Impact of skin capsular distance on the performance of controlled attenuation parameter in patients with chronic liver disease

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 prediction of esophageal varices by stiffness and platelet in non-alcoholic fatty liver disease cirrhosis

BACKGROUND & AIMS

Baveno VI and expanded Baveno VI criteria can avoid the need for esophagogastroduodenoscopy (EGD) to screen for varices needing treatment (VNT) in a substantial proportion of compensated patients with viral and/or alcoholic cirrhosis. This multicenter, cross-sectional study aims to validate these criteria in patients with compensated cirrhosis due to non-alcoholic fatty liver disease (NAFLD), accounting for possible differences in liver stiffness measurement (LSM) values between M and XL probes.

METHODS

We assessed 790 patients with NAFLD-related compensated cirrhosis who had EGD within six months of a reliable LSM, measured by FibroScan® using M and/or XL probe. Baveno VI and expanded Baveno VI criteria were tested. The main variable used to optimize criteria was the percentage of endoscopies spared, keeping the risk of missing large VNT below a 5% threshold.

RESULTS

LSM was measured by both M and XL probes (training set) in 314 patients, while only M or XL probe (validation sets) were used to measure LSM in 338 and 138 patients, respectively. In the training set, use of Baveno VI and expanded Baveno VI criteria reduced the number of EGD by 33.3% and by 58%, with 0.9% and 3.8% of large esophageal varices missed, respectively. The best thresholds to rule-out VNT were identified as platelet count >110,000/mm³ and LSM <30 kPa for M probe, and platelet count >110,000/mm³ and LSM <25 kPa for XL probe (NAFLD cirrhosis criteria). Thus, usage of NAFLD cirrhosis criteria would have led to an absolute reduction in the number of EGD screened patients of 34.7% and 10.5% with respect to Baveno VI and expanded Baveno VI criteria, respectively.

CONCLUSION

The new NAFLD cirrhosis criteria, established for the FibroScan probe, can reduce the use of EGD for screening of VNT in NAFLD cirrhosis by more than half, with a chance of missing VNT below 5%.

LAY SUMMARY

In non-alcoholic fatty liver disease-related compensated cirrhosis, the expanded Baveno VI criteria work better than the Baveno VI criteria for ruling out the presence of varices needing treatment, sparing unnecessary and invasive screening procedures. New diagnostic criteria for this patient group, based on liver stiffness measurement and platelet count, and optimized for the specific FibroScan^® probe used, work better than both Baveno VI and expanded Baveno VI criteria. The accuracy of all non-invasive scoring criteria was lower in non-obese patients.

Controlled attenuation parameter in NAFLD identifies risk of suboptimal glycaemic and metabolic control

AIMS

To examine the relationship between steatosis quantified by controlled attenuation parameter (CAP) values and glycaemic/metabolic control.

METHODS

230 patients, recruited from an Endocrine clinic or primary care underwent routine Hepatology assessment, with liver stiffness measurements and simultaneous CAP. Multivariable logistic regression was performed to identify potential predictors of Metabolic Syndrome (MetS), HbA1c ≥ 7%, use of insulin, hypertriglyceridaemia and CAP ≥ 300 dB/m.

RESULTS

Patients were 56.7 ± 12.3 years of age with a high prevalence of MetS (83.5%), T2DM (81.3%), and BMI ≥ 40 kg/m² (18%). Median CAP score was 344 dB/m, ranging from 128 to 400 dB/m. BMI (aOR 1.140 95% CI 1.068-1.216), requirement for insulin (aOR 2.599 95% CI 1.212-5.575), and serum ALT (aOR 1.018 95% CI 1.004-1.033) were independently associated with CAP ≥ 300 dB/m. Patients with CAP interquartile range < 40 (68%) had a higher median serum ALT level (p = 0.029), greater prevalence of BMI ≥ 40 kg/m² (p = 0.020) and higher median CAP score (p < 0.001). Patients with higher CAP scores were more likely to have MetS (aOR 1.011 95% CI 1.003-1.019), HBA1c ≥ 7 (aOR 1.010 95% CI 1.003-1.016), requirement for insulin (aOR 1.007 95% CI 1.002-1.013) and hypertriglyceridemia (aOR 1.007 95% CI 1.002-1.013).

CONCLUSIONS

Our data demonstrate that an elevated CAP reflects suboptimal metabolic control. In diabetic patients with NAFLD, CAP may be a useful point-of-care test to identify patients at risk of poorly controlled metabolic comorbidities or advanced diabetes.

Noninvasive Quantitative Detection Methods of Liver Fat Content in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) ranges from simple steatosis to NAFLD-related liver cirrhosis and is a main cause of chronic liver diseases. Patients with nonalcoholic steatohepatitis and fibrosis are at a great risk of the progression to cirrhosis or hepatocellular carcinoma, both of which are tightly associated with liver-related mortality. Liver biopsy is still the gold standard for the diagnosis of NAFLD, but some defects, such as serious complications, sampling error and variability in histologic evaluation among pathologists, remain problematic. Therefore, noninvasive, repeatable and accurate diagnostic methods are urgently needed. Ultrasonography is a well-established and lower-cost imaging technique for the diagnosis of hepatic steatosis, especially suitable for population census, but limited by its low sensitivity to diagnose mild steatosis and being highly operator-dependent. Computed tomography also lacks the sensitivity to detect mild steatosis and small changes in fat content, and presents a potential radiation hazard. Controlled attenuation parameter based on the FibroScan^® technology is a promising tool for noninvasive semiquantitative assessment of liver fat content, but the accuracy rate depends on the operator's expertise and is affected by age, width of the intercostal space, skin capsular distance and body mass index. Magnetic resonance imaging and magnetic resonance spectroscopy are regarded as the most accurate quantitative methods for measuring liver fat content in clinical practice, especially for longitudinal follow up of NAFLD patients. In this review, we mainly introduce the current imaging methods that are in use for evaluation of liver fat content and we discuss the advantages and disadvantages of each method.

Noninvasive Assessment of Advanced Fibrosis Based on Hepatic Volume in Patients with Nonalcoholic Fatty Liver Disease

Background/Aims

Noninvasive liver fibrosis evaluation was performed in patients with nonalcoholic fatty liver disease (NAFLD). We used a quantitative method based on the hepatic volume acquired from gadoxetate disodium-enhanced (Gd-EOB-DTPA-enhanced) magnetic resonance imaging (MRI) for diagnosing advanced fibrosis in patients with NAFLD.

Methods

A total of 130 patients who were diagnosed with NAFLD and underwent Gd-EOB-DTPA-enhanced MRI were retrospectively included. Histological data were available for 118 patients. Hepatic volumetric parameters, including the left hepatic lobe to right hepatic lobe volume ratio (L/R ratio), were measured. The usefulness of the L/R ratio for diagnosing fibrosis ≥F3–4 and F4 was assessed using the area under the receiver operating characteristic (AUROC) curve. Multiple regression analysis was performed to identify variables (age, body mass index, serum fibrosis markers, and histological features) that were associated with the L/R ratio.

Results

The L/R ratio demonstrated good performance in differentiating advanced fibrosis (AUROC, 0.80; 95% confidence interval, 0.72 to 0.88) from cirrhosis (AUROC, 0.87; 95% confidence interval, 0.75 to 0.99). Multiple regression analysis showed that only fibrosis was significantly associated with the L/R ratio (coefficient, 0.121; p<0.0001).

Conclusions

The L/R ratio, which is not influenced by pathological parameters other than fibrosis, is useful for diagnosing cirrhosis in patients with NAFLD.

Haptoglobin Genotype and Vitamin E Versus Placebo for the Treatment of Nondiabetic Patients with Nonalcoholic Steatohepatitis in China: A Multicenter, Randomized, Placebo-Controlled Trial Design

INTRODUCTION

Vitamin E is one of the most promising agents for nonalcoholic steatohepatitis (NASH) treatment, and its drug responsiveness may be closely associated with haptoglobin (Hp) genotype. However, its efficacy and safety remain unknown in China. This clinical trial of vitamin E versus placebo for the treatment of nondiabetic patients with nonalcoholic steatohepatitis (VENS) is conducted to evaluate (a) the efficacy and safety of treatment with vitamin E softgel (300 mg/day) determined from standardized histologic scoring of liver biopsies, (b) whether treatment with vitamin E improves biochemical parameters, cytokines, anthropometric parameters, controlled attenuation parameter (CAP), and transient elastography (TE) values determined by Fibroscan and health-related quality of life (SF-36), (c) whether the efficacy of vitamin E treatment is associated with the Hp genotype in nondiabetic adults with NASH.

METHODS

VENS is a multicenter, randomized, double-masked, placebo parallel controlled trial to evaluate the efficacy and safety of treatment with vitamin E softgel in nondiabetic adults with NASH versus treatment with placebo in China. Liver biopsies are read by a pathological evaluation committee independently according to the NASH Clinical Research Network (CRN) scoring system. The NAFLD activity score (NAS) represents the sum of scores for steatosis, lobular inflammation, and hepatocyte ballooning. The definition of histologic improvement requires all three of the following criteria to be met: (a) either improvement in NAS by at least 2 points or post-treatment NAS score no higher than 3, (b) at least 1-point improvement in the score for ballooning, and (c) no worsening of fibrosis stages. We plan to recruit 120 biopsy-proven NASH patients from13 centers in China. Participants will be randomly assigned to groups treated with either with vitamin E (100 mg, tid) or placebo for 96 weeks then followed by 24 weeks of post-treatment observation. Biochemical parameters, cytokines, anthropometric parameters, CAP and TE values, Hp genotype, and several questionnaires will be collected as per the schedule. This protocol was approved by the Ethics Committee of Hangzhou Normal University Affiliated Hospital to ensure patients safety, and R&G Pharmastudies Co., Ltd. was established for monitoring the accumulated interim data to review efficacy and quality of data collection and overall study management.

RESULTS

As a preliminary study, a mobile phone application (app) for lifestyle modification and database recording ( http://laiyivens.365hy.com ) was exploited for every participant. The percentage of NAFLD patients with Hp 2-2 allele is much higher than that of Western patients (65.71% vs 36%, respectively), which suggests that the Chinese benefit more from vitamin E treatment.

CONCLUSION

VENS is the first randomized controlled trial (RCT) to evaluate the efficacy of Vitamin E in treating nondiabetic NASH patients in China.

TRIAL REGISTRATION

This study registered at https://clinicaltrials.gov (registration number: NCT02962297).

FUNDING

Zhejiang Medicine Co., Ltd.

Systematic review and meta-analysis: non-invasive detection of non-alcoholic fatty liver disease related fibrosis in the obese

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a significant disease burden in obesity. Liver fibrosis is an important prognostic factor in NAFLD, and detection is vital. The pathophysiological changes of obesity can alter the accuracy of non-invasive NAFLD tests. We aimed to review current evidence for common non-invasive tests for NAFLD-related fibrosis in obesity.

METHODS

We systematically searched for studies assessing the diagnostic accuracy of 11 biomarker panels and elastography techniques for NAFLD-related fibrosis in obesity. Meta-analyses were performed where possible.

RESULTS

Thirty-eight studies were identified assessing the selected tests in obese populations. Simple biomarker panels (e.g. NAFLD fibrosis score) were the most validated. Evidence showed better accuracy of complex biomarker panels (NAFLD fibrosis score: summary receiver operator characteristic [SROC] 0.795-0.813 vs. enhanced liver fibrosis: SROC 0.962); however, these were poorly validated in obesity. Elastography techniques were better studied and had high diagnostic accuracy (transient elastography: SROC 0.859; magnetic resonance elastography: SROC 0.965) but were limited by BMI-dependent failure. Limited evidence was found to validate the accuracy of any test in exclusively obese populations.

CONCLUSION

In obese subjects, complex biomarker panels and elastography have been reasonable to good accuracy for NAFLD-related fibrosis; however, these methods have not been well validated. Further study in this high-risk population is needed.

Imaging evaluation of non-alcoholic fatty liver disease: focused on quantification

Non-alcoholic fatty liver disease (NAFLD) has been an emerging major health problem, and the most common cause of chronic liver disease in Western countries. Traditionally, liver biopsy has been gold standard method for quantification of hepatic steatosis. However, its invasive nature with potential complication as well as measurement variability are major problem. Thus, various imaging studies have been used for evaluation of hepatic steatosis. Ultrasonography provides fairly good accuracy to detect moderate-to-severe degree hepatic steatosis, but limited accuracy for mild steatosis. Operator-dependency and subjective/qualitative nature of examination are another major drawbacks of ultrasonography. Computed tomography can be considered as an unsuitable imaging modality for evaluation of NAFLD due to potential risk of radiation exposure and limited accuracy in detecting mild steatosis. Both magnetic resonance spectroscopy and magnetic resonance imaging using chemical shift technique provide highly accurate and reproducible diagnostic performance for evaluating NAFLD, and therefore, have been used in many clinical trials as a non-invasive reference of standard method.

The correlation of controlled attenuation parameter results with ultrasound-identified steatosis in real-world clinical practice

BACKGROUND/PURPOSE

Controlled attenuation parameter (CAP) is a method for measuring steatosis based on FibroScan. Despite observer dependency, ultrasound (US) robustly diagnoses moderate and severe steatosis. Here, we aimed to evaluate the correlation of CAP with US-identified steatosis in real-world clinical practice.

METHODS

CAP and US were performed for 1554 chronic liver disease (CLD) patients. CAP was performed by two technicians, and US was performed by 30 hepatologists. The performance of the CAP as compared with the US results was assessed using the area under the receiver operating characteristic curve (AUROC).

RESULTS

532 (34.2%) of the patients had hepatitis C virus (HCV) infection, 723 (46.5%) of the patients had hepatitis B virus (HBV) infection, and the rest were patients with metabolic risk factors. CAP values were significantly correlated with the steatosis grades identified by US for all the patients (ρ = 0.497, P < 0.001), for the HBV-infected patients (ρ = 0.495, P < 0.001), for the HCV-infected patients (ρ = 0.343, P < 0.001), and for the patients with metabolic risk factors (ρ = 0.515, P < 0.001). Using CAP, the AUROC values were 0.759, 0.795, 0.715, and 0.716 for ≥moderate steatosis identified by US in, respectively, all the patients, the HBV-infected patients, the HCV-infected patients, and the patients with metabolic risk factors. The AUROC values were 0.791, 0.868, 0.807 and 0.701 for severe steatosis identified by US in, respectively, all the patients, the HBV-infected patients, the HCV-infected patients, and the patients with metabolic risk factors.

CONCLUSION

CAP values were well correlated with the steatosis grades assessed by US in real-world clinical practice.

Serum Monounsaturated Triacylglycerol Predicts Steatohepatitis in Patients with Non-alcoholic Fatty Liver Disease and Chronic Hepatitis B

Chronic liver disease is associated with lipid metabolic disruption. We carried out a study to determine serum lipidomic features of patients with non-alcoholic fatty liver disease (NAFLD) and active chronic hepatitis B (CHB) and explored the biomarkers for non-alcoholic steatohepatitis (NASH). Serum lipidomic profiles of healthy controls (n = 23) and of biopsy–proven NAFLD (n = 42), CHB with NAFLD (n = 22) and without NAFLD (n = 17) were analyzed by ultra-performance liquid chromatography–tandem mass spectrometry. There were distinct serum lipidome between groups of NAFLD and CHB without NAFLD. Most of the neutral lipids and ceramide were elevated in the NAFLD group but were decreased in the CHB without NAFLD group. Plasmalogens were decreased in both groups. Triacylglycerols (TAGs) with lower carbon numbers and double bonds were increased in subjects with NASH. Serum monounsaturated TAG was a significant predictor of NASH (OR = 3.215; 95%CI 1.663–6.331) and positively correlated with histological activity (r = 0.501; P < 0.001). It showed good predictability for NASH in the NAFLD group [area under the receiver operating characteristic curves (AUROC) = 0.831] and was validated in the CHB group (AUROC = 0.833); this characteristic was superior to that of cytokeratin-18 and alanine transaminase. The increase in monounsaturated TAG might be a specific marker for NASH in both NAFLD and CHB patients.

Validity criteria for the diagnosis of fatty liver by M probe-based controlled attenuation parameter

BACKGROUND & AIMS

Controlled attenuation parameter (CAP) can be performed together with liver stiffness measurement (LSM) by transient elastography (TE) and is often used to diagnose fatty liver. We aimed to define the validity criteria of CAP.

METHODS

CAP was measured by the M probe prior to liver biopsy in 754 consecutive patients with different liver diseases at three centers in Europe and Hong Kong (derivation cohort, n=340; validation cohort, n=414; 101 chronic hepatitis B, 154 chronic hepatitis C, 349 non-alcoholic fatty liver disease, 37 autoimmune hepatitis, 49 cholestatic liver disease, 64 others; 277 F3-4; age 52±14; body mass index 27.2±5.3kg/m²). The primary outcome was the diagnosis of fatty liver, defined as steatosis involving ≥5% of hepatocytes.

RESULTS

The area under the receiver-operating characteristics curve (AUROC) for CAP diagnosis of fatty liver was 0.85 (95% CI 0.82-0.88). The interquartile range (IQR) of CAP had a negative correlation with CAP (r=-0.32, p<0.001), suggesting the IQR-to-median ratio of CAP would be an inappropriate validity parameter. In the derivation cohort, the IQR of CAP was associated with the accuracy of CAP (AUROC 0.86, 0.89 and 0.76 in patients with IQR of CAP <20 [15% of patients], 20-39 [51%], and ≥40dB/m [33%], respectively). Likewise, the AUROC of CAP in the validation cohort was 0.90 and 0.77 in patients with IQR of CAP <40 and ≥40dB/m, respectively (p=0.004). The accuracy of CAP in detecting grade 2 and 3 steatosis was lower among patients with body mass index ≥30kg/m² and F3-4 fibrosis.

CONCLUSIONS

The validity of CAP for the diagnosis of fatty liver is lower if the IQR of CAP is ≥40dB/m. Lay summary: Controlled attenuation parameter (CAP) is measured by transient elastography (TE) for the detection of fatty liver. In this large study, using liver biopsy as a reference, we show that the variability of CAP measurements based on its interquartile range can reflect the accuracy of fatty liver diagnosis. In contrast, other clinical factors such as adiposity and liver enzyme levels do not affect the performance of CAP.

Factors affecting accuracy of controlled attenuation parameter by Fibrotouch in assessing hepatic steatosis

AIM

To explore the factors influencing controlled attenuation parameter (CAP) obtained by Fibrotouch in patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

Patients with NAFLD diagnosed by liver biopsy in the First Affiliated Hospital of Zhengzhou University from December 2015 to December 2016 were collected. CAP was detected and recorded by Fibrotouch before liver biopsy. Clinical data were collected, including gender, age, body mass index (BMI), alanine transaminase, triacylglycerol (TG), fasting insulin, steatosis, lobular inflammation, ballooning, and fibrosis stage. Multiple linear regression analysis was used for identifying the factors influencing CAP.

RESULTS

Multiple linear regression analysis showed that CAP value was positively correlated with BMI (β = 0.216, P = 0.024), TG (β = 0.269, P = 0.022), steatosis (β = 0.448, P = 0.000), and ballooning (β = 0.200, P = 0.039) (F = 18.202, P < 0.001). The regression equation was CAP = 183.574 + 1.866 × BMI + 4.527 × TG + 15.602 × steatosis + 10.503 × ballooning. Single factor variance analysis of insulin level was performed in different degrees of hepatic steatosis, which suggested that insulin level had no significance to distinguish different degrees of steatosis (F = 2.664, P > 0.05).

CONCLUSION

The value of CAP is affected by BMI, TG, steatosis, and ballooning.

Correlation of cell-free DNA plasma concentration with severity of non-alcoholic fatty liver disease

BACKGROUND

The assessment of fibrosis and inflammatory activity is essential to identify patients with non-alcoholic fatty liver disease (NAFLD) at risk for progressive disease. Serum markers and ultrasound-based methods can replace liver biopsy for fibrosis staging, whereas non-invasive characterization of inflammatory activity remains a clinical challenge. Cell-free DNA (cfDNA) is a novel non-invasive biomarker for assessing cellular inflammation and cell death, which has not been evaluated in NAFLD.

METHODS

Patients and healthy controls from two previous studies were included. NAFLD disease activity and severity were non-invasively characterized by liver stiffness measurement (transient elastography, TE) including steatosis assessment with controlled attenuation parameter (CAP), single-proton magnetic resonance spectroscopy (¹H-MRS) for determination of hepatic fat fraction, aminotransferases and serum ferritin. cfDNA levels (90 and 222 bp fragments) were analyzed using quantitative real-time PCR.

RESULTS

Fifty-eight NAFLD patients (age 62 ± 11 years, BMI 28.2 ± 3.5 kg/m²) and 13 healthy controls (age 38 ± 12 years, BMI 22.4 ± 2.1 kg/m²) were included. 90 bp cfDNA levels were significantly higher in NAFLD patients compared to healthy controls: 3.7 (1.3-23.1) vs. 2.9 (1.4-4.1) ng/mL (p = 0.014). In the NAFLD cohort, circulating cfDNA correlated significantly with disease activity and severity, especially in patients with elevated liver stiffness (n = 13, 22%) compared to cases with TE values ≤7 kPa: cf90 bp 6.05 (2.41-23.13) vs. 3.16 (1.29-7.31) ng/mL (p < 0.001), and cf222 bp 14.41 (9.27-22.90) vs. 11.32 (6.05-18.28) ng/mL (p = 0.0041).

CONCLUSIONS

Cell-free DNA plasma concentration correlates with established non-invasive markers of NAFLD activity and severity. Therefore, cfDNA should be further evaluated as biomarker for identifying patients at risk for progressive NAFLD.

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.

Improved noninvasive prediction of liver fibrosis by liver stiffness measurement in patients with nonalcoholic fatty liver disease accounting for controlled attenuation parameter values

Liver stiffness measurement (LSM) frequently overestimates the severity of liver fibrosis in nonalcoholic fatty liver disease (NAFLD). Controlled attenuation parameter (CAP) is a new parameter provided by the same machine used for LSM and associated with both steatosis and body mass index, the two factors mostly affecting LSM performance in NAFLD. We aimed to determine whether prediction of liver fibrosis by LSM in NAFLD patients is affected by CAP values. Patients (n = 324) were assessed by clinical and histological (Kleiner score) features. LSM and CAP were performed using the M probe. CAP values were grouped by tertiles (lower 132-298, middle 299-338, higher 339-400 dB/m). Among patients with F0-F2 fibrosis, mean LSM values, expressed in kilopascals, increased according to CAP tertiles (6.8 versus 8.6 versus 9.4, P = 0.001), and along this line the area under the curve of LSM for the diagnosis of F3-F4 fibrosis was progressively reduced from lower to middle and further to higher CAP tertiles (0.915, 0.848-0.982; 0.830, 0.753-0.908; 0.806, 0.723-0.890). As a consequence, in subjects with F0-F2 fibrosis, the rates of false-positive LSM results for F3-F4 fibrosis increased according to CAP tertiles (7.2% in lower versus 16.6% in middle versus 18.1% in higher). Consistent with this, a decisional flowchart for predicting fibrosis was suggested by combining both LSM and CAP values.

CONCLUSIONS

In patients with NAFLD, CAP values should always be taken into account in order to avoid overestimations of liver fibrosis assessed by transient elastography. (Hepatology 2017;65:1145-1155).

A Pilot Comparative Study of Quantitative Ultrasound, Conventional Ultrasound, and MRI for Predicting Histology-Determined Steatosis Grade in Adult Nonalcoholic Fatty Liver Disease

OBJECTIVE

The purpose of this study is to explore the diagnostic performance of two investigational quantitative ultrasound (QUS) parameters, attenuation coefficient and backscatter coefficient, in comparison with conventional ultrasound (CUS) and MRI-estimated proton density fat fraction (PDFF) for predicting histology-confirmed steatosis grade in adults with nonalcoholic fatty liver disease (NAFLD).

SUBJECTS AND METHODS

In this prospectively designed pilot study, 61 adults with histology-confirmed NAFLD were enrolled from September 2012 to February 2014. Subjects underwent QUS, CUS, and MRI examinations within 100 days of clinical-care liver biopsy. QUS parameters (attenuation coefficient and backscatter coefficient) were estimated using a reference phantom technique by two analysts independently. Three-point ordinal CUS scores intended to predict steatosis grade (1, 2, or 3) were generated independently by two radiologists on the basis of QUS features. PDFF was estimated using an advanced chemical shift-based MRI technique. Using histologic examination as the reference standard, ROC analysis was performed. Optimal attenuation coefficient, backscatter coefficient, and PDFF cutoff thresholds were identified, and the accuracy of attenuation coefficient, backscatter coefficient, PDFF, and CUS to predict steatosis grade was determined. Interobserver agreement for attenuation coefficient, backscatter coefficient, and CUS was analyzed.

RESULTS

CUS had 51.7% grading accuracy. The raw and cross-validated steatosis grading accuracies were 61.7% and 55.0%, respectively, for attenuation coefficient, 68.3% and 68.3% for backscatter coefficient, and 76.7% and 71.3% for MRI-estimated PDFF. Interobserver agreements were 53.3% for CUS (κ = 0.61), 90.0% for attenuation coefficient (κ = 0.87), and 71.7% for backscatter coefficient (κ = 0.82) (p < 0.0001 for all).

CONCLUSION

Preliminary observations suggest that QUS parameters may be more accurate and provide higher interobserver agreement than CUS for predicting hepatic steatosis grade in patients with NAFLD.

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.

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.