Applicability and variability of liver stiffness measurements according to probe position

Screening for Liver Steatosis and Fibrosis in Patients with Inflammatory Bowel Disease Using Vibration Controlled Transient Elastography with Controlled Attenuation Parameter

BACKGROUND AND AIMS

Inflammatory bowel diseases (IBD) are frequently associated with extraintestinal manifestations, hepatic injury being of concern in these patients. Current literature reports an increased prevalence of liver steatosis and fibrosis in subjects with IBD and the pathophysiology is yet to be completely understood. The aim of this study was to assess the prevalence of non-alcoholic fatty liver disease (NAFLD) in patients with IBD, as well as to determine the factors that connect these two disorders.

METHODS

From September 2021 to June 2022, 82 consecutive IBD patients were enrolled from a tertiary care center hospital in Iasi. Vibration-Controlled Transient Elastography with Controlled Attenuation Parameter (CAP) was used to assess the presence of NAFLD, with a cut-off score for CAP of 248 dB/m. Significant liver fibrosis was considered at a cut-off for liver stiffness measurements (LSM) of 7.2 kPa.

RESULTS

In total, 82 IBD patients (54.8% men, mean age of 49 ± 13 years) were included, 38 (46.3%) of them being diagnosed with NAFLD, with a mean CAP score of 286 ± 35.4 vs. 203 ± 29.7 in patients with IBD only. Age (β = 0.357, p = 0.021), body mass index (BMI) (β = 0.185, p = 0.048), disease duration (β = 0.297, p = 0.041), C-reactive protein (β = 0.321, p = 0.013), fasting plasma glucose (β = 0.269, p = 0.038), and triglycerides (β = 0.273, p = 0.023) were strongly associated with the presence of liver steatosis. The multivariate analysis showed that older age, BMI, and disease duration were strongly associated with significant liver fibrosis in our group.

CONCLUSIONS

NAFLD is a multifaced pathology with growing prevalence among IBD patients. Additional studies are needed to completely understand this problem and to create a solid evidence-based framework for more effective preventative and intervention strategies.

Are we missing varices by implementing Baveno-VI recommendation of not screening patients with Compensated Advanced Chronic Liver Disease?

OBJECTIVES

This study aimed to validate Baveno-VI recommendations for variceal screening in cACLD in our region and proposed our own cutoff values.

METHODS

Prospective cross-sectional study was conducted on cACLD patients from August 2020 till April 2021. Patients segregated into Group-A, having Liver stiffness measurement (LSM) of ≥ 20 kPa and platelet of ≤ 150 × 109 cells/L; and Group-B having LSM of < 20 kPa and PLT of > 150 × 109 cells/L. Gastroscopic findings were segregated into three categories, VNT, Varices Not Needing Treatment (VNNT) and No Varix (NV). ROC plots were generated for LSM and Platelet for VNT for sensitivity, specificity, Negative and Positive Predictive Values were calculated.

RESULTS

A total of 134 patients of cACLD were included. Group-A had 72 (53.7%) patients and Group-B had 62 (46.3%) patients. Group-A had 6 (8.3%) NV; 18 (25.0%) VNNT and 48 (66.7%) VNT. Group-B had 26 (41.9%) NV, 24 (38.7%) VNNT and 12 (19.4%) VNT. The sensitivity of 66.7%, specificity of 80.6% and NPV of 67.56% was obtained. Thus 19.4% VNT were missed on following Baveno VI recommendations. ROC in our study suggested cutoff value of 11.5 kPa with sensitivity of 100% and 1-sepcifity pf 78% (AUROC = 0.865; p < .001) of LSM below which screening gastroscopy could be avoided. The positive and negative predicted values for 84.85% and 100% respectively. Cut off value of platelet count for VNNT came out to be ≥ 97.5 × 109 cells/L with AUROC 0.891 (p < .001), having sensitivity of 100 % and 1-specificity of 83.3%.

CONCLUSIONS

Substantial number of VNT in cACLD patients are missed by following Baveno-VI recommendations and these needs to be revised on regional basis.

Does standoff material affect acoustic radiation force impulse elastography? A preclinical study of a modified elastography phantom

PURPOSE

This study was conducted to determine the influence of standoff material on acoustic radiation force impulse (ARFI) measurements in an elasticity phantom by using two different probes.

METHODS

Using ARFI elastography, 10 observers measured the shear wave velocity (SWV, m/sec) in different lesions of an elasticity phantom with a convex 4C1 probe and a linear 9L4 probe. The experimental setup was expanded by the use of an interposed piece of porcine muscle as standoff material. The probe pressure on the phantom was registered.

RESULTS

Faulty ARFI measurements occurred more often when quantifying the hardest lesion (74.0 kPa 4.97 m/sec) by the 9L4 probe with the porcine muscle as a standoff material interposed between the probe and the phantom. The success rate for ARFI measurements in these series was 52.4%, compared with 99.5% in the other series. The SWV values measured with the 9L4 probe were significantly higher (3.33±1.39 m/sec vs. 2.60±0.74 m/sec, P<0.001 in the group without muscle) and were closer to the reference value than those measured with the 4C1 probe (0.25±0.23 m/sec vs. 0.85±1.21 m/sec, P<0.001 in the same group). The SWV values measured when using the muscle as a standoff material were lower than those without the muscle (significant for 9L4, P=0.040). The deviation from the reference value and the variance increased significantly with the 9L4 probe if the muscle was in situ (B=0.27, P=0.004 and B=0.32, P<0.001). In our study, the pressure exerted by the operator had no effect on the SWV values.

CONCLUSION

The presence of porcine muscle acting as a standoff material influenced the occurrence of failed measurements as well as the variance and the accuracy of the measured values. The linear high-frequency probe was particularly affected.

Learning curve and intra/interobserver agreement of transient elastography in chronic hepatitis C patients with or without HIV co-infection

BACKGROUND AND OBJECTIVES

Liver stiffness measurement (LSM) by transient elastography has been validated as a noninvasive method to stage liver fibrosis. Few studies have evaluated the learning curve of this method and its reproducibility has led to controversy results. We aimed to evaluate the intra- and interobserver agreement of transient elastography as well as its learning curve for definition of an experimented operator.

METHODS

We retrospectively analyzed 922 examinations performed in 544 patients during a training program of transient elastography. Patients with chronic hepatitis C with or without HIV co-infection that had two examinations by the training operator (intraobserver analysis; n=125) or examination by both training and experimented operators (interobserver analysis; n=151) in the same day were included. LSM was converted to METAVIR score: <7.1 as F0F1, 7.1-9.4 as F2, 9.5-12.4, as F3 and >12.4 kPa as F4.

RESULTS

The overall intra- and interobserver intraclass correlation coefficient [ICC 95% CI] were 0.926 (0.901-0.951) and 0.912 (0.885-0.939), respectively. Measurements were correlated [Spearman's] in intra- [0.906, P<0.0001] and interobserver [0.907, P<0.0001] analysis. Reliability values [kappa (SE)] were k=0.74 (0.09) and k=0.85 (0.08) for fibrosis stages F ≥ 2 and k=0.77 (0.09) and k=0.75 (0.08) for cirrhosis in intra- and interobserver analysis, respectively. Agreement was improved when operator's experience was higher than 100 exams. However, it was observed discordance for fibrosis staging between examinations in a quarter of patients.

CONCLUSION

Although there was a considerable discrepancy on fibrosis staging between examinations and a small power, transient elastography had an acceptable reproducibility in our population. Performance of at least 100 examinations should be used to define an experimented operator.

Factors That Could Impact on Liver Fibrosis Staging by Transient Elastography

Transient elastography (TE) based on liver stiffness measurement (LSM) is one of the most validated noninvasive methods for liver fibrosis staging in patients with chronic liver diseases. This method is painless, has no potential complications, is rapid (<10 min), and can be performed at the patient's bedside. However, several points should be considered when interpreting TE results. This review aims to discuss the critical points that might influence liver stiffness and TE results. Spectrum bias and the impact of the prevalence of fibrosis stages should be taken into account when interpreting the studies that validated this method using liver biopsy as a gold-standard. LSM might be influenced by nonfasting status, flare of transaminases, heart failure, extrahepatic cholestasis, presence of steatosis, aetiology of liver disease, type and position of probe, and operator's experience. In addition, interobserver variability can impact on the management of patients with chronic liver diseases. TE should be performed by an experienced operator (>100 exams), in a 3-hour fasting status, and its results should be handled by specialist clinicians that are aware of the limitations of this method.

Interobserver variability in transient elastography analysis of patients with chronic hepatitis C

BACKGROUND & AIMS

Transient elastography based on liver stiffness measurement is a non-invasive method to assess hepatic fibrosis. However, interobserver variability has led to controversy over its use in fibrosis evaluation. To evaluate the interobserver variation in transient elastography in chronic hepatitis C.

METHODS

We performed a cross-sectional study, analysing findings from two experienced operators who each assessed 195 patients by transient elastography on the same day. Liver stiffness measurement used to define fibrosis stages, based on METAVIR score, was: <7.1 as F0F1, 7.1-9.4 as F2, 9.5-12.4, as F3 and >12.4 kPa as F4. We also assessed interobserver variation in identification of potential oesophageal varices screening based on transient elastography.

RESULTS

The interobserver intraclass correlation coefficient was 0.940 (95% CI 0.863-0.967) and measurements made by operators correlated [Spearman's ρ = 0.924; P < 0.001]. However, the median liver stiffness measurement assessed by first operators was higher (11.5 vs 9.8 kPa; P < 0.001). The discordance between operators was 35% for at least one stage of fibrosis and 5% for two or more stages. Interobserver reliability values were κ = 0.61 for fibrosis stages F ≥ 2 and κ = 0.80 for cirrhosis. Among the 74 patients determined to have cirrhosis by at least one operator, there was considerable discordance in identification of those with indication for oesophageal varices screening (κ values from 0.13 to 0.61) according to several cut-offs.

CONCLUSION

Although a high correlation of liver stiffness measurement between operators, interobserver variability in transient elastography was not negligible. This method should not be used as the only screening tool for oesophageal varices in chronic hepatitis C.

Transient elastography for diagnosis of stages of hepatic fibrosis and cirrhosis in people with alcoholic liver disease

BACKGROUND

The presence and progression of hepatic (liver) fibrosis into cirrhosis is a prognostic variable having impact on survival in people with alcoholic liver disease. Liver biopsy, although an invasive method, is the recommended 'reference standard' for diagnosis and staging of hepatic fibrosis in people with liver diseases. Transient elastography is a non-invasive method for assessing and staging hepatic fibrosis.

OBJECTIVES

To determine the diagnostic accuracy of transient elastography for diagnosis and staging hepatic fibrosis in people with alcoholic liver disease when compared with liver biopsy. To identify the optimal cut-off values for differentiating the five stages of hepatic fibrosis.

SEARCH METHODS

The Cochrane Hepato-Biliary Group Controlled and Diagnostic Test Accuracy Studies Registers, The Cochrane Library, MEDLINE (OvidSP), EMBASE (OvidSP), and the Science Citation Index Expanded (last search August 2014).

SELECTION CRITERIA

Diagnostic cohort and diagnostic case-control study designs that assessed hepatic fibrosis in participants with alcoholic liver disease with transient elastography and liver biopsy, irrespective of language or publication status. The study participants could be of any sex and ethnic origin, above 16 years old, hospitalised or managed as outpatients. We excluded participants with viral hepatitis, autoimmunity, metabolic diseases, and toxins.

DATA COLLECTION AND ANALYSIS

We followed the guidelines in the draft Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy.

MAIN RESULTS

Five retrospective and nine prospective cohort studies with 834 participants provided data for the review analyses. Authors of seven of those studies sent us individual participant data. The risk of bias in the included studies was high in all but three studies. We could identify no serious concerns regarding the applicability of the studies in answering the main study question of our review, namely to use transient elastography to diagnose hepatic fibrosis. We could not identify the optimal cut-off values for the fibrosis stages. The definition of the diagnosis of alcoholic liver disease was not provided in one study and was not clearly defined in two studies, but it was clear in the remaining 11 studies. The study authors used different liver stiffness cut-off values of transient elastography for the hepatic fibrosis stages.There was only one study (103 participants) with data on hepatic fibrosis stage F1 or worse, with a cut-off of 5.9 kPa, and reporting sensitivity of 0.83 (95% confidence interval (CI) 0.74 to 0.90) and specificity of 0.88 (95% CI 0.47 to 1.00). The summary sensitivity and specificity of transient elastography for F2 or worse (seven studies with 338 participants and with cut-offs around 7.5 kPa (range 7.00 to 7.8 kPa)) were 0.94 and 0.89 with LR+ 8.2 and LR- 0.07, which suggests that transient elastography could be useful to rule out the presence of significant hepatic fibrosis, thus avoiding liver biopsy.Due to the wide range of cut-off values (from 8.0 to 17.0 kPa) found in the 10 studies with 760 participants with hepatic fibrosis F3 or worse, we fitted a hierarchical summary receiver operating characteristic (HSROC) model and estimated a summary ROC (SROC) curve. The sensitivity of the 10 studies varied from 72% to 100% and the specificity from 59% to 89%. We performed an additional analysis by including the studies with a cut-off value of around and equal to 9.5 kPa (range 8.0 to 11.0 kPa). The summary sensitivity and specificity of transient elastography (eight studies with 564 participants) were 0.92 and 0.70 with LR+ 3.1 and LR- 0.11, which suggests that transient elastography could also be useful to rule out the presence of severe hepatic fibrosis (F3 or worse), avoiding liver biopsy. We carried out a sensitivity analysis by considering only the studies with a cut-off value equal to 9.5 kPa and the result did not differ.We performed an HSROC analysis and reported an SROC curve for hepatic fibrosis stage F4 (cirrhosis). The HSROC analysis suggested that when the cut-off value changes, there is a wide variation in specificity and a more limited variation in sensitivity. We performed an additional analysis with the studies with the most commonly used cut-off value of 12.5 kPa. The summary sensitivity and specificity of transient elastography (seven studies with 330 participants) were 0.95 and 0.71 with LR+ 3.3 and LR- 0.07, which again suggests that transient elastography could be useful to rule out the presence of cirrhosis, avoiding liver biopsy.

AUTHORS' CONCLUSIONS

We identified a small number of studies with a few participants and were unable to include several studies, which raises the risk of outcome reporting bias. With these caveats in mind, transient elastography may be used as a diagnostic method to rule out liver cirrhosis (F4) in people with alcoholic liver disease when the pre-test probability is about 51% (range 15% to 79%). Transient elastography may also help in ruling out severe fibrosis (F3 or worse). Liver biopsy investigation remains an option if the certainty to rule in or rule out the stage of hepatic fibrosis or cirrhosis remains insufficient after a clinical follow-up or any other non-invasive test considered useful by the clinician.The proposed cut-off values for the different stages of hepatic fibrosis may be used in clinical practice, but caution is needed, as those values reported in this review are only the most common cut-off values used by the study authors. The best cut-off values for hepatic fibrosis in people with alcoholic liver disease could not be established yet.In order to diagnose correctly the stage of hepatic fibrosis in people with alcoholic liver disease using transient elastography assessment, the studies should consider a single aetiology. Hepatic fibrosis should be diagnosed with both transient elastography and liver biopsy and in this sequence, and transient elastography cut-off values should be pre-specified and validated. The time interval between the two investigations should not exceed three months, which is the interval mainly valid for people without cirrhosis, and assessment of results should be properly blinded. Only studies with low risk of bias, fulfilling the Standards for Reporting of Diagnostic Accuracy may answer the review question.

Liver stiffness using transient elastography is applicable to canines for hepatic disease models

Background

The objectives of this study were to evaluate the best position and best exploration probe for determining liver stiffness (LS) in dogs using transient liver elastography (TE). Thirteen dogs were used in the study.

Methodology/Principal Findings

Morphometric measurements taken were thoracic circumference, weight and height. Elastographic measurements were taken in 4 anatomical positions using two different probes: medium (M) and small (S). The exploration was considered correct when the success rate was above 60% and the interquartile range of the measurements did not exceed 30%. The best measurements were obtained in the middle of the 6th–9th intercostal spaces, with the dog in the left lateral position and using probe M for preference in adults and probe S mandatory for animals <2 years. The correlation between probes was 99%. Intra-observer variability showed an intra-class correlation of 97.6%.

Conclusions/Significance

TE is a technique that is reproducible in dogs.

Evaluation of curative effect of autologous bone marrow stem cell transplantation on decompensated cirrhosis by Fibroscan

AIM: To evaluate the efficacy of autologous bone marrow stem cell transplantation in the treatment of decompensated cirrhosis by Fibroscan combined with multiple parameters.

METHODS: A total of 58 patients with decompensated cirrhosis were divided into transplantation group (n = 27) and control group (n = 31). Baseline examinations, including liver biopsy and Fibroscan, were performed before therapy. Both groups underwent routine medical treatment, and the transplantation group additionally underwent autologous bone marrow stem cell transplantation. At 2, 4, 8, 12, 24 and 48 wk after therapy, liver function and coagulation function were measured. Fibroscan and FIB-4 tests were performed at 12, 24 and 48 wk. At 48 wk after therapy, some patients underwent a liver biopsy. Then the efficacy of autologous bone marrow stem cell transplantation in the treatment of cirrhosis and the role of Fibroscan in evaluation of the curative effect were analyzed comprehensively.

RESULTS: Successful transplantation was achieved in all the 27 patients. Seven patients from each group underwent a liver biopsy, and they were clearly diagnosed with cirrhosis by histopathology. At 8 wk after therapy, the improvement in symptoms and physical signs in the transplantation group was better than that in the control group. The liver function and coagulation function improved in both groups, and the improvement was more significant in the transplantation group than in the control group. The liver stiffness values in the transplantation group did not differ significantly between before treatment and 12 and 24 wk after transplantation (31.66 kPa ± 6.97 kPa vs 31.98 kPa ± 7.36 kPa, 31.35 kPa ± 6.73 kPa, both P > 0.05), but were significantly higher at 48 wk than at other time points (31.78 kPa ± 7.35 kPa, P < 0.05). The liver stiffness values in the control group increased gradually from 32.05 kPa ± 9.09 kPa at pretreatment to 36.39 kPa ± 9.39 kPa at 48 wk after therapy (P < 0.05), and there was a statistical difference in the liver stiffness values between the two groups at 48 wk. The level of HA in the transplantation group decreased more significantly than that in the control group (P < 0.05 at 24 wk).

CONCLUSION: Autologous bone marrow stem cell transplantation can significantly improve symptoms and liver function in patients with decompensated cirrhosis. Fibroscan is an important means of evaluating the curative effect of autologous bone marrow stem cell transplantation on decompensated cirrhosis.

Relationship between hepatic haemodynamics assessed by Doppler ultrasound and liver stiffness

AIM

We tested the relationship between hepatic haemodynamics assessed by Doppler ultrasonography and liver stiffness assessed by Transient Elastography in hepatitis C related chronic liver disease.

METHODS

Three liver Doppler ultrasound parameters (hepatic artery resistance index, splenic artery resistance index and waveform pattern in hepatic veins) and liver stiffness measured by Transient Elastography were analysed in one hundred consecutive patients affected by hepatitis C related chronic liver disease.

RESULTS

Hepatic and splenic arteries resistance indexes correlate significantly (p<0.0001 for both) with liver stiffness. A hepatic artery resistance index cut-off value of 0.64 provided sensitivity and specificity respectively of 84.4% and 69.1% for predicting liver stiffness ≤or >13 kPa, whereas a splenic artery resistance index cut-off value of 0.56 provided sensitivity and specificity respectively of 81.3% and 48.5%. The coincidental finding of both resistance indexes above the respective cut-off values showed a good accuracy in identifying patients with liver stiffness values >13 kPa (accuracy=78%, +LR=2.90, -LR=0.31). A significant difference in liver stiffness values was evident between patients with triphasic and bi- or monophasic waveform pattern (p=0.005).

CONCLUSIONS

Hepatic and splenic arteries resistance indexes and the hepatic veins waveform pattern assessed by Doppler ultrasound may provide information similar to that of Transient Elastography in hepatitis C related chronic liver disease.

Acoustic radiation force impulse imaging (ARFI) for non-invasive detection of liver fibrosis: examination standards and evaluation of interlobe differences in healthy subjects and chronic liver disease

OBJECTIVE

Acoustic radiation force impulse imaging (ARFI) is a non-invasive method for the quantification of liver stiffness. We aimed to develop standards for the measuring procedure and studied the impact of different measuring sites.

MATERIALS AND METHODS

ARFI was tested in a tissue phantom and in 50 healthy volunteers. In addition, 116 patients with chronic liver disease underwent ARFI. The results were compared with histological staging (non-viral liver disease) and transient elastography (hepatitis C). ARFI diagnostic performance was evaluated with receiver operating characteristic curves.

RESULTS

ARFI results were not normally distributed in >20% of cases. Deep inspiration significantly increased ARFI values by 13% (p < 0.05). The mean shear-wave velocity in healthy individuals was 1.28 ± 0.19 m/s in the left liver lobe and 1.15 ± 0.17 m/s in the right liver lobe (p < 0.001). Similarly, in 79/116 patients with chronic liver disease a significant difference of shear-wave velocity between both liver lobes was detected. The histological staging correlated with ARFI results of the biopsy site (r = 0.661, p < 0.001) in non-viral liver disease (n = 47). The mean shear-wave velocity in cases with F1 and F2 fibrosis was increased in the left compared with the right liver lobe (2.1 ± 0.73 m/s vs. 1.75 ± 0.89 m/s, p = 0.041). Similar results were obtained in patients with hepatitis C (n = 69).

CONCLUSION

Our study strengthens the necessity for definition of examination standards and demonstrates the usefulness of ARFI in non-viral liver disease. Interlobe variations of liver stiffness demand further investigation.

FibroTest and Fibroscan performances revisited in patients with chronic hepatitis C. Impact of the spectrum effect and the applicability rate

BACKGROUND

Two widely used biomarkers of fibrosis, FibroTest and liver stiffness measurement (LSM), have been mostly validated in patients with chronic hepatitis C (CHC) using the standard area under the ROC curve (sAUROC) which is not the most appropriate method due to the risk of fibrosis spectrum effect. Furthermore the performance of these biomarkers have not been assessed in "intention to diagnose" which takes into account the failures and non-reliable results.

AIM

The aim was to compare the accuracy of FibroTest and LSM for the diagnosis of fibrosis using sAUROC, the pairwise comparison of fibrosis stages by Obuchowski measure (wAUROC), and these AUROCs reassessed after taking into account the applicability rates.

METHODS

One thousand two hundred and eighty-nine patients with CHC and 604 healthy volunteers were analyzed. The performances of biomarkers assessed were compared in a patients-only group (P1: n=1289), in a population combining both patients and healthy volunteers (P2: n=1893) and in a simulated population (P3: n=1893) with the prevalence of stages observed in a reference population, to demonstrate the impact of spectrum effect. Applicability rates were estimated prospectively in 24,872 consecutive FibroTest and in 13,669 consecutive LSM examinations.

RESULTS

Using wAUROC, the conclusions of studies with reliable results in P1 were different than in those of P2 and in P3. There was a lower performance of FibroTest versus LSM in P1 (0.864 [0.855-0.873] vs. 0.883 [0.874-0.892]; P=0.002) which was not found in P2 (0.893 [0.887-0.900] vs. 0.894 [0.887-0.901]; P=0.86) and in P3 (0.899 [0.893-0.905] vs 0.902 [0.895-0.909]; P=0.60). Using the sAUROC, in P1, P2 and P3, there was no significant difference between FibroTest and LSM performance for advanced fibrosis and a lower performance of FibroTest versus LSM for cirrhosis. In intention to diagnose, using wAUROCs performances were higher for FibroTest vs. LSM in P1 (0.857 [0.848-0.866] vs. 0.814 [0.807-0.821]; P<0.0001) and P2 (0.885 [0.879-0.892] vs. 0.743 [0.737-0.749]; P<0.0001), without difference in P3 (0.891 [0.885-0.897] vs. 0.894 [0.887-0.901]; P=0.90). Using sAUROC, the significant differences in favor of FibroTest vs LSM persisted also for the diagnosis of advanced fibrosis, both in P1 and P2 (P<0.0001) and for the diagnosis of cirrhosis in P1 (P<0.001).

CONCLUSION

When the spectrum effects and applicability rates were taken into account, LSM had lower performance results than FibroTest for the diagnosis of fibrosis stages.

Progression of liver fibrosis in HIV/HCV genotype 1 co-infected patients is related to the T allele of the rs12979860 polymorphism of the IL28B gene

OBJECTIVE

HIV/HCV co-infection is characterised by accelerated progression of liver disease. Recently, the rs12979860 C/T polymorphism in the IL28B gene has been linked to progression towards cirrhosis in HCV mono-infected patients and to treatment response of HCV-infection in HIV/HCV co-infected patients. Our aim was to clarify by non-invasive techniques if this polymorphism affects fibrosis progression in HIV/HCV co-infection.

METHODS

In a cross-sectional design, liver stiffness (transient elastography), surrogate markers of liver fibrosis (APRI and FIB-4 scores) and rs12979860 genotypes were analysed in 84 HCV/HIV co-infected patients. IL28B genotypes were determined by real-time PCR using a light cycler. In 56 HIV/HCV co-infected patients we also studied progression of fibrosis in relation to rs12979860 C/T genotypes over two years.

RESULTS

82% of the patients were on HAART (74% without detectable HI viremia) and 67% were haemophiliacs, respectively. HCV genotype 1 was present in 62%. Cross-sectional median liver stiffness was 7.4 kPa and correlated with APRI and FIB-4 scores (r = 0.6 each, p < 0.001). Frequencies of IL28B genotypes were: CC 50%, CT 43% and TT 7%. In the cross-sectional analysis liver stiffness values were not different between the various IL28B-genotypes. Upon follow-up under HAART carriers of a C allele did not show further progression, while liver stiffness significantly increased in HIV/HCV co-infected patients with the T allele (p = 0.047).

CONCLUSION

Although progression of liver fibrosis was low under HAART in our cohort, progression was more pronounced in HIV/HCV genotype 1 co-infected patients with the T allele.

New method for assessing liver fibrosis based on acoustic radiation force impulse: a special reference to the difference between right and left liver

BACKGROUND

Virtual touch tissue quantification (VTTQ) based on acoustic radiation force impulse (ARFI) imaging has been developed as a noninvasive bedside method for the assessment of liver stiffness. In this study, we examined the diagnostic performance of ARFI imaging in 103 patients, focusing on the difference in VTTQ values between the right and left liver lobes.

METHODS

We evaluated VTTQ values of the right and left lobes in 79 patients with chronic liver disease who underwent histological examination of liver fibrosis and in 24 healthy volunteers. The diagnostic accuracy of VTTQ was compared with several serum markers, including hyaluronic acid, type 4 collagen, and aspartate transaminase to platelet ratio index.

RESULTS

The VTTQ values (meters per second) in the right and left lobes were 1.61 ± 0.51 and 1.90 ± 0.68, respectively, and the difference was statistically significant (P < 0.0001). The VTTQ values in both liver lobes were correlated significantly with histological fibrosis grades (P < 0.001). The standard deviations of the VTTQ values in the right lobe were significantly lower than those in the left lobe (P < 0.001). The area under the receiver-operating characteristic curve for the diagnosis of fibrosis (F ≥ 3) using VTTQ values in both liver lobes was superior to serum markers, especially in the right lobe.

CONCLUSIONS

VTTQ is an accurate and reliable tool for the assessment of liver fibrosis. VTTQ of the right lobe was more accurate for diagnosing liver fibrosis than in the left lobe.

Transient elastography

In clinical practice, it is important to assess the severity of liver fibrosis in patients with various liver diseases to determine the prognosis, decide treatment, and monitor disease progression and response to treatment. Liver biopsy is limited by its invasiveness and patient acceptability. The development of transient elastography provides clinicians with a non-invasive, accurate, and reproducible tool to estimate liver fibrosis. The technique has been validated among many liver diseases and requires only simple training. Due to its non-invasive nature and ease of use, transient elastography can be used repeatedly on patients, and is optimal for large-scale epidemiological studies, in which stable patients with no indication for liver biopsy can also be included. However, falsely-high liver stiffness measurements might occur during acute hepatitis, extrahepatic cholestasis, congestive heart failure, and amyloidosis. Failed acquisition is also common in obese patients. The development of S and XL probes might cater for different population groups, but calibration in patients with liver biopsy is essential.

Liver biopsy for histological assessment: The case in favor

Liver biopsy (LB) is the gold standard method for assessment of liver histology. It provides valuable, otherwise unobtainable information, regarding the degree of fibrosis, parenchymal integrity, degree and pattern of inflammation, bile duct status and deposition of materials and minerals in the liver. This information provides immense help in the diagnosis and prognostication of a variety of liver diseases. With careful selection of patients, and performance of the procedure appropriately, the complications become exceptionally rare in current clinical practice. Furthermore, the limitations of sampling error and inter-/intra-observer variability may be avoided by obtaining adequate tissue specimen and having it reviewed by an experienced liver pathologist. Current noninvasive tools are unqualified to replace LB in clinical practice in the face of specific limitations for each tool, compounded by a poorer performance towards the assessment of the degree of liver fibrosis, particularly for intermediate stages.

Recent advances in the use of Fibroscan for diagnosis of liver fibrosis

In recent years, non-invasive methods for assessment of liver fibrosis have attracted worldwide attention. However, although many biochemical markers and imaging examinations have been used for evaluation of liver fibrosis, their sensitivity and specificity are low. Fibroscan (transient elastography) is a new non-invasive technology to assess the degree of liver fibrosis by measuring liver stiffness. Although Fibroscan has been extensively used to evaluate chronic hepatitis C and its complications in other countries, its use is uncommon in China. In this article, we will review its working principle, diagnostic value, and application status.