hepatitis B (CHB) virus infection. After adjustment, the steatosis grade (OR = 37.12; 95%CI: 21.63-52.60, P < 0.001) and body mass index (BMI, OR = 6.20; 95%CI: 2.92-9.48, P < 0.001) were found independently associated with CAP by multivariate linear regression analysis. CAP was not influenced by inflammation, fibrosis or aetiology. The median CAP values and interquartile ranges among patients with S0, S1, S2 and S3 steatosis were 211 (181-240) dB/m, 270 (253-305) dB/m, 330 (302-360) dB/m, and 346 (313-363) dB/m, respectively. The cut-offs for the CAP values in all patients with steatosis ≥ 5%, ≥ 34% and ≥ 67% were 253 dB/m, 285 dB/m and 310 dB/m, respectively. The areas under the curves were 0.92, 0.92 and 0.88 for steatosis ≥ 5%, ≥ 34% and ≥ 67%, respectively. No significant differences were found in the CAP values between the NAFLD group and the CHB group in each steatosis grade.

CONCLUSION: CAP appears to be a promising tool for the non-invasive detection and quantification of hepatic steatosis, but is limited by BMI.

Noninvasive evaluation of NAFLD

A common clinical concern in patients with NAFLD is whether they have NASH or simple steatosis and, more importantly, what the stage of fibrosis is and whether the level of fibrosis has increased over time. Such concern is based on the fact that patients with NAFLD with advanced fibrosis are at greatest risk of developing complications of end-stage liver disease. Although it lacks sensitivity, ultrasonography is an accepted tool for steatosis screening. The controlled attenuation parameter or CAP seems a promising screening technique, but requires further validation. Cytokeratin-18 has been extensively validated, but it is an imperfect serum marker of NASH. Ultrasonography-based transient elastography can exclude advanced fibrosis and cirrhosis, but its main limitation is its reduced applicability in patients with NAFLD, which is not completely solved by use of the XL probe. Of the noninvasive serum markers, the NAFLD fibrosis score is the most validated and has appropriate accuracy in distinguishing patients with and without advanced fibrosis. Although noninvasive methods require further validation, they could be useful for selecting those patients with NAFLD who require a liver biopsy. This Review discusses the advantages and limitations of noninvasive methods for the management of adults with NAFLD, including diagnosis and quantification of steatosis, diagnosis of NASH and staging of hepatic fibrosis.