Performance of Acoustic Radiation Force Impulse imaging for the staging of liver fibrosis: a pooled meta-analysis

Diagnostic Accuracy of Acoustic Radiation Force Impulse (ARFI) in Diagnosis of Liver Fibrosis among Egyptian Patients with Chronic HCV Infection

BACKGROUND:

Acoustic radiation force impulse (ARFI) evaluates liver stiffness non-invasively and was invented recently. This technique can easily and accurately assess the degree of liver fibrosis in clinical practice.

AIM:

The aim of this study was to detect the diagnostic performance of ARFI elastography in the staging of fibrosis in some Egyptian patients with chronic HCV infection.

PATIENTS AND METHODS:

One hundred ninety patients with chronic HCV infection; 142 men and 48 women were enrolled in the study. They underwent liver biopsy examination for liver fibrosis detection. All demographic; clinical and biochemical data were recoded. ARFI examination was done for all subjects to detect liver stiffness measurement in relation to liver fibrosis detected by pathological examination of liver biopsies.

RESULTS:

Medians of liver stiffness measurement by shear wave velocity showed a significant increase as a grade of liver fibrosis increases (p ≤ 0.0001, highly significant). Liver stiffness was directly correlated to age, AST; ALT; INR and liver steatosis (p values were: 0.009; 0.0001; 0.013; 0.006 and 0.04 respectively, significant). On the other hand, liver stiffness was inversely correlated to albumin; prothrombin concentration and platelets (p values were: 0.0001; 0.001, and 0.0001, respectively, significant). We found that shear wave velocity can predict F1; F2; F3 and F4 at cut-off values: 1.22; 1.32; 1.44 and 1.8 respectively.

CONCLUSION:

ARFI is a diagnostic noninvasive promising technique for liver fibrosis diagnosis among Egyptian patients with chronic HCV infection.

Ultrasound and Point Shear Wave Elastography in Livers of Patients with Primary Sclerosing Cholangitis

Point shear wave elastography (pSWE) is an ultrasound-based method for non-invasive quantification of liver fibrosis. The objective of this study was to explore liver pSWE in patients with primary sclerosing cholangitis (PSC) for assessment of fibrosis. Fifty-five non-transplant patients with PSC (38 males, 17 females; mean age: 46.4 y) were included and compared with 24 matched controls. Median (range) PSC duration was 8.1 (0-33) y. Ultrasonographic scanning followed by liver stiffness measurement by pSWE was performed using a conventional ultrasound system (Philips iU22). Signs of liver fibrosis on B-mode were identified in 21 patients (38%). Splenomegaly was found in 19 patients (35%) and ascites in two patients (4%). Successful pSWE measurements were achieved in the right liver lobe of all individuals and in the left liver lobe of 36 patients (65.5%). PSC patients had significantly higher median shear wave velocity (SWV) than controls in the right liver (median [range] SWV 1.26 [0.73-2.57] m/s vs. 1.09 [0.88-1.25] m/s, p < 0.001). SWV measured in the left liver lobe and spleen did not differ between PSC patients and controls. Our findings indicate that PSC patients have increased median SWV, indicating more fibrosis compared with controls; however, a wide range of SWV values were obtained among PSC patients, possibly reflecting the various stages in disease development.

Shear wave elastography with a new reliability indicator

Non-invasive methods for liver stiffness assessment have been introduced over recent years. Of these, two main methods for estimating liver fibrosis using ultrasound elastography have become established in clinical practice: shear wave elastography and quasi-static or strain elastography. Shear waves are waves with a motion perpendicular (lateral) to the direction of the generating force. Shear waves travel relatively slowly (between 1 and 10 m/s). The stiffness of the liver tissue can be assessed based on shear wave velocity (the stiffness increases with the speed). The European Federation of Societies for Ultrasound in Medicine and Biology has published Guidelines and Recommendations that describe these technologies and provide recommendations for their clinical use. Most of the data available to date has been published using the Fibroscan (Echosens, France), point shear wave speed measurement using an acoustic radiation force impulse (Siemens, Germany) and 2D shear wave elastography using the Aixplorer (SuperSonic Imagine, France). More recently, also other manufacturers have introduced shear wave elastography technology into the market. A comparison of data obtained using different techniques for shear wave propagation and velocity measurement is of key interest for future studies, recommendations and guidelines. Here, we present a recently introduced shear wave elastography technology from Hitachi and discuss its reproducibility and comparability to the already established technologies.

ARFI: from basic principles to clinical applications in diffuse chronic disease-a review

Abstract

The many factors influencing the shear wave velocity (SWV) measured with Acoustic Radiation Force Impulse (ARFI) are examined in order to define the most correct examination technique. In particular, attention is given to the information achieved by experimental models, such as phantoms and animal studies. This review targets the clinical applications of ARFI in the evaluation of chronic diffuse disease, especially of liver and kidneys. The contribution of ARFI to the clinical workout of these patients and some possible perspectives are described.

Teaching Points

• Stiffness significantly varies among normal and abnormal biological tissues.

• In clinical applications physical, geometrical, anatomical and physiological factors influence the SWV.

• Elastographic techniques can quantify fibrosis, which is directly related to stiffness.

• ARFI can be useful in chronic diffuse disease of liver and kidney.

Prospective Comparison of Liver Stiffness Measurements between Two Point Shear Wave Elastography Methods: Virtual Touch Quantification and Elastography Point Quantification

Objective

To prospectively compare technical success rate and reliable measurements of virtual touch quantification (VTQ) elastography and elastography point quantification (ElastPQ), and to correlate liver stiffness (LS) measurements obtained by the two elastography techniques.

Materials and Methods

Our study included 85 patients, 80 of whom were previously diagnosed with chronic liver disease. The technical success rate and reliable measurements of the two kinds of point shear wave elastography (pSWE) techniques were compared by χ² analysis. LS values measured using the two techniques were compared and correlated via Wilcoxon signed-rank test, Spearman correlation coefficient, and 95% Bland-Altman limit of agreement. The intraobserver reproducibility of ElastPQ was determined by 95% Bland-Altman limit of agreement and intraclass correlation coefficient (ICC).

Results

The two pSWE techniques showed similar technical success rate (98.8% for VTQ vs. 95.3% for ElastPQ, p = 0.823) and reliable LS measurements (95.3% for VTQ vs. 90.6% for ElastPQ, p = 0.509). The mean LS measurements obtained by VTQ (1.71 ± 0.47 m/s) and ElastPQ (1.66 ± 0.41 m/s) were not significantly different (p = 0.209). The LS measurements obtained by the two techniques showed strong correlation (r = 0.820); in addition, the 95% limit of agreement of the two methods was 27.5% of the mean. Finally, the ICC of repeat ElastPQ measurements was 0.991.

Conclusion

Virtual touch quantification and ElastPQ showed similar technical success rate and reliable measurements, with strongly correlated LS measurements. However, the two methods are not interchangeable due to the large limit of agreement.

Ultrasound Elastography Used for Preventive Non-Invasive Screening in Early Detection of Liver Fibrosis

Background

Early discovery of liver fibrosis is becoming more popular because of enhanced incidence of hepatocellular carcinoma. Ultrasound-based liver elastography is a method used to approve suspected liver fibrosis or cirrhosis. We assessed the clinical usefulness of acoustic radiation force impulse shear wave elasticity imaging (ARFI-SWEI) as a preventive screening method to uncover fibrosis.

Methods

We screened 382 patients by native routine sonography for abnormal liver results and divided them into six groups: group 1: normal liver, groups 2-4: fatty liver grade I-III, group 5: liver cirrhosis, and group 6: inhomogenic liver tissue. Then ARFI-SWEI was performed and the results were compared with published shear wave velocity cut-off values that were predictive of each fibrosis stage (F0-4). A control group consisted of 20 healthy volunteers.

Results

The part of liver fibrosis ≥ F2 was in groups 1-4: 20-32%, group 5: 100%, and group 6: 91%. Main causes for fibrosis stage ≥ F2 were (non)-alcoholic steatohepatitis, chronic viral or autoimmune hepatitis and chronic heart failure.

Conclusions

Screening of the liver tissue in b-mode ultrasound can underestimate possible liver fibrosis; by using ARFI-SWEI, liver fibrosis can be uncovered early. It is a suitable preventive method comparable to colonoscopy for colon cancer.

Liver elasticity measurement before and after biliary drainage in patients with obstructive jaundice: a prospective cohort studya prospective cohort study

BACKGROUND

Obstructive jaundice has been reported to influence liver elasticity, independent of liver fibrosis. The aim of our prospective study was to evaluate the changes in liver elasticity, before and after biliary drainage, in patients with obstructive jaundice, and to evaluate the correlation between elasticity measures and serum markers of liver fibrosis.

METHODS

This is a prospective cohort study of 20 patients with obstructive jaundice. Liver elasticity was assessed by Transient Elastography (TE) and Virtual Touch™ Quantification (VTQ). Serum total bilirubin (T-Bil) level was measured before biliary drainage (Day 0), with measures repeated at 2 days (Day 2) and 7 days (Day 7) after biliary drainage. Serum levels of the following markers of liver fibrosis were also obtained on Day 0 and Day 7: hyaluronic acid (HA), procollagen-III-peptide (P-III-P).

RESULTS

T-Bil, TE, and VTQ for the left (VTQ-L) and right (VTQ-R) lobes of the liver were all elevated before biliary drainage, with respective levels, measured at Day 0, of 11.9 ± 1.5 mg/dl, 12.1 ± 0.9 kPa, 2.23 ± 0.10 m/s, and 1.85 ± 0.10 m/s. All values decreased on Day 7 after drainage: T-Bil, 4.7 ± 1.0 mg/dl (P < 0.001); TE, 7.6 ± 0.6 kPa (P < 0.001); VTQ-L, 1.53 ± 0.08 m/s (P < 0.001); and VTQ-R, 1.30 ± 0.05 m/s (P < 0.001). Similar changes were observed in serum markers of liver fibrosis. Liver elasticity measures correlated with serum levels of T-Bil, P-III-P, and HA (r = 0.35-0.67, P < 0.001).

CONCLUSIONS

This study confirmed decreases in liver elasticity, measured by TE and VTQ, after biliary drainage. Measures of liver elasticity correlated to levels of T-Bil and serum markers of liver fibrosis. (UMIN ID: UMIN00001284313).

REGISTRATION NUMBER

University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN ID: UMIN00001284313 ); Registration date: 2014-01-14.

Light and sound - emerging imaging techniques for inflammatory bowel disease

Patients with inflammatory bowel disease are known to have a high demand of recurrent evaluation for therapy and disease activity. Further, the risk of developing cancer during the disease progression is increasing from year to year. New, mostly non-radiant, quick to perform and quantitative methods are challenging, conventional endoscopy with biopsy as gold standard. Especially, new physical imaging approaches utilizing light and sound waves have facilitated the development of advanced functional and molecular modalities. Besides these advantages they hold the promise to predict personalized therapeutic responses and to spare frequent invasive procedures. Within this article we highlight their potential for initial diagnosis, assessment of disease activity and surveillance of cancer development in established techniques and recent advances such as wide-view full-spectrum endoscopy, chromoendoscopy, autofluorescence endoscopy, endocytoscopy, confocal laser endoscopy, multiphoton endoscopy, molecular imaging endoscopy, B-mode and Doppler ultrasound, contrast-enhanced ultrasound, ultrasound molecular imaging, and elastography.

Critical comparison of elastography methods to assess chronic liver disease

Staging of liver fibrosis and diagnosis, or exclusion, of early compensated liver cirrhosis are important in the treatment decisions and surveillance of patients with chronic liver disease. Good diagnostic accuracy, increased availability and the possibility to perform follow-up examinations led to the implementation of noninvasive methods into clinical practice. Noninvasive tests are increasingly included in national and international guidelines, leaving liver biopsy reserved for patients with unexplained discordance or suspected additional aetiologies of liver disease. In addition to staging of liver fibrosis, data on the prognostic value of these methods have increased in the past few years and are of great importance for patient care. This Review focuses on elastography methods for noninvasive assessment of liver fibrosis, disease severity and prognosis. Although liver elastography started with transient elastography, at present all large ultrasonography companies offer an elastography technique integrated in their machines. The goal of this Review is to summarize the methodological problems of noninvasive tests in general, in addition to providing an overview on currently available techniques and latest developments in liver elastography.

The performance of acoustic radiation force impulse imaging in predicting liver fibrosis in chronic liver diseases

Sonography-based noninvasive liver fibrosis assessment is promising in the prediction of treatment efficacy and prognosis in chronic liver disease (CLD) patients. Acoustic radiation force impulse imaging (ARFI) is a newly-developed transient elastography (TE) method integrated into a conventional ultrasound machine. The study aimed to assess the performance of ARFI imaging in the diagnosis of liver fibrosis in Taiwanese CLD patients. We also aimed to search for the optimal cut-off values in different fibrosis stages. A total of 60 CLD patients (40 males; mean age, 51.8±11 years) were consecutively included. They received standard ARFI measurement within 2 weeks at the time of liver biopsy. There were eight patients with Metavir fibrosis stage 0 (F0), 16 patients with F1, 20 patients with F2, eight patients with F3, and eight patients with F4, respectively. The mean values among patient with F0, F1, F2, F3, and F4 were 1.17±0.13, 1.30±0.17, 1.31±0.24, 2.01±0.45, and 2.69±0.91, respectively (p<0.001). The optimal cut-off ARFI value for significant fibrosis (F≥2) was 1.53 with the accuracy of 0.733, while it was 1.66 for advanced fibrosis (F≥3) with the accuracy of 0.957. Our study demonstrated that ARFI imaging is competent for fibrosis diagnosis, particularly in CLD patients with advanced fibrosis.

Novel 3D Magnetic Resonance Elastography for the Noninvasive Diagnosis of Advanced Fibrosis in NAFLD: A Prospective Study

OBJECTIVES

Recent studies show two-dimensional (2D)-magnetic resonance elastography (MRE) is accurate in diagnosing advanced fibrosis (stages 3 and 4) in nonalcoholic fatty liver disease (NAFLD) patients. Three-dimensional (3D)-MRE is a more advanced version of the technology that can image shear-wave fields in 3D of the entire liver. The aim of this study was to prospectively compare the diagnostic accuracy of 3D-MRE and 2D-MRE for diagnosing advanced fibrosis in patients with biopsy-proven NAFLD.

METHODS

This cross-sectional analysis of a prospective study included 100 consecutive patients (56% women) with biopsy-proven NAFLD who also underwent MRE. Area under the receiver operating characteristic (AUROC) analysis was performed to assess the accuracy of 2D- and 3D-MRE in diagnosing advanced fibrosis.

RESULTS

The mean (±s.d.) of age and body mass index were 50.2 (±13.6) years and 32.1 (±5.0) kg/m(2), respectively. The AUROC for diagnosing advanced fibrosis was 0.981 for 3D-MRE at 40 Hz, 0.927 for 3D-MRE at 60 Hz (standard shear-wave frequency), and 0.921 for 2D-MRE at 60 Hz (standard shear-wave frequency). At a threshold of 2.43 kPa, 3D-MRE at 40 Hz had sensitivity 1.0, specificity 0.94, positive predictive value 0.72, and negative predictive value 1.0 for diagnosing advanced fibrosis. 3D-MRE at 40 Hz had significantly higher AUROC (P<0.05) than 2D-MRE at 60 Hz for diagnosing advanced fibrosis.

CONCLUSIONS

Utilizing a prospective study design, we demonstrate that 3D MRE at 40 Hz has the highest diagnostic accuracy in diagnosing NAFLD advanced fibrosis. Both 2D- and 3D-MRE at 60 Hz, the standard shear-wave frequency, are also highly accurate in diagnosing NAFLD advanced fibrosis.

Acoustic radiation force impulse accuracy and the impact of hepatic steatosis on liver fibrosis staging

INTRODUCTION

The accuracy of Acoustic Radiation Force Impulse (ARFI) imaging has been validated in the setting of hepatitis C, however, the accuracy in the setting of fatty liver disease (FLD) has been less well-established. The aim of this study was to assess the accuracy of ARFI in the setting of hepatic steatosis.

METHODS

Patients with biopsy proven or sonographically diagnosed liver steatosis were assessed for ARFI trends including: inter-operator concordance, interquartile range, ARFI failure rate, relationship between ARFI velocity and steatosis severity, and concordance between biopsy and ARFI fibrosis scores.

RESULTS

Three hundred and forty-nine patients were assessed (53 'biopsy' cohort and 296 'ultrasound' cohort), with 28 patients having biopsy on the same day as ARFI. Low stages of fibrosis (F0/1) were over-estimated by ARFI in 62% of cases with biopsy correlation (n = 16, P < 0.001), with ARFI offering increased accuracy in regard to higher-stage fibrosis (14/15 cases, 93%). In both the biopsy and ultrasound cohorts the failure rate and median inter-quartile range increased with increasing steatosis, and the inter-operator concordance remained good across all liver steatosis severities.

CONCLUSION

In the setting of steatosis, ARFI is very sensitive in detecting, and accurate in diagnosing, higher stages of fibrosis regardless of steatosis severity. It tends to overestimate the fibrosis category in lower stages of fibrosis. The present study does not show conclusively if the presence of steatosis or its severity independently alters ARFI measurements.

Non-invasive Markers of Liver Fibrosis: Adjuncts or Alternatives to Liver Biopsy?

Liver fibrosis reflects sustained liver injury often from multiple, simultaneous factors. Whilst the presence of mild fibrosis on biopsy can be a reassuring finding, the identification of advanced fibrosis is critical to the management of patients with chronic liver disease. This necessity has lead to a reliance on liver biopsy which itself is an imperfect test and poorly accepted by patients. The development of robust tools to non-invasively assess liver fibrosis has dramatically enhanced clinical decision making in patients with chronic liver disease, allowing a rapid and informed judgment of disease stage and prognosis. Should a liver biopsy be required, the appropriateness is clearer and the diagnostic yield is greater with the use of these adjuncts. While a number of non-invasive liver fibrosis markers are now used in routine practice, a steady stream of innovative approaches exists. With improvement in the reliability, reproducibility and feasibility of these markers, their potential role in disease management is increasing. Moreover, their adoption into clinical trials as outcome measures reflects their validity and dynamic nature. This review will summarize and appraise the current and novel non-invasive markers of liver fibrosis, both blood and imaging based, and look at their prospective application in everyday clinical care.

Liver Fibrosis Evaluation Using Real-time Shear Wave Elastography in Hepatitis C-Monoinfected and Human Immunodeficiency Virus/Hepatitis C-Coinfected Patients

OBJECTIVES

A few studies have evaluated real-time shear wave elastography (SWE) for assessing liver fibrosis by measuring liver stiffness in patients with chronic hepatitis C virus (HCV) infection, but they excluded human immunodeficiency virus/HCV-coinfected patients. We investigated the diagnostic performance of liver stiffness measured by SWE as a noninvasive predictor of liver fibrosis in HCV using liver biopsy as a reference standard, including monoinfected and coinfected patients.

METHODS

We measured liver stiffness in patients with HCV undergoing liver biopsy (METAVIR fibrosis staging).

RESULTS

Eighty patients (53 monoinfected and 27 coinfected) were included. There was a significant correlation between liver stiffness and fibrosis stage (ρ = 0.685; P < .001). Areas under the receiver operating characteristic curve were 0.841, 0.879, and 0.975 when comparing fibrosis stages F0-F1 versus F2-F4, F0-F2 versus F3-F4, and F0-F3 versus F4, respectively. Suggested cutoff values were 8.5 kPa for F2, 10.4 kPa for F3, and 11.3 kPa for F4, with sensitivity and specificity of 81% and 84%, 81% and 95%, and 100% and 90%. There was no significant difference between the liver stiffness of monoinfected and coinfected patients (P = .453). When combining SWE with the fibrosis-4 score, accuracy increased from 82% to 88% and from 88% to 96%, with incongruent results of 26% and 29%, for F0-F1 versus F2-F4 and F0-F2 versus F3-F4.

CONCLUSIONS

Shear wave elastography of the liver is an effective noninvasive predictor of liver fibrosis in patients with HCV. There was no significant difference between monoinfected and coinfected patients; hence, the same cutoff values can be used for both groups. Combination of SWE with the fibrosis-4 score leads to higher accuracy, although at the expense of inconclusive results in some patients.

Influence of Food Intake on 2-D Shear Wave Elastography Assessment of Liver Stiffness in Healthy Subjects

Transient elastography and Acoustic Radiation Force Impulse imaging are useful non-invasive methods for liver stiffness estimation, although both are influenced by food intake. The aim of the work described here was to identify liver stiffness variation after a standardized meal using 2-D shear wave elastography. Liver stiffness was estimated in 31 apparently healthy subjects, under fasting conditions and after a standardized meal (20, 40, 60, 80, 100 and 120 min after food intake). In most of the cases, liver stiffness values increased between 20 and 40 min after the meal (p < 0.05) and then significantly decreased between 60 and 80 min (p < 0.05). At 120 min after food intake, liver stiffness values were significantly lower compared with liver stiffness values under fasting conditions (p < 0.05). Gender, but not body mass index, had an important role in liver stiffness variation after food intake (p < 0.01). In conclusion, to avoid the influence of food intake on liver stiffness estimation, 2-D shear wave elastography should be performed only under fasting conditions.

Diagnostic Accuracy of Real-Time Shear Wave Elastography for Staging of Liver Fibrosis: A Meta-Analysis

BACKGROUND The present meta-analysis, based on previous studies, was aimed to evaluate the test accuracy of real-time shear wave elastography (SWE) for the staging of liver fibrosis. MATERIAL AND METHODS A systematic search on MEDLINE, PubMed, Embase, and Google Scholar databases was conducted, and data on SWE tests and liver fibrosis staging were collected. For each cut-off stage of fibrosis (F≥2, F≥3, and F≥4), pooled results of sensitivity, specificity, and area under summary receiver operating characteristic (SROC) curve were analyzed. The study heterogeneity was evaluated by χ2 and I2 tests. I2>50% or P≤0.05 indicates there was heterogeneity, and then a random-effects model was applied. Otherwise, the fixed-effects model was used. The publication bias was evaluated using Deeks funnel plots asymmetry test and Fagan plot analysis was performed. RESULTS Finally, 934 patients from 8 published studies were included in the analysis. The pooled sensitivity and specificity of SWE for F≥2 were 85.0% (95% CI, 82-88%) and 81% (95% CI, 71-88%), respectively. The area under the SROC curve with 95% CI was presented as 0.88 (95% CI, 85-91%). The pooled sensitivity and specificity of SWE for F≥3 were 90.0% (95% CI, 83.0-95.0%) and 81.0% (95% CI, 75.0-86.0%), respectively, corresponding to an area of SROC of 0.94 (95% CI, 92-96%). The pooled sensitivity and specificity of SWE for F≥4 were 87.0% (95% CI, 80.0-92.0%) and 88.0% (95% CI, 80.0-93.0%), respectively, corresponding to an area of SROC of 0.92 (95% CI, 89-94%). CONCLUSIONS The overall accuracy of SWE is high and clinically useful for the staging of liver fibrosis. Compared to the results of meta-analyses on other tests, such as RTE, TE, and ARFI, the performance of SWE is nearly identical in accuracy for the evaluation of cirrhosis. For the evaluation of significant liver fibrosis (F≥2), the overall accuracy of SWE seems to be similar to ARFI, but more accurate than RTE and TE.

ACOUSTIC RADIATION FORCE IMPULSE IS EQUIVALENT TO LIVER BIOPSY TO EVALUATE LIVER FIBROSIS IN PATIENTS WITH CHRONIC HEPATITIS C AND NONALCOHOLIC FATTY LIVER DISEASE

BACKGROUND

Liver biopsy is recommended as the gold standard method for assessing the stage of liver fibrosis in patients with chronic liver disease. However, it is invasive, with potential risks and complications. Elastography is an ultrasound technique that provides information of changes in the liver tissue, evaluating tissue elasticity and acoustic radiation force impulse is one of the available techniques.

OBJECTIVE

The main objective of this study was to evaluate the sensitivity and specificity of acoustic radiation force impulse comparing to liver biopsy to evaluate fibrosis in patients with chronic hepatitis C virus and nonalcoholic fatty liver disease.

METHODS

Twenty four patients were included, everyone underwent liver biopsy and acoustic radiation force impulse, and the results were compared with values described in the literature by several authors.

RESULTS

In the population of patients with chronic hepatitis C, our data were better correlated with data published by Carmen Fierbinteanu-Braticevici et al., with an accuracy of 82.4%, sensitivity of 71.4% and specificity of 90%. For nonalcoholic fatty liver disease, our data were better correlated with data published by Masato Yoneda et al., with an accuracy of 85.7%, sensitivity 80% and specificity of 100%.

CONCLUSION

Acoustic radiation force impulse is a method with good accuracy to distinguish initial fibrosis from advanced fibrosis in hepatitis C virus and nonalcoholic fatty liver disease and can replace biopsy in most cases.

Liver Shear-Wave Velocity and Serum Fibrosis Markers to Diagnose Hepatic Fibrosis in Patients with Chronic Viral Hepatitis B

Objective

To compare several noninvasive indices of fibrosis in chronic viral hepatitis B, including liver shear-wave velocity (SWV), hyaluronic acid (HA), collagen type IV (CIV), procollagen type III (PCIII), and laminin (LN).

Materials and Methods

Acoustic radiation force impulse (ARFI) was performed in 157 patients with chronic viral hepatitis B and in 30 healthy volunteers to measure hepatic SWV (m/s) in a prospective study. Serum markers were acquired on the morning of the same day of the ARFI evaluation. Receiver operating characteristic (ROC) analysis was performed to evaluate and compare the accuracies of SWV and serum markers using METAVIR scoring from liver biopsy as a reference standard.

Results

The most accurate test for diagnosing fibrosis F ≥ 1 was SWV with the area under the ROC curve (AUC) of 0.913, followed by LN (0.744), HA (0.701), CIV (0.690), and PCIII (0.524). The best test for diagnosing F ≥ 2 was SWV (AUC of 0.851), followed by CIV (0.671), HA (0.668), LN (0.562), and PCIII (0.550). The best test for diagnosing F ≥ 3 was SWV (0.854), followed by CIV (0.693), HA (0.675), PCIII (0.591), and LN (0.548). The best test for diagnosing F = 4 was SWV (0.965), followed by CIV (0.804), PCIII (0.752), HA (0.744), and LN (0.662). SWV combined with HA and CIV did not improve diagnostic accuracy (AUC = 0.931 for F ≥ 1, 0.863 for F ≥ 2, 0.855 for F ≥ 3, 0.960 for F = 4).

Conclusion

The performance of SWV in diagnosing liver fibrosis is superior to that of serum markers. However, the combination of SWV, HA, and CIV does not increase the accuracy of diagnosing liver fibrosis and cirrhosis.

Imaging methods for evaluation of liver fibrosis

Liver fibrosis is a development stage of various chronic liver diseases. Since liver fibrosis is still a reversible process, the development of irreversible cirrhosis can be delayed or prevented if the patient is early diagnosed and receives timely and effective treatment. Therefore, how to accurately, effectively and easily evaluate the severity of liver fibrosis remains a clinical problem to be solved. Ultrasound, CT and MRI are common examinations for hepatic lesions. Imaging examinations can non-invasively and accurately evaluate the degree of liver fibrosis. With the development and application of new imaging technologies, flexible technology has been widely applied in the assessment of liver fibrosis. This article reviews the application of various imaging modalities, especially elastic technology, for assessment of hepatic fibrosis.

Management of HCV-Associated Liver Cirrhosis

BACKGROUND

Treatment of chronic hepatitis C infection is most urgent in patients with severe liver fibrosis and cirrhosis because of the high risk of decompensation, hepatocellular carcinoma, and consecutively death. The development and approval of several direct-acting antiviral drugs (DAA) in the past years has revolutionized antiviral therapy especially for patients with liver cirrhosis.

METHODS

This review will focus on recent data from clinical trials and recommendations for the therapy of hepatitis C-infected patients with compensated cirrhosis.

RESULTS

Clinical data for cirrhotic patients mainly exist for a combination of the nucleotide analog sofosbuvir with either a protease inhibitor (simeprevir) or an NS5A inhibitor (daclatasvir, ledipasvir) or a three-DAA combination consisting of an NS3 protease inhibitor, an NS5A inhibitor, and a non-nucleoside NS5B inhibitor (paritaprevir/ritonavir, ombitasvir, and dasabuvir). Rates of sustained virologic response in patients with compensated cirrhosis are comparable to patients without cirrhosis; however, the addition of ribavirin and/or longer treatment durations are especially recommended when other negative predictors are present, such as prior treatment failure, features of advanced cirrhosis, or the presence of baseline resistance.

CONCLUSION

Nowadays, a highly active, short, and safe interferon-free treatment regimen is available for almost all patients.

Ultrasound elastographic techniques in focal liver lesions

Elastographic techniques are new ultrasound-based imaging techniques developed to estimate tissue deformability/stiffness. Several ultrasound elastographic approaches have been developed, such as static elastography, transient elastography and acoustic radiation force imaging methods, which include point shear wave and shear wave imaging elastography. The application of these methods in clinical practice aims at estimating the mechanical tissues properties. One of the main settings for the application of these tools has been liver stiffness assessment in chronic liver disease, which has been studied mainly using transient elastography. Another field of application for these techniques is the assessment of focal lesions, detected by ultrasound in organs such as pancreas, prostate, breast, thyroid, lymph nodes. Considering the frequency and importance of the detection of focal liver lesions through routine ultrasound, some studies have also aimed to assess the role that elestography can play in studying the stiffness of different types of liver lesions, in order to predict their nature and thus offer valuable non-invasive methods for the diagnosis of liver masses.

Liver Fibrosis Staging with MR Elastography: Comparison of Diagnostic Performance between Patients with Chronic Hepatitis B and Those with Other Etiologic Causes

Purpose To evaluate the diagnostic performance of magnetic resonance (MR) elastography in staging liver fibrosis in patients with chronic hepatitis B (CHB) and other etiologic causes. Materials and Methods This retrospective study was institutional review board-approved and the requirement for informed consent was waived. Before surgery, MR elastographic imaging was performed in 352 patients with chronic liver diseases (281 patients with CHB, 71 patients without CHB) and hepatocellular carcinomas and 64 living liver donor candidates. Liver stiffness (LS) values were measured on quantitative shear-stiffness maps of MR elastography, and the diagnostic performance of MR elastography in staging liver fibrosis was evaluated by using receiver operating characteristic curve analysis and the Obuchowski measure with the histopathologic analysis of liver fibrosis in the CHB group and in the group composed of other etiologic causes. In 120 patients (97 with CHB, 23 without CHB) and 51 donors, diagnostic performance of MR elastography was validated. Results Areas under the curve of LS values for the diagnosis of significant fibrosis (≥stage F2), severe fibrosis (≥stage F3), and cirrhosis (stage F4) in the CHB group were 0.972 (95% confidence interval: 0.948, 0.987), 0.946 (95% confidence interval: 0.916, 0.968), and 0.920 (95% confidence interval: 0.885, 0.947), respectively. Obuchowski measures were similarly high in the CHB group and in the group composed of other etiologic causes (0.970 vs 0.977). However, the estimated cutoff value for stage F4 in the group with CHB was substantially lower than in the participants with other etiologic causes: 3.67 kPa versus 4.65 kPa. In the validation study for stage F1 or greater, stage F2 or greater, stage F3 or greater, and stage F4, the Youden indexes were 0.807, 0.842, 0.806, and 0.639, respectively, in the group with CHB, and 0.783, 0.900, 1.000, and 0.917, respectively, in the group without CHB. Conclusion The diagnostic performance of MR elastography in liver fibrosis staging was similarly high in the groups with and without CHB, but the cutoff LS values for diagnosing liver cirrhosis differed between the groups with and without CHB. (©) RSNA, 2016 Online supplemental material is available for this article.

Diagnostic Accuracy of SuperSonic Shear Imaging for Staging of Liver Fibrosis: A Meta-analysis

OBJECTIVES

The purpose of this study was to assess the performance of SuperSonic shear imaging (SuperSonic Imagine SA, Aix-en-Provence, France) for diagnosis of liver fibrosis.

METHODS

Literature databases were searched to identify relevant studies from inception to February 28, 2015. Sensitivity, specificity, and other information were extracted from the studies. Pooled data were calculated by a bivariate mixed-effects binary regression model. Subgroup and sensitivity analyses were performed. Publication bias was tested by funnel plots.

RESULTS

Twelve studies were included in this meta-analysis and reported on 1635 patients. The pooled sensitivity and specificity were 0.78 (95% confidence interval [CI], 0.69-0.85) and 0.95 (95% CI, 0.75-0.99), respectively, for fibrosis stages F≥1, 0.84 (95% CI, 0.81-0.86) and 0.81 (95% CI, 0.74-0.87) for F≥2, 0.89 (95% CI, 0.85-0.93) and 0.84 (95% CI, 0.77-0.89) for F≥3, and 0.88 (95% CI, 0.82-0.91) and 0.86 (95% CI, 0.81-0.90) for F=4. The areas under the summary receiver operating characteristic curves were 0.87 (95% CI, 0.84-0.90) for F≥1, 0.85 (95% CI, 0.81-0.88) for F≥2, 0.93 (95% CI, 0.91-0.95) for F≥3, and 0.93 (95% CI, 0.90-0.95) for F=4. No significant publication bias was found.

CONCLUSIONS

SuperSonic shear imaging could be used for staging of liver fibrosis. Especially, it has high diagnostic accuracy for severe fibrosis and cirrhosis.

New combined parameter of liver and splenic stiffness as determined by elastography in healthy volunteers

BACKGROUND

The diagnosis of chronic liver disease (CLD) leading to fibrosis, cirrhosis, and portal hypertension had witnessed dramatic changes after the introduction of noninvasive figure accessible tools over the past few years. Imaging techniques that are based on evaluation of the liver stiffness was particularly useful in this respect. Acoustic radiation force impulse (ARFI) emerged as an interesting figure tool with reliable repute and high precision.

AIMS

To evaluate liver stiffness measurement (LSM) and splenic stiffness measurement (SSM) in healthy volunteers as concluded by the ARFI technique and to out a numeric calculated ratio that may reflect their correlation in the otherwise healthy liver.

PATIENTS AND METHODS

A ratio (splenic stiffness/liver stiffness in kPa) was determined in 207 consenting healthy subjects and was investigated with respect to age, gender, ethnic origin, body mass index (BMI), liver and spleen sizes healthy volunteers, alanine aminotransferase (ALT), aspartate aminotransferase (AST), platelet count (PLT), APRI, and FIB-4 scores.

RESULTS

Data from this work led to computing an index of 4.72 (3.42-7.33) in healthy persons on an average. Females had a higher index than males 6.37 vs 4.92, P=0.002. There was not any significant difference of the ratio in different age groups; ethnic origins; any correlation between SSM/LSM ratio and BMI; liver and spleen sizes; or ALT, AST, PLT, APRI, and FIB-4 scores.

CONCLUSIONS

A quantifiable numeric relationship between splenic and liver stiffness in the healthy subjects could be computed to a parameter expressed as SSM/LSM ratio. We believe that this ratio can be a useful reference tool for further researches in CLD.

The effect of applied transducer force on acoustic radiation force impulse quantification within the left lobe of the liver

Introduction: Acoustic Radiation Force Impulse (ARFI) Quantification measures shear wave velocities (SWVs) within the liver. It is a reliable method for predicting the severity of liver fibrosis and has the potential to assess fibrosis in any part of the liver, but previous research has found ARFI quantification in the right lobe more accurate than in the left lobe. A lack of standardised applied transducer force when performing ARFI quantification in the left lobe of the liver may account for some of this inaccuracy. The research hypothesis of this present study predicted that an increase in applied transducer force would result in an increase in SWVs measured.

Methods: ARFI quantification within the left lobe of the liver was performed within a group of healthy volunteers (n = 28). During each examination, each participant was subjected to ARFI quantification at six different levels of transducer force applied to the epigastric abdominal wall.

Results: A repeated measures ANOVA test showed that ARFI quantification was significantly affected by applied transducer force (p = 0.002). Significant pairwise comparisons using Bonferroni correction for multiple comparisons showed that with an increase in applied transducer force, there was a decrease in SWVs.

Conclusion: Applied transducer force has a significant effect on SWVs within the left lobe of the liver and it may explain some of the less accurate and less reliable results in previous studies where transducer force was not taken into consideration. Future studies in the left lobe of the liver should take this into account and control for applied transducer force.

Impact of Fibrotic Tissue on Shear Wave Velocity in Thyroid: An Ex Vivo Study with Fresh Thyroid Specimens

We sought to elucidate the correlation between shear wave velocity (SWV) and fibrosis in thyroid by precisely assessing pathological structures inside 5 × 5 mm(2) regions of interest (ROIs) of resected specimens, under conditions that excluded physical artifacts. The materials were unselected thyroid and lymph node specimens resected during thyroid surgery. Immediately after surgery, fresh unfixed thyroid and metastatic lymph node specimens were suspended in gel phantoms, and SWV was measured. Upon pathological examination of each specimen, the extent of fibrosis was graded as none, moderate, or severe. A total of 109 specimens were evaluated: 15 normal thyroid, 16 autoimmune thyroiditis, 40 malignant nodules, 19 benign thyroid nodules, and 19 metastatic lymph nodes. When all specimens were classified according to the degree of fibrosis determined by pathological imaging, the mean SWV was 1.49 ± 0.39 m/s for no fibrosis, 2.13 ± 0.66 m/s for moderate fibrosis, and 2.68 ± 0.82 m/s for severe fibrosis. The SWVs of samples with moderate and severe fibrosis were significantly higher than those of samples without fibrosis. The results of this study demonstrate that fibrosis plays an important role in determining stiffness, as measured by SWV in thyroid.

Acoustic radiation force impulse quantification of spleen elasticity for assessing liver fibrosis

PURPOSE

The purpose of this study is to assess the correlation between liver fibrosis and spleen stiffness measured by ARFI in patients with chronic viral hepatitis (B or C) and to explore the possible complementary role of spleen and liver ARFI in grading liver fibrosis.

METHODS

84 subjects (51 patients, 33 healthy volunteers) were enrolled. ARFI of the spleen and the liver was performed. Patients subsequently underwent liver biopsy for grading liver fibrosis according to Knodell scoring system. Multivariate logistic regression and decision tree analysis were adopted to test the relationship between spleen and liver stiffness (independent variables) and liver fibrosis (F1< vs. ≥F3). Leave-One-Out Cross-Validation was used for validating the predictive classification models. Area under the ROC curve (AUROCC) was used as accuracy metric.

RESULTS

Spleen ARFI was able to discriminate early (F1) from severe (≥F3) liver fibrosis with an optimal cut-off of 3.05 m/s: AUROCC 0.807, cross-validated AUROCC 0.614. Liver ARFI was superior to spleen ARFI, using a cut-off of 2.11 m/s: AUROCC 0.879, cross-validated AUROCC 0.672. Neither spleen nor liver ARFI was able to differentiate healthy volunteers from F1 patients. Odds ratios derived from logistic regression were 23.1 and 9.9 for liver and spleen ARFI, respectively; resulting AUROCC was 0.905 (cross-validated 0.848). A decision tree considering the sequential use of liver and spleen ARFI with cut-off of 2.14 and 3.39 m/s, respectively, resulted in AUROCC of 0.903 (cross-validated 0.7).

CONCLUSIONS

Spleen ARFI has the potential to discriminate early from severe liver fibrosis. Spleen and liver ARFI, when combined, show a better discriminative power than liver ARFI alone.

Imaging Based Methods of Liver Fibrosis Assessment in Viral Hepatitis: A Practical Approach

Liver fibrosis represents the repair mechanism in liver injury and is a feature of most chronic liver diseases. The degree of liver fibrosis in chronic viral hepatitis infections has major clinical implications and presence of advanced fibrosis or cirrhosis determines prognosis. Treatment initiation for viral hepatitis is indicated in most cases of advanced liver fibrosis and diagnosis of cirrhosis entails hepatology evaluation for specialized clinical care. Liver biopsy is an invasive technique and has been the standard of care of fibrosis assessment for years; however, it has several limitations and procedure related complications. Recently, several methods of noninvasive assessment of liver fibrosis have been developed which require either serologic testing or imaging of liver. Imaging based noninvasive techniques are reviewed here and their clinical use is described. Some of the imaging based tests are becoming widely available, and collectively they are shown to be superior to liver biopsy in important aspects. Clinical utilization of these methods requires understanding of performance and quality related parameters which can affect the results and provide wrong assessment of the extent of liver fibrosis. Familiarity with the strengths and weaknesses of each modality is needed to correctly interpret the results in appropriate clinical context.

Portal Hypertension in Patients with Liver Cirrhosis: Diagnostic Accuracy of Spleen Stiffness

PURPOSE

To evaluate the accuracy of spleen stiffness (SS) and liver stiffness (LS) measured by using acoustic radiation force impulse imaging in the diagnosis of portal hypertension in patients with liver cirrhosis, with the hepatic venous pressure gradient (HVPG) as a reference standard.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained for this prospective single-center study. From February 2012 to August 2013, 60 patients with liver cirrhosis (mean age, 70.8 years; age range, 34-88 years; 34 men, 26 women) with HVPG, LS, and SS measurements and gastrointestinal endoscopy and laboratory data were included if they met the following criteria: no recent episodes of gastrointestinal bleeding, no history of splenectomy, no history of partial splenic embolization, no history of β-blocker therapy, and absence of portal thrombosis. The efficacy of the parameters for the evaluation of portal hypertension was analyzed by using the Spearman rank-order correlation coefficient and receiver operating characteristic (ROC) curve analysis.

RESULTS

The correlation coefficient between SS and HVPG (r = 0.876) was significantly better than that between LS and HVPG (r = 0.609, P < .0001). The areas under the ROC curve of SS for the identification of clinically important portal hypertension (HVPG ≥ 10 mm Hg), severe portal hypertension (HVPG ≥ 12 mm Hg), esophageal varices (EVs), and high-risk EVs were significantly higher (0.943, 0.963, 0.937, and 0.955, respectively) than those of LS, spleen diameter, platelet count, and platelet count to spleen diameter ratio (P < .05 for all). SS could be used to accurately rule out the presence of clinically important portal hypertension, severe portal hypertension, EVs, and high-risk EVs (negative likelihood ratios, 0.051, 0.056, 0.054, and 0.074, respectively).

CONCLUSION

SS is reliable and has better diagnostic performance than LS for identifying portal hypertension in liver cirrhosis.

Non-invasive diagnosis of liver fibrosis and cirrhosis

The evaluation and follow up of liver fibrosis and cirrhosis have been traditionally performed by liver biopsy. However, during the last 20 years, it has become evident that this “gold-standard” is imperfect; even according to its proponents, it is only “the best” among available methods. Attempts at uncovering non-invasive diagnostic tools have yielded multiple scores, formulae, and imaging modalities. All are better tolerated, safer, more acceptable to the patient, and can be repeated essentially as often as required. Most are much less expensive than liver biopsy. Consequently, their use is growing, and in some countries the number of biopsies performed, at least for routine evaluation of hepatitis B and C, has declined sharply. However, the accuracy and diagnostic value of most, if not all, of these methods remains controversial. In this review for the practicing physician, we analyze established and novel biomarkers and physical techniques. We may be witnessing in recent years the beginning of the end of the first phase for the development of non-invasive markers. Early evidence suggests that they might be at least as good as liver biopsy. Novel experimental markers and imaging techniques could produce a dramatic change in diagnosis in the near future.

Ultrasound-based elastography for the diagnosis of portal hypertension in cirrhotics

Progressive fibrosis is encountered in almost all chronic liver diseases. Its clinical signs are diagnostic in advanced cirrhosis, but compensated liver cirrhosis is harder to diagnose. Liver biopsy is still considered the reference method for staging the severity of fibrosis, but due to its drawbacks (inter and intra-observer variability, sampling errors, unequal distribution of fibrosis in the liver, and risk of complications and even death), non-invasive methods were developed to assess fibrosis (serologic and elastographic). Elastographic methods can be ultrasound-based or magnetic resonance imaging-based. All ultrasound-based elastographic methods are valuable for the early diagnosis of cirrhosis, especially transient elastography (TE) and acoustic radiation force impulse (ARFI) elastography, which have similar sensitivities and specificities, although ARFI has better feasibility. TE is a promising method for predicting portal hypertension in cirrhotic patients, but it cannot replace upper digestive endoscopy. The diagnostic accuracy of using ARFI in the liver to predict portal hypertension in cirrhotic patients is debatable, with controversial results in published studies. The accuracy of ARFI elastography may be significantly increased if spleen stiffness is assessed, either alone or in combination with liver stiffness and other parameters. Two-dimensional shear-wave elastography, the ElastPQ technique and strain elastography all need to be evaluated as predictors of portal hypertension.

Evaluation of Transient Elastography, Acoustic Radiation Force Impulse Imaging (ARFI), and Enhanced Liver Function (ELF) Score for Detection of Fibrosis in Morbidly Obese Patients

BACKGROUND

Liver fibrosis induced by non-alcoholic fatty liver disease causes peri-interventional complications in morbidly obese patients. We determined the performance of transient elastography (TE), acoustic radiation force impulse (ARFI) imaging, and enhanced liver fibrosis (ELF) score for fibrosis detection in bariatric patients.

PATIENTS AND METHODS

41 patients (median BMI 47 kg/m2) underwent 14-day low-energy diets to improve conditions prior to bariatric surgery (day 0). TE (M and XL probe), ARFI, and ELF score were performed on days -15 and -1 and compared with intraoperative liver biopsies (NAS staging).

RESULTS

Valid TE and ARFI results at day -15 and -1 were obtained in 49%/88% and 51%/90% of cases, respectively. High skin-to-liver-capsule distances correlated with invalid TE measurements. Fibrosis of liver biopsies was staged as F1 and F3 in n = 40 and n = 1 individuals. However, variations (median/range at d-15/-1) of TE (4.6/2.6-75 and 6.7/2.9-21.3 kPa) and ARFI (2.1/0.7-3.7 and 2.0/0.7-3.8 m/s) were high and associated with overestimation of fibrosis. The ELF score correctly classified 87.5% of patients.

CONCLUSION

In bariatric patients, performance of TE and ARFI was poor and did not improve after weight loss. The ELF score correctly classified the majority of cases and should be further evaluated.

Hepatic and Splenic Acoustic Radiation Force Impulse Shear Wave Velocity Elastography in Children with Liver Disease Associated with Cystic Fibrosis

BACKGROUND

Liver disease associated with cystic fibrosis (CFLD) is the second cause of mortality in these patients. The diagnosis is difficult because none of the available tests are specific enough. Noninvasive elastographic techniques have been proven to be useful to diagnose hepatic fibrosis. Acoustic radiation force impulse (ARFI) imaging is an elastography imaging system. The purpose of the work was to study the utility of liver and spleen ARFI Imaging in the detection of CFLD. Method. 72 patients with cystic fibrosis (CF) were studied and received ARFI imaging in the liver and in the spleen. SWV values were compared with the values of 60 healthy controls. Results. Comparing the SWV values of CFLD with the control healthy group, values in the right lobe were higher in patients with CFLD. We found a SWV RHL cut-off value to detect CFLD of 1.27 m/s with a sensitivity of 56.5% and a specificity of 90.5%. CF patients were found to have higher SWC spleen values than the control group. Conclusions. ARFI shear wave elastography in the right hepatic lobe is a noninvasive technique useful to detect CFLD in our sample of patients. Splenic SWV values are higher in CF patients, without any clinical consequence.

The Role of Ultrasound Elasticity Imaging in Predicting Ileal Fibrosis in Crohn's Disease Patients

BACKGOUND

Bowel wall fibrosis is associated with a complicated disease behavior in patients with Crohn's disease (CD). The quantitative assessment of fibrosis severity in CD-affected bowel can help clinical decision making. Our aim was to evaluate the feasibility, reliability, and reproducibility of ultrasound elasticity imaging (UEI) toward the assessment of ileal fibrosis in CD patients.

METHODS

Twenty-three consecutive patients with ileal or ileocolonic CD, elected for surgical resection of the terminal ileum, underwent bowel ultrasound and UEI. Twenty inflammatory CD patients without complications were enrolled as controls. Bowel wall stiffness was evaluated with UEI by means of color scale and quantitative strain ratio measurement. The severity of bowel wall fibrosis and inflammation were evaluated on histological sections by semiquantitative and quantitative image analysis and used as a reference standard.

RESULTS

The UEI strain ratio measurement was significantly correlated with the severity of bowel fibrosis at both semiquantitative and quantitative histological image analysis: it was characterized by an excellent discriminatory ability for severe bowel fibrosis (area under the receiver operating characteristic curve: 0.917; 95% confidence interval, 0.788-1.000). UEI strain ratio measurements were characterized by an excellent interrater agreement. At multivariate analysis, bowel wall fibrosis proved the only independent determinant of the strain ratio. The ileal strain ratio of inflammatory CD patients was significantly lower than in operated CD patients with severe fibrosis.

CONCLUSIONS

UEI can be used to assess ileal fibrosis in CD patients.

Liver fibrosis and Gd-EOB-DTPA-enhanced MRI: A histopathologic correlation

Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a hepatocyte-specific MRI contrast agent. Because the hepatic uptake of Gd-EOB-DTPA depends on the integrity of the hepatocyte mass, this uptake can be quantified to assess liver function. We report the relationship between the extent of Gd-EOB-DTPA uptake and the degree of liver fibrosis. T1-weighted volume-interpolated breath-hold examination (VIBE) sequences with fat suppression were acquired before and 20 minutes after contrast injection. Strong correlations of the uptake characteristics of Gd-EOB-DTPA with the relative enhancement (RE) of the liver parenchyma and the grade of fibrosis/cirrhosis, classified using the Ishak scoring system, were observed. The subdivisions between the grades of liver fibrosis based on RE were highly significant for all combinations, and a ROC revealed sensitivities ≥82% and specificities ≥87% for all combinations. MR imaging is a satisfactorily sensitive method for the assessment of liver fibrosis/cirrhosis.

[Ultrasound elastography]

Noninvasive, ultrasound-based methods for visualizing and measuring tissue elasticity are becoming more and more common in routine practice. Using hepatic shear wave elastography, cut-off levels can help to detect the degree of relevant fibrosis (F ≥ 2) with a diagnostic accuracy using the area under the reader operating characteristic (AUROC) of 87 % and cirrhosis (F = 4, AUROC 93 %). Normal values virtually exclude liver cirrhosis (negative predictive value up to 97 %) and high shear wave velocities predict complications in the course of primary sclerosing cholangitis, liver cirrhosis and chronic hepatitis B or C. Elastography is of no relevant help in the differentiation of the dignity of hepatic lesions. Concerning thyroid or breast lesions, low shear wave velocities are indicative of benign lesions and in contrast, high velocities of malignant lesions. A differentiation between benign and malignant thyroid nodules is performed by elastography with a sensitivity of 89 % and a specificity of 82 %. In breast lesions a differentiation of nodes can be improved with elastography compared to B-mode ultrasound alone with a sensitivity of 97 % and a specificity of 83 %. Invasive biopsy punctures can therefore be specifically performed or can be omitted. Due to several influencing factors, in particular during liver elastography, the measurements need to be interpreted in the clinical context. In summary, ultrasound-based elastography provides helpful information for the detection of hepatic fibrosis and for further characterization of thyroid or breast lesions in addition to classical techniques, such as B-mode imaging and color Doppler.

Wisteria floribunda agglutinin positive human Mac-2-binding protein as a predictor of hepatocellular carcinoma development in chronic hepatitis C patients

AIMS

Wisteria floribunda agglutinin (WFA)-positive human Mac-2-binding protein (WFA(+) -M2BP) is a new glycol marker related to liver fibrosis. The aim of the present study was to evaluate WFA(+) -M2BP as a predictor of hepatocellular carcinoma (HCC) development in patients with chronic hepatitis C.

METHODS

This case-control study included 14 patients with chronic hepatitis C who developed HCC and 52controls, matched for age, gender, and fibrosis stage. WFA(+) -M2BP was measured at biopsy and follow-up. Time zero was set at the date of liver biopsy.

RESULTS

WFA(+) -M2BP increased stepwise with progression of liver fibrosis (p < 0.001). Cumulative incidence of HCC development was significantly higher in patients with WFA(+) -M2BP ≥4.2 (p < 0.001) or in those with time-course changes in WFA(+) -M2BP (ΔWFA(+) -M2BP/year) ≥0.3 (p = 0.03). Multivariate analyses demonstrated that WFA(+) -M2BP ≥4.2 [hazard ratio (HR): 4.1, 95% confidence interval (CI): 1.1-15, p = 0.04], ΔWFA(+) -M2BP/year ≥0.3 (HR: 5.5, 95% CI: 1.5-19, p = 0.008), and AFP ≥10 ng/ml (HR: 4.7, 95% CI: 1.1-19, p = 0.03) were independent predictive factors of HCC development. Based on these data, we developed a simple scoring system to predict HCC development using these three factors. Using these scores, patients were classified into four groups; cumulative incidence of HCC development significantly increased with increasing scores (p < 0.001).

CONCLUSIONS

WFA(+) -M2BP measurements and time-course changes in WFA(+) -M2BP can be used to identify patients at high risk of HCC development. Real-time monitoring of WFA(+) -M2BP can be a novel predictor of HCC development.

Nonalcoholic fatty liver disease - current status and future directions

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver disease worldwide with a reported prevalence ranging 6-33%, depending on the studied populations. It encompasses a spectrum of liver manifestations ranging from simple steatosis (also known as nonalcoholic fatty liver, NAFL) to nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis, which may ultimately progress to hepatocellular carcinoma. NAFLD is strongly associated with the components of metabolic syndrome, mainly obesity and type 2 diabetes mellitus. NAFLD patients are at increased risk of liver-related as well as cardiovascular mortality. Current paradigm suggests a benign course for NAFL whereas NASH is considered to be the progressive phenotype. Although previously under-recognized accumulating evidence suggests that NAFL may also progress, suggesting a higher number of patients at risk than previously appreciated. Liver biopsy remains the gold standard for definitive diagnosis, but the majority of patients can be diagnosed accurately by noninvasive methods. Approved therapies for NAFLD are still lacking and lifestyle modifications aiming at weight loss remain the mainstay of NAFLD treatment. Intensive research could identify insulin resistance, lipotoxicity and dysbiosis of the gut microbiota as major pathophysiological mechanisms, leading to the development of promising targeted therapies which are currently investigated in clinical trials. In this review we summarized the current knowledge of NAFLD epidemiology, natural history, diagnosis, pathogenesis and treatment and considered future directions.

Liver and spleen transient elastography and Acoustic Radiation Force Impulse Measurements. Performance and comparison of measurements in the same area concurrently assessed for liver fibrosis by biopsy

PURPOSE

The estimation of the degree of liver fibrosis is important for prognosis, surveillance, and treatment of chronic liver disease. Although liver biopsy is the gold standard for diagnosis, it is subject to sampling error, while ultrasound-based techniques, such as Acoustic Radiation Force Impulse (ARFI) and transient elastography, have gained popularity. However, no previous comparative study has performed these ultrasound techniques at the time of biopsy. The aim of this study was to compare the reliability of these techniques to define the severity of liver fibrosis in viral hepatitis patients.

PATIENTS AND METHODS

We compared liver transient elastography and Acoustic Radiation Force Impulse measurements, performed along the intended biopsy track, with liver biopsy results in 46 viral hepatitis patients, all measured on the same morning. Fibrosis was measured by histology using the Ishak fibrosis staging.

RESULTS

The relative sensitivity and specificity of different incremental cut-off values for both techniques, and the predictive ability of pairwise comparison of the 3 tests (including APRI) and of their combined use with more severe grades of histology-measured liver fibrosis, show that the single variable with greatest sensitivity and specificity is TE with a cut-off of >10.0.

CONCLUSION

Transient elastography has a better performance than ARFI, which has a lower sensitivity, in the diagnosis of severe stages of fibrosis. Also ARFI of the spleen is correlated with Ishak fibrosis staging, and could be a possible additional tool for the diagnosis of liver fibrosis.

Assessment of liver fibrosis with 2-D shear wave elastography in comparison to transient elastography and acoustic radiation force impulse imaging in patients with chronic liver disease

Two-dimensional shear wave elastography (2-D SWE) is an ultrasound-based elastography method integrated into a conventional ultrasound machine. It can evaluate larger regions of interest and, therefore, might be better at determining the overall fibrosis distribution. The aim of this prospective study was to compare 2-D SWE with the two best evaluated liver elastography methods, transient elastography and acoustic radiation force impulse (point SWE using acoustic radiation force impulse) imaging, in the same population group. The study included 132 patients with chronic hepatopathies, in which liver stiffness was evaluated using transient elastography, acoustic radiation force impulse imaging and 2-D SWE. The reference methods were liver biopsy for the assessment of liver fibrosis (n = 101) and magnetic resonance imaging/computed tomography for the diagnosis of liver cirrhosis (n = 31). No significant difference in diagnostic accuracy, assessed as the area under the receiver operating characteristic curve (AUROC), was found between the three elastography methods (2-D SWE, transient elastography, acoustic radiation force impulse imaging) for the diagnosis of significant and advanced fibrosis and liver cirrhosis in the "per protocol" (AUROCs for fibrosis stages ≥2: 0.90, 0.95 and 0.91; for fibrosis stage [F] ≥3: 0.93, 0.95 and 0.94; for F = 4: 0.92, 0.96 and 0.92) and "intention to diagnose" cohort (AUROCs for F ≥2: 0.87, 0.92 and 0.91; for F ≥3: 0.91, 0.93 and 0.94; for F = 4: 0.88, 0.90 and 0.89). Therefore, 2-D SWE, ARFI imaging and transient elastography seem to be comparably good methods for non-invasive assessment of liver fibrosis.

Correlation between quantitative shear wave elastography and pathologic structures of thyroid lesions

The aim of this study was to determine the correlation between shear wave velocity (SWV) generated by acoustic radiation force impulse and the pathologic structure of thyroid lesions. A total of 599 thyroid tissue samples were divided into four groups based on pathologic structure: 254 normal thyroid tissue samples as a control, 128 with chronic autoimmune thyroiditis (CAT) that demonstrated diffuse fibrosis, 165 with benign nodules that had high cell density and 52 with papillary thyroid carcinoma (PTC) that showed high cell density and fibrosis. The mean SWVs in each group were as follows: 1.60 ± 0.18 m/s in normal thyroid, 2.55 ± 0.28 m/s in CAT, 1.72 ± 0.31 m/s in benign nodules and 2.66 ± 0.95 m/s in PTC. The SWVs of CAT and PTC were significantly higher than those of normal thyroid, (p < 0.001). SWV was significantly affected by fibrosis.

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

The Society of Radiologists in Ultrasound convened a panel of specialists from radiology, hepatology, pathology, and basic science and physics to arrive at a consensus regarding the use of elastography in the assessment of liver fibrosis in chronic liver disease. The panel met in Denver, Colo, on October 21-22, 2014, and drafted this consensus statement. The recommendations in this statement are based on analysis of current literature and common practice strategies and are thought to represent a reasonable approach to the noninvasive assessment of diffuse liver fibrosis.

Liver reserve function assessment by acoustic radiation force impulse imaging

AIM: To evaluate the utility of liver reserve function by acoustic radiation force impulse (ARFI) imaging in patients with liver tumors.

METHODS: Seventy-six patients with liver tumors were enrolled in this study. Serum biochemical indexes, such as aminotransferase (ALT), aspartate aminotransferase (AST), serum albumin (ALB), total bilirubin (T-Bil), and other indicators were observed. Liver stiffness (LS) was measured by ARFI imaging, measurements were repeated 10 times, and the average value of the results was taken as the final LS value. Indocyanine green (ICG) retention was performed, and ICG-K and ICG-R15 were recorded. Child-Pugh (CP) scores were carried out based on patient’s preoperative biochemical tests and physical condition. Correlations among CP scores, ICG-R15, ICG-K and LS values were observed and analyzed using either the Pearson correlation coefficient or the Spearman rank correlation coefficient. Kruskal-Wallis test was used to compare LS values of CP scores, and the receiver-operator characteristic (ROC) curve was used to analyze liver reserve function assessment accuracy.

RESULTS: LS in the ICG-R15 10%-20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant (2.19 ± 0.27 vs 1.59 ± 0.32, P < 0.01). LS in the ICG-R15 > 20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant (2.92 ± 0.29 vs 1.59 ± 0.32, P < 0.01). The LS value in patients with CP class A was lower than in patients with CP class B (1.57 ± 0.34 vs 1.86 ± 0.27, P < 0.05), while the LS value in patients with CP class B was lower than in patients with CP class C (1.86 ± 0.27 vs 2.47 ± 0.33, P < 0.01). LS was positively correlated with ICG-R15 (r = 0.617, P < 0.01) and CP score (r = 0.772, P < 0.01). Meanwhile, LS was negatively correlated with ICG-K (r = -0.673, P < 0.01). AST, ALT and T-Bil were positively correlated with LS, while ALB was negatively correlated with LS (P < 0.05). The ROC curve revealed that the when the LS value was 2.34 m/s, the Youden index was at its highest point, sensitivity was 69.2% and specificity was 92.1%.

CONCLUSION: For patients with liver tumors, ARFI imaging is a useful tool for assessing liver reserve function.