Acoustic radiation force impulse of the liver

Fibrosis-4 index stratifies risks of hepatocellular carcinoma in patients with chronic hepatitis C

BACKGROUND AND AIMS

Risk stratification for patients with a higher risk of hepatocellular carcinoma (HCC) is crucial. We aimed to investigate the role of the Fibrosis-4 (FIB-4) index in predicting chronic hepatitis C (CHC)-related HCC.

METHODS

A retrospective cohort study consecutively included treatment-naive CHC patients receiving longitudinal follow-up at the National Taiwan University Hospital from 1986 to 2014. The clinical data were collected and traced for HCC development. Multivariable Cox proportional hazard regression analysis was used to investigate the predictors for HCC.

RESULTS

A total of 1285 patients in the ERADICATE-C cohort were included. The median age was 54, 56% were females, and 933 had HCV viremia. There were 33%, 38%, and 29% of patients having FIB-4 index <1.45, 1.45-3.25, and ≥3.25, respectively. After a median of 9-year follow-up, 186 patients developed HCC. Multivariable analysis revealed that older age, AFP≥20 ng/mL, cirrhosis, and a higher FIB-4 index were independent predictors for HCC. Compared with patients with FIB-4 index <1.45, those with FIB-4 1.45-3.25 had a 5.51-fold risk (95% confidence interval [CI]: 2.65-11.46), and those with FIB-4 ≥ 3.25 had 7.45-fold risk (95% CI: 3.46-16.05) of HCC. In CHC patients without viremia, FIB-4 index 1.45-3.25 and FIB-4 ≥ 3.25 increased 6.78-fold and 16.77-fold risk of HCC, respectively, compared with those with FIB-4 < 1.45.

CONCLUSION

The baseline FIB-4 index can stratify the risks of HCC in untreated CHC patients, even those without viremia. The FIB-4 index should thus be included in the management of CHC.

Assessing the Utility of Acoustic Radiation Force Impulse in the Evaluation of Non-Alcoholic Fatty Liver Disease with Severe Obesity or Steatosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) encompasses a heterogeneous spectrum ranging from simple steatosis to fibrosis and cirrhosis. Fibrosis, associated with long-term overall mortality and liver-related events, requires evaluation. Traditionally, liver biopsy has been the gold standard for diagnosing fibrosis. However, its invasive nature, potential complications, and sampling variability limit widespread use. Consequently, various non-invasive tests have been developed as alternatives for diagnosing fibrosis in NAFLD patients.

AIM

This study aimed to compare the accuracy of non-invasive tests (NITs) and evaluate the diagnostic accuracy of acoustic radiation force impulse (ARFI), one of the point shear wave techniques, compared to conventional methods, assessing its effective role in diagnosis.

METHODS

This is a retrospective study; a total of 136 patients diagnosed with fatty liver disease through ultrasonography were enrolled. The anthropometric data of the patients were collected on the day of admission and blood tests, measurements of ARFI, and a point shear test were conducted using abdominal ultrasound; a biopsy was performed the following day. In addition, we calculated the aspartate aminotransferase-to-platelet ratio index (APRI) index based on four factors (FIB-4) and the NAFLD fibrosis score (NFS). Subsequently, we assessed the diagnostic accuracy of NITs within various subgroups based on the extent of obesity, steatosis, or NAFLD activity score.

RESULTS

ARFI has been shown to have the highest diagnostic value among various NITs, with AUROC values of 0.832, 0.794, 0.767, and 0.696 for ARFI, APRI, FIB-4, and NFS, respectively. In the morbidly obese subgroup, the AUROC values of ARFI, APRI, FIB-4, and NFS were 0.805, 0.769, 0.736, and 0.674. In the group with severe steatosis or non-alcoholic steatohepatitis (NASH), the AUROC values were 0.679, 0.596, 0.661, and 0.612, respectively, for severe steatosis and 0.789, 0.696, 0.751, and 0.691, respectively, for NASH.

CONCLUSIONS

In conclusion, ARFI is not affected by various factors and maintains diagnostic accuracy compared to serum NITs. Therefore, we can recommend ARFI as a valuable diagnostic test to screen for advanced fibrosis in patients with NAFLD.

Comparative evaluation of shear wave elastography elasticity values in thyroid nodules with cytology results and TI-RADS scoring in differentiation of benign-malignant nodules

PURPOSE

The aim of this prospective study was to investigate the diagnostic performance of shear wave elastography (SWE) in differentiating benign and malignant thyroid nodules and their correlation with the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS).

METHODS

This prospective study included 370 thyroid nodules in 308 patients aged 18-70 years. All the patients underwent B-mode ultrasound (US), Doppler examination, and SWE and were given an ACR TI-RADS risk score before fine needle aspiration biopsy (FNAB) and/or surgery. The correlation between SWE parameters and ACR TI-RADS categories was investigated statistically and compared with histopathologic results. Additionally, the diagnostic performance of SWE was evaluated to distinguish malignant and benign thyroid nodules.

RESULTS

One hundred and thirty-five of the 370 thyroid nodules were malignant, and 235 nodules were benign. The mean shear wave velocity (SWV) value of the malignant nodules (3.70 ± 0.98 m/s) was statistically higher than that of the benign nodules (2.70 ± 0.37 m/s). The best cutoff value of the mean SWV for differentiating benign and malignant nodules was found to be 2.94 m/s (sensitivity 90.4%, specificity 89.9%, positive predictive value 81.3%, negative predictive value 94.1%, p < 0.001). The average score of the nodules according to the ACR TI-RADS was 3.57 ± 1.83 in benign nodules and 7.38 ± 2.69 in malignant nodules (p ≤ 0.001).

CONCLUSION

This study showed that combining SWE and TI-RADS improves the specificity of TI-RADS alone in differentiating benign and malignant nodules.

Economic evaluation of non-invasive liver tests for the diagnosis of liver fibrosis in chronic liver diseases: a systematic review protocol

OBJECTIVE

The objective of this review is to determine the costs and benefits of non-invasive liver tests vs liver biopsy in patients with chronic liver diseases.

INTRODUCTION

Hepatic diseases can lead to liver fibrosis, cirrhosis, and hepatocellular carcinoma. In the past, liver biopsy was the only option for diagnosing fibrosis degree. Liver biopsy is an invasive procedure that depends on the sample size to be able to deliver an accurate diagnosis. In recent years, non-invasive liver tests have been increasingly used to estimate liver fibrosis degree; however, there is a lack of economic assessments of technology implementation outcomes.

INCLUSION CRITERIA

This review will include partial (cost studies) and complete economic evaluation studies on hepatitis B, hepatitis C, alcoholic liver disease, and non-alcoholic fatty liver disease that compare non-invasive liver tests with liver biopsies. Studies published in English, French, Spanish, German, Italian, or Portuguese will be included. No date limits will be applied to the search.

METHODS

This review will identify published and unpublished studies. Published studies will be identified using MEDLINE (PubMed), Cochrane Library (CENTRAL), Embase, Web of Science, Scopus, and LILACS. Sources of unpublished studies and gray literature will include sources from health technology assessment agencies, clinical practice guidelines, regulatory approvals, advisories and warnings, and clinical trial registries, as well as Google Scholar. Two independent reviewers will screen and assess studies, and extract and critically appraise the data. Data extracted from the included studies will be analyzed and summarized to address the review objective using narrative text, and the JBI dominance ranking matrix.

REVIEW REGISTRATION

PROSPERO CRD42023404278.

A Comprehensive Review of Liver Allograft Fibrosis and Steatosis: From Cause to Diagnosis

Despite advances in posttransplant care, long-term outcomes for liver transplant recipients remain unchanged. Approximately 25% of recipients will advance to graft cirrhosis and require retransplantation. Graft fibrosis progresses in the context of de novo or recurrent disease. Recurrent hepatitis C virus infection was previously the most important cause of graft failure but is now curable in the majority of patients. However, with an increasing prevalence of obesity and diabetes and nonalcoholic fatty liver disease as the most rapidly increasing indication for liver transplantation, metabolic dysfunction-associated liver injury is anticipated to become an important cause of graft fibrosis alongside alloimmune hepatitis and alcoholic liver disease. To better understand the landscape of the graft fibrosis literature, we summarize the associated epidemiology, cause, potential mechanisms, diagnosis, and complications. We additionally highlight the need for better noninvasive methods to ameliorate the management of graft fibrosis. Some examples include leveraging the microbiome, genetic, and machine learning methods to address these limitations. Overall, graft fibrosis is routinely seen by transplant clinicians, but it requires a better understanding of its underlying biology and contributors that can help inform diagnostic and therapeutic practices.

The relationship between shear wave velocity in transverse carpal ligament and carpal tunnel pressure: A finite element analysis

Elevated carpal tunnel pressure in carpal tunnel syndrome (CTS) patients is one of the major causes of nerve damage but cannot be measured non-invasively. This study proposed to use shear wave velocity (SWV) in the transverse carpal ligament (TCL) to measure the surrounding carpal tunnel pressure. The relationship between the carpal tunnel pressure and the SWV in the TCL was investigated through a subject-specific carpal tunnel finite element model reconstrued by MRI imaging. Parametric analysis was conducted to study the effect of TCL Young's modulus and carpal tunnel pressure on the TCL SWV. The SWV in TCL was found to be strongly dependent on the carpal tunnel pressure and TCL Young's modulus. The calculated SWV ranged from 8.0 m/s to 22.6 m/s under a combination of carpal tunnel pressure (0-200 mmHg) and TCL Young's modulus (1.1-11 MPa). An empirical equation was used to fit the relationship between the SWV in TCL and carpal tunnel pressure, with TCL Young's modulus as a confounding factor. The equation proposed in this study provided an approach to estimate carpal tunnel pressure by measuring the SWV in the TCL for a potential non-invasive diagnosis of CTS and may shed light on the mechanical nerve damage mechanism.

Risk of advanced fibrosis in first-degree relatives of patients with nonalcoholic fatty liver disease

BACKGROUNDA pilot, single-center study showed that first-degree relatives of probands with nonalcoholic fatty liver disease (NAFLD) cirrhosis have a high risk of advanced fibrosis. We aimed to validate these findings using 2 independent cohorts from the US and Europe.METHODSThis prospective study included probands with NAFLD with advanced fibrosis, NAFLD without advanced fibrosis, and non-NAFLD, with at least 1 first-degree relative. A total of 396 first-degree relatives - 220 in a derivation cohort and 176 in a validation cohort - were enrolled in the study, and liver fibrosis was evaluated using magnetic resonance elastography and other noninvasive imaging modalities. The primary outcome was prevalence of advanced fibrosis in first-degree relatives.RESULTSPrevalence of advanced fibrosis in first-degree relatives of probands with NAFLD with advanced fibrosis, NAFLD without advanced fibrosis, and non-NAFLD was 15.6%, 5.9%, and 1.3%, respectively (P = 0.002), in the derivation cohort, and 14.0%, 2.6%, and 1.3%, respectively (P = 0.004), in the validation cohort. In multivariable-adjusted logistic regression models, age of ≥50 years (adjusted OR [aOR]: 2.63, 95% CI 1.0-6.7), male sex (aOR: 3.79, 95% CI 1.6-9.2), diabetes mellitus (aOR: 3.37, 95% CI 1.3-9), and a first-degree relative with NAFLD with advanced fibrosis (aOR: 11.8, 95% CI 2.5-57) were significant predictors of presence of advanced fibrosis (all P < 0.05).CONCLUSIONFirst-degree relatives of probands with NAFLD with advanced fibrosis have significantly increased risk of advanced fibrosis. Routine screening should be done in the first-degree relatives of patients with advanced fibrosis.FUNDINGSupported by NCATS (5UL1TR001442), NIDDK (U01DK061734, U01DK130190, R01DK106419, R01DK121378, R01DK124318, P30DK120515, K23DK119460), NHLBI (P01HL147835), and NIAAA (U01AA029019); Academy of Finland grant 309263; the Novo Nordisk, EVO, and Sigrid Jusélius Foundations; and the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement 777377. This Joint Undertaking receives support from the European Union's Horizon 2020 research and innovation program and the EFPIA.

Point shear wave velocity(pSWV) evaluation of the placenta of pregnant women who had recovered from COVID-19: A prospective cohort study from a tertiary pandemic center

Introduction

To assess the placental elasticity using point shear wave velocity (pSWV) in pregnant women who had recovered from coronavirus COVID-19.

Methods

A total of 40 pregnant women who had recovered from moderate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and 40 healthy pregnant women were included in this study. We evaluated placental elasticity by using transabdominal pSWV method. Three measurements were made, and their average was accepted as the mean placental velocity value in each case. The results were compared between the post-COVID-19 and control groups.

Results

The mean pSWV values were significantly higher in the post-COVID-19 group compared to the control group, indicating that the women with a history of COVID-19 had stiffer placentas. Furthermore, the pSWV values were significantly and positively correlated with the uterine artery pulsatility index. We also found that the NICU requirement was statistically higher in the post-COVID 19 group.

Discussion

The pregnant women who had recovered from COVID-19 had rigid placentas than the healthy controls. The use of pSWV for the assessment of placental velocity may provide valuable information in the diagnosis and management of post-COVID-19 patients as a complementary tool to the existing ultrasonography methods.

Clinical Model for the Prediction of Severe Liver Fibrosis in Adult Patients with Type II Diabetes Mellitus

Background and Objectives: Non-alcoholic fatty liver disease (NAFLD)-related severe liver fibrosis is associated with a higher risk of progressing to decompensated cirrhosis and hepatic failure and developing NAFLD-related hepatocellular carcinoma (HCC), particularly in populations with diabetes. Our pilot study aims to evaluate the performances of various noninvasive methods in predicting liver fibrosis in a population of patients with diabetes and to establish a new scoring system for the prediction of severe fibrosis (>F3). Materials and Methods: A total of 175 patients with diabetes were enrolled for liver fibrosis evaluation. Using the degree of agreement (concordance) between a noninvasive score based on serum biomarkers (NAFLD fibrosis score) and point shear-wave elastography (pSWE) as the reference method, we generated receiver operating characteristic (ROC) curves and performed a multivariate analysis to predict severe liver fibrosis. Results: In our population of patients with diabetes, gamma-glutamyltransferase (GGT), age, body mass index (BMI), the homeostatic model assessment of insulin resistance (HOMA-IR), and glycosylated hemoglobin (HbA1C) were significant predictors for the diagnosis of the F3/F4 group (area under the ROC: 0.767, 0.743, 0.757, 0.772, and 0.7, respectively; p < 0.005 for all). Moreover, the combined composite score (the sum of GGT, age, BMI, HOMA index, and HbA1C) had the highest diagnostic performance at a cut-off value of 3 (AUROC—0.899; p < 0001). The sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 91.20%, 79%, 79%, and 89%, respectively, and 89% of patients were correctly classified as having severe liver fibrosis. In contrast with the Fibrosis 4 (FIB-4) score and the AST-to-platelet ratio index (APRI), the composite score had the best accuracy in discriminating advanced fibrosis. Conclusions: The proposed composite score had a reliable and acceptable diagnostic accuracy in identifying patients with diabetes at risk of having severe fibrosis using readily available laboratory and clinical data.

ARFI elastography of the omentum: feasibility and diagnostic performance in differentiating benign from malignant omental masses

Objective

To evaluate the feasibility and diagnostic performance of acoustic radiation force impulse (ARFI) elastography in different omental masses (OM).

Design

This was a retrospective analysis of 106 patients with OM defined as omental thickness ≥1 cm, who underwent abdominal B-mode ultrasound (US) and standardised ARFI examinations of the OM between September 2018 and June 2021 at our university hospital. A cytohistological confirmation was available in 91/106 (85.8%) of all OM, including all 65/65 (100%) malignant OM (mOM) and 26/41 (63.4%) of benign OM (bOM). In 15/41 (36.6%) of bOM; cross-sectional imaging and or US follow-up with a mean duration of 19.8±3.1 months was performed. To examine the mean ARFI velocities (MAV) for potential cut-off values between bOM and mOM a receiver operating characteristic analysis was implemented.

Results

The MAV in the mOM group (2.71±1.04 m/s) was significantly higher than that of bOM group (1.27±0.87 m/s) (p<0.001). Using 1.97 m/s as a cut-off yielded a sensitivity and specificity of 76.9% and 85.4%, respectively, in diagnosing mOM (area under the curve=0.851, 95% CI=0.774 to 0.928).

Conclusion

ARFI elastography is feasible in the omentum and may represent a good non-invasive additional tool in differentiating bOM from mOM.

Diagnostic Performance of Point Shear Wave Elastography Using Acoustic Radiation Force Impulse Technology in Peripheral Pulmonary Consolidations: A Feasibility Study

The aim of the study described here was to evaluate the diagnostic performance of lung ultrasound point shear wave elastography using acoustic radiation force impulse (ARFI) in peripheral pulmonary consolidations (PPCs). A total of 87 patients with PPCs diagnosed from April to December 2020 were included retrospectively in the study. The inclusion criteria were (i) a PPC >1 cm; (ii) valid ARFI measurements; and (iii) confirmation of the diagnosis of a PPC by histocytological examination and/or clinical and radiological follow-up. The presence of pleural effusions and mean ARFI velocities (MAVs) of PPCs were evaluated. To examine the MAV for potential cutoff values between benign and malignant PPCs, a receiver operating characteristic analysis was implemented. In total, 48 of 87 PPCs (55.2%) were accompanied by pleural effusions. Benign PPCs had significantly lower MAVs than malignant PPCs (1.82 ± 0.97 m/s vs. 3.05 ± 0.73 m/s, p < 0.001). Selecting 2.21 m/s as a cutoff value yielded a sensitivity and specificity of 89.7% and 75.9%, respectively, in diagnosing malignant PPCs (area under the curve = 0.852, 95% confidence interval: 0.773-0.931). In summary, ARFI elastography may be an additional non-invasive tool for differentiating benign from malignant PPCs. Furthermore, the feasibility of using ARFI elastography in PPCs associated with pleural effusions was proved. However, there is some degree of overlap between different disease entities, and diagnosis should always take into account the clinical background.

Diagnostic Performance of Point Shear Wave Elastography (pSWE) Using Acoustic Radiation Force Impulse (ARFI) Technology in Mesenteric Masses: A Feasibility Study

Purpose: To evaluate the diagnostic performance of ultrasound point shear wave elastography (pSWE) using acoustic radiation force impulse (ARFI) technology in different benign and malignant mesenteric masses (MMs). Methods: A total of 69 patients with MMs diagnosed from September 2018 to November 2021 were included retrospectively in the study. The inclusion criteria were (1) an MM over 1 cm; (2) valid ARFI measurements; and (3) confirmation of the diagnosis of an MM by histological examination and/or clinical and radiological follow-up. To examine the mean ARFI velocities (MAVs) for potential cut-off values between benign and malignant MMs, a receiver operating characteristics analysis was implemented. Results: In total, 37/69 of the MMs were benign (53.6%) and 32/69 malignant (46.4%). Benign MMs demonstrated significantly lower MAVs than mMMs (1.59 ± 0.93 vs. 2.76 ± 1.01 m/s; p < 0.001). Selecting 2.05 m/s as a cut-off value yielded a sensitivity and specificity of 75.0% and 70.3%, respectively, in diagnosing malignant MMs (area under the curve = 0.802, 95% confidence interval 0.699–0.904). Conclusion: ARFI elastography may represent an additional non-invasive tool for differentiating benign from malignant MMs. However, to validate the results of this study, further prospective randomized studies are required.

Role of Noninvasive Tests in Clinical Gastroenterology Practices to Identify Patients With Nonalcoholic Steatohepatitis at High Risk of Adverse Outcomes: Expert Panel Recommendations

Nonalcoholic fatty liver disease (NAFLD) is generally considered a silent and potentially reversible condition. The subtype of NAFLD that can be classified as nonalcoholic steatohepatitis (NASH) can progress to advanced fibrosis and cirrhosis. Because of the metabolic nature of the pathogenic mechanism underlying NAFLD and NASH, it is often accompanied by common comorbidities such as obesity, insulin resistance, and type 2 diabetes mellitus. The increase in the prevalence of these comorbidities has resulted in a parallel increase in the prevalence of NAFLD and NASH, globally, nationally, and even in children. In recent years, it has been identified that the stage of fibrosis is the most important predictor of liver outcomes; therefore, identifying patients with NAFLD and NASH with more advanced stages of fibrosis can be essential for optimal management. Several noninvasive tools for diagnosing and staging NAFLD and NASH are available, but simple and straightforward recommendations on the use of these tools are not. Recognizing these unmet needs, hepatologists who are members of the American College of Gastroenterology and the Chronic Liver Disease Foundation created a practical decision tree/algorithm to risk stratify NAFLD/NASH as a resource in gastroenterology/hepatology clinical practices. This review will provide insight into how this algorithm was developed, describe it in detail, and provide recommendations for its use in clinical practice.

Clinical assessment and management of liver fibrosis in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is among the most frequent etiologies of cirrhosis worldwide, and it is associated with features of metabolic syndrome; the key factor influencing its prognosis is the progression of liver fibrosis. This review aimed to propose a practical and stepwise approach to the evaluation and management of liver fibrosis in patients with NAFLD, analyzing the currently available literature. In the assessment of NAFLD patients, it is important to identify clinical, genetic, and environmental determinants of fibrosis development and its progression. To properly detect fibrosis, it is important to take into account the available methods and their supporting scientific evidence to guide the approach and the sequential selection of the best available biochemical scores, followed by a complementary imaging study (transient elastography, magnetic resonance elastography or acoustic radiation force impulse) and finally a liver biopsy, when needed. To help with the selection of the most appropriate method a Fagan′s nomogram analysis is provided in this review, describing the diagnostic yield of each method and their post-test probability of detecting liver fibrosis. Finally, treatment should always include diet and exercise, as well as controlling the components of the metabolic syndrome, +/- vitamin E, considering the presence of sleep apnea, and when available, allocate those patients with advanced fibrosis or high risk of progression into clinical trials. The final end of this approach should be to establish an opportune diagnosis and treatment of liver fibrosis in patients with NAFLD, aiming to decrease/stop its progression and improve their prognosis.

The diagnostic accuracy of liver fibrosis in non-viral liver diseases using acoustic radiation force impulse elastography: A systematic review and meta-analysis

BACKGROUND

Acoustic radiation force impulse (ARFI) imaging is an ultrasound-based elastography method that has been studied in the staging of hepatic fibrosis, especially in chronic hepatitis. However, the diagnostic accuracy of ARFI in non-viral hepatopathies, such as autoimmune hepatitis and non-alcoholic fatty liver disease, has not been systematically determined.

AIM

To systematically assess the diagnostic accuracy of ARFI in non-viral hepatopathies.

METHODS

The databases of PubMed, Embase, Cochrane Library and clinicaltrials.gov were systematically searched for candidate studies reporting the diagnostic accuracy of ARFI for hepatic fibrosis. The pooled estimates of the sensitivity, specificity, diagnostic odds ratio, and positive and negative likelihood ratios were calculated with the summary receiver operating curve (sROC) performed using STATA software.

RESULTS

In detail, a total of 29 diagnostic studies were included for further analysis. The quality of the included studies was relatively high using QUADAS method. The pooled sensitivity and specificity were 0.79 (0.73, 0.83) and 0.81 (0.75, 0.86), with AUROC 0.87 (0.83, 0.89) for the staging of significant fibrosis (F≥2). Meanwhile, for the staging of severe fibrosis (F≥3), the pooled sensitivity and specificity were 0.92 (0.87, 0.95) and 0.85 (0.80, 0.89), with AUROC 0.94 (0.92, 0.96). Furthermore, the pooled sensitivity and specificity were 0.89 (0.79, 0.95) and 0.89 (0.85, 0.92), with AUROC 0.94 (0.92, 0.96) for ARFI in staging cirrhosis (F = 4), which were similar to the data for severe fibrosis. No significant publication bias was present in this study.

CONCLUSION

This meta-analysis demonstrated that ARFI exerted satisfactory diagnostic performance in staging non-viral hepatic fibrosis, especially severe fibrosis (F≥3) and cirrhosis (F = 4).

Application of acoustic radiation force impulse elastography combined with serum markers in Child-Pugh grading

OBJECTIVES

Acoustic radiation force impulse (ARFI) elastography, the aspartate aminotransferase-to-alanine aminotransferase ratio (AAR), aspartate aminotransferase-to-platelet ratio index (APRI), and the fibrosis-4 (FIB-4) index are widely used to assess liver fibrosis. However, efficacies of these methods in the evaluation of hepatic functional reserve remain unclear. In this study, we investigated the relationship between ARFI elastography combined with either AAR, APRI, or FIB-4 index and Child-Pugh (CP) class for the evaluation of hepatic functional reserve in patients with chronic hepatitis B (CHB)-related cirrhosis.

METHODS

The shear wave velocities of 104 patients with clinically confirmed CHB-related cirrhosis were determined using the ARFI; and clinical serum markers (e.g. ALT, AST, PLT) were used to calculate the AAR, APRI, and FIB-4 index. Cirrhosis patients were scored according to their CP class. The ARFI, AAR, APRI, and FIB-4 index were compared with the CP class. The efficacy of each indicator in diagnosis was analyzed using the receiver operating characteristic (ROC) curve and the ARFI combined with either the AAR, APRI, or FIB-4 index, which is used to predict decompensated cirrhosis.

RESULTS

No significant differences were observed in gender and age among CP classes A, B, and C patients (p>0.05). The ARFI values and the AAR, APRI, and FIB-4 index of patients with CP classes A, B, and C were significantly different (p<0.05). With an increasing CP class, the ARFI, AAR, APRI, and FIB-4 values increased. The correlation between the ARFI and the CP class was stronger than that between the AAR, APRI, and FIB-4 index and the CP class. The area under the ROC curve for the diagnosis of decompensated cirrhosis using the ARFI was 0.841, which was higher than that for the AAR, APRI, and FIB-4 index. According to the area under the curve results, no significant differences were found when the ARFI was combined with either the AAR, APRI, or FIB-4 index and when the ARFI alone was used.

CONCLUSIONS

The ARFI value has a strong correlation with the CP class. Therefore, ARFI elastography complements CP class in the assessment of the hepatic functional reserve in patients with CHB-related cirrhosis.

The clinical usefulness of elastography in the evaluation of nonalcoholic fatty liver disease patients: A biopsy-controlled study

BACKGROUND

We aimed at determination of the usefulness of elastography [acoustic radiation force impulse (ARFI) and FibroScan] for evaluation of nonalcoholic fatty liver disease (NAFLD) patients.

PATIENTS AND METHODS

A prospective cross-sectional study included 60 biopsy-proven NAFLD patients (mean age: 45 years) was carried out. All patients were subjected to lab works, liver biopsy, and measurement of liver stiffness by ARFI and FibroScan and steatosis by controlled attenuation parameter (CAP). CAP measurements were adjusted for the presence of NAFLD and presence or absence of diabetes and according to BMI.

RESULTS

Linear regression analysis showed that CAP is an independent predictor for significant hepatic steatosis (P<0.001). No significant difference was found in diagnostic accuracy between adjusted and nonadjusted CAP values for diagnosis of mild (>S1) or significant (>S2) hepatic steatosis (P=0.17 and 0.29 respectively). The median ARFI velocities for F1, F2, F3, and F4 were 0.92, 1.08, 1.07, and 2.58 m/s, respectively. Although there was an overall significant increase in ARFI values across the fibrosis grades (P<0.04), the difference in ARFI values was only significant between fibrosis grades F1 and F4 (P=0.02).

CONCLUSION

Elastography is a promising noninvasive tool for diagnosis and grading of hepatic steatosis and fibrosis in patients with NAFLD/nonalcoholic steatohepatitis with good sensitivity and specificity, especially in moderate to marked grades.

Pediatric Fontan Associated Liver Disease: Non-invasive Evaluation with Serologic Markers and Acoustic Radiation Force Impulse (ARFI) Elastography

Hepatic fibrosis is a significant complication in adult Fontan patients suggesting development as a function of time since the surgery. Children with Fontan circulation are not routinely assessed for development of liver disease. We aimed to evaluate the effectiveness of serologic biomarkers and acoustic radiation force impulse (ARFI) elastography to detect liver disease in pediatric Fontan patients. Patients ≥ 1 year after Fontan operation prospectively had hepatic US with acoustic radiation force impulse and laboratory testing. Clinical cardiac data (echocardiograms, cardiac catheterizations) were reviewed. Statistical analysis was performed using Pearson's correlation coefficient, Wilcoxon rank-sum test and Kruskal-Wallis test. Forty patients were enrolled with median age of 11 years and median time since Fontan of 6.5 years. Platelet count negatively correlated with years since Fontan (p < 0.000). Thrombocytopenia was noted in 15% of patients with the lowest platelet count of 78 K/cu mm, in a patient >10 years from the Fontan (DORV) operation. Alanine transaminase (ALT, p = 0.034) and aspartate aminotransferase (AST, p = 0.009) were higher in patients with Extracardiac Conduit Fontan and not in other Fontan operations. Heterogeneous echotexture on liver ultrasound correlated with years since Fontan (p = 0.022), however all acoustic radiation force impulse values were elevated (> 1.34 m/s) and did not correlate with age, years since Fontan, labs or imaging. FibroSure values did not correlate with years since Fontan. This suggests that ARFI may be elevated due to passive hepatic congestion, limiting its value in this patient population. Additional testing is necessary to identify reliable noninvasive screening modalities for hepatic fibrosis in Fontan patients. Our study is the largest pediatric study to evaluate ARFI in patients after the Fontan operation and showed increased shear wave speed for all patients with no correlation with time since palliation. Decreasing platelet count may indicate the development of liver fibrosis.

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.

Magnetic resonance elastography: basic principles, technique, and clinical applications in the liver

Magnetic resonance elastography (MRE) is a constantly advancing technique for assessment of stiffness of tissues with newer technology and sequences. It is being increasingly used for the assessment of liver fibrosis. In this article, we discuss the advantages of MRE over biopsy and noninvasive methods such as US elastography in the assessment of liver fibrosis. Image acquisition and interpretation of liver MRE is also discussed.

The role of imaging in prediction of post-hepatectomy liver failure

Post-hepatectomy liver failure (PHLF) is not only a leading cause of mortality but also a leading cause of life-threatening complications in patients undergoing liver resection. The ability to accurately detect the emergence of PHLF represents a crucially important step. Currently, PHLF can be predicted by a comprehensive evaluation of biological, clinical, and anatomical parameters. With the development of new technologies, imaging methods including elastography, diffusion-weighted magnetic resonance imaging, and gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid-enhanced MRI play a more significant role in the pre-operative prediction and assessment of PHLF. In this review, we summarize the mainstream studies, with the aim of evaluating the role of imaging and improving the clinical value of existing scoring systems for predicting PHLF.

Non-invasive assessments for liver fibrosis: The crystal ball we long for

Non-invasive assessment of liver fibrosis has been one of the most rapidly advancing fields in hepatology in the last decade. Progressive liver fibrosis results in cirrhosis, hepatocellular carcinoma (HCC), and various liver-related complications in essentially all chronic liver diseases. Assessment of liver fibrosis allows clinicians to determine the prognosis, need of treatment, disease progression, and response to treatment in patients with chronic liver disease. Liver biopsy has been the gold standard in last few decades and most adopted diagnostic tool in clinical trials. Nonetheless, it is impractical to apply the test in a large number of patients or to do it serially. Hence, various non-invasive assessments have been developed and adopted in some international management guidelines. Liver stiffness measurement (LSM) with transient elastography is one of the most widely validated non-invasive assessments for liver fibrosis. It is an accurate and reproducible method to predict advanced fibrosis in chronic hepatitis B. Using transient elastography, it is possible to perform repeated liver fibrosis assessments on a large number of asymptomatic patients. The key challenge of his tool is the confounding effect of alanine aminotransferase (ALT) level, such that decrease in LSM may only reflect ALT normalization, hence not accurate enough to indicate regression of liver fibrosis. This may be partially handled by combining LSM with a serum-based formula, which is independent of ALT such as the Forns index and enhanced liver fibrosis test. An LSM-based HCC risk score is useful to prioritize patients for HCC surveillance.

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.

Perioperative liver and spleen elastography in patients without chronic liver disease

AIM

To investigate changes in hepatic and splenic stiffness in patients without chronic liver disease during liver resection for hepatic tumors.

METHODS

Patients scheduled for liver resection for hepatic tumors were considered for enrollment. Tissue stiffness measurements on liver and spleen were conducted before and two days after liver resection using point shear-wave elastography. Histological analysis of the resected liver specimen was conducted in all patients and patients with marked liver fibrosis were excluded from further study analysis. Patients were divided into groups depending on size of resection and whether they had received preoperative chemotherapy or not. The relation between tissue stiffness and postoperative biochemistry was investigated.

RESULTS

Results are presented as median (interquartile range). 35 patients were included. The liver stiffness increased in patients undergoing a major resection from 1.41 (1.24-1.63) m/s to 2.20 (1.72-2.44) m/s (P = 0.001). No change in liver stiffness in patients undergoing a minor resection was found [1.31 (1.15-1.52) m/s vs 1.37 (1.12-1.77) m/s, P = 0.438]. A major resection resulted in a 16% (7%-33%) increase in spleen stiffness, more (P = 0.047) than after a minor resection [2 (-1-13) %]. Patients who underwent preoperative chemotherapy (n = 20) did not differ from others in preoperative right liver lobe [1.31 (1.16-1.50) vs 1.38 (1.12-1.56) m/s, P = 0.569] or spleen [2.79 (2.33-3.11) vs 2.71 (2.37-2.86) m/s, P = 0.515] stiffness. Remnant liver stiffness on the second postoperative day did not show strong correlations with maximum postoperative increase in bilirubin (R² = 0.154, Pearson’s r = 0.392, P = 0.032) and international normalized ratio (R² = 0.285, Pearson’s r = 0.534, P = 0.003).

CONCLUSION

Liver and spleen stiffness increase after a major liver resection for hepatic tumors in patients without chronic liver disease.

Measurement of Liver Stiffness Using Shear Wave Elastography in a Rat Model: Factors Impacting Stiffness Measurement with Multiple- and Single-Tracking-Location Techniques

The clinical use of elastography for monitoring fibrosis progression is challenged by the subtle changes in liver stiffness associated with early-stage fibrosis and the comparatively large variance in stiffness estimates provided by elastography. Single-tracking-location (STL) shear wave elasticity imaging (SWEI) is an ultrasound elastography technique previously found to provide improved estimate precision compared with multiple-tracking-location (MTL) SWEI. Because of the improved precision, it is reasonable to expect that STL-SWEI would provide improved ability to differentiate liver fibrosis stage compared with MTL-SWEI. However, this expectation has not been previously challenged rigorously. In this work, the performance of STL- and MTL-SWEI in the setting of a rat model of liver fibrosis is characterized, and the advantages of STL-SWEI in staging fibrosis are explored. The purpose of this study was to determine what advantages, if any, arise from using STL-SWEI instead of MTL-SWEI in the characterization of fibrotic liver. Thus, the ability of STL-SWEI to differentiate livers at various METAVIR fibrosis scores, for ex vivo postmortem measurements, is explored. In addition, we examined the effect of the common confounding factor of fluid versus solid boundary conditions in SWEI experiments. Sprague-Dawley rats were treated with carbon tetrachloride over several weeks to produce liver disease of varying severity. STL and MTL stiffness measurements were performed ex vivo and compared with the METAVIR scores from histological analysis and the duration of treatment. A strong association was observed between liver stiffness and weeks of treatment with the liver toxin carbon tetrachloride. Direct comparison of STL- and MTL-SWEI measurements revealed no significant difference in ability to differentiate fibrosis stages based on SWEI mean values. However, image interquartile range was greatly improved in the case of STL-SWEI, compared with MTL-SWEI, at small beam spacing.

Point shear wave ultrasound elastography with Esaote compared to real-time 2D shear wave elastography with supersonic imagine for the quantification of liver stiffness

PURPOSE

Different shear wave elastography (SWE) machines able to quantify liver stiffness (LS) have been recently introduced by various companies. The aim of this study was to investigate the agreement between point SWE with Esaote MyLab Twice (pSWE.ESA) and 2D SWE with Aixplorer SuperSonic (2D SWE.SSI). Moreover, we assessed the correlation of these machines with Fibroscan in a subgroup of patients.

METHODS

A total of 81 liver disease patients and 27 subjects without liver disease accessing the ultrasound lab were considered. Exclusion criteria were liver nodules, BMI >35, and severe comorbidities. LS was sampled from the same intercostal space with both pSWE.ESA and 2D SWE.SSI and values were tested with Lin's analysis and Bland-Altman analysis (B&A). Agreement between each SWE machine and Fibroscan was assessed in 26 liver disease patients with Spearman correlation.

RESULTS

Precision and accuracy between pSWE.ESA and 2D SWE.SSI were, respectively, 0.839 and 0.999. B&A showed a mean of only -0.2 kPa, with no systematic deviation between the techniques and limits of agreement at -11.6 and 11.3 kPa. Spearman's rho correlation versus Fibroscan was 0.849 for pSWE.ESA and 0.878 for 2D SWE.SSI. The relationship became less strict in the higher range of LS (≥15.2 kPa), corresponding to cirrhosis.

CONCLUSION

The overall degree of concordance of pSWE.ESA and 2D SWE.SSI in measuring LS resulted remarkable, also when compared with Fibroscan. The less strict correlation for patients with LS in the higher range would not affect the staging of disease as such patients are anyhow classified as cirrhotic.

Application of Ultrasound Elastography for Chronic Allograft Dysfunction in Kidney Transplantation

Interstitial fibrosis is the main characteristic of chronic allograft dysfunction, which remains the key factor affecting long-term allograft survival after kidney transplantation. Ultrasound elastography (UE), including real-time elastography, transient elastography, and acoustic radiation force impulse, has been applied widely in breast, thyroid, and liver diseases, especially in the assessment of liver fibrosis. Recently, numerous studies have reported the efficacy of UE methods in evaluating renal allograft fibrosis. This review aims to investigate the clinical applications, limitations, and future roles of UE in current clinical practice in light of changing management paradigms. In current clinical practice, UE methods, especially transient elastographic measurement, appear to be useful for ruling out fibrosis but do not have sufficient accuracy to distinguish between various stages of allograft fibrosis. Moreover, there remain considerable issues to be solved for the application of UE in kidney transplantation. Thus, UE methods cannot replace the crucial role of renal allograft biopsy in the diagnosis and evaluation of allograft fibrosis in kidney transplantation. Perhaps UE methods could be of more importance in the long-term observation and evaluation of allograft fibrosis during follow-up.

A pilot study of ultrasound elastography as a non-invasive method to monitor liver disease in children with short bowel syndrome

BACKGROUND

Our objective was to evaluate the accuracy of acoustic radiation force impulse (ARFI) elastography in determining extent of liver fibrosis in pediatric patients with short bowel syndrome (SBS).

METHODS

This prospective cohort study included pediatric patients with SBS who underwent ultrasound with ARFI measurements of shear wave speed (SWS) and liver biopsy within 30days of each other between 12/2014-9/2015. The mean and median SWS were compared to the stage of fibrosis. Receiver operating characteristic curves (ROC) were also generated to assess the classification accuracy of SWS measurements for mild (F0-F1) versus moderate/severe fibrosis (F2-F4).

RESULTS

Twelve patients were included with median age 1.4years and median weight 11.3kg. The median direct bilirubin level was 0.3mg/dL at the time of biopsy. On liver biopsy, 6 patients had mild fibrosis (F1), 3 had septal fibrosis (F3), and 3 had cirrhosis (F4). The area under the ROC curve for elastography to differentiate moderate/severe liver fibrosis from mild disease was 0.83 (95CI 0.58-1.00) and 0.86 (95CI 0.63-1.00) for the median SWS and mean SWS, respectively.

CONCLUSIONS

These early results suggest that ARFI ultrasound elastography may be a reliable non-invasive method to monitor liver fibrosis in pediatric patients with SBS.

TYPE OF STUDY

Prospective observational cohort.

LEVEL OF EVIDENCE

3.

Sonoelastography in the musculoskeletal system: Current role and future directions

Ultrasound is an essential modality within musculoskeletal imaging, with the recent addition of elastography. The elastic properties of tissues are different from the acoustic impedance used to create B mode imaging and the flow properties used within Doppler imaging, hence elastography provides a different form of tissue assessment. The current role of ultrasound elastography in the musculoskeletal system will be reviewed, in particular with reference to muscles, tendons, ligaments, joints and soft tissue tumours. The different ultrasound elastography methods currently available will be described, in particular strain elastography and shear wave elastography. Future directions of ultrasound elastography in the musculoskeletal system will also be discussed.

Acoustic Radiation Force Impulse Imaging for the Differentiation of Benign and Malignant Lymph Nodes: A Systematic Review and Meta-Analysis

Objective

To evaluate the overall performance of acoustic radiation force impulse imaging (ARFI) in differentiating between benign and malignant lymph nodes (LNs) by conducting a meta-analysis.

Methods

PubMed, Embase, Web of Science, the Cochrane Library and the China National Knowledge Infrastructure were comprehensively searched for potential studies through August 13th, 2016. Studies that investigated the diagnostic power of ARFI for the differential diagnosis of benign and malignant LNs by using virtual touch tissue quantification (VTQ) or virtual touch tissue imaging quantification (VTIQ) were collected. The included articles were published in English or Chinese. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used to evaluate the methodological quality. The pooled sensitivity, specificity, and the area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated by means of a bivariate mixed-effects regression model. Meta-regression analysis was performed to identify the potential sources of between study heterogeneity. Fagan plot analysis was used to explore the clinical utilities. Publication bias was assessed using Deek’s funnel plot.

Results

Nine studies involving 1084 LNs from 929 patients were identified to analyze in the meta-analysis. The summary sensitivity and specificity of ARFI in detecting malignant LNs were 0.87 (95% confidence interval [CI], 0.83–0.91) and 0.88 (95% CI, 0.82–0.92), respectively. The AUC was 0.93 (95% CI, 0.90–0.95). The pooled DOR was 49.59 (95% CI, 26.11–94.15). Deek’s funnel plot revealed no significant publication bias.

Conclusion

ARFI is a promising tool for the differentiation of benign and malignant LNs with high sensitivity and specificity.

Application of DTI and ARFI imaging in differential diagnosis of parotid tumours

OBJECTIVES

To explore the utility of diffusion tensor imaging (DTI) and acoustic radiation force impulse (ARFI) imaging in the diagnosis of parotid tumours.

METHODS

51 patients with parotid tumours were examined with DTI on 3.0-T MRI and ARFI imaging on an ultrasound scanner before surgery. Values of apparent diffusion coefficient (ADC), fractional anisotropy (FA) and shear-wave velocity (SWV) were calculated and analyzed with independent samples Wilcoxon-Mann-Whitney test. Cut-off values, sensitivity and specificity were calculated with receiver-operating characteristic (ROC) curve analysis. The value of combination was calculated through parallel test for the cut-off value of ADC, FA and SWV (combination = 0 or 1); then, ROC analysis was performed with pathological results as the gold standard to calculate the sensitivity and specificity for the combination of the three parameters distinguishing benign and malignant parotid tumours. Pathological diagnosis for every patient was made post-operatively from the tumour tissue taken during operation.

RESULTS

There was a significant difference between benign and malignant tumours in the values of ADC, FA and SWV (p = 0.032, p = 0.011 and p < 0.0001); a significant difference in the values was also found between pleomorphic adenoma and malignant tumour (p = 0.0012, p < 0.0001 and p = 0.0002). The diagnosis cut-off points between benign and malignant tumours for ADC, FA and SWV were 1.02 × 10(-3) mm(2) s(-1), 0.24 and 2.76 m s(-1), respectively; the sensitivity for ADC, FA and SWV was 87.50, 62.50 and 68.75%; the specificity was 45.71, 82.86 and 97.14%. Analysis of the combination of the three parameters increased the sensitivity, specificity, Youden index and area under the ROC curve compared with analysis of each parameter alone for distinguishing benign and malignant tumours.

CONCLUSIONS

The diagnostic value of the combination of the three parameters for distinguishing benign and malignant parotid tumours is the best; SWV is the preferred indicator. Parameters of DTI and ARFI may reflect the histological characteristics of parotid tumours and predict benignancy and malignancy and could provide quantitative information about the tumour. Combination of DTI with ARFI imaging had obvious advantage for the diagnosis of parotid tumours than each alone.

Non-invasive assessment of liver fibrosis and prognosis

Over the past decade, several advances have been made in the non-invasive assessment of liver fibrosis. Both serum markers and imaging-based tissue elastography predict the presence of advanced fibrosis compared with liver biopsy. Serum markers may be indirect or direct markers of liver structure and function. Imaging-based techniques measure liver stiffness as a surrogate for fibrosis and include ultrasound and MRI-based methods. Most non-invasive techniques work well at identifying subjects at the extremes of fibrosis but may not accurately discern intermediate stages. In addition to being a diagnostic tool, elastography may have an evolving role in prognosis. Increasing stiffness is associated with higher rates of liver decompensation, need for transplantation, hepatocellular carcinoma, and death. There are special populations of patients where elastography may serve as a non-invasive method to impart useful clinical information, such as patients after liver transplantation, those with congenital heart disease and those being treated for chronic viral hepatitis. The role of non-invasive markers in accurately predicting the presence of fibrosis in obese patients needs to be further refined.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Combined acoustic radiation force impulse, aminotransferase to platelet ratio index and Forns index assessment for hepatic fibrosis grading in hepatitis B

AIM: To investigate the combined diagnostic accuracy of acoustic radiation force impulse (ARFI), aspartate aminotransferase to platelet ratio index (APRI) and Forns index for a non-invasive assessment of liver fibrosis in patients with chronic hepatitis B (CHB).

METHODS: In this prospective study, 206 patients had CHB with liver fibrosis stages F0-F4 classified by METAVIR and 40 were healthy volunteers were measured by ARFI, APRI and Forns index separately or combined as indicated.

RESULTS: ARFI, APRI or Forns index demonstrated a significant correlation with the histological stage (all P < 0.001). According to the AUROC of ARFI and APRI for evaluating fibrotic stages more than F2, ARFI showed an enhanced diagnostic accuracy than APRI (P < 0.05). The combined measurement of ARFI and APRI exhibited better accuracy than ARFI alone when evaluating ≥ F2 fibrotic stage (Z = 2.77, P = 0.006). Combination of ARFI, APRI and Forns index did not obviously improve the diagnostic accuracy compared to the combination of ARFI and APRI (Z = 0.958, P = 0.338).

CONCLUSION: ARFI + APRI showed enhanced diagnostic accuracy than ARFI or APRI alone for significant liver fibrosis and ARFI + APRI + Forns index shows the same effect with ARFI + APRI.

Assessment of the Stiffness of Major Salivary Glands in Primary Sjögren's Syndrome through Quantitative Acoustic Radiation Force Impulse Imaging

The purpose of the study described here was to evaluate salivary gland stiffness in primary Sjögren's syndrome (pSS) via acoustic radiation force impulse imaging, including Virtual Touch tissue quantification (VTQ) and Virtual Touch tissue imaging quantification (VTIQ). Twenty-one patients with pSS and 11 healthy patients were included, and the paired parotid and submandibular glands of all of the patients were examined using VTQ and VTIQ. Differences between the two groups were compared with independent and paired t-tests. The VTQ value for the parotid in the pSS group was significantly higher than that obtained for the control group (1.33 ± 0.22 and 1.18 ± 0.04 m/s, respectively, p < 0.01). The VTIQ values for the parotid and submandibular gland were both significantly higher in the pSS group than in the control group (p < 0.05). In the pSS group, a positive correlation was observed between the VTQ and VTIQ results for the parotid and submandibular glands. In summary, the stiffness of the major salivary glands in patients with pSS was increased compared with that of patients with normal glands. This finding indicates that VTQ and VTIQ imaging may be valuable adjuncts to gray-scale ultrasonography for the clinical diagnosis of pSS.

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

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

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

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

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Acoustic radiation force impulse with shear wave speed quantification of pancreatic masses: A prospective study

BACKGROUND

Acoustic Radiation Force Impulse (ARFI) is a new ultrasound technique that evaluates mechanical properties of tissues. To evaluate the use of ARFI with shear waves speed quantification for pancreatic masses characterization during the ultrasound examination.

METHODS

123 pancreatic lesions were prospectively evaluated. Median shear waves speeds were compared with Mann-Whitney U test. Two reading methods were applied for the characterization of adenocarcinoma: more than one measurement above the top shear waves speed (SWS) value. Two reading methods were applied to diagnose mucinous lesion: at least 2 (method 1) or 3 (method 2) numerical measurements. Sensitivity, specificity, positive and negative predictive values and accuracy of each reading method were calculated. Forty volunteers were included for normal ARFI values.

RESULTS

In the adenocarcinoma group median SWS value was 2.74 m/s. In the volunteers group the median SWS value was 1.17 m/s. Significant difference between SWS median values of adenocarcinoma and normal pancreas was found (P < 0.05). For the diagnosis of pancreatic solid masses if more than one measurement is above the top SWS value of 4.00 m/s results in the study, the diagnosis of ductal adenocarcinoma is highly specific with specificity and PPV of 100%. Good sensitivity (73.3%) and specificity (83.3%) were obtained for the characterization of mucinous cystic lesions.

CONCLUSIONS

Acoustic Radiation Force Impulse imaging could help in the non-invasive characterization of solid and cystic lesions of the pancreas during a conventional US examination.

Incorporation of Noninvasive Measures of Liver Fibrosis Into Clinical Practice: Diagnosis and Prognosis

Noninvasive methods are increasingly used for the assessment of liver fibrosis. Two categories of markers include serum-based markers (biologic properties) or ultrasound and magnetic resonance imaging-based techniques that use the principles of elastography (physical properties) to indirectly assess liver fibrosis. Serum markers can be either direct or indirect markers of the fibrosis process. Common elastography-based studies include vibration-controlled transient elastography, point shear wave elastography, and 2-dimensional shear wave elastography and magnetic resonance elastography. A common theme among all techniques is the inability to accurately differentiate between minimal or moderate stages of fibrosis but superior performance in identifying subjects with cirrhosis or normal liver parenchyma. Noninvasive markers may also serve as prognostic tools to course the natural history of chronic liver disease as well as identify cirrhotic patients at highest risk of future decompensation. Further research is needed to identify the role of noninvasive markers in following asymptomatic individuals, especially in patients with nonalcoholic fatty liver disease.

Liver Cirrhosis: Evaluation, Nutritional Status, and Prognosis

The liver is the major organ for the metabolism of three major nutrients: protein, fat, and carbohydrate. Chronic hepatitis C virus infection is the major cause of chronic liver disease. Liver cirrhosis (LC) results from different mechanisms of liver injury that lead to necroinflammation and fibrosis. LC has been seen to be not a single disease entity but one that can be graded into distinct clinical stages related to clinical outcome. Several noninvasive methods have been developed for assessing liver fibrosis and these methods have been used for predicting prognosis in patients with LC. On the other hand, subjects with LC often have protein-energy malnutrition (PEM) and poor physical activity. These conditions often result in sarcopenia, which is the loss of skeletal muscle volume and increased muscle weakness. Recent studies have demonstrated that PEM and sarcopenia are predictive factors for poorer survival in patients with LC. Based on these backgrounds, several methods for evaluating nutritional status in patients with chronic liver disease have been developed and they have been preferably used in the clinical field practice. In this review, we will summarize the current knowledge in the field of LC from the viewpoints of diagnostic method, nutritional status, and clinical outcomes.

Placental elasticity evaluation using virtual touch tissue quantification during pregnancy

INTRODUCTION

Virtual touch tissue quantification (VTTQ) has been developed to evaluate tissue elasticity. Our previous study using delivered placentas showed increased elasticity in fetal growth restriction (FGR). Therefore, we investigated changes in placental elasticity during pregnancy, including complicated pregnancies.

METHODS

Based on complications, 199 women were divided into 5 groups (normal, FGR, pregnancy induced hypertension (PIH), diabetes mellitus and collagen disease), and shear wave velocity (SWV) of the placenta, measured using VTTQ, was compared. A cross-sectional study was performed with the 143 normal cases to construct the reference range. The association between placental SWV and the expression ratio of collagen fibers in the placenta stained with Masson's trichrome was determined.

RESULTS

The SWV was safely measured for all participants. The correlation between SWV and gestational weeks was not significant. The mean ± SD SWVs in the normal, FGR, and PIH groups were 0.98 ± 0.21, 1.28 ± 0.39, and 1.60 ± 0.45 m/sec, respectively. The FGR and PIH groups had significantly higher SWVs than that of the normal group. SWV and the expression ratio of collagen fibers were significantly correlated.

DISCUSSION

Based on the present findings, changes in SWV during pregnancy were associated with placental fibrosis, and increased SWV in PIH and/or FGR cases might be influenced by infarction, ischemic changes, and inflammation, as well as fibrosis. In conclusion, the measurement of placental SWV is potentially useful to evaluate the condition of the placenta during pregnancy.

Acoustic radiation force impulse elastography of the liver in healthy patients: test location, reference range and influence of gender and body mass index

The objective of this study was to evaluate the best test location and study factors associated with acoustic radiation force impulse (ARFI) elastography measurements in healthy individuals. When ARFI elastography was performed on 68 healthy patients after controlling for all known test condition factors except segmental location, the median shear wave velocities (SWVs) derived from five valid measurements in the area between S5 and S8 in patients in the supine position had a significantly lower mean and the narrowest 95% confidence interval, followed by those for the S8 supine and S8 semidecubitus locations (p = 0.045). Analysis of mean SWVs revealed similar, although statistically insignificant, findings (p = 0.078). Male patients had significantly higher median SWVs (p = 0.0073) and mean SWVs (p = 0.0043) than female patients. Patients with body mass indexes >22 had significantly lower median SWVs (p = 0.0033) and mean SWVs (p = 0.0008) than those with body mass indexes ≤22. S5/8 supine was the better test location for ARFI. The reference ranges for median and mean SWV were 0.81-1.27 and 0.82-1.27 m/s, respectively. Gender and body mass index, but not age, were the significant factors associated with ARFI SWV values.

Noninvasive diagnosis of cirrhosis: A review of different imaging modalities

Progressive hepatic fibrosis can lead to cirrhosis, so its early detection is fundamental. Staging fibrosis is also critical for prognosis and management. The gold standard for these aims is liver biopsy, but it has several drawbacks, as it is invasive, expensive, has poor acceptance, is prone to inter observer variability and sampling errors, has poor repeatability, and has a risk of complications and mortality. Therefore, non-invasive imaging tests have been developed. This review mainly focuses on the role of transient elastography, acoustic radiation force impulse imaging, and magnetic resonance-based methods for the noninvasive diagnosis of cirrhosis.