Acoustic Radiation Force Impulse elastography for fibrosis evaluation in patients with chronic hepatitis C: an international multicenter study

Imaging-based noninvasive liver disease assessment for staging liver fibrosis in chronic liver disease: A systematic review supporting the AASLD Practice Guideline

BACKGROUND AND AIMS

Transient elastography (TE), shear wave elastography, and/or magnetic resonance elastography (MRE), each providing liver stiffness measurement (LSM), are the most studied imaging-based noninvasive liver disease assessment (NILDA) techniques. To support the American Association for the Study of Liver Diseases guidelines on NILDA, we summarized the evidence on the accuracy of these LSM methods to stage liver fibrosis (F).

APPROACH AND RESULTS

A comprehensive search for studies assessing LSM by TE, shear wave elastography, or MRE for the identification of significant fibrosis (F2-4), advanced fibrosis (F3-4), or cirrhosis (F4), using histopathology as the standard of reference by liver disease etiology in adults or children from inception to April 2022 was performed. We excluded studies with <50 patients with a single disease entity and mixed liver disease etiologies (with the exception of HCV/HIV coinfection). Out of 9447 studies, 240 with 61,193 patients were included in this systematic review. In adults, sensitivities for the identification of F2-4 ranged from 51% to 95%, for F3-4 from 70% to 100%, and for F4 from 60% to 100% across all techniques/diseases, whereas specificities ranged from 36% to 100%, 74% to 100%, and 67% to 99%, respectively. The largest body of evidence available was for TE; MRE appeared to be the most accurate method. Imaging-based NILDA outperformed blood-based NILDA in most comparisons, particularly for the identification of F3-4/F4. In the pediatric population, imaging-based NILDA is likely as accurate as in adults.

CONCLUSIONS

LSM from TE, shear wave elastography, and MRE shows acceptable to outstanding accuracy for the detection of liver fibrosis across various liver disease etiologies. Accuracy increased from F2-4 to F3-4 and was the highest for F4. Further research is needed to better standardize the use of imaging-based NILDA, particularly in pediatric liver diseases.

Correlation Between Real-Time Shear Wave Elastography and Liver Serum Markers in Determining the Stage of Liver Fibrosis in Patients with Chronic Liver Diseases

Introduction: Non-invasive methods aim to predict the stage of liver fibrosis in line with histological findings via biopsy. Shear wave elastography and serum markers are proven as accurate non-invasive methods for determining liver fibrosis as a modern non-invasive methods compared to liver biopsy in staging hepatic fibrosis. Aims: This study aims to determine the correlation between Shear Wave Elastography and indirect and direct serum markers of fibrosis when staging liver fibrosis. Material and methods: The study was conducted in the Clinic of Gastroenterohepatology, the Institute of Immunology and Human Genetics, and the Institute of Pathology between 2021 and 2023. The study comprises 70 patients with liver lesions, diagnosed based on clinical results, laboratory tests, and ultra-sound imaging. All patients underwent liver biopsy, classified according to Ishak and Metavir score as a reference method for diagnosing liver fibrosis. Real-time shear wave elastography was also performed as a non-invasive method and serum markers were checked for liver fibrosis. Findings: The statistical analysis indicated a positive correlation between the values of direct and indirect liver fibrosis markers and Shear Wave Elastography results. Conclusion: Our study has demonstrated that shear wave elastography has a significant positive correlation with biochemical markers of liver lesions and serum markers of liver fibrosis, whereas it has a negative correlation with platelets.

Verification of effect of interference between multiple scatterers on the evaluation of backscattering coefficient

Backscatter coefficient analysis methods for biological tissues have been clinically applied but assume a homogeneous scattering medium. In addition, there are few examples of actual measurement studies in the HF band, and the consistency with theory has not been sufficiently confirmed. In this paper, the effect of correlations among scatterer positions on backscattering was investigated by performing experiments on inhomogeneous media having two types of scattering source with different structural and acoustic properties. In the echo data of phantoms containing two types of scatterer acquired by multiple sensors, the power and frequency dependence of the backscatter coefficient were different from theoretical calculations due to the interference effects of each scatterer. The effect of interference between the two types of scatterer was confirmed to be particularly strong for echoes acquired by the sensor at high intensity and HF, or for a higher number density of strong scatterers.

Prospective evaluation of liver shearwave elastography measurements with 3 different technologies and same day liver biopsy in patients with chronic liver disease

BACKGROUND

Most ultrasound-based methods for assessing liver fibrosis still need further validation with liver biopsy used as gold standard to assess their accuracy.

AIMS

To assess accuracy of three shear wave elastography (SWE) methods: 1) Philips Elast Point Quantification (ElastPQTM), 2) Siemens Virtual TouchTM Quantification (VTQ) acoustic radiation force impulse (ARFI), and 3) transient elastography (TE) measured by Echosens FibroscanTM.

METHODS

160 patients underwent liver stiffness measurements (LSM) with three SWE methods immediately prior to liver biopsy.

RESULTS

The number of LSM required for reliable studies could be reduced to 6 for ElastPQ and to 7 for VTQ from standard recommendations of 10. Significant fibrosis and interquartile range/median (IQR/M)> 30 were independent predictors for lower reliability for detection of liver fibrosis. Ordinal logistic regression corrected for age showed that there was a significant interaction between steatosis (p = 0.008) and lobular inflammation (p = 0.04) and VTQ (ARFI) and between lobular inflammation and TE (p = 0.006).

CONCLUSIONS

We showed variations in SWE measurements using different ARFI technologies. TE and ElastPQ achieved good diagnostic performance, whereas VTQ showed lower diagnostic accuracy. The number of measurements required for reliable studies can be reduced to 6 for ElastPQ and to 7 for VTQ, which have important clinical implications.

Multisample Ultrasound Point Shear Wave Elastography of the Liver: Repeatability and Agreement With Conventional Point Shear Wave Elastography

OBJECTIVE

To characterize the technical performance of a multisample ultrasound point shear wave elastography (pSWE) technique that allows 15 individual measurements of liver stiffness in a single acquisition.

METHODS

In 56 overweight and obese adults, research ultrasound examinations were performed using conventional pSWE and multisample pSWE (Sequoia; Siemens Healthineers). Five independent measurements were acquired with the conventional technique over five consecutive breath holds (5C1 and DAX transducers). A single multisample acquisition (DAX transducer) of up to 15 unique measurements was acquired during a single breath hold. All imaging was performed before (baseline) and after a "coffee break" (repeat). Median liver stiffness measurements between techniques and between baseline and repeat imaging were compared using Pearson correlation (r) and intra-class correlation (ICC) coefficients.

RESULTS

Mean participant age was 33.7 ± 11.4 years; 40 participants were female. There was high correlation between conventional pSWE measurements obtained using the 5C1 and DAX transducers at baseline (r = .75 [95% CI: 0.61-0.85], P < .0001) and repeat (r = .88 [95% CI: 0.78-0.92], P < .0001). There was moderate agreement between conventional pSWE measurements obtained using the 5C1 and DAX transducers at baseline (ICC = 0.69 [95% CI: 0.52-0.81]), and good agreement at repeat (ICC = 0.81 [95% CI: 0.65-0.90]). There was moderate correlation (r = .59 [95% CI: 0.39-0.74], P < .0001) and moderate agreement (ICC = 0.58 [95% CI: 0.38-0.73]) between baseline conventional and multisample pSWE measurements acquired using the DAX transducer; there was high correlation (r = .73 [95% CI: 0.57-0.83], P < .0001) and moderate agreement (ICC = 0.72 [95% CI: 0.56-0.82] between techniques at repeat. There was moderate correlation (r = .65 [95% CI: 0.46-0.78], P < .0001) and moderate agreement (ICC = 0.64 [95% CI: 0.45-0.77]) between baseline and repeat multisample pSWE measurements.

CONCLUSIONS

Multisample pSWE, allowing up to 15 measurements in a single breath hold, showed moderate to high correlation and moderate agreement with conventional pSWE.

Characterization of uterine involution using B-mode ultrasonography, color Doppler and elastography (acoustic radiation force impulse) for assessing postpartum in Santa Inês ewes

The aim of this study was to investigate uterine involution using ultrasonography techniques during postpartum. Postpartum ultrasonography evaluation (B-mode, color Doppler and Acoustic Radiation Force Impulse elastography) of the uterus was performed by transabdominal approach at immediate after birth and sequentially every 48 hours, during 30 days. The uterine echotexture did not present significant variations (P >0.05) being homogeneous in most evaluations; echogenicity of the uterus increased along the evaluation period (P =0.0452). Progressive and remarkable decrease of the total uterine diameter (UD) were observed (P <0.0001), especially during the first days postpartum. The thickness of uterine wall gradually decreased, as well the endometrial, myometrium and lumen diameters (P <0.0001). Uterine blood flow was assessed by Doppler and decreased during postpartum period, being significantly lower (P=0.0225) on the 30^th day of postpartum. Uterine parenchyma presented as homogeneous dark areas (not deformable) on qualitative ultrasound elastography and the means shear velocity values of the uterine wall on quantitative elastography did not differ. This is the first study that evaluate the stiffness of uterine wall in healthy ewes, providing baseline data about quantitative and qualitative stiffness of the normal uterus, and it may be a useful tool for early diagnosis of uterine alterations during the postpartum period, using the reference parameter established for the assessment of uterine integrity during postpartum period.

Efficacy of shear wave elastography for the diagnosis of chronic pancreatitis

BACKGROUND/PURPOSE

Shear wave elastography (SWE) is a clinical method used to evaluate liver hardness. In this study, we assessed its applicability in assessing the pancreas and its potential for diagnosing chronic pancreatitis.

METHODS

We performed SWE on 59 patients who underwent abdominal ultrasound, and measured the computed tomography (CT) values of the pancreas. Patients were classified as having a normal pancreas (NP), early chronic pancreatitis (ECP), or chronic pancreatitis (CP). SW elasticity (SWe), SW dispersion (SWd), and CT values between groups were analyzed.

RESULTS

SWe significantly differed between the CP and NP/ECP groups (NP vs CP; P = 0.001, ECP vs CP; P = 0.026,), while SWd showed a significant difference only between the NP and CP group (NP vs CP; P = 0.001). The CT values were significantly different between the CP and NP/ECP groups (NP vs CP; P = 0.0006, ECP vs CP; P = 0.0027).

CONCLUSION

Pancreatic SWE and CT values were helpful in the diagnosis of chronic pancreatitis. SWd may reveal status changes in ECP.

Diagnostic accuracy of magnetic resonance elastography and point-shear wave elastography for significant hepatic fibrosis screening: Systematic review and meta-analysis

The hepatic diseases are extremely common in clinical practice. The correct classification of liver fibrosis is extremely important, as it influences therapy and predicts disease outcomes. The purpose of this study is to compare the diagnostic performance of point-shear wave elastography (pSWE) and magnetic resonance elastography (MRE) in the hepatic fibrosis diagnostic. A meta-analysis was carried out based on articles published until October 2020. The articles are available at following databases: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Scientific Electronic Library Online, LILACS, Scopus, and CINAHL. Diagnostic performances were analyzed per METAVIR F2, using 3.5kPa as target fibrosis. Assessment of the methodological quality of the incorporated papers by the QUADAS-2 tool for pSWE and MRE. A total 2,153 studies articles were evaluated and 44 studies, comprising 6,081 patients with individual data, were included in the meta-analysis: 28 studies for pSWE and 16 studies for MRE. The pooled sensitivity and specificity were 0.86 (95%CI 0.80-0.90) and 0.88 (95%CI 0.85-0.91), respectively, for pSWE, compared with 0.94 (95%CI 0.89-0.97) and 0.95 (95%CI 0.89-0.98) respectively, for MRE. The pooled SROC curve for pSWE shows in the area under the curve (AUC) of 0.93 (95%CI 0.90-0.95), whereas the AUC for MRE was 0.98 (95%CI 0.96-0.99). The diagnostic odds ratio for pSWE and MRE were 41 (95%CI 24-72) and 293 (95%CI 86-1000), respectively. There was statistically significant heterogeneity for pSWE sensitivity (I² = 85.26, P<0.001) and specificity (I² = 89.46, P<0.001). The heterogeneity for MRE also was significant for sensitivity (I² = 73.28, P<0.001) and specificity (I² = 87.24, P<0.001). Therefore, both pSWE and MRE are suitable modalities for assessing liver fibrosis. In addition, MRE is a more accurate imaging technique than pSWE and can be used as alternative to invasive biopsy.

Preliminary Study on Grading Diagnosis of Early Knee Osteoarthritis by Shear Wave Elastography

Knee osteoarthritis (KOA) is the most common chronic bone joint disease. The WHO points out that KOA has become the fourth most disabling disease in the world, and the main clinical treatment is prevention. At present, the clinical diagnosis of knee osteoarthritis with deformation is mainly made by X-ray and two-dimensional ultrasound, and the preventive treatment effect is not good. Shear wave elastography (SWE) has been widely used in clinical practice for its advantages of noninvasive, simple, rapid, and high accuracy in soft tissue hardness. This study investigates the feasibility of using SWE in the grading diagnosis of KOA and the detection of early skeletal muscle injury. 60 patients were enrolled with unilateral KOA who met the inclusion criteria. Routine scanning and SWE exploration were carried out and compared between the affected and healthy knee joints. The measurements included morphology, damage degree of cartilage, joint effusion, joint synovial thickness, the degree of meniscus convexity, and shear wave speed (SWS) in the tendon attachment area of the quadriceps femoris superior patella, and tendon thickness and SWS between and within groups. The affected was scored according to the ultrasonic characteristics. The correlation between them was analyzed to evaluate the feasibility of SWE in grading the diagnosis of KOA. 57 cases had knee cavity effusion (57/60, 95.0%), 58 cases had knee cartilage injury (58/60, 96.6%), and 35 cases had a lateral process of the medial meniscus (35/60, 53.3%); 30 cases had synovial hyperplasia (30/60, 50%), 21 cases had osteophyte formation (21/60, 35%), and no one had a popliteal cyst. There was no significant difference in tendon thickness between and within groups (p > 0.05), but a significant difference in SWS (p < 0.01); the SWS of the quadriceps femoris tendon is negatively correlated with ultrasound score (r = 0.955, p < 0.01). There is a strong negative correlation between SWS and the degree of KOA. It can be used in the grading diagnosis of KOA to help find more early strain points.

The Efficacy of Acoustic Radiation Force Impulse Elastography for Predicting Clinical Outcomes in Living Donor Liver Transplant

PURPOSE

Acoustic radiation force impulse (ARFI) elastography is widely used for evaluating liver fibrosis. Here we evaluated the efficacy of ARFI elastography for estimating graft quality and clinical outcomes in living donor liver transplant (LDLT).

METHODS

We retrospectively evaluated the cases of 87 LDLT donors who preoperatively underwent ARFI elastography at Nagasaki University Hospital between August 2010 and June 2016. We analyzed whether the velocity of shear wave (Vs) obtained by ARFI elastography affected the regeneration rate of each donor's remnant liver and the 1-year survival rate of the recipients.

RESULTS

There were no significant correlations between Vs value and the donors' age. Only 1 donor (1.1%) showed significant fibrosis, F2 (portal fibrosis with few septa) in zero-biopsy. The 7 donors (8.0%), including 1 case, showed a high Vs value (> 1.33) that was equal to F2, although there was no abnormal pathologic finding except in 1 case. In those cases, the regeneration rate of the remnant liver after hepatectomy was significantly lower compared to other cases. The 1-year survival rate of the recipients paired with the high-Vs donors was also significantly poorer than that of the other cases (high-Vs: 57.1%, others: 84.2%, P = .04).

CONCLUSIONS

ARFI elastography might be an effective examination for the preoperative evaluation of the graft quality in LDLT.

Arrival-Time Parametric Imaging in Contrast-Enhanced Ultrasound for Diagnosing Fibrosis in Primary Biliary Cholangitis

Liver biopsy is usually required for diagnosing fibrosis in primary biliary cholangitis (PBC), but contrast-enhanced ultrasonography (CEUS) is a possible alternative. The aim of this study was to investigate arrival-time parametric imaging (At-PI) in for diagnosing fibrosis in PBC. Forty-eight patients (male/female, 8/40; mean age, 60 ± 13 years) with PBC diagnosed by liver biopsy underwent CEUS during 2009-2019. Of these, 27 who also underwent shear wave elastography (SWE) were further analyzed. Perflubutane was intravenously injected and CEUS performed. Contrast dynamics of hepatic segment V and the right kidney were recorded and At-PI generated. The ratio of red indicating contrast arrival time <5 seconds to the entire liver contrast-enhanced area was calculated and compared with shear wave velocity (Vs) measured by SWE by fibrosis stage (F0-F3), bile duct loss score, cholangitis activity, hepatitis activity (HA0-HA3), and disease stage, as determined by liver biopsy. Ratio of red significantly differed between F0 and F2-F3 and between F1 and F2-F3. Using ratio of red to diagnose ≥F1 (≥F2), area under the receiver operating characteristic curve was 0.77 (0.92) (cutoff, 36.7% [47.1%]; sensitivity, 0.75 [0.92]; specificity, 0.82 [0.81]). At-PI was useful for diagnosing fibrosis, especially F2 or worse, in PBC, suggesting that At-PI can correctly diagnose fibrosis regardless of hepatic inflammation.

The severity of portal hypertension by a non-invasive assessment: acoustic structure quantification analysis of liver parenchyma

Background

Acoustic structure quantification (ASQ) has been applied to evaluate liver histologic changes by analyzing the speckle pattern seen on B-mode ultrasound. We aimed to assess the severity of portal hypertension (PHT) through hepatic ultrasonography.

Methods

Sixty patients diagnosed with PHT and underwent surgical treatment with portosystemic shunts were enrolled. Portal pressure (PP) was measured intraoperatively. Patients were divided into subgroups according to the severity of gastroesophageal varices and Child–Pugh class. Three difference ratio (C_m²) values on ASQ histogram mode were analyzed for their relationships with PP, degree of gastroesophageal varices and Child–Pugh liver function. Thirty healthy volunteers matched with the patients for gender and age were enrolled as controls. Comparisons among groups and correlation of the parameters with PP were analyzed. Area under the receive operating characteristic curve was used to evaluate the predicting value of ASQ parameters.

Results

In the patients, the ASQ parameters peak C_m² (C_m²_max), mean C_m² (C_m²_mean) and the highest occurred C_m² value of the obtained red curve (R_maxC_m²) were all greatly increased (P < 0.0001, P < 0.0001, P = 0.027). Multiple comparisons indicated that, regardless of Child–Pugh class and degree of gastroesophageal varices, the patients had significantly increased C_m²_max and C_m²_mean compared with the controls (all P < 0.0001). No differences among subgroups were observed. C_m²_max was significantly statistically correlated with PP (r = 0.3505, P < 0.01), degree of varices (r = 0.4998, P < 0.0001). Youden’s index for C_m²_max with a cut-off value of 140.3 for predicting the presence of PHT, gastroesophageal varices and liver function equal to or worse than Child–Pugh class B were 0.8, 0.91 and 0.84, respectively.

Conclusions

ASQ analysis of ultrasonographic images may have a role in the evaluation of the severity of PHT by detecting liver histologic changes in the speckle pattern caused by cirrhosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-022-00817-2.

Retrospective Evaluation of Non-Invasive Assessment Based on Routine Laboratory Markers for Assessing Advanced Liver Fibrosis in Chronic Hepatitis B Patients

Background

At present, there is a lack of cheap, effective and convenient detection methods for hepatitis B-related liver fibrosis, especially in the developing area.

Aim

To evaluate the non-invasive methods for the significant and advanced fibrosis stage in chronic hepatitis B virus (HBV) patients in basic hospitals and to assess their diagnostic utility.

Methods

The study included 436 consecutive naive HBV individuals who had their livers biopsied. They were examined in one week using aspartate aminotransferase-to-aspartate aminotransferase ratio (AAR), age-platelet index (API), aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis-4 (FIB-4), Forns, gamma-glutamyl transpeptidase-to-platelet ratio (GPR), S-index and transient elastography (TE). Scheuer scoring system was used to determine the histologic fibrosis grades (S0–S4). The diagnostic effectiveness was assessed using AUROCs and the DeLong test, both of which were based on statistical comparisons.

Results

For both substantial (≧S2) and advanced (≧S3) fibrosis phases, TE had good diagnostic performance in determining the hepatic fibrosis. Similar diagnostic performance was shown with Forns and S-index when it came to detecting fibrosis stages lower than S3. One model’s diagnostic value was not significantly improved by combining serum models. Correlation coefficients between clinical features and fibrosis phases were greatest for Forns (r = 0.397), S-index (r = 0.382) and TE (r = 0.535) when compared to other variables.

Conclusion

This investigation showed that Forns and S-index may be helpful strategies for detecting advanced fibrosis in HBV patients admitted to community hospitals.

Usefulness of New Shear Wave Elastography Technique for Noninvasive Assessment of Liver Fibrosis in Patients with Chronic Hepatitis B: A Prospective Multicenter Study

PURPOSE

 To explore the usefulness of liver stiffness measurements (LSMs) by sound touch elastography (STE) and sound touch quantification (STQ) in chronic hepatitis B (CHB) patients for staging fibrosis.

METHODS

 This prospective multicenter study recruited normal volunteers and CHB patients between May 2018 and October 2019. The volunteers underwent LSM by STE and supersonic shear imaging (SSI) or by STQ and acoustic radiation force impulse imaging (ARFI). CHB patients underwent liver biopsy and LSM by both STE/STQ. The areas under the receiver operating characteristic curves (AUCs) for staging fibrosis were calculated.

RESULTS

 Overall, 97 volunteers and 524 CHB patients were finally eligible for the study. The successful STE and STQ measurement rates were both 100 % in volunteers and 99.4 % in CHB patients. The intraclass correlation coefficients (ICCs) for the intra-observer stability of STE and STQ (0.94; 0.90) were similar to those of SSI and ARFI (0.95; 0.87), respectively. STE and STQ showed better accuracy than the aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) (AUC: 0.87 vs 0.86 vs 0.73 vs 0.77) in staging cirrhosis. However, both STE and STQ were not superior to APRI and FIB-4 in staging significant fibrosis (AUC: 0.76 vs 0.73 vs 0.70 vs 0.71, all P-values > 0.05).

CONCLUSION

 STE and STQ are convenient techniques with a reliable LSM value. They have a similar diagnostic performance and are superior to serum biomarkers in staging cirrhosis in CHB patients.

Two-dimensional shear wave elastography of the pancreas: measurement success rate, repeatability, and factors affecting measurement values

PURPOSE

We aimed to evaluate the success rate, repeatability, and factors affecting the measurement values of two-dimensional ultrasonic shear wave elastography (2D-SWE) for measuring pancreatic stiffness.

METHODS

This prospective study recruited 100 healthy participants. 2D-SWE was performed on the pancreatic head, body, and tail. We compared the success rates of pancreatic stiffness measurements of different body positions and ultrasonic scans, with and without probe pressurization, as well as the effects of sex, age, body mass index (BMI), and region of interest (ROI) depth on measurement values. Intra- and inter-operator repeatabilities were assessed in 20 participants. The influence of ROI depth was verified using a tissue-like phantom.

RESULTS

The median 2D-SWE measurements of the pancreatic head, body, and tail were 1.44, 1.45, and 1.56 m/s, respectively. The success rates for the pancreatic head and body were significantly higher than that of the tail. The success rate for the semi-recumbent position was higher than that of the supine position (P < 0.001). The intra-operator values for same-day and inter-operator reliability were excellent. Univariate analyses showed that probe pressurization, age, BMI, and ROI depth were correlated with pancreatic shear wave velocity (SWV) (P < 0.05); only ROI depth had a significant effect on SWV values. The inclusion phantom showed that the SWV value increased as the ROI depth increased.

CONCLUSIONS

2D-SWE had a high success rate and good repeatability for measuring pancreatic head and body stiffness. The ROI depth was the main factor affecting pancreatic SWV, which increased with ROI depth.

Potential role of noninvasive biomarkers during liver fibrosis

Various types of liver disease exist, such as hepatitis and alcoholic liver disease. These liver diseases can result in scarring of liver tissue, cirrhosis, and finally liver failure. During liver fibrosis, there is an excess and disorganized accumulation of extracellular matrix (ECM) components which cause the loss of normal liver cell functions. For patients with chronic liver disease, fibrosis prediction is an essential part of the assessment and management. To diagnose liver fibrosis, several invasive and noninvasive markers have been proposed. However, the adoption of invasive markers remains limited due to their inherent characteristics and poor patient acceptance rate. In contrast, noninvasive markers can expedite the clinical decision through informed judgment about disease stage and prognosis. These noninvasive markers are classified into two types: Imaging techniques and serum biomarkers. However, the diagnostic values of biomarkers associated with liver fibrosis have also been analyzed. For example, the serum levels of ECM proteins can react to either matrix accumulation or degradation. During virus-host interactions, several regulatory steps take place to control gene expression, such as the change in cellular microRNA expression profiles. MicroRNAs are a class of non-coding RNAs (18-20 long nucleotides) that function by post-transcriptional regulation of gene expression. Although various noninvasive markers have been suggested in recent years, certain limitations have restricted their clinical applications. Understanding the potential of non-invasive biomarkers as a therapeutic option to treat liver fibrosis is still in progress.

Non-invasive staging of liver fibrosis by two-dimensional shear wave elastography (2D-SWE) in patients with chronic hepatitis C and B

Background

Non-invasive shear wave-based techniques have been developed for estimating liver fibrosis in patients with chronic liver diseases. Two-dimensional shear wave elastography provides in real-time, a tow dimensional quantitative map of tissue stiffness and enables measuring the stiffness by adjustment of a region of interest of tissue. The aim of this study was to highlight the role of tow dimensional shear wave elastography (2D-SWE) in detecting the degree of liver fibrosis in patients with chronic hepatitis C and B, in correlation with liver enzymes level and fibrotest.

Results

This study included 50 patients with chronic hepatitis C and B whose ages were (range, 30-65 years; mean, 48 years). Shear wave elastography cutoff values were 1.35 m/s, 5.48 KPa for (F>0); 1.66 m/s, 8.29 kPa for (F>1); 1.77 m/s, 9.40 kPa for (F>2); and 1.99 m/s, 11.9 kPa for (F>3). An excellent agreement was found between shear wave elastography and Fibrotest in staging of liver fibrosis in 88% of patients (κw=0.943, 95% CI, 0.88 to 1.00) achieving a highly statistical significance (P<0.001). There was a significant moderate positive concordance between US scoring and staging by 2D-SWE and staging by Fibrotest (rs, 0.49; P<0.01) and (rs, 0.48; P<0.01) respectively. However, no significant concordances were noticed between staging by AST and ALT and 2D-SWE and staging by Fibrotest (P>0.05).

Conclusions

2D shear wave elastography showed better diagnostic performance than visual assessment by conventional US for detection of chronic liver diseases, as well as for evaluation of their severity and prognosis. Elastograhy—Fibrotest combination gives best diagnostic performance in detecting the degree of fibrosis non-invasively and can be used reliably as a first-line pre-therapeutic evaluation of fibrosis in HCV and HBV-infected patients.

Liver stiffness measured by virtual touch quantification predicts the occurrence of posthepatectomy refractory ascites in patients with hepatocellular carcinoma

PURPOSE

This study assessed the significance of measuring liver stiffness using virtual touch quantification before hepatectomy to predict posthepatectomy refractory ascites.

METHODS

A total of 267 patients with hepatocellular carcinoma who underwent hepatectomy were prospectively analyzed. Liver stiffness was defined as the median value of the virtual touch quantification (Vs; m/s) by acoustic radio-force-impulse-based virtual touch.

RESULTS

A multivariate analysis showed that Vs and the aspartate aminotransferase-to-platelet ratio index were independent risk factors for postoperative refractory ascites (odds ratio = 3.27 and 3.08, respectively). The cutoff value for Vs was 1.52 m/s (sensitivity: 59.5%, specificity: 88.6%) as determined by the analysis of the receiver-operating characteristic curve, and the area under the receiver-operating characteristic curve was 0.79. The cutoff value for the aspartate aminotransferase-to-platelet ratio was 0.952 (sensitivity: 65.5%, specificity: 82.9%), and the area under the receiver-operating characteristic curve was 0.75.

CONCLUSIONS

Vs is an independent risk factor for refractory ascites after hepatectomy. The measurement of liver stiffness by virtual touch quantification before hepatectomy can help estimate the risk of postoperative refractory ascites. Nonsurgical treatments should be considered for the management of patients who are at high risk for refractory ascites.

Measurements of Serum Mac-2-Binding Protein Glycosylation Isomer and Shear Wave Velocity in Health Checkups Are Useful in Screening for Non-Alcoholic Steatohepatitis

Liver-related mortality rates in patients with non-alcoholic steatohepatitis (NASH) increase with advancing liver fibrosis stage. The present study aimed to elucidate whether adding non-invasive liver fibrosis tests to a comprehensive health checkup system is useful for NASH screening. Both serum Mac-2-binding protein glycosylation isomer (M2BPGi) and point shear wave elastography (pSWE) using ultrasonography were performed for 483 health checkup subjects who consented to participate in this prospective study. Outcomes in positive subjects were surveyed 1 year later. Eighty-eight subjects (18%) showed positive results for at least one liver fibrosis test, with 63 subjects positive for pSWE, 33 subjects positive for M2BPGi, and 72 subjects showing no significant elevation of liver enzymes. The secondary consultation rate for positive subjects was 52% (46/88). However, as 15 of those 46 subjects visited a non-liver-specialist and could not undergo detailed examination, the secondary examination rate was only 35% (31/88). For the 31 subjects who received secondary examination, NASH was diagnosed in 14 subjects, other chronic liver disease (CLD) in 6 subjects, and no CLD in 11 subjects. Additional liver fibrosis tests using M2BPGi and pSWE appear useful in health checkups when screening for CLD, especially for NASH.

Role of real-time shear-wave elastogarphy in differentiating hepatocellular carcinoma from other hepatic focal lesions

BACKGROUND

Hepatocellular carcinoma (HCC) has an increasing incidence worldwide, and is considered the second cause of cancer-related death.

AIM

The aim of the study is to assess the usefulness of real-time shear-wave elastography in differentiating HCC from other hepatic focal lesions.

PATIENTS AND METHODS

The current study was conducted on 110 patients in addition to 10 healthy subjects, divided into four groups as follows: liver cirrhosis, HCC, hepatic focal lesions other than HCC, and control. Demographic, laboratory and imaging data were collected and then elastographic assessment of the hepatic focal lesions and the surrounding liver parenchyma using elastograph point quantification (ElastPQ) (iU22x MATRIX, Philips) was done.

RESULTS

ElastPQ (iU22x MATRIX, Philips) has shown its ability to differentiate between HCC and cystic focal lesions, HCC and cholangiocarcinoma, and HCC and focal nodular hyperplasia (FNH). Cystic lesions demonstrated lower stiffness in comparison to HCC; however, cholangiocarcinoma and FNH demonstrated higher stiffness in comparison to HCC. ElastPQ was unable to differentiate between stiffness in both 'HCC and hemangioma' and 'HCC and metastatic focal lesions'. ElastPQ showed that HCC, cystic focal lesions, and cholangiocarcinoma had lower stiffness in comparison to their surrounding liver parenchyma, whereas FNH had higher stiffness in comparison to the surrounding liver parenchyma. ElastPQ showed that the surrounding liver parenchyma of the HCC group has the highest stiffness amongst all studied hepatic focal lesions surrounding liver parenchyma.

CONCLUSION

'Point' shear-waves elastography (ElastPQ; Philips iU22x MATRIX, Philips) is a noninvasive, quantitative and nonradiating method for evaluation of tissue elasticity, and is helpful in differentiating HCC from other hepatic focal lesions.

Comparison of 2-D Shear Wave Elastography and Point Shear Wave Elastography for Assessing Liver Fibrosis

Progressive liver fibrosis may result in cirrhosis, portal hypertension and increased risk of hepatocellular carcinoma. We performed a meta-analysis to compare liver fibrosis staging in chronic liver disease patients using 2-D shear wave elastography (2-D SWE) and point shear wave elastography (pSWE). The PubMed, Web of Science and Cochrane Library databases were searched until May 31, 2020 for studies evaluating the diagnostic performance of 2-D SWE and pSWE in assessing liver fibrosis. Pooled sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratios and area under receiver operating characteristic curve were estimated using the bivariate random effects model. As a result, 71 studies with 11,345 patients were included in the analysis. The pooled sensitivities of 2-D SWE and pSWE significantly differed for the detection of significant fibrosis (F ≥ 2; 0.84 vs. 0.76, p < 0.001) and advanced fibrosis (F ≥ 3; 0.90 vs. 0.83, p = 0.003), but not for detection of cirrhosis (F = 4; 0.89 vs. 0.85, p = 0.090). The pooled specificities of 2-D SWE and pSWE did not significantly differ for detection of F ≥ 2 (0.81 vs. 0.79, p = 0.753), F ≥ 3 (0.87 vs. 0.83, p = 0.163) or F = 4 (0.87 vs. 0.84, p = 0.294). Both 2-D SWE and pSWE have high sensitivity and specificity for detecting each stage of liver fibrosis. Two-dimensional SWE has higher sensitivity than pSWE for detection of significant fibrosis and advanced fibrosis.

Utility of Mac-2 Binding Protein Glycosylation Isomer to Evaluate Graft Status After Liver Transplantation

Mac-2 binding protein glycosylation isomer (M2BPGi) is a novel liver fibrosis biomarker, but there are few studies on M2BPGi in liver transplantation (LT) recipients. This study aimed to evaluate the utility of M2BPGi measurement in LT recipients. We collected the clinicopathological data of 233 patients who underwent a liver biopsy at Kyoto University Hospital after LT between August 2015 and June 2019. The median values of M2BPGi in patients with METAVIR fibrosis stages F0, F1, F2, and ≥F3 were 0.61, 0.76, 1.16, and 1.47, respectively, whereas those in patients with METAVIR necroinflammatory indexes A0, A1, and ≥A2 were 0.53, 1.145, and 2.24, respectively. Spearman rank correlation test suggested that the necroinflammatory index had a stronger correlation to the M2BPGi value than the fibrosis stage. The area under the receiver operating characteristic curve of M2BPGi to predict ≥A1 was 0.75, which was significantly higher than that of any other liver fibrosis and inflammation marker. Patients with a rejection activity index (RAI) of ≥3 had a higher M2BPGi value than those with RAI ≤ 2 (P = 0.001). Patients with hepatitis C virus viremia had a higher M2BPGi value than sustained virological responders or those with other etiologies. In conclusion, the present study demonstrated that M2BPGi values are more strongly influenced by necroinflammatory activity and revealed M2BPGi, which has been thought to be a so-called fibrosis marker, as a disease activity marker in transplant recipients. M2BPGi measurement may be useful to detect early stage liver inflammation that cannot be detected by routine blood examination of LT recipients.

Comparison of Elastography Point Quantification with Transient Elastography in Patients with Chronic Viral Hepatitis and Nonalcoholic Fatty Liver Disease: A Pilot Study

AIMS

The objective of this study was to compare diagnostic accuracy of elastography point quantification (ElastPQ) with transient elastography (TE) and liver histology for measuring liver stiffness in patients with chronic viral hepatitis (CVH) and nonalcoholic fatty liver disease (NAFLD).

METHODS

Thirty-two patients with chronic liver disease (CVH and NAFLD) were evaluated by ElastPQ and TE within 7 days of liver biopsy. Within the CVH group, subgroup analysis was carried out in patients with end-stage renal disease (ESRD) and without ESRD. Area under the receiver operating characteristic (AUROC) curves were calculated for ElastPQ and TE.

RESULTS

There were 15 patients with CVH and 17 patients with NAFLD. In the CVH group, there were 8 patients with ESRD and 7 patients without ESRD. Taking liver histopathology as the gold standard, liver stiffness measurement by ElastPQ (ρ = 0.826;P < 0.0001) and TE (ρ = 0.649; P < 0.0001) correlated significantly with the stage of fibrosis. AUROCs of ElastPQ and TE for the diagnosis of any fibrosis (F ≥ 1), significant fibrosis (F ≥ 2), and advanced fibrosis (F ≥ 3) were 0.907, 0.959, 0.926 and 0.870, 0.770, 0.881, respectively, in both CVH and NAFLD groups. However, the accuracy of both these techniques was poor in patients with CVH and ESRD (AUROCs for ElastPQ and TE of 0.667 and 0.167 for the diagnosis of significant fibrosis, respectively, and 0.429 and 0.143 for the diagnosis of advanced fibrosis, respectively). The diagnostic accuracy of both ElastPQ and TE for detecting significant fibrosis was excellent in patients with NAFLD (AUROC of 1.000 and 0.936, respectively). ElastPQ was superior to TE in the diagnosis of significant fibrosis in the combined analysis (P = 0.0149) and in the CVH group (P = 0.0391), while both modalities were comparable in patients of the NAFLD group (P = 0.2539).

CONCLUSION

ElastPQ may be equally accurate as Fibroscan, and large prospective studies are required to validate the same.

2-D Ultrasound Shear Wave Elastography With Multi-Sphere-Source External Mechanical Vibration: Preliminary Phantom Results

Ultrasound shear wave elastography (SWE) imaging is emerging as a quantitative and non-invasive tissue characterization modality. Shear wave generation using external mechanical vibration (EMV) has received extensive research interest over acoustic radiation force impulse (ARFI) because of its low cost and potential for portability. In this paper, we propose an EMV concept with multiple spherical sources that can be easily reconfigured in three configurations to induce unique shear wave propagation patterns. We introduce two design embodiments of this concept bench test design for proof of concept and a clinically deployable design. The latter is designed to incorporate size, ergonomics, portability and power consumption considerations and constraints. Experimental validation on elasticity phantoms using both EMV designs demonstrates shear wave generation and elasticity reconstruction comparable in performance to ElastQ, a commercial ARFI-based shear elastography technology from Philips. In addition, the local displacement amplitude induced by EMV is 10 times greater than that induced by ARFI at the same given depth. Finally, the multiple configurations of the presented EMV design would allow exploration of advanced elastography methods such as tissue anisotropic elasticity.

Ultrasound-based liver elastography in the assessment of fibrosis

Ultrasound-based elastography has rapidly replaced the need for liver biopsy in most patients with chronic liver disease in recent years. The technique is now widely supported by many manufacturers. This review will introduce various current ultrasound-based elastography techniques, review the physics and scanning techniques, discuss potential cofounding factors as well as summarising the evidence for its use in staging liver fibrosis using shear-wave elastography among different disease aetiologies. Future challenges and directions will be also be discussed.

Interobserver agreement and diagnostic accuracy of shearwave elastography for the staging of hepatitis C virus-associated liver fibrosis

PURPOSE

Our study aimed to evaluate the technical success rate, interobserver reproducibility, and accuracy of shearwave elastography (SWE) in the staging of hepatitis C virus (HCV)-associated liver fibrosis.

METHODS

A total of 10 healthy controls and 49 patients with chronic liver disease were enrolled prospectively. Two examiners performed point shearwave elastography (pSWE) and two-dimensional shearwave elastography (2D-SWE) measurements with an RS85A ultrasound scanner using the S-Shearwave application (Samsung Medison, Hongcheon, Korea). The performance of S-Shearwave in the staging (METAVIR F0-F4) of liver fibrosis was compared with prior transient elastography (TE) with receiver operating characteristic (ROC) curve analysis.

RESULTS

The interobserver reproducibility was excellent with pSWE (ICC = 0.92, 95% CI: 0.86-0.95, P < .001). A very good agreement was found between pSWE and TE measurements (ICC =0.85, 95% CI: 0.78-0.89, P < .001). The ROC analysis determined the optimal cut-off values of pSWE for the staging of chronic hepatitis C-associated fibrosis (F2, 1.46 m/s; F3, 1.63 m/s; F4, 1.95 m/s). Both observers achieved excellent diagnostic accuracy (AUROC: 94% vs 97%) in the detection of significant (≥F2) liver fibrosis.

CONCLUSION

The interobserver agreement is excellent with S-Shearwave pSWE, and observers can diagnose significant liver fibrosis with a comparable accuracy to TE.

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.

Diagnostic accuracy of acoustic radiation force impulse elastography (ARFI) in comparison to other non-invasive modalities in staging of liver fibrosis in chronic HCV patients: single-center experience

PURPOSE

To evaluate the reliability of ARFI elastography for liver fibrosis staging and compare it to other non-invasive assessment of hepatic fibrosis (FIB-4 and APRI) in chronic HCV (CHC) patients.

METHODS

A single-center, prospective study included 2103 CHC patients. Liver stiffness (LS) was evaluated by TE and ARFI elastography. FIB-4 and APRI were calculated. The area under the receiver-operating characteristic curve (AUROCs) was used to assess the diagnostic performance of ARFI elastography for staging of liver fibrosis using TE as a reference standard.

RESULTS

The best cut off values of ARFI elastography for diagnosis of ≥ F2, ≥ F3and F4 were 1.36 m/s, 1.45 m/s, and 1.7 m/s with AUROCs of 0.89, 0.94 and 0.95, respectively. ARFI elastography cut offs are lower in patients with normal ALT level compared to those with ALT level (1.1-< 3 ULN) and those with ALT level ≥ 3ULN (1.35 m/s vs 1.39 m/s vs 1.54 for F ≥ 2, 1.44 m/s vs 1.58 m/s vs 1.6 m/s for F3, 1.69 m/s, 1.84 m/s, 1.86 m/s for F4). FIB-4 (0.82-0.86) and APRI (0.78-0.82) yielded lower AUC in prediction of significant fibrosis and cirrhosis than ARFI elastography (0.89-0.95).

CONCLUSION

ARFI elastography is a reliable method for non-invasive staging of liver fibrosis in CHC patients when compared to TE with a good diagnostic performance comparable to FIB-4 and APRI scores for the prediction of significant fibrosis and cirrhosis.

Flash Imaging Used in the Post-vascular Phase of Contrast-Enhanced Ultrasonography is Useful for Assessing the Progression in Patients with Hepatitis C Virus-Related Liver Disease

Sonazoid is a commonly used contrast agent for characterizing liver tumors in ultrasonography (US). We performed flash imaging in the post-vascular phase of contrast-enhanced US (CEUS) to investigate associations between collapse of Sonazoid microbubbles (MB) and progression of liver disease. This study enrolled 409 patients (205 men, 204 women) with hepatitis C virus-related liver disease (CLD) between 2007 and 2017 (mean age 60 ± 14 y; range 20-90 y). In the post-vascular phase, 10 min after administering Sonazoid, flash imaging was performed to burst MB in the liver parenchyma; the range of bubble destruction was measured from the surface of the liver. The range of bubble destruction, stage of fibrosis, shear wave velocity (Vs), serologic markers and fibrosis-4 (FIB4) index were analyzed in 259 patients who underwent liver biopsy. Fibrosis stage was F0-1 in 108 patients, F2 in 73, F3 in 38 and F4 in 40. In 150 patients with cirrhosis, diagnosis was made based on imaging findings. The range of bubble destruction was 42.0 ± 10.4 mm in F0-1 patients, 42.9 ± 13.2 mm in F2, 51.5 ± 15.9 mm in F3 and 55.4 ± 17.3 mm in F4 and was significantly increased according to progression of fibrosis staging. The range of bubble destruction was positively correlated with Vs (r = 0.34; p < 0.01), total bilirubin (r = 0.25; p < 0.01) and FIB4 index (r = 0.38; p < 0.01). In contrast, the range of bubble destruction was negatively correlated with serum levels of albumin (r = -0.34; p < 0.01), platelet count (r = -0.35; p < 0.01) and prothrombin time (r = -0.36; p < 0.01). The results indicated that flash imaging in the post-vascular phase of CEUS was a non-invasive assessment and could predict disease progression in patients with CLD.

Efficiency of acoustic radiation force impulse imaging for the staging of graft fibrosis after liver transplantation

AIM

Liver biopsy is the gold standard for assessing liver fibrosis (LF) after liver transplantation (LT), but its invasiveness limits its utility. This study aimed to evaluate the usefulness of liver stiffness measurement (LSM) using acoustic radiation force impulse (ARFI) imaging to assess LF after LT.

METHODS

Between September 2013 and January 2017, 278 patients who underwent liver biopsy after LT in Kyoto University Hospital (Kyoto, Japan) were prospectively enrolled. Liver stiffness measurement was carried out using ARFI imaging; its value was expressed as shear wave velocity (Vs) [m/s]. The LF was evaluated according to METAVIR score (F0-F4). The diagnostic performance of Vs for F2≤ and F3≤ was assessed and compared with that of laboratory tests using receiver operating characteristic (ROC) analysis.

RESULTS

The median Vs values increased according to the progression of LF (F0, 1.18 (0.78-1.92); F1, 1.35 (0.72-3.54); F2, 1.55 (1.05-3.37); F3, 1.84 (1.41-2.97)). The Vs had the highest area under the ROC curve (AUROC) for the prediction of both F2 ≤ and F3 ≤ fibrosis (F2, 0.77; and F3, 0.85). With the cut-off value of Vs >1.31, sensitivity, specificity, positive predictive value, and negative predictive value were 89.4%, 53.3%, 37.3%, and 94.2% in predicting F2≤, respectively. Shear wave velocity diagnosed LF better than any laboratory tests regardless of the type of primary disease.

CONCLUSIONS

Acoustic radiation force impulse helps to assess graft LF after LT. The high sensitivity suggested that ARFI might reduce the frequency of liver biopsies by detecting patients who are unlikely to have significant fibrosis after LT. (Unique trial no. UMIN R000028296.).

Liver stiffness measurement by acoustic radiation forced impulse and transient elastography in patients with intrahepatic cholestasis

BACKGROUND

Transient elastography (TE) and acoustic radiation force impulse (ARFI) imaging enable a noninvasive assessment of liver stiffness measurement (LSM) and liver fibrosis/cirrhosis staging. However, their use in cholestatic diseases is still scarce.

AIM

The aim of this study was to evaluate the performance of TE and ARFI for the initial assessment of hepatic fibrosis in intrahepatic cholestatic (IHC) diseases and assess LSM changes after 3 months of specific therapy.

PATIENTS AND METHODS

This prospective study was carried out on 50 IHC patients. Assessment at baseline and after 3 months of LSM by TE and ARFI was performed.

RESULTS

Overall, 60% of the patients were women (36.5±9.2 years). IHC etiologies were 23 (46%) autoimmune hepatitis, eight (16%) primary sclerosing cholangitis, eight (16%) drug induced, and five (10%) primary biliary cirrhosis. TE could diagnose ≥F2, ≥F3, and F4 stages at cutoffs of at least 6.7, 9.4, and 14.0 kPa, sensitivity/specificity were 100/50% for ≥F2, 88.2/83% for ≥F3, and 90/100% for F4. Moreover, the sensitivity and specificity of ARFI were 93/50% for ≥F2 (cutoff: 1.53 m/s); 71/67% for ≥F3 (cutoff 1.77 m/s); and 90/100% for F4 (cutoff: 2.43 m/s).Follow-up showed a significant decrease in TE and ARFI values by 27 and 22.3% (P<0.001 and <0.001, respectively) and, accordingly, fibrosis stages decreased significantly by both TE and ARFI (P=0.002 and <0.001, respectively).

CONCLUSION

TE and ARFI represent noninvasive methods with adequate diagnostic performance for the assessment of fibrosis, and monitoring disease progression and treatment response in intrahepatic cholestasis.

Chronic hepatitis C infection - Noninvasive assessment of liver fibrosis in the era of direct acting antivirals

Significant advancements in the diagnosis and treatment of chronic hepatitis C infection and its associated fibrosis have revolutionized treatment of these patients over the last several years. Liver biopsy, the gold standard diagnostic method for evaluating liver fibrosis level, was routinely used prior to initiation of hepatitis C therapy, placing patients at an inherent risk of adverse events. The recent advent of noninvasive serologic and nonserologic measures of hepatic fibrosis level has reduced the need for liver biopsy significantly, thereby minimizing its associated risks. These noninvasive methods have been extensively studied in the era of interferon therapies and are increasingly recognized in the realm of direct acting antiviral agents as well. Their validation of use after having achieved a sustained virologic response is yet to occur, but the future remains promising. This review focuses on the various non-invasive diagnostic modalities of liver fibrosis and discusses how they can be applied to the care of patients undergoing direct acting antiviral therapy for hepatitis C. In the constantly evolving landscape of hepatitis C therapy, the review underscores the important prognostic value of fibrosis staging prior to HCV treatment and suggests potential uses for non-invasive fibrosis assessment following successful HCV eradication.

Influence of Probe Pressure on Ultrasound-Based Shear Wave Elastography of the Liver Using Comb-Push 2-D Technology

It has been postulated that in the liver, applying increased probe pressure during ultrasound-based shear wave elastography (SWE) might lead to a false increase in the SWE result. We aimed to determine the influence of increased intercostal probe pressure when performing SWE of the liver. We also investigated the number of measurements required to achieve technically successful and reliable SWE examinations. This prospective, clinical study included 112 patients and 2240 SWE measurements of the liver. We applied probe pressure intercostally, to reduce the skin-to-liver capsule distance (SCD), which could stabilize the SWE signal and thus increase the number of technically successful measurements. We performed 10 measurements with maximum probe pressure and 10 with normal pressure in each patient. Thus, two analysis groups were compared for differences. Compared with normal pressure, maximum probe pressure significantly reduced the SCD (p < 0.001) and significantly increased the number of technically successful measurements from 981 to 1098, respectively (p < 0.001). The SWE results with normal and maximum probe pressure were 5.96 kPa (interquartile range: 2.41) and 5.45 kPa (interquartile range: 1.96), respectively (p < 0.001). In obese patients, a large SCD poses a diagnostic challenge for ultrasound SWE. We found that maximum intercostal probe pressure could reduce the SCD and increase the number of technically successful measurements, without falsely increasing the SWE result. Only three measurements were required to achieve technically successful and reliable SWE examinations.

Whole-Exome Sequencing Identifies a Variant in Phosphatidylethanolamine N-Methyltransferase Gene to be Associated With Lean-Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of liver diseases with simple steatosis on one end and hepatocellular carcinoma on the other. Although obesity is a known risk factor for NAFLD, individuals with normal body mass index (BMI) also have hepatic fatty infiltration, now termed "lean-NAFLD". It represents a distinct entity with a strong underlying genetic component. The present study aimed to sequence the complete exonic regions of individuals with lean-NAFLD to identify germline causative variants associated with disrupted hepatic fatty acid metabolism, thereby conferring susceptibility to NAFLD.

METHODS

Whole blood was collected from patients with lean-NAFLD (n = 6; BMI < 23.0 kg/m²) and matched lean controls (n = 2; discovery set). Liver fat was assessed using acoustic radiation force impulse (ARFI) imaging. Patients with ultrasound-detected NAFLD (n = 191) and controls (n = 105) were part of validation set. DNA was isolated, and whole-exome sequencing (WES) was performed in the discovery cohort (Ion Proton™; Ion AmpliSeq™ Exome RDY Kit). Data were analyzed (Ion Reporter software; Life Technologies), and variants identified. Validation of variants was carried out (Taqman probes; Real time-PCR). Student's t test and Fisher's exact test were used to analyze the statistical significance.

RESULTS

Although WES identified ∼74,000 variants in individual samples, using various pipelines. variants in genes namely phosphatidylethanolamine N-methyltransferase (PEMT) and oxysterol-binding protein-related protein10 (OSBPL10) that have roles in dietary choline intake and regulation of cholesterol homeostasis, respectively, were identified (discovery set). Furthermore, significant differences were noted in BMI (p = 0.006), waist/hip circumference (p > 0.001), waist/hip ratio (p > 0.001), aspartate aminotransferase (p > 0.001), alanine aminotransferase (p > 0.001), and triglycerides (p = 0.002) between patients and controls. Validation of variants (rs7946-PEMT and rs2290532-OSBPL10) revealed that variant in PEMT but not OSBPL10 gene was associated (p = 0.04) with threefold increased risk of NAFLD in lean individuals.

CONCLUSION

Our results demonstrate the association of rs7946 with lean-NAFLD. WES may be an effective strategy to identify causative variants underlying lean-NAFLD.

Evaluation of Pancreatic Fibrosis With Acoustic Radiation Force Impulse Imaging and Automated Quantification of Pancreatic Tissue Components

OBJECTIVES

The aim of this study was to determine whether computer-assisted digital analysis and acoustic radiation force impulse (ARFI) imaging were useful for assessing pancreatic fibrosis, and if ARFI imaging predicted postoperative pancreatic fistula (POPF).

METHODS

Seventy-eight patients scheduled to undergo pancreatic resection were enrolled. Shear wave velocity (SWV) at the pancreatic neck was measured preoperatively using ARFI imaging. Pancreatic tissue components on a whole slide image were quantified using an automatic image processing software. The relationship between SWV, fibrotic tissue content, and POPF incidence and clinical severity was analyzed.

RESULTS

The median collagen fiber, fatty tissue, and acinar cell contents were 11.6%, 8.5%, and 61.3%, respectively. Unlike fatty tissue, collagen fiber content and acinar cells were correlated with SWV (ρ = 0.440, P < 0.001 and ρ = -0.428, P < 0.001, respectively). Although collagen fiber content and SWV were associated with the overall incidence of POPF (P = 0.004 and 0.001, respectively), collagen fiber content and SWV had no statistical correlation with clinically relevant POPF (P = 0.268 and 0.052, respectively).

CONCLUSIONS

We objectively quantified the pancreatic tissue components using an automatic image processing software. Shear wave velocity was significantly related to collagen fiber content and suggests that ARFI imaging can be useful for evaluating pancreatic fibrosis.

On Patient Related Factors and Their Impact on Ultrasound-Based Shear Wave Elastography of the Liver

The aim of the study was to investigate patient-related factors associated with either reliable or poorly reliable measurement results of ultrasound-based shear wave elastography (SWE) of the liver. A total of 188 patients were analyzed prospectively with binary logistic regression using the interquartile range/median as cutoff to define two groups based on reliable and poorly reliable SWE results. SWE results correlated significantly with liver biopsy. Factors associated with reliable SWE results (i.e., no negative impact on measurements) were age, sex, cirrhosis, antiviral and/or cardiovascular medication, smoking habits and body mass index. Factors associated with poorly reliable SWE results were increased skin-to-liver capsule distance (odds ratio = 3.08, 95% confidence interval: 1.70-5.60) and steatosis (odds ratio = 2.89, 95% confidence interval: 1.33-6.28). These findings indicate that the interquartile range/median as a quality parameter is useful in avoiding poorly reliable SWE results. How best to examine patients with increased skin-to-liver capsule distance is a matter of some controversy, as the incidences of obesity, diabetes and metabolic syndrome are increasing worldwide; however, our results indicate that reliable SWE results can be obtained in this group of patients by using ultrasound-based SWE.

Measurements of renal shear wave velocities in chronic kidney disease patients

Background Chronic kidney disease (CKD) patients have advanced glomerulosclerosis and renal interstitial fibrosis. Shear wave elastography (SWE) is useful to diagnose liver fibrosis. However, there are few data available regarding evaluation of kidney function on the use of SWE. Purpose To assess the utility of SWE by evaluating the correlation between renal function and renal elasticity using SWE. Material and Methods A total of 187 participants who had available serum creatinine levels and also underwent SWE of the kidney using a transabdominal ultrasonography were recruited at Nagoya University Hospital. We measured the depth of the shear wave (SW) in the right and left kidneys and calculated the measurement success rates. The glomerular filtration rate (GFR) classification and shear wave value (SWV) were compared. Results The success rates of the right and left kidneys were 93.6% and 71.6%, respectively. Based on these results, the correlation between GFR classification and SWV were analyzed in only the right kidneys because the success rates and the number of enrolled patients were low for the left kidney. There were significant differences found between G1 and G3a, G2 and G3a, G3a and G3b, G3a and G4, and G3a and G5. SWV significantly negatively and positively correlated with the G2-G3a and G3a-G3b classifications. Conclusion There is no correlation between renal function and SW. However, we can diagnose the progression to the CKD stages G3a and G3b by observing the changes over time using the SWV.

Noninvasive Assessment of Portal Hypertension in Advanced Chronic Liver Disease: An Update

The assessment of portal hypertension is a relevant step in the evaluation of newly diagnosed advanced chronic liver disease (ACLD). The current gold standard includes the invasive evaluation of hepatic venous pressure gradient (HVPG) and endoscopy. However, noninvasive or minimally invasive techniques to assess portal hypertension have been proposed and well established. In the present manuscript, we review clinical studies on the use of noninvasive or minimally invasive techniques to assess portal hypertension in ACLD patients.

Utility of shear-wave elastography to differentiate low from advanced degrees of liver fibrosis in patients with hepatitis C virus infection of native and transplant livers

OBJECTIVE

To determine the accuracy of shear-wave elastography (SWE) to differentiate low from advanced degrees of liver fibrosis in hepatitis C patients.

MATERIAL & METHOD

Consented native/transplant hepatitis C patients underwent SWE using a C1-6 MHz transducer before ultrasound (US)-guided liver biopsy. Five interpretable SWE samples were obtained from the right lobe of the liver immediately before US-guided random biopsy of the right lobe. Average kilopascal (kPa) values were compared to the meta-analysis of histological data in viral hepatitis (METAVIR) fibrosis grading. SWE values were correlated with the degree of inflammation and fatty infiltration.

RESULTS

Study population consisted of 115 patients (63 with transplant, and 52 with native liver) including 29 women and 86 men, with a mean ± SD age of 56 ± 8.7 years. Mean ± SD SWE values were 7.9 ± 3 kPa in 83 patients with METAVIR scores of 0-2 and 13.2 ± 5.9 kPa in 32 patients with METAVIR scores of 3 or 4 (P < .001). Area under curve (AUC) of a Receiver Operating Characteristics curve for advanced degrees of fibrosis was 0.81 (95% CI: 0.71, 0.90) (P < .001). AUCs of transplant versus native livers (0.78 [CI:0.62, 0.94] versus 0.85 [CI: 0.73, 0.96]), degree of inflammation (0.81 [CI: 0.65, 0.97] versus 0.72 [0.56, 0.88]), or degree of fat deposition (0.81 [CI:0.70, 0.92] versus 0.80 [CI:0.61, 1]) were not statistically different (P > .05). for kPa threshold of SWE value of 10.67 kPa to differentiate advanced from low degree of fibrosis had a sensitivity of 59% (CI: 41%-76%) and specificity of 90% (CI: 82%-96%).

CONCLUSION

Liver stiffness evaluated by SWE can differentiate low from advanced liver fibrosis.

Diagnosis and staging of fibrosis in patients with chronic hepatitis C: comparison and critical overview of current strategies

In the past years, what has always been considered undisputed true in liver fibrosis staging has been challenged. Diagnostic performance of histological evaluation has proven to be significantly influenced by sample- and observer-related variabilities. Differentiation between lower levels of fibrosis remains difficult for many, if not all, test modalities, including liver biopsy but, perhaps, such a distinction is not indispensable in light of current therapeutic approaches. Biomarkers and elastography offer, nonetheless, high predictive values for advanced fibrosis and cirrhosis and correlate well with liver-related outcomes. Necroinflammation, steatosis, and hemodynamic changes may significantly interfere with elastography-based techniques, and longitudinal follow-up strategies must be tailored in light of these findings. Knowledge of different test modalities and diagnostic performance indicators can allow for better clinical decision-making and resource allocation.

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.

Acoustic Radiation Force-Induced Creep-Recovery (ARFICR): A Noninvasive Method to Characterize Tissue Viscoelasticity

Ultrasound shear wave elastography is a promising noninvasive, low cost, and clinically viable tool for liver fibrosis staging. Current shear wave imaging technologies on clinical ultrasound scanners ignore shear wave dispersion and use a single group velocity measured over the shear wave bandwidth to estimate tissue elasticity. The center frequency and bandwidth of shear waves induced by acoustic radiation force depend on the ultrasound push beam (push duration, -number, etc.) and the viscoelasticity of the medium, and therefore are different across scanners from different vendors. As a result, scanners from different vendors may give different tissue elasticity measurements within the same patient. Various methods have been proposed to evaluate shear wave dispersion to better estimate tissue viscoelasticity. A rheological model such as the Kelvin-Voigt model is typically fitted to the shear wave dispersion to solve for the elasticity and viscosity of tissue. However, these rheological models impose strong assumptions about frequency dependence of elasticity and viscosity. Here, we propose a new method called Acoustic Radiation Force Induced Creep-Recovery (ARFICR) capable of quantifying rheological model-independent measurements of elasticity and viscosity for more robust tissue health assessment. In ARFICR, the creep-recovery time signal at the focus of the push beam is used to calculate the relative elasticity and viscosity (scaled by an unknown constant) over a wide frequency range. Shear waves generated during the ARFICR measurement are also detected and used to calculate the shear wave velocity at its center frequency, which is then used to calibrate the relative elasticity and viscosity to absolute elasticity and viscosity. In this paper, finite-element method simulations and experiments in tissue mimicking phantoms are used to validate and characterize the extent of viscoelastic quantification of ARFICR. The results suggest that ARFICR can measure tissue viscoelasticity reliably. Moreover, the results showed the strong frequency dependence of viscoelastic parameters in tissue mimicking phantoms and healthy liver.

Improvement of liver stiffness in patients with hepatitis C virus infection who received direct-acting antiviral therapy and achieved sustained virological response

BACKGROUND AND AIM

There is insufficient research on whether direct-acting antiviral (DAA) therapy can improve liver fibrosis in patients with chronic hepatitis C virus (HCV). We evaluated sequential changes in liver stiffness using shear wave elastography in patients with HCV who received DAA therapy.

METHODS

A total of 210 patients with HCV who received daclatasvir and asunaprevir therapy and achieved sustained virological response (SVR) were analyzed. Liver stiffness, as evaluated by shear wave elastography, and laboratory data were assessed before treatment (baseline), at end of treatment (EOT), and at 24 weeks after EOT (SVR24).

RESULTS

Alanine aminotransferase levels (ALT) decreased over time, and there were significant differences between baseline and EOT and between EOT and SVR24. Although platelet counts did not significantly differ between baseline and EOT, they increased significantly from EOT to SVR24. The median (interquartile range) liver stiffness values at baseline, EOT, and SVR24 were 10.2 (7.7-14.7), 8.8 (7.1-12.1), and 7.6 (6.3-10.3) kPa, respectively (P < 0.001, baseline vs EOT; P < 0.001, EOT vs SVR24). Additionally, in patients with ALT ≤ 30 (indicating low necroinflammatory activity in the liver) and Fibrosis-4 index > 2.0 (n = 75), the liver stiffness values at baseline, EOT, and SVR24 were 9.6 (7.7-15.2), 9.2 (7.3-12.1), and 7.7 (6.3-10.1) kPa, respectively (P < 0.001, baseline vs EOT; P < 0.001, EOT vs SVR24).

CONCLUSION

These results suggest that early improvement of liver stiffness starts during the administration of DAAs in patients who achieve SVR, and this effect is particularly pronounced in patients with progressive liver fibrosis.

Establishing ultrasound based transient elastography cutoffs for different stages of hepatic fibrosis and cirrhosis in Egyptian chronic hepatitis C patients

BACKGROUND AND STUDY AIM

Transient elastography is widely used to assess fibrosis stage in chronic hepatitis C (CHC). We aimed to establish and validate different transient elastography cut-off values for significant fibrosis and cirrhosis in CHC genotype 4 patients.

PATIENTS AND METHODS

The data of 100 treatment-naive CHC patients (training set) and 652 patients (validation set) were analysed. The patients were subjected to routine pretreatment laboratory investigations, liver biopsy and histopathological staging of hepatic fibrosis according to the METAVIR scoring system. Transient elastography was performed before and in the same week as liver biopsy using FibroScan (Echosens, Paris, France). Transient elastography results were correlated to different stages of hepatic fibrosis in both the training and validation sets.

RESULTS

ROC curves were constructed. In the training set, the best transient elastography cut-off values for significant hepatic fibrosis (≥F2 METAVIR), advanced hepatic fibrosis (≥F3 METAVIR) and cirrhosis (F4 METAVIR) were 7.1, 9 and 12.2 kPa, with sensitivities of 87%, 87.5% and 90.9% and specificities of 100%, 99.9% and 99.9%, respectively. The application of these cut-offs in the validation set showed sensitivities of 85.5%, 82.8% and 92% and specificities of 86%, 89.4% and 99.01% for significant hepatic fibrosis, advanced hepatic fibrosis and cirrhosis, respectively.

CONCLUSION

Transient elastography performs well for significant hepatic fibrosis, advanced hepatic fibrosis and cirrhosis, with validated cut-offs of 7.1, 9 and 12.2 kPa, respectively, in genotype 4 CHC patients.

Noninvasive Liver Assessment in Adult Patients With Fontan Circulation Using Acoustic Radiation Force Impulse Elastography and Hepatic Magnetic Resonance Imaging

BACKGROUND

Patients who have undergone the Fontan procedure are at risk of developing hepatic dysfunction. However, broad recommendations regarding liver monitoring are limited. The purpose of this study was to characterize the frequency of liver disease in adult Fontan patients using multimodality imaging (hepatic magnetic resonance imaging [MRI], acoustic radiation force impulse [ARFI] elastography, or hepatic ultrasound).

METHODS

In a prospective cross-sectional analysis of adult patients palliated with a Fontan procedure, hepatic MRI, ARFI, and hepatic ultrasound were used to assess for liver disease. The protocol compared (1) varying prevalence of liver disease based on each imaging technique, (2) agreement between different techniques, and (3) association between noninvasive imaging diagnosis of liver disease and clinical variables, including specific liver disease biomarkers.

RESULTS

Thirty-seven patients were enrolled. The ARFI results showed high wave propagation velocity in 35 patients (94.6%). All patients had some abnormality in the hepatic MRI. Specifically, 8 patients (21.6%) showed signs of chronic liver disease, 10 patients (27%) had significant liver fibrosis, and 27 patients (73%) had congestion. No correlation was found between liver stiffness measured as propagation velocity and hepatic MRI findings. Only 7 patients had an abnormal hepatic ultrasound study.

CONCLUSIONS

There is an inherent liver injury in adult Fontan patients. Signs of liver disease were observed in most patients by both hepatic MRI and ARFI elastography but not by ultrasound imaging. Increased liver stiffness did not identify specific disease patterns from MRI, supporting the need for multimodality imaging to characterize liver disease in Fontan patients.

Non-invasive Assessment of Liver Fibrosis with ElastPQ: Comparison with Transient Elastography and Serologic Fibrosis Marker Tests, and Correlation with Liver Pathology Results

We investigated the feasibility of using ultrasound shear wave elastography point quantification (ElastPQ) for liver fibrosis staging and compared it with other non-invasive tools with respect to efficacy in liver stiffness measurement. A total of 106 patients who underwent liver stiffness measurements, using ElastPQ and biochemical investigations, before parenchymal liver biopsy or surgery were included. Among these, 51 also underwent transient elastography (TE). Correlations of ElastPQ, TE and aspartate aminotransferase-to-platelet ratio index (APRI) with histopathological findings (as the reference standard) were determined using Spearman's correlation coefficient. The diagnostic performance of ElastPQ, TE and APRI was evaluated using receiver operating characteristic (ROC) curve analysis. ElastPQ had good diagnostic accuracy in identifying each liver fibrosis stage, with an area under the ROC curve (AUC) of 0.810 to 0.864. Stiffness values obtained using ElastPQ, TE and APRI were significantly positively correlated (r = 0.686, r = 0.732 and r = 0.454, respectively) with histologic fibrosis staging (p < 0.001). According to the AUC for the diagnosis of significant fibrosis (≥F2) and cirrhosis (=F4), ElastPQ had better diagnostic accuracy (AUC = 0.929 and 0.834, respectively) than APRI (AUC = 0.656 and 0.618, respectively) (p < 0.05), and was similar to TE (AUC = 0.915 and 0.879, respectively). ElastPQ is a promising ultrasound-based imaging technique for evaluation of liver fibrosis, with a diagnostic accuracy comparable to that of TE.