Liver elastography - an update

Multiparametric ultrasound as a new concept of assessment of liver tissue damage

Liver disease accounts for approximately 2 million deaths per year worldwide. All chronic liver diseases (CLDs), whether of toxic, genetic, autoimmune, or infectious origin, undergo typical histological changes in the structure of the tissue. These changes may include the accumulation of extracellular matrix material, fats, triglycerides, or tissue scarring. Noninvasive methods for diagnosing CLD, such as conventional B-mode ultrasound (US), play a significant role in diagnosis. Doppler US, when coupled with B-mode US, can be helpful in evaluating the hemodynamics of hepatic vessels and detecting US findings associated with hepatic decompensation. US elastography can assess liver stiffness, serving as a surrogate marker for liver fibrosis. It is important to note that interpreting these values should not rely solely on a histological classification. Contrast-enhanced US (CEUS) provides valuable information on tissue perfusion and enables excellent differentiation between benign and malignant focal liver lesions. Clinical evaluation, the etiology of liver disease, and the patient current comorbidities all influence the interpretation of liver stiffness measurements. These measurements are most clinically relevant when interpreted as a probability of compensated advanced CLD. B-mode US offers a subjective estimation of fatty infiltration and has limited sensitivity for mild steatosis. The controlled attenuation parameter requires a dedicated device, and cutoff values are not clearly defined. Quan-titative US parameters for liver fat estimation include the attenuation coefficient, backscatter coefficient, and speed of sound. These parameters offer the advantage of providing fat quantification alongside B-mode evaluation and other US parameters. Multiparametric US (MPUS) of the liver introduces a new concept for complete noninvasive diagnosis. It encourages examiners to utilize the latest features of an US machine, including conventional B-mode, liver stiffness evaluation, fat quantification, dispersion imaging, Doppler US, and CEUS for focal liver lesion characterization. This comprehensive approach allows for diagnosis in a single examination, providing clinicians worldwide with a broader perspective and becoming a cornerstone in their diagnostic arsenal. MPUS, in the hands of skilled clinicians, becomes an invaluable predictive tool for diagnosing, staging, and monitoring CLD.

Liver fibrosis assessment in pediatric population - can ultrasound elastography be an alternative method to liver biopsy? A systematic review

Liver diseases of various etiologies are becoming increasingly common in the pediatric population. So far, the gold diagnostic standard in these disorders is liver biopsy. This procedure is invasive, painful and requires general anesthesia in this group of patients. Due to the continuous development of new research techniques, such as liver elastography, it is necessary to evaluate them in the context of their diagnostic usefulness. Ultrasound elastography, as a quick and effective method, is being used more and more often in the assessment and monitoring of liver dysfunction in both adults and children. There are several techniques of liver elastography, such as transient elastography, shear wave elastography consisting of various subtypes such as two-dimensional shear wave elastography, acoustic radiation force impulse and point shear wave elastography, which differ in terms of the measurement technique and the achieved results. The purpose of our review was to determine whether techniques of liver elastography could replace liver biopsy. Although now, based on the analyzed papers, elastography cannot replace liver biopsy, in our opinion, the role of this tool in monitoring pediatric patients with liver diseases will grow in the coming years.

Transient elastography (FibroScan) in critical care: Applications and limitations

FibroScan^® is a non-invasive device that assesses the ‘hardness’ (or stiffness) of the liver via the technique of transient elastography. Because fibrous tissue is harder than normal liver, the degree of hepatic fibrosis can be inferred from the liver hardness. This technique is increasingly being employed to diagnose liver fibrosis, even in critically ill patients. It is now being used not only for diagnosis and staging of liver cirrhosis, but also for outcome prognostication. However, the presence of several confounding factors, especially in critically ill patients, may make interpretation of these results unreliable. Through this review we aim to describe the indications and pitfalls of employing FibroScan in patients admitted to intensive care units.

Ultrasound-New Techniques Are Extending the Applications

BACKGROUND

Sonography is often the first imaging procedure to be used in diagnostic investigation of the abdomen. The aim of this article is to provide a new interdisciplinary overview of recent groundbreaking advances in this modality.

METHODS

A selective survey of the literature in PubMed was conducted. The literature search was carried out in 2021-2022 and included publications over the period 2004-2022.

RESULTS

The novel sonographic software techniques can be divided into algorithms that deal with conventional B-scan optimization and new programs that extend the scope of sonographic examination. The latter include elastography, contrast-enhanced sonography, and image fusion in combination with other cross-sectional imaging modalities. Elastography can be used to assess the presence of steatosis, fibrosis, or cirrhosis in patients with liver disease. One study reported diagnostic accuracy of 84-87% for the diagnosis of significant fibrosis (F2), 89-91% for the diagnosis of severe fibrosis (F3), and 92-93% for the diagnosis of liver cirrhosis (F4). Contrast-enhanced sonography is used for evaluation of tumors and trauma. A prospective multicenter study found sensitivity of 95.8% for the characterization of malignant lesions and specificity of 83.1% for benign lesions. Image fusion has the potential to improve the diagnostic assessment of parenchymatous organs, vascular conditions, and the prostate.

CONCLUSION

With continuous improvement of the B-scan and the development of high-frequency probes and novel investigation techniques, sonography has become established as an increasingly autonomous examination procedure.

Relationship between Novel Elastography Techniques and Renal Fibrosis-Preliminary Experience in Patients with Chronic Glomerulonephritis

INTRODUCTION

A renal biopsy represents the gold standard in the diagnosis, prognosis, and management of patients with glomerulonephritis. So far, non-invasive elastographic techniques have not confirmed their utility in replacing a biopsy; however, the new and improved software from Hologic Supersonic Mach 30 is a promising method for assessing the renal tissue's stiffness and viscosity. We investigated whether this elastography technique could reveal renal tissue fibrosis in patients with chronic glomerulonephritis.

MATERIALS AND METHODS

Two-dimensional-shear wave elastography (SWE) PLUS and viscosity plane-wave ultrasound (Vi PLUS) assessments were performed in 40 patients with chronic glomerulopathies before being referred for a renal biopsy. For each kidney, the mean values of five stiffness and viscosity measures were compared with the demographic, biological, and histopathological parameters of the patients.

RESULTS

In total, 26 men and 14 women with a mean age of 52.35 ± 15.54 years, a mean estimated glomerular filtration rate (eGFR) of 53.8 ± 35.49 mL/min/1.73m2, and a mean proteinuria of 6.39 ± 7.42 g/24 h were included after providing their informed consent. Out of 40 kidney biopsies, 2 were uninterpretable with inappropriate material and were divided into four subgroups based on their fibrosis percentage. Even though these elastography techniques were unable to differentiate between separate fibrosis stages, when predicting between the fibrosis and no-fibrosis group, we found a cut-off value of <20.77 kPa with the area under the curve (AUC) of 0.860, a p < 0.001 with 88.89% sensitivity, and a 75% specificity for the 2D SWE PLUS measures and a cut-off value of <2.8 Pa.s with an AUC of 0.792, a p < 0.001 with 94% sensitivity, and a 60% specificity for the Vi PLUS measures. We also found a cut-off value of <19.75 kPa for the 2D SWE PLUS measures (with an AUC of 0.789, p = 0.0001 with 100% sensitivity, and a 74.29% specificity) and a cut-off value of <1.28 Pa.s for the Vi PLUS measures (with an AUC 0.829, p = 0.0019 with 60% sensitivity, and a 94.29% specificity) differentiating between patients with over 40% fibrosis and those with under 40%. We also discovered a positive correlation between the glomerular filtration rate (eGFR) and 2D-SWE PLUS values (r = 0.7065, p < 0.0001) and Vi PLUS values (r = 0.3637, p < 0.0211). C reactive protein (CRP) correlates with the Vi PLUS measures (r = -0.3695, p = 0.0189) but not with the 2D SWE PLUS measures (r = -0.2431, p = 0.1306).

CONCLUSION

Our findings indicate that this novel elastography method can distinguish between individuals with different stages of renal fibrosis, correlate with the renal function and inflammation, and are easy to use and reproducible, but further research is needed for them to be employed routinely in clinical practice.

Serum Markers as a Predictor of Hepatic Fibrosis Compared to Fibroscan in chronic hepatitis B Infected Egyptian patients: A Cross-sectional Study

Background & Aims:

The gamma-glutamyl transpeptidase (GGT) to platelet ratio (GPR), the gamma-glutamyl transpeptidase to albumin (GAR) and S-index are novel biomarkers suggested to assess liver fibrosis. The aim of the work was to assess the correlation between GGT and other related markers as GAR and GPR among other previous documented markers and the degree of fibrosis and steatosis in chronic HBV Egyptian patients as measured by fibroscan.

Materials And Methods:

After ethical approval of the protocol, a total of 170 chronic HBV patients were recruited from tropical medicine department, Tanta University. They underwent fibroscan examination for fibrosis and steatosis measurement with concomitant testing of liver functions and complete blood picture. Proposed serum markers were calculated. The relation between these ratios with the fibrosis and steatosis measured by fibroscan were tested using Pearson rank correlation.

Results:

There was a highly significant positive correlation between gamma-glutamyl transpeptidase and platelet ratio (GPR), GAR, GGT, Fib4, APRI and fibrosis (p=<0.001, <0.001,<0.001,<0.001,0.011 and <0.001 respectively), while there was no correlation with the degree of steatosis (p=0.922,0.66,0.936,0.214,0.591 and 0.760 respectively). Also these markers were significantly higher in patients with higher grades of fibrosis (f2-4) (p= 0.007,0.013,<0.001,0.018,0.029,and 0.002 respectively), they also showed high sensitivity and low specificity in detecting higher grades of fibrosis with no statistically significant difference between the AUC of GPR and GAR (p=0.89).

Conclusion:

Noninvasive serum markers including GGT, GPR, GAR, Fib4, APRI, and S-index are positively correlated to the degree of fibrosis in CHB patients with high sensitivity and low specificity. They were good negative tests for diagnosis of significant fibrosis.

Endogenous motion of liver correlates to the severity of portal hypertension

BACKGROUND

Degree of portal hypertension (PH) is the most important prognostic factor for the decompensation of liver cirrhosis and death, therefore adequate care for patients with liver cirrhosis requires timely detection and evaluation of the presence of clinically significant PH (CSPH) and severe PH (SPH). As the most accurate method for the assessment of PH is an invasive direct measurement of hepatic venous pressure gradient (HVPG), the search for non-invasive methods to diagnose these conditions is actively ongoing.

AIM

To evaluate the feasibility of parameters of endogenously induced displacements and strain of liver to assess degree of PH.

METHODS

Of 36 patients with liver cirrhosis and measured HVPG were included in the case-control study. Endogenous motion of the liver was characterized by derived parameters of region average tissue displacement signal (d_antero, d_retro, d_RMS) and results of endogenous tissue strain imaging using specific radiofrequency signal processing algorithm. Average endogenous strain µ and standard deviation σ of strain were assessed in the regions of interest (ROI) (1 cm × 1 cm and 2 cm × 2 cm in size) and different frequency subbands of endogenous motion (0-10 Hz and 10-20 Hz).

RESULTS

Four parameters showed statistically significant (P < 0.05) correlation with HVPG measurement. The strongest correlation was obtained for the standard deviation of strain (estimated at 0-10 Hz and 2 cm × 2 cm ROI size). Three parameters showed statistically significant differences between patient groups with CSPH, but only d_retro showed significant results in SPH analysis. According to ROC analysis area under the curve (AUC) of the σ_{ROI[0…10Hz, 2 cm × 2 cm]} parameter reached 0.71 (P = 0.036) for the diagnosis of CSPH; with a cut-off value of 1.28 μm/cm providing 73% sensitivity and 70% specificity. AUC for the diagnosis of CSPH for µ_{ROI[0…10Hz, 1 cm × 1 cm]} was 0.78 (P = 0.0024); with a cut-off value of 3.92 μm/cm providing 73% sensitivity and 80% specificity. D_retro parameter had an AUC of 0.86 (P = 0.0001) for the diagnosis of CSPH and 0.84 (P = 0.0001) for the diagnosis of SPH. A cut-off value of -132.34 μm yielded 100% sensitivity for both conditions, whereas specificity was 80% and 72% for CSPH and SPH respectively.

CONCLUSION

The parameters of endogenously induced displacements and strain of the liver correlated with HVPG and might be used for non-invasive diagnosis of PH.

Applications of Elastography in Ablation Therapies: An Animal Model In Vivo Study

Background: Ablation therapies are one of the main local treatments for solid organ tumors. After applying any ablation therapy, few days should be waited to perform an imaging study and analyze the result. In this work, we analyzed the correlation between elastography monitoring after procedure and the result of ablation. The objective of this study is to determine tissue changes in vivo in short term after the application of ablation systems using different diagnostic imaging methods. Materials and Methods: Descriptive study in an in vivo swine model. Different types of ablation therapies (radiofrequency ablation, microwave ablation [MWA], and LASER ablation [LA]) were applied in the liver and kidneys. We compared their results by medical image monitoring (ultrasound, computed tomography, elastography) and macroscopic analysis. Results: All the animals survived the procedures. No major intraoperative complications were reported. We determined the characteristics of each procedure. MWA session was faster than the other types of ablation therapies. Regarding ablation area diameters, the largest was achieved with MWA and the smallest with LA. Macroscopically, we observed a central ablation zone, a peripheral ablation zone, and surrounding normal tissue. It was correlated with elastography images. Conclusion: Monitoring of the results of ablation therapies shortly after their application is possible through imaging studies. It allows determining the size of the ablation zone, its characteristics, ruling out complications, and its early results. Elastography could efficiently support this goal.

Noninvasive Assessment of Liver Fibrosis: Current and Future Clinical and Molecular Perspectives

Liver fibrosis is one of the risk factors for hepatocellular carcinoma (HCC) development. The staging of liver fibrosis can be evaluated only via a liver biopsy, which is an invasive procedure. Noninvasive methods for the diagnosis of liver fibrosis can be divided into morphological tests such as elastography and serum biochemical tests. Transient elastography is reported to have excellent performance in the diagnosis of liver fibrosis and has been accepted as a useful tool for the prediction of HCC development and other clinical outcomes. Two-dimensional shear wave elastography is a new technique and provides a real-time stiffness image. Serum fibrosis markers have been studied based on the mechanism of fibrogenesis and fibrolysis. In the healthy liver, homeostasis of the extracellular matrix is maintained directly by enzymes called matrix metalloproteinases (MMPs) and their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs). MMPs and TIMPs could be useful serum biomarkers for liver fibrosis and promising candidates for the treatment of liver fibrosis. Further studies are required to establish liver fibrosis-specific markers based on further clinical and molecular research. In this review, we summarize noninvasive fibrosis tests and molecular mechanism of liver fibrosis in current daily clinical practice.

Reference values of normal liver stiffness in healthy children by two methods: 2D shear wave and transient elastography

TE and 2D-SWE are well-documented in studies performed on adults, but those on pediatric patients are limited. The aim of this study was to establish pediatric reference values for liver stiffness using two elastography methods: 2D-SWE and TE. We performed an observational study on 206 healthy children. All children underwent anamnesis, clinical exam, laboratory tests, US exam, TE and 2D-SWE for liver stiffness assessment. The mean liver stiffness value by 2D-SWE for all children was 3.72 ± 0.48 kPa. The mean values ranged between 3.603 ± 0.2678 kPa (3–5 years of age) and 3.774 ± 0.4038 kPa (9–11 years). The reference values varied between 4.1386 kPa (3–5 years of age) and 4.88 kPa (12–15 years). The mean liver stiffness value by TE was 3.797 ± 0.4859 kPa. The values ranged between 3.638 ± 0.4088 kPa (6–8 years of age) and 3.961 ± 0.5695 kPa (15–18 years). The cutoff values varied from 4.4064 kPa (3–5 years of age) to 5.1 kPa (15–18 years). We found a significant positive correlation between E Median values by TE and age [95% CI: 0.1160 to 0.3798, r = 0.2526, p = 0.0002]. Our findings revealed that the mean values of liver stiffness for all children on 2D-SWE and TE were almost identical, 3.72 ± 0.48 kPa versus 3.797 ± 0.4859 kPa.

Correlation between Liver Elasticity by Ultrasound Elastography and Liver Functional Reserve

No worldwide consensus on the assessment tool for liver functional reserve is currently available. The aim of this study was to evaluate the correlation between liver elasticity of both hepatic lobes and liver functional reserve tests. This prospective observational study comprised 40 patients scheduled for hepatectomy. Liver elasticity was assessed by Virtual Touch Quantification (VTQ). The mean VTQ value for the right and left lobes was defined as the mVTQ. Liver functional reserve was measured with technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin scintigraphy as LHL15 and HH15 and the indocyanine green (ICG) excretion test as ICG-R15 and ICG-K. All examinations were measured after biliary decompression confirmed serum a total bilirubin level ≤2 mg/dL. Mean VTQ values were moderately correlated with LHL15 (r = -0.42, p < 0.01), HH15 (r = 0.48, p < 0.01), ICG-R15 (r = 0.53, p < 0.01) and ICG-K (r = -0.61, p < 0.01) values. In conclusion, the liver elasticity determined by VTQ would be a useful predictor of liver functional reserve in patients scheduled for hepatectomy.

Pentraxin 3 Detects Clinically Significant Fibrosis in Patients with Chronic Viral Hepatitis C

Pentraxin 3 (PTX3) plays a pathogenic role in experimental models of chronic liver injury and contributes to the progression of fibrosis. The detection of advanced fibrosis (METAVIR F≥3) is important to identify patients who are in urgent need of antiviral treatments versus those whose treatment could be deferred (F≥2). The aim was to assess the diagnostic value of PTX3 as a potential biomarker for clinically significant and advanced fibrosis. PTX3 associations with biochemical and histological parameters of inflammatory activity and fibrosis were investigated in 138 patients with chronic viral hepatitis C (HCV) before antiviral treatment. METAVIR histological scores of activity and fibrosis were obtained. PTX3 was measured by enzyme-linked immunosorbent assay. The diagnostic accuracy of serum PTX3 levels was compared to that of other fibrosis markers, including transforming growth factor‐β₁ (TGF-β₁), hyaluronic acid (HA), aspartate transaminase to platelet ratio index (APRI), fibrosis score based on four factors (FIB4), gamma-glutamyltranspeptidase to platelet ratio (GPR), and the liver stiffness measurement (LSM) by transient elastography (FibroScan®). In HCV patients the PTX3 level increased in parallel with the METAVIR histological score of activity, being independently associated with the METAVIR fibrosis score (P < 0.001). Using the receiver operating characteristics analysis, the best marker for detecting F≥2 and F≥3 was PTX3 with AUC = 0.802 and AUC = 0.867, respectively. The area under the curve of PTX3 for predicting significant fibrosis (F≥2) was significantly greater than those for the GPR ratio (AUC = 0.648) and FIB-4 score (AUC = 0.770) and similar to that for APRI index (AUC = 0.831). PTX3 provided clinically relevant diagnostic accuracy as a single marker of significant fibrosis.

Utility of Shear Wave Elastography for Assessing Allograft Fibrosis in Renal Transplant Recipients: A Pilot Study

OBJECTIVES

To evaluate the utility of ultrasound-based shear wave elastography (SWE) as a noninvasive method to accurately detect and potentially stage the severity of renal allograft fibrosis and assess its user reproducibility.

METHODS

In this Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant prospective study, 70 renal transplant recipients underwent an SWE evaluation of their allograft followed directly by biopsy. Two radiologists performed separate SWE measurement acquisitions and the mean, median, and standard deviation of 10 SWE measurements, obtained separately within the cortex and the medulla, were automatically computed. Each patient's SWE results were subsequently compared to their histologic fibrosis scores. The Fisher exact test and univariate logistic regression models were fit to test for associations between the presence of fibrosis (yes/no) as well as categorical SWE results based on the fibrosis severity, ranging from F0 (no fibrosis) to F3 (severe fibrosis), correlating with histologic scores according to the 2007 Banff classification system. Interobserver and intraobserver correlations were also examined.

RESULTS

Our median medulla SWE values reached statistical significance (P = .04) in association with fibrosis. Furthermore, for every unit increase in the median medulla SWE measurement, the odds of fibrosis increased by approximately 20%. No statistical significance was found for mean cortical, median cortical, or mean medullary SWE values (P = .32, .37, and .06, respectively) in association with fibrosis.

CONCLUSIONS

The use of SWE for assessing renal allograft fibrosis is challenging but promising. Further investigation with a larger sample size remains to validate our initial results and establish clinical relevance.

Improvement of liver stiffness measurement, acoustic radiation force impulse measurements, and noninvasive fibrosis markers after direct-acting antivirals for hepatitis C virus G4 recurrence post living donor liver transplantation: Egyptian cohort

Progression of recurrent hepatitis C is accelerated in liver transplant (LT) recipients. Direct-acting antivirals (DAAs) have recently emerged as a promising therapeutic regimen for the treatment of hepatitis C virus infection. Rates of sustained virological response (SVR) have drastically improved since the introduction of DAAs. The aim is to elucidate the changes in liver stiffness measurement (LSM) by transient elastography (TE) as well as acoustic radiation force impulse (ARFI) elastography and fibrosis scores after DAA treatment in LT recipients with hepatitis C virus recurrence. A single-center, prospective study including 58 LT recipients with hepatitis C recurrence who received different sofosbuvir-based treatment regimens. Transient elastography and ARFI elastography values were recorded as well as fibrosis 4 score (FIB-4) and aspartate aminotransferase-to-platelet ratio index were calculated at baseline and SVR at week 24 (SVR24). The outcome was improvement in LSM and at least a 20% decrease in LSM at SVR24 compared with baseline. The sustained virological response was 98.1%. There was improvement of platelet counts, alanine aminotransferase, and aspartate aminotransferase, which in turn caused improvement in fibrosis scores at SVR24. LSM by TE and ARFI elastography decreased from the baseline median value of 6.3 kPa (interquartile range [IQR]; 4.6 to 8.8 kPa) and 1.28 m/s (IQR; 1.07 to 1.53 m/s) to an SVR24 median value of 6.2 kPa (IQR; 4.85 to 8.9 kPa) and 1.12 (IQR; 0.97 to 1.30 m/s), respectively. Logistic regression analysis showed that baseline viral load was the only significant predictor of improvement in LS after DAA therapy at SVR24. Sofosbuvir-based treatment resulted in an early improvement in parameters of liver fibrosis in post-LT patients with hepatitis C recurrence.

Acoustic radiation force impulse (ARFI) elastography in a cohort of alpha-1 antitrypsin-deficient individuals and healthy volunteers

Background

Acoustic radiation force impulse (ARFI) elastography has been used to assess liver stiffness non-invasively. However, its usefulness in alpha-1 antitripsin-deficient (AATD) individuals is unknown.

Purpose

To assess if liver fibrosis is present in a cohort of AATD individuals using ARFI elastography.

Material and Methods

Eighty-three participants aged 38–39 years, except for two who were aged 40 years, underwent ultrasound elastography of the liver with ARFI technique. Twenty-nine were homozygote ZZ genotype, PiZZ (14 men, 15 women); 12 were SZ genotype, Pi SZ (8 men, 4 women), and 42 were healthy volunteers, PiMM (16 men, 26 women). Three specific liver anatomical regions were examined: segments 2/3 (left lobe) in the subcostal plane, and 5/6 and 7/8 (right lobe) in the intercostal space. In each region, three measurements were registered.

Results

There was no statistically significant difference between ARFI-median in the AATD group and the control group (P value = 0.877) and neither between AATD groups (PiZZ and PiSZ) with a P value = 0.259. The ARFI-median was lower in the right liver lobe than in the left lobe in all groups and the difference between both lobes was statistically significant (P = 0.001). No statistically significant difference was found in ARFI-median of the right liver lobe between the AATD group and the control group (P = 0.759), nor between the AATD group (P = 0.384). No gender difference was found in ARFI-median.

Conclusions

ARFI values in AATD individuals aged 38–39 years showed no difference compare to healthy participants.

Usefulness of virtual touch quantification for staging liver fibrosis in patients with hepatitis C, and factors affecting liver stiffness measurement failure compared with liver biopsy

AIM

The assessment of liver fibrosis in patients with hepatitis C is important to predict carcinogenesis. In this study, we evaluated the usefulness of virtual touch quantification (VTQ) for staging liver fibrosis, and investigated factors causing discrepancies between the estimated fibrosis stage using VTQ and the pathological fibrosis stage.

METHODS

Patients with hepatitis C (n = 302) were assessed using VTQ and underwent pathological liver investigation within 1 week before and after VTQ. A receiver operator characteristic (ROC) curve was obtained for VTQ, fibrosis-4 (FIB-4) index, and aspartate aminotransferase-to-platelet ratio index (APRI), and each area under the ROC curve (AUROC) was compared to predict fibrosis stage. We used univariate and multivariate analyses to investigate the factors related to the discrepancy between the estimated fibrosis stage using VTQ and the pathological fibrosis stage.

RESULTS

At any stage, VTQ was the most accurate for staging liver fibrosis. The VTQ cut-off values were 1.33 m/s (AUROC = 0.822) for ≥F2, 1.51 m/s (AUROC = 0.836) for ≥F3, and 1.92 m/s (AUROC = 0.890) for F4. Skin liver capsule distance (SCD) was the most relevant factor for the discrepancy between the estimated fibrosis stage using VTQ and the pathological fibrosis stage. The SCD cut-off value was 17.5 mm.

CONCLUSIONS

Virtual touch quantification is a non-invasive, simple method that is more accurate for staging liver fibrosis than the FIB-4 index and APRI. However, when the SCD is longer than 17.5 mm, there may be measurement failures.

Real-time elastography evaluation of differential penetrating liver trauma in a rabbit model

BACKGROUND

Real-time ultrasound elastography (RTE) is used to examine liver fibrosis and benign and malignant lesions, but its use for the diagnosis of liver trauma has not been examined. The purpose of this study was to examine the use of RTE for the evaluation of differential penetrating liver trauma in a rabbit model.

MATERIAL AND METHODS

Eighty New Zealand rabbits were divided into 2 groups. In one group, a single incision (type "-" lesion) was made, and in the other group a hash mark incision (type "#" lesion) was made (about 0.5cm in depth; 1.0-2.0cm in length). RTE was performed at 10, 30, and 60min after injury.

RESULTS

There were no differences in mean RTE scores between the 2 types of lesions at 10 and 30min. However, the mean values for the 2 types of lesions increased from 10min to 60min (type '-' lesion: 0.88±0.32 to 2.06±0.88; type '#' lesion: 0.89±0.34 to 2.63±1.16). At 60min, the mean elasticity score in the type '#' lesion group was significantly higher than in the type '-' lesion group (P<.001). Strain ratios were not different between the groups at each time point, but in each group the values decreased from the 10min time point to the 60min time point (P-value for the trends, <.001).

CONCLUSIONS

RTE may be able to distinguish mild or severe penetrating liver trauma at 60min or more after injury.

Hepatic Stiffness Using Shear Wave Elastography and the Related Factors for a Fontan Circulation

Hepatic problems related to a Fontan circulation have been highlighted and elastography using ultrasound is a non-invasive tool that can measure the severity of hepatic stiffness. We investigated the hepatic stiffness using shear wave elastography (SWE) and related factors in patients with a Fontan circulation. This study enrolled 64 patients with a Fontan circulation who underwent cardiac catheterization and abdominal ultrasound from 2011 to 2015. The correlation between the laboratory tests, hemodynamic factors by cardiac catheterization, and SWE was evaluated. The patients were classified into non-cirrhotic level (≥ 2.0 m/s) and cirrhotic level (< 2.0 m/s) groups by the SWE value. The mean age was 17.6 years and the mean duration after the Fontan operation was 12.1 years. The mean value of SWE in patients (1.95 m/s) was higher than the normal (< 1.3 m/s). The SWE was higher in patients without than those with a fenestration (2.03 vs. 1.75 m/s, P = 0.003). In a multiple regression analysis between SWE and other factors, the CVP, fenestration, and lipoprotein Apo B had a significant correlation. In a multivariate analysis of cirrhotic level group, the CVP was the only significant factor. The hepatic stiffness had significantly progressed in most patients with a Fontan circulation. A low CVP and Fontan circulation with a fenestration might reduce the progression of the hepatic stiffness.

Hepatic Fibrosis in Dogs

Hepatic fibrosis is commonly diagnosed in dogs, often as a sequela to chronic hepatitis (CH). The development of fibrosis is a crucial event in the progression of hepatic disease that is of prognostic value. The pathophysiology of hepatic fibrosis in human patients and rodent models has been studied extensively. Although less is known about this process in dogs, evidence suggests that fibrogenic mechanisms are similar between species and that activation of hepatic stellate cells is a key step. Diagnosis and staging of hepatic fibrosis in dogs requires histopathological examination of a liver biopsy specimen. However, performing a liver biopsy is invasive and assessment of fibrotic stage is complicated by the absence of a universally accepted staging scheme in veterinary medicine. Serum biomarkers that can discriminate among different fibrosis stages are used in human patients, but such markers must be more completely evaluated in dogs before clinical use. When successful treatment of its underlying cause is feasible, reversal of hepatic fibrosis has been shown to be possible in rodent models and human patients. Reversal of fibrosis has not been well documented in dogs, but successful treatment of CH is possible. In human medicine, better understanding of the pathomechanisms of hepatic fibrosis is leading to the development of novel treatment strategies. In time, these may be applied to dogs. This article comparatively reviews the pathogenesis of hepatic fibrosis, its diagnosis, and its treatment in dogs.

Shear wave elastography imaging for assessing the chronic pathologic changes in advanced diabetic kidney disease

Objective

The assessment of the grade of renal fibrosis in diabetic kidney disease (DKD) requires renal biopsy, which may be associated with certain risks. To assess the severity of chronic pathologic changes in DKD, we performed a quantitative analysis of renal parenchymal stiffness in advanced DKD, using shear wave elastography (SWE) imaging.

Patients and methods

Twenty-nine diabetic patients with chronic kidney disease (CKD) grades 3–4 due to DKD, and 23 healthy subjects were enrolled. Combined conventional ultrasound and SWE imaging were performed on all participants. The length, width, and cortical thickness and stiffness were recorded for each kidney.

Results

Cortical thickness was lower in patients with DKD than in healthy subjects (13.8±2.2 vs 14.8±1.6 mm; P=0.002) and in DKD patients with CKD grade 4 than in those with grade 3 (13.0±3.5 vs 14.7±2.1 mm; P<0.001). Cortical stiffness was greater in patients with DKD than in healthy subjects (23.72±14.33 vs 9.02±2.42 kPa; P<0.001), in DKD patients with CKD grade 4 than in those with grade 3 (30.4±16.2 vs 14.6±8.1 kPa; P<0.001), and in DKD patients with CKD grade 3b, than in those with CKD grade 3a (15.7±6.7 vs 11.0±4.2 kPa; P=0.03). Daily proteinuria was higher in DKD patients with CKD grade 4 than in those with grade 3 (5.52±0.96 vs 1.13±0.72; P=0.001), and in DKD patients with CKD grade 3b, than in those with CKD grade 3a (1.59±0.59 vs 0.77±0.48; P<0.001). Cortical stiffness was inversely correlated with the estimated glomerular filtration rate (r=−0.65, P<0.001) and with cortical thickness (r=−0.43, P<0.001) in patients with DKD.

Conclusions

In patients with advanced DKD, SWE imaging may be utilized as a simple and practical method for quantitative evaluation of the chronic morphological changes and for the differentiation between CKD grades.

Prediction of Renal Allograft Acute Rejection Using a Novel Non-Invasive Model Based on Acoustic Radiation Force Impulse

Point shear wave elastography based on acoustic radiation force impulse is a novel technology used to quantify tissue stiffness by measuring shear wave speed. A total of 115 kidney transplantation recipients were consecutively enrolled in this prospective study. The patients were subdivided into two groups using 1 mo post-transplantation as the cutoff time for determining the development of acute rejection (AR). Shear wave speed was significantly higher in the AR group than in the non-AR group. We created a model called SEV, comprising shear wave speed, estimated glomerular filtration rate and kidney volume change, that could successfully discriminate patients with or without AR. The area under the receiver operating characteristic curve of SEV was 0.89, which was higher than values for other variables; it was even better in patients within 1 mo post-transplantation (0.954), but was lower than the estimated glomerular filtration rate in patients after 1 mo post-transplantation. Therefore, the SEV model may predict AR after renal transplantation with a high degree of accuracy, and it may be more useful in the early post-operative stage after renal transplantation.

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.

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.

Serum hyaluronic acid predicts protein-energy malnutrition in chronic hepatitis C

Serum hyaluronic acid (HA) is a well-established marker of fibrosis in patients with chronic liver disease (CLD). However, the relationship between serum HA level and protein-energy malnutrition (PEM) in patients with CLD is an unknown. We aimed to examine the relationship between serum HA level and PEM in patients with chronic hepatitis C (CHC) compared with the relationships of other serum markers of fibrosis. A total of 298 CHC subjects were analyzed. We defined patients with serum albumin level of ≤3.5 g/dL and nonprotein respiratory quotient <0.85 using indirect calorimetry as having PEM. We investigated the effect of serum HA level on the presence of PEM. Receiver operating characteristic curve (ROC) analysis was performed for calculating the area under the ROC (AUROC) for serum HA level, platelet count, aspartate aminotransferase (AST) to platelet ratio index, FIB-4 index, AST to alanine aminotransferase ratio, and Forns index for the presence of PEM. The median serum HA level in this study was 148.0 ng/mL (range: 9.0-6340.0 ng/mL). In terms of the degree of liver function (chronic hepatitis, Child-Pugh A, B, and C), the analyzed patients were well stratified according to serum HA level (overall significance, P < 0.0001). The median value (range) of serum HA level in patients with PEM (n = 61) was 389.0 ng/mL (43.6-6340.0 ng/mL) and that in patients without PEM (n = 237) was 103.0 ng/mL (9.0-783.0 ng/mL) (P < 0.0001). Among 6 fibrosis markers, serum HA level yielded the highest AUROC with a level of 0.849 at an optimal cut-off value of 151.0 ng/mL (sensitivity 93.4%; specificity 62.0%; P < 0.0001). In the multivariate analysis, serum HA level was found to be a significant prognostic factor related to the presence of PEM (P = 0.0001).In conclusion, serum HA level can be a useful predictor of PEM in patients with CHC.

Appropriate use of virtual touch quantification and FibroScan M and XL probes according to the skin capsular distance

BACKGROUND

Appropriate utilization of different diagnostic modalities is essential for the accurate liver stiffness measurements (LSM) in patients with chronic liver diseases. The aim of this study was to evaluate the efficacy of Virtual Touch Quantification (VTQ) and the FibroScan M and XL probes in term of accurate LSM and to identify factors associated with inadequate measurements in obese and non-obese Japanese patients.

METHODS

A total of 664 consecutive patients with chronic liver disease were prospectively enrolled. LSM were evaluated concurrently with VTQ and the FibroScan M and XL probes. LSM quality was categorized as inadequate (success rate <60% and/or interquartile range/median value of ≥30%) or adequate.

RESULTS

No significant differences in the rate of inadequate LSM were observed among the three diagnostic modalities. In multivariate analysis, skin capsule distance (SCD) was strongly associated with inadequate rates obtained with VTQ and the M probe [odds ratio (OR) 1.28, P < 0.0001 and OR 1.20, P < 0.0001, respectively]. Inadequate LSM rates with both VTQ and the M probe increased with longer SCD, with a significant difference between subgroups at an SCD of ≥22.5 mm (VTQ 54.0%; M probe 51.1%; XL probe 25.2%; P < 0.0001). The rates of inadequate LSM rates with VTQ were significantly lower than those with the XL probe at an SCD of <17.5 mm. A total of 15 liver biopsy specimens obtained from nonalcoholic fatty liver disease patients confirmed the diagnostic accuracy and high applicability of the XL probe.

CONCLUSIONS

Long SCD reduced the diagnostic performance of the FibroScan® M probe and VTQ. LSM modalities should be selected according to SCD.

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.

Renal elasticity quantification by acoustic radiation force impulse applied to the evaluation of kidney diseases: a review

For centuries, clinicians have used palpation to evaluate abdominal organs. After exploring almost all the different methods of interaction between x-rays, ultrasound, and magnetic fields on tissues, recent interest has focused on the evaluation of their mechanical properties.Acoustic radiation force impulse (ARFI) is a recent, established ultrasound-based diagnostic technique that allows physicians to obtain a measure of the elastic properties of an organ. Shear wave velocity, obtained by the ARFI technique, depends on the elasticity of tissues.To date, there are studies on the ARFI technique applied to normal kidneys, chronic kidney diseases, and kidney transplants. Mechanical properties of the kidney, such as stiffness and deformity, depend on various conditions that alter its histology, in particular the amount of fibrosis in the renal parenchyma; urinary pressure and renal blood perfusion may be other important contributing factors. Unfortunately, the ARFI technique applied to native renal pathologies is still limited, and not all studies are comparable because they used different methods. Therefore, the results reported in recent literature encourage further improvement of this method and the drawing up of standardized guidelines of investigation.

Fibroscan improves the diagnosis sensitivity of liver fibrosis in patients with chronic hepatitis B

The aim of the present study was to investigate the diagnostic accuracy of Fibroscan for liver fibrosis in patients with chronic hepatitis B (CHB) with alanine aminotransferase (ALT) levels <2 times the upper normal limit. A total of 263 consecutive patients with CHB and ALT levels <2 times the upper normal limit were enrolled in the present study. Liver biopsies and liver stiffness measurements (LSM) were conducted. Receiver operating characteristic (ROC) analysis was used to determine the predictive ability of LSM for the development of liver fibrosis in patients with stage S1, S2 and S3 liver fibrosis. Bivariate Spearman rank correlation analysis was performed in order to determine the association between liver stiffness value, which was measured by Fibroscan, and liver fibrosis stage, which was measured by liver biopsy. The liver stiffness value was found to be positively correlated with the liver fibrosis stage (r=0.522, P<0.001) and necroinflammatory activity (r=0.461, P<0.001), which was measured by liver biopsy. The optimal cut-off value in the patients with stage S1, S2 and S3 liver fibrosis was 5.5, 8.0 and 10.95 kPa, respectively. The area under the ROC curve for the prediction of the development of liver fibrosis in these patients was 0.696, 0.911 and 0.923, respectively. The threshold of the optimal cut-off value exhibited a high sensitivity and specificity. The results of the present study suggested that Fibroscan may improve the sensitivity of the diagnosis of liver fibrosis in patients with CHB and ALT levels <2 times the upper normal limit, and that this sensitivity may increase with the progression of liver fibrosis.

Hepatic Hemodynamics and Elevation of Liver Stiffness as Possible Predictive Markers of Late-onset Hepatic Failure

A 52-year-old Japanese woman admitted to our hospital for the treatment of liver dysfunction due to an undetermined cause developed disorientation on the 58th hospital day and was diagnosed with late-onset liver failure. Abdominal ultrasound examinations were performed several times from the admission. Before the disorientation appeared, the results of the examinations revealed that the portal flow decreased, after which the hepatic arterial flow increased and the degree of liver stiffness became elevated. Although the pathophysiology of these changes remains unclear, hemodynamic changes and elevation of liver stiffness might be predictive markers of severe liver tissue damage.

Clinical perspective on renal elasticity quantification by acoustic radiation force impulse: Where we are and where we are going

Recent interests have focused on the exploration of the mechanical properties (elasticity, stiffness and deformity) of parenchymatous organs using tissue strain imaging techniques and elastosonography. Measures of the mechanical properties of the kidneys have given conflicting results. There are various conditions that affect the variability of renal parenchymal measures, the main target of the investigations. They can be classified as intrinsic (depending upon the patient), extrinsic (depending upon the operator) and mixed (both intrinsic and extrinsic). Indeed, the mechanical properties of the kidney depend on various conditions that alter its histology, mainly the amount of fibrosis in the renal parenchymal interstitium. Anatomical factors play an important role because the kidney is a highly anisotropic organ with important differences when considering the cortex and the medulla. Physical factors include the frequency of the probe, compression and distance from source to target. Many factors can affect measurements and it is necessary to find an accurate technique in order to avoid mistakes and to obtain reproducible data. Indeed, it is imperative to define a standardized examination technique in order to get comparable results. Therefore, the utility of acoustic radiation force imaging technique to predict only renal fibrosis or progression of chronic kidney disease is of dubious value because several variables - blood perfusion and urinary pressure - can contribute to a given measure, even with a standardized method able to minimize intra- and inter-operator variability.

Quantification of kidney fibrosis using ultrasonic shear wave elastography: experimental study with a rabbit model

OBJECTIVES

The purpose of this study was to evaluate the feasibility of ultrasonic shear wave elastography for quantification of renal fibrosis in an experimental rabbit model.

METHODS

Thirty-eight kidneys of 19 rabbits were studied and categorized into 3 groups: group I, ureter obstruction (n = 9); group II, renal vein occlusion (n = 10); and group III, normal control (n = 19). Before surgery, we measured stiffness at the renal cortex using shear wave elastography and evaluated the sonographic findings, including size, echogenicity, and resistive index. We repeated the same sonographic examinations weekly until the fourth week. The degree of histologically quantified fibrosis and the measured stiffness values were statistically compared.

RESULTS

There was no significant difference in the mean stiffness values for the renal cortex in the 3 groups before surgery (8.95 kPa in group I, 9.06 kPa in group II, and 9.74 kPa in group III; P > .05). However, the mean stiffness in each group on the last sonographic examination was significantly different (10.91 kPa in group I, 13.92 kPa in group II, and 9.77 kPa in group III; P = .003). Pathologically, the degree of fibrosis was also significantly different (3.62% in group I, 11.70% in group II, and 0.70% in group III; P< .001). The fibrosis degree and stiffness were positively correlated (ρ = 0.568; P = 0.01).

CONCLUSIONS

Tissue stiffness measured by ultrasonic shear wave elastography was positively correlated with histopathologic renal fibrosis. Ultrasonic shear wave elastography may be used as a noninvasive tool for predicting renal fibrosis.

A new metabolism-related index correlates with the degree of liver fibrosis in hepatitis C virus-positive patients

Background. Only a few biomarkers based on metabolic parameters for evaluating liver fibrosis have been reported. The aim of this study was to investigate the relevance of an index obtained from three metabolic variables (glycated albumin: GA, glycated hemoglobin: HbA1c, and branched-chain amino acids to tyrosine ratio: BTR) to the degree of liver fibrosis in hepatitis C virus virus- (HCV-) positive patients. Methods. A total of 394 HCV-positive patients were assessed based on the values of a new index (GA/HbA1c/BTR). The index findings were used to investigate the relationship with the degree of liver fibrosis. Results. The new index showed an association with the stage of fibrosis (METAVIR scores: F0-1: 0.42 ± 0.10, F2: 0.48 ± 0.15, F3: 0.56 ± 0.22, and F4: 0.71 ± 0.30). The index was negatively correlated with three variables of liver function: the prothrombin time percentage (P < 0.0001), albumin level (P < 0.0001), and cholinesterase level (P < 0.0001). The new index showed a higher correlation related to liver function than FIB-4 and the APRI did. In addition, the index showed a higher AUROC value than that of FIB-4 and the APRI for prediction of liver cirrhosis. Conclusion. The new metabolism-related index, GA/HbA1c/BTR value, is shown to relate to the degree of liver fibrosis in HCV-positive patients.

A preliminary study of acoustic radiation force impulse quantification for the assessment of skin in diffuse cutaneous systemic sclerosis

OBJECTIVE

To investigate skin elasticity using acoustic radiation force impulse (ARFI) quantification in systemic sclerosis (SSc), and compare the modified Rodnan skin score (mRSS) with measured shear wave velocity (SWV) and thickness of the skin.

METHODS

Fifteen patients with diffuse cutaneous SSc (dcSSc) and 15 age-matched and sex-matched healthy controls were evaluated. The SWV and thickness of skin were measured at 17 sites corresponding to those assessed in the mRSS in each participant. The SWV measurements of skin were compared between patients with dcSSc and healthy controls. The correlations between the mRSS and the skin SWV and thickness were explored using Spearman's correlation.

RESULTS

The SWV values were higher in patients with dcSSc compared with healthy controls at right hand dorsum, right forearm, left hand dorsum, left forearm, right foot dorsum, and left foot dorsum (p < 0.05). In patients with dcSSc, the SWV values of uninvolved skin were higher than those of controls (p < 0.001), and the SWV values increased with increasing skin scores except for skin score 3 (p < 0.05). The sum of the SWV values correlated with total clinical skin score (r = 0.841, p < 0.001), and the sum of the skin thickness correlated with total clinical skin score (r = 0.740, p = 0.002).

CONCLUSION

ARFI quantification is feasible and reliable for assessing the skin involvement in dcSSc. ARFI quantification could identify early skin change that may precede palpable skin involvement, and may be a valuable adjunct to skin evaluation in patients with SSc.

Diagnostic accuracy of real-time tissue elastography for the staging of liver fibrosis: a meta-analysis

OBJECTIVE

To evaluate the overall accuracy of real-time tissue elastography (RTE) for the staging of liver fibrosis.

METHODS

We systematically reviewed 15 studies (1,626 subjects) in which sensitivity and specificity of RTE for liver fibrosis are available. For each cut-off stage of fibrosis, i.e., F ≥ 1, F ≥ 2, F ≥ 3, and F ≥ 4, summary sensitivity and specificity were estimated using a bivariate random-effects model. Publication bias was assessed using funnel plots and Egger's test.

RESULTS

Summary sensitivity and specificity were 0.79 and 0.76 for F ≥ 2, 0.82 and 0.81 for F ≥ 3, and 0.74 and 0.84 for F ≥ 4, respectively. Meta-regressions revealed scoring methods of RTE and liver diseases in the samples might not influence sensitivity and specificity of RTE. However, the estimated accuracy of RTE might be overestimated due to publication bias (p = 0.004 for F ≥ 2, p < 0.001 for F ≥ 3, and p = 0.002 for F ≥ 4).

CONCLUSIONS

RTE is not highly accurate for any cut-off stage of fibrosis. Compared with findings of meta-analyses on Transient Elastography and Acoustic Radiation Force Impulse imaging, the overall accuracy of RTE seems to be nearly identical for the evaluation of significant liver fibrosis, but less accurate for the evaluation of cirrhosis.

KEY POINTS

• Non-invasive methods for evaluating liver fibrosis are necessary to replace liver biopsy. • ARFI is as accurate as TE for evaluating liver fibrosis. • RTE may be as accurate as TE and ARFI for fibrosis. • RTE may be less accurate than TE and ARFI for cirrhosis. • The estimated accuracy of RTE may be overestimated by publication bias.

Liver stiffness measured by transient elastography in patients with acute pancreatitis

BACKGROUND

Alcohol abuse constitutes a risk factor for acute pancreatitis and liver cirrhosis, and cirrhosis in turn may delay the recovery from pancreatitis. We evaluated the occurrence and significance of liver fibrosis or cirrhosis in patients with acute pancreatitis by applying transient elastography (TE).

METHODS

TE was carried out in 78 patients with acute pancreatitis. Comparisons were made to the severity and recurrence of pancreatitis, to biological markers for fibrosis (APRI test), alcohol intake (AST/ALT ratio, AUDIT), and prothrombin time (TT-SPA). A cut-off value of ≥7.5 kilopascals (kPa) was set for increased liver stiffness, and ≥10 kPa for significant fibrosis.

RESULTS

The aetiology of pancreatitis was alcohol intake in 62 patients, gallstones in 11, idiopathic in 3, tumour in 1 and medication in 1. TE was successful in 64 out of 78 patients. The median TE value was 6.5 kPa (range 2.5-61.1); 22 (35%) had values ≥7.5 kPa and 7 (11%) ≥10 kPa. Values ≥7.5 were associated with older age, higher APRI ratio, and lower TT-SPA. It did not predict the length of hospitalization or the recurrence of pancreatitis. Increased AST/ALT ratio was associated with high TE values, whereas AUDIT values were not. Values ≥10 kPa seemed to indicate manifest cirrhosis, hepatitis or subsequent development of diabetes.

CONCLUSIONS

TE values ≥7.5 kPa did not predict the length of hospital stay or recurrence of pancreatitis but there were some findings of impaired liver function. Values ≥10 kPa may indicate subsequent development of diabetes and a more severe course of acute pancreatitis.