Liver elasticity in healthy individuals by two novel shear-wave elastography systems-Comparison by age, gender, BMI and number of measurements. PLoS One. 2018;13:e0203486. [PMID: 30216377 PMCID: PMC6138384 DOI: 10.1371/journal.pone.0203486]

Rapid synthesis of degradable ester/thioether monomers and their incorporation into thermoset polyurethane foams for traumatic wound healing

Polyurethane (PUr) foam hemostatic dressings are highly effective at controlling bleeding in traumatic wounds, but their traditionally slow degradation rate requires dressing removal, which could result in wound rebleeding. Incorporating degradable linkages into the PUr network can provide a biodegradable dressing that could be left in place during healing, eliminating rebleeding upon removal and providing scaffolding for new tissue ingrowth with no remains of the applied dressing after healing. In this work, a library of degradable PUr foams was synthesized from degradable monomers based on hydrolytically labile esters and oxidatively labile thioethers using rapid click-chemistry reactions. In a twelve-week in vitro degradation study in 3% hydrogen peroxide and 0.1 M sodium hydroxide, incorporation of degradable monomers resulted in significantly increased PUr foam mass loss, offering biodegradable foam dressings that could better match the rate of traumatic wound healing. Changes to foam chemical, mechanical, thermal, and physical properties throughout degradation were also analyzed. Furthermore, the degradable PUr foams had increased platelet interactions, which could improve foam-induced clotting for a more effective hemostatic dressing. Overall, a biodegradable PUr foam hemostatic dressing could significantly improve healing outcomes in traumatic wounds. STATEMENT OF SIGNIFICANCE: A simple, solvent-free, rapid synthesis technique was developed to provide degradable polythiol monomers for use in polyurethane synthesis. The degradable monomers were incorporated into hemostatic polyurethane foams to provide materials with tunable degradation rates within clinically-relevant time frames. The resulting foams and their degradation byproducts were cytocompatible and hemocompatible, and foams made with the new degradable monomers had enhanced blood clotting, enabling their future use as hemostatic dressings.

Profiles associated with significant hepatic fibrosis consisting of alanine aminotransferase >30 U/L, exercise habits, and metabolic dysfunction-associated steatotic liver disease

AIM

In patients with steatotic liver disease (SLD), significant hepatic fibrosis is a prognostic factor with various etiologies, including inflammation and metabolic dysfunction. This study aimed to investigate independent factors and profiles associated with significant hepatic fibrosis, including alanine aminotransferase (ALT) levels >30 U/L and metabolic dysfunction-associated SLD (MASLD), in health check-up examinees.

METHODS

This single-center, retrospective, observational cohort study enrolled 1378 consecutive health checkup examinees from April 2018 to September 2022. Shear wave elastography (SWE) was performed during a routine ultrasound examination, and patients with liver stiffness ≥6.60 kPa were defined as having significant hepatic fibrosis. Patients were classified into nonsignificant hepatic fibrosis (n = 1220) or a significant hepatic fibrosis (n = 158) group according to this definition.

RESULTS

In multivariate analysis, the independent factor for significant hepatic fibrosis was aging (≥65 years; OR 9.637, 95% CI 6.704-13.852, p < 0.0001). According to decision tree analysis, the initial classifier was aging (≥65 years). After aging, an ALT level >30 U/L was the second relevant factor for significant hepatic fibrosis, regardless of age. An undirected graphical model showed that an ALT level of >30 U/L was directly associated with significant hepatic fibrosis. In patients aged ≥65 years with an ALT level >30 U/L, significant hepatic fibrosis was observed in 52% of the patients. Meanwhile, in patients aged ≥65 years with an ALT level ≤30 U/L, MASLD was the third classifier, with significant hepatic fibrosis observed in 38% of patients.

CONCLUSIONS

ALT levels >30 U/L and MASLD may be involved in the pathogenesis of significant hepatic fibrosis in patients aged ≥65 years.

Mechanical properties of human hepatic tissues to develop liver-mimicking phantoms for medical applications

Using liver phantoms for mimicking human tissue in clinical training, disease diagnosis, and treatment planning is a common practice. The fabrication material of the liver phantom should exhibit mechanical properties similar to those of the real liver organ in the human body. This tissue-equivalent material is essential for qualitative and quantitative investigation of the liver mechanisms in producing nutrients, excretion of waste metabolites, and tissue deformity at mechanical stimulus. This paper reviews the mechanical properties of human hepatic tissues to develop liver-mimicking phantoms. These properties include viscosity, elasticity, acoustic impedance, sound speed, and attenuation. The advantages and disadvantages of the most common fabrication materials for developing liver tissue-mimicking phantoms are also highlighted. Such phantoms will give a better insight into the real tissue damage during the disease progression and preservation for transplantation. The liver tissue-mimicking phantom will raise the quality assurance of patient diagnostic and treatment precision and offer a definitive clinical trial data collection.

Shear wave elastography in chronic kidney disease - the physics and clinical application

Chronic kidney disease is a leading public health problem worldwide. The global prevalence of chronic kidney disease is nearly five hundred million people, with almost one million deaths worldwide. Estimated glomerular filtration rate, imaging such as conventional ultrasound, and histopathological findings are necessary as each technique provides specific information which, when taken together, may help to detect and arrest the development of chronic kidney disease, besides managing its adverse outcomes. However, estimated glomerular filtration rate measurements are hampered by substantial error margins while conventional ultrasound involves subjective assessment. Although histopathological assessment is the best tool for evaluating the severity of the renal pathology, it may lead to renal insufficiency and haemorrhage if complications occurred. Ultrasound shear wave elastography, an emerging imaging that quantifies tissue stiffness non-invasively has gained interest recently. This method applies acoustic force pulses to generate shear wave within the tissue that propagate perpendicular to the main ultrasound beam. By measuring the speed of shear wave propagation, the tissue stiffness is estimated. This paper reviews the literature and presents our combined experience and knowledge in renal shear wave elastography research. It discusses and highlights the confounding factors on shear wave elastography, current and future possibilities in ultrasound renal imaging and is not limited to new sophisticated techniques.

Gunshot wounds in parenchymatous organs: the morphology mainly depends on the physical properties of the affected tissues

In contrast to gunshot wounds in skin and bone, the medico-legal literature pays little attention to the appearance of bullet penetration sites in abdominal organs. It was only in 1983 that Metter and Schulz published an article entitled "Morphological features of gunshot wounds in the liver and spleen." According to their observations, the organs in question showed stellate tears at the bullet penetration sites resembling skin wounds from contact shots to body regions having a bony support. The study presented simulated the real conditions by means of test shots to composite models consisting of porcine organs embedded in ballistic gelatin. The ammunition used was pistol cartridges 9 mm Luger with full metal jacket round nose bullets. The shots were video-documented with a high-speed camera in order to record the bullet's travel through the target. In addition, the composite models fired at underwent CT examinations followed by a macroscopic assessment of the organs. The study confirmed the findings of Metter and Schulz with regard to the star-like appearance of gunshot wounds in the liver and spleen. Likewise, the kidney showed radiating tears originating from the bullet path, whereas the wound track in pulmonary tissue was tube-shaped and lacked additional cracks. The varying wound patterns in parenchymatous organs can reasonably be explained as a consequence of the respective viscoelastic tissue properties.

A single-center, retrospective, cross-sectional study comparing the number of non-diagnostic measurements ratio in the pSWE and SSI ultrasound elastography methods

The point shear wave elastography and supersonic shear imaging methods were compared regarding incorrect measurements during the liver examinations. A report-based, single-center, retrospective analysis of 425 liver elastography examinations was performed. A lower success ratio was observed for the point shear wave elastography method, as well as the older and obese patients pre-dominated in non-diagnostic studies. In our center experience, it is easier to obtain diagnostic data using the supersonic shear imaging method. However, further investigation of the subject is needed.

Emerging Applications of Extracardiac Ultrasound in Critically Ill Cardiac Patients

Point-of-care ultrasound has evolved as an invaluable diagnostic modality and procedural guidance tool in the care of critically ill cardiac patients. Beyond focused cardiac ultrasound, additional extracardiac ultrasound modalities may provide important information at the bedside. In addition to new uses of existing modalities, such as pulsed-wave Doppler ultrasound, the development of new applications is fostered by the implementation of additional features in mid-range ultrasound machines commonly acquired for intensive care units, such as tissue elastography, speckle tracking, and contrast-enhanced ultrasound quantification software. This review explores several areas in which ultrasound imaging technology may transform care in the future. First, we review how lung ultrasound in mechanically ventilated patients can enable the personalization of ventilator parameters and help to liberate them from mechanical ventilation. Second, we review the role of venous Doppler in the assessment of organ congestion and how tissue elastography may complement this application. Finally, we explore how contrast-enhanced ultrasound could be used to assess changes in organ perfusion.

Comparison of Visual Transient Elastography, Vibration Controlled Transient Elastography, Shear Wave Elastography and Sound Touch Elastography in Chronic liver Disease assessment using liver biopsy as 'Gold Standard'

PURPOSE

Chronic liver disease (CLD) is considered one of the main causes of death. Ultrasound Elastography (USE) is a CLD assessment imaging method. This study aims to evaluate a recently introduced commercial alternative of USE, Visual Transient Elastography (ViTE), and to compare it with three established USE methods, Vibration Controlled Transient Elastography (VCTE), Shear Wave Elastography (SWE) and Sound Touch Elastography (STE), using Liver Biopsy (LB) as 'Gold Standard'.

METHOD

152 consecutive subjects underwent a liver ViTE, VCTE, SWE and STE examination. A Receiver Operator Characteristic (ROC) analysis was performed on the measured stiffness values of each method. An inter- intra-observer analysis was also performed.

RESULTS

The ViTE, VCTE, SWE and STE ROC analysis resulted in an AUC of 0.9481, 0.9900, 0.9621 and 0.9683 for F ≥ F1, 0.9698, 0.9767, 0.9931 and 0.9834 for F ≥ F2, 0.9846, 0.9651, 0.9835 and 0.9763 for F ≥ F3, and 0.9524, 0.9645, 0.9656, and 0.9509 for F = F4, respectively. ICC scores were 0.98 for Inter-observer and 0.97 for Intra-observer variability analysis.

CONCLUSION

ViTE performance in CLD stage differentiation is comparable to the performance of VCTE, SWE and STE.

Liver Elastography in Healthy Children Using Three Different Systems - How Many Measurements Are Necessary?

PURPOSE

 Liver elastography is increasingly being applied in screening for and follow-up of pediatric liver disease, and has been shown to correlate well with fibrosis staging through liver biopsy. Because time is of the essence when examining children, we wanted to evaluate if a reliable result can be achieved with fewer acquisitions.

MATERIALS AND METHODS

 243 healthy children aged 4-17 years were examined after three hours of fasting. Participants were divided into four age groups: 4-7 years; 8-11 years; 12-14 years and 15-17 years. Both two-dimensional shear wave elastography (2D-SWE; GE Logiq E9) and point shear wave elastography (pSWE; Samsung RS80A with Prestige) were performed in all participants, while transient elastography (TE, Fibroscan) was performed in a subset of 87 children aged 8-17 years. Median liver stiffness measurement (LSM) values of 3, 4, 5, 6, 7, and 8 acquisitions were compared with the median value of 10 acquisitions (reference standard). Comparison was performed for all participants together as well as within every specific age group. We investigated both the intraclass correlation coefficient (ICC) with absolute agreement and all outliers more than 10 %, 20 % or ≥ 0.5 or 1.0 kPa from the median of 10 acquisitions.

RESULTS

 For all three systems there was no significant difference between three and ten acquisitions, with ICCs ≥ 0.97. All systems needed 4 acquisitions to achieve no LSM deviating ≥ 1.0 kPa of a median of ten. To achieve no LSM deviating ≥ 20 % of a median of ten acquisitions, pSWE and TE needed 4 acquisitions, while 2D-SWE required 6 acquisitions.

CONCLUSION

 Our results contradict recommendations of 10 acquisitions for pSWE and TE and only 3 for 2D-SWE.

Agreement and accuracy of shear-wave techniques (point shear-wave elastography and 2D-shear-wave elastography) using transient elastography as reference

OBJECTIVE

We aimed to evaluate the agreement/accuracy of point shear-wave elastography (p-SWE) and 2D-shear-wave elastography (2D-SWE) for liver fibrosis staging using transient elastography (TE) as the reference.

METHODS

This retrospective study analyzed data from people with chronic liver diseases submitted to TE, p-SWE, and 2D-SWE. Liver fibrosis stages were defined using the TE's 'rule of five': normal (<5 kPa); suggestive of compensated-advanced chronic liver disease (cACLD) (10-15 kPa); highly suggestive of cACLD (15-20 kPa); suggestive of clinically significant portal hypertension (>20 kPa). Agreement and accuracy of p-SWE and 2D-SWE were assessed. Optimal cutoffs for p-SWE and 2D-SWE were identified using the point nearest to the upper left corner of the ROC curves.

RESULTS

A total of 289 participants were included. The correlation between TE and 2D-SWE (rho = 0.59; P < 0.001) or p-SWE (rho = 0.69; P < 0.001) was satisfactory. The AUROCs (95% CI) of 2D-SWE and p-SWE for TE ≥ 5 kPa; TE ≥ 10 kPa; TE ≥ 15 kPa and TE ≥ 20 kPa were 0.757 (0.685-0.829) and 0.741 (0.676-0.806); 0.819 (0.770-0.868) and 0.870 (0.825-0.915); 0.848 (0.803-0.893) and 0.952 (0.927-0.978); 0.851 (0.806-0.896) and 0.951 (0.920-0.982), respectively. AUROCs of 2D-SWE were significantly lower compared with p-SWE for detecting cACLD. Optimal thresholds of 2D-SWE and p-SWE for TE ≥ 15 kPa were 8.82 kPa (sensitivity = 86% and specificity = 79%) and 8.86 kPa (sensitivity = 90% and specificity = 92%), respectively.

CONCLUSION

LSM by p-SWE and 2D-SWE techniques were correlated with TE. LSM by p-SWE seems to be more accurate than 2D-SWE to identify patients with more advanced fibrosis.

Pancreatic Steatosis Is Associated with Both Metabolic Syndrome and Pancreatic Stiffness Detected by Ultrasound Elastography

INTRODUCTION

There is increasing evidence that pancreatic steatosis (PS) is associated with metabolic syndrome (MS). However, it is not known whether it is associated with PS grade and pancreatic stiffness, or not. We aimed to evaluate the relationship between PS and its grade detected by transabdominal ultrasound, and pancreatic stiffness determined by two-dimensional shearwave elastography (2D-SWE), whether it has clinical significance and its relationship with MS.

METHODS

Patients with and without PS were evaluated prospectively.

RESULTS

Patients with PS had higher odds ratio for MS (OR 5.49). Also, ultrasonographic grade of PS was associated with MS parameters and hepatosteatosis. Pancreatic SWE value was significantly higher in PS group and positively correlated with PS grade, liver fat, MS, number of MS criteria.

DISCUSSION/CONCLUSION

PS and its grade were associated with MS. In this first comprehensive PS-SWE study, we found that pancreas stiffness increased in the presence of PS, in correlation with PS grade and MS.

2D-shear wave elastography: number of acquisitions can be reduced according to clinical setting

BACKGROUND

The factors affecting intra-operator variability of two-dimensional shear wave elastography (2D-SWE) have not been clearly established. We evaluated 2D-SWE variability according to the number of measurements, clinical and laboratory features, and liver stiffness measurements (LSM).

METHODS

At least three LSM were performed in 452 patients who underwent LSM by 2D-SWE (supersonic shear imaging) out of an initial database of 1650 patients. The mean value of the three LSM was our best measurement method. Bland-Altman plots were used to evaluate intra-operator variability when considering only one, or the first two measurements. Variability was assessed by taking the absolute value of the difference between the first LSM and the mean of the three LSM. Logistic regression was used to assess the factors associated with the highest tertile of variability.

RESULTS

The limit of agreement was narrower with the mean of the first and second measurements than with each measurement taken separately (- 2.83 to 2.99 kPa vs. - 5.86 to 6.21 kPa and - 5.77 to 5.73 kPa for the first and second measurement, respectively). A BMI ≥ 25 kg/m2 and a first LSM by 2D-SWE ≥ 7.1 kPa increased the odds of higher variability by 3.4 and 3.9, respectively. Adding a second LSM didn't change the variability in patients with BMI < 25 and a first LSM by 2D-SWE < 7.1 kPa.

CONCLUSIONS

Intra-operator variability of LSM by 2D-SWE increases with both a high BMI and high LSM value. In patients with BMI < 25 kg/m2 and a first LSM < 7.1 kPa we recommend performing only one LSM.

Significant decrease in liver stiffness detected by two dimensional shear-wave elastography after treatment with direct-acting antiviral agents in patients with chronic Hepatitis C

BACKGROUND/AIMS

Two-dimensional shear-wave (2D-SWE) elastography is one of the noninvasive methods for the evaluation of liver fibrosis. The purpose of this study is to investigate the changes in liver stiffness (LS) by employing 2D-SWE as well as its correlation with noninvasive fibrosis markers in patients with chronic hepatitis C (CHC), who are undergoing direct-acting antiviral (DAA) therapy.

MATERIALS AND METHODS

The researchers included all the patients with CHC who are scheduled for DAA treatment in this study. 2D-SWE measurements were performed at baseline, end of treatment (EOT), and 12 weeks after the treatment. According to the latest EFSUMB guidelines, elastography measurements were performed during the ultrasonographic evaluation and recorded in kilopascals (unit). The correlation between biochemical and viral responses, and noninvasive fibrosis scores (FIB-4, AST-to-platelet ratio index (APRI)) was also evaluated.

RESULTS

This study employed 230 patients who underwent treatment with DAAs between September 2016 and September 2017. However, 131 patients were able to complete the study, of which 48 (36.6%) were male and 83 (63.4%) were female. The mean age was 65.0 (±11.18) years. Both EOT and sustained viral response (SVR) had the same rate of 99.2% (130/131). The SWE measurement (mean) values at pretreatment, EOT, and 12 weeks after treatment was 12.92, 10.45, and 9.07 kPa, respectively (p<0.05), whereas the APRI scores were 0.76, 0.39, and 0.30, respectively (p<0.05). Additionally, the FIB-4 scores at pretreatment, EOT, and 12 weeks after treatment were 2.98, 2.43, and 2.03, respectively (p<0.05). The results of liver stiffness measurements (LSM) were similar in all the groups of cirrhotic, noncirrhotic, treatment-experienced, and treatment-naive patients.

CONCLUSION

DAA treatments in the patients with CHC led to almost a complete SVR and a considerable decrease in LS in a short time.

The course and prognostic value of increased pancreas stiffness detected by ultrasound elastography during acute pancreatitis

BACKGROUND

In this study, we determined the pancreatic stiffness (PS) changes in the course of acute pancreatitis (AP) by ultrasound elastography and evaluated its relation with prognosis.

MATERIAL/METHODS

Pancreatic shear wave velocity measurements (SWM) were evaluated at the time of admission to the hospital, following clinical improvement, and one-month after for AP patients and compared to healthy volunteers. Its relationship with clinical severity indexes was evaluated.

RESULTS

The pancreatic SWM value in the healthy group was 7.72 ± 2.50 kPa, and in AP group was 10.97 ± 2.26 kPa (p = 0.000). There was no difference between mild and severe pancreatitis. The mean SWM was 8.96 ± 1.53 kPa after disease remission, and 8.83 ± 1.24 kPa after 1-month.

CONCLUSIONS

PS increases significantly during AP and decreases with clinical improvement, but this was still higher than controls, and it kept its elevation after 1-month. We think that larger, long-term studies are needed to determine the clinicopathological significance of this.

Utility of Transient Elastography for the Screening of Liver Disease in Patients with Alpha1-Antitrypsin Deficiency

Screening of liver disease in alpha-1 antitrypsin deficiency (AATD) is usually carried out with liver enzymes, with low sensitivity. We conducted a multicenter cross-sectional study aiming to describe the utility of transient elastography for the identification of liver disease in patients with AATD. A total of 148 AATD patients were included. Among these, 54.7% were Pi*ZZ and 45.3% were heterozygous for the Z allele. Between 4.9% and 16.5% of patients had abnormal liver enzymes, without differences among genotypes. Liver stiffness measurement (LSM) was significantly higher in Pi*ZZ individuals than in heterozygous Z (5.6 vs. 4.6 kPa; p = 0.001). In total, in 8 (5%) individuals LSM was >7.5 kPa, considered significant liver fibrosis, and ≥10 kPa in 3 (1.9%) all being Pi*ZZ. Elevated liver enzymes were more frequently observed in patients with LSM > 7.5 kPa, but in 5 out of 8 of these patients all liver enzymes were within normal range. In patients with AATD, the presence of abnormal liver enzymes is frequent; however, most of these patients do not present significant liver fibrosis. Transient elastography can help to identify patients with liver fibrosis even with normal liver enzymes and should be performed in all Z-allele carriers to screen for liver disease.

Establishing Reliability Criteria for Liver ElastPQ Shear Wave Elastography (ElastPQ-SWE): Comparison Between 10, 5 and 3 Measurements

PURPOSE

 ElastPQ is a new elastography technique for non-invasive liver fibrosis staging. However, it does not have validated reliability criteria. We tested the reliability of a different number of measurements in patients with chronic liver disease and explored whether the application of quality criteria improves the diagnostic performance.

MATERIALS AND METHODS

 All patients underwent liver stiffness assessment (LSM) with ElastPQ and Fibroscan (F-TE). The mean, median, standard deviation (SD) and interquartile range (IQR) of 10, 5 and 3 measurements were retrospectively collected for each patient and compared to each other. Liver histology was available in a subset of patients.

RESULTS

 Overall, 400 patients met the inclusion criteria. Non-alcoholic fatty liver disease (NAFLD) was the most represented etiology (75 %), followed by primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH). The correlation of medians was significantly better between 10 and 5 measurements than between 10 and 3. The difference of medians was significant only in the comparison between 10 and 3 measurements. The correlation between ElastPQ and F-TE was equally good for 10 and 5 measurements and significantly improved after an IQR/median ≤ 30 % was applied. The diagnostic performance of ElastPQ was better with the median value of 10 and 5 measurements and improved if LSM values were obtained with IQR/M ≤ 30 %.

CONCLUSION

 The median value of 5 valid LSMs suffices for the reliable estimation of liver stiffness using ElastPQ. The quality criterion of IQR/M ≤ 30 % should also be followed when using this technique.

Comparison of liver stiffness measurements by a 2D-shear wave technique and transient elastography: results from a European prospective multi-centre study

OBJECTIVES

To compare liver stiffness measurement (LSM) provided by Canon 2D-shear wave elastography (2D-SWE) and transient elastography (TE), the latter being the reference method.

METHODS

Prospective study conducted in four European centres from 2015 to 2016 including patients with various chronic liver diseases who had LSMs with both 2D-SWE and TE on the same day. Median of 10 valid measurements (in kPa) was used for comparison using paired t test, Pearson correlation, intraclass correlation coefficient (ICC) and Bland-Altman plot. The ability of 2D-SWE to stratify patient according to recognised LSM-TE thresholds was assessed by ROC curve analysis.

RESULTS

Six hundred forty patients were scanned, where 593 (92.7%), 572 (89.4%) and 537 (83.9%) had reliable LSMs by TE, 2D-SWE and both combined, respectively. In the latter (n = 537, 310 [57.7%] male, mean 55.3 ± 14.8 years), median LSM-TE and LSM-2D-SWE had a mean of 10.1 ± 9.4 kPa (range 2.4-75) and 9.1 ± 6.1 kPa (range 3.6-55.7) (paired t test: p < 0.001), respectively. These were significantly correlated (Pearson r = 0.932, p < 0.001, ICC 0.850 (0.825-0.872), bias 0.99 ± 4.33 kPa [95% limits of agreement - 9.48 to + 7.49] with proportional error towards higher LSM values). LSM-2D-SWE values significantly increased with TE categories (ANOVA: p < 0.001). AUROCs ranged from 0.935 ± 0.010 (95% CI 0.910-0.954) to 0.973 ± 0.009 (95% CI 0.955-0.985), resulting in correct classification of 390/537 (73%) patients. Three 2D-SWE measurements were sufficient for reliable LSMs.

CONCLUSION

LSM using 2D-SWE correlates well with TE. It tends to underestimate higher stages of liver fibrosis but correctly classifies the majority of patients. It may be used in TE-derived algorithms to manage patients.

KEY POINTS

• Liver stiffness measurement (LSM) by 2D-shear wave elastography (2D-SWE) and transient elastography (TE) are strongly correlated. • 2D-SWE shows proportionately lower LSM values compared to TE, particularly with the higher LSM range. • Three individual measurements by 2D-SWE are sufficient to assess LSM reliably.

Prevalence of advanced liver fibrosis and steatosis in type-2 diabetics with normal transaminases: A prospective cohort study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and type-2 diabetes mellitus (T2DM) have an intricate bidirectional relationship. Individuals with T2DM, not only have a higher prevalence of non-alcoholic steatosis, but also carry a higher risk of progression to nonalcoholic steatohepatitis. Experts still differ in their recommendations of screening for NAFLD among patients with T2DM.

AIM

To study the prevalence of NAFLD and advanced fibrosis among our patient population with T2DM.

METHODS

During the study period (November 2018 to January 2020), 59 adult patients with T2DM and 26 non-diabetic control group individuals were recruited prospectively. Patients with known significant liver disease and alcohol use were excluded. Demographic data and lab parameters were recorded. Liver elastography was performed in all patients.

RESULTS

In the study group comprised of patients with T2DM and normal alanine aminotransferase levels (mean 17.8 ± 7 U/L), 81% had hepatic steatosis as diagnosed by elastography. Advanced hepatic fibrosis (stage F3 or F4) was present in 12% of patients with T2DM as compared to none in the control group. Patients with T2DM also had higher number of individuals with grade 3 steatosis [45.8% vs 11.5%, (P < 0.00001) and metabolic syndrome (84.7% vs 11.5%, P < 0.00001)].

CONCLUSION

A significant number of patients with T2DM, despite having normal transaminase levels, have NAFLD, grade 3 steatosis and advanced hepatic fibrosis as measured by liver elastography.

Interobserver and Intraobserver Reliability of Hepatic Shear Wave Elastography and the Influence of Fasted Versus Nonfasted States in Healthy Volunteers

OBJECTIVES

The primary objective of this study was to assess the effect of fasting versus ingestion of food and water on hepatic measurements by shear wave elastography (SWE) in healthy participants. The secondary objective was to assess inter- and intra-reader reliability of hepatic elastography in healthy participants.

METHODS

Twenty healthy participants were enrolled in this prospective study and underwent quantitative SWE under fasting conditions and after the ingestion of water and food and water. Two blinded sonographers each independently performed a total of 6 sessions of hepatic SWE in each participant. Sessions 1 to 3 were performed on day 0 and sessions 4 to 6 on day 7. Statistical tests used included the Wilcoxon signed ranks test, the intraclass correlation coefficient, and Bland-Altman plots.

RESULTS

There were no significant differences in hepatic SWE measurements after the ingestion of water versus the fasting state. Statistical significance was assessed as P < 0.05. The postprandial status had a statistically significant effect on hepatic SWE measurements at 1 hour (P = .04) but not at 3 hours (P = .08). By the intraclass correlation coefficient, there was poor-to-moderate inter-reader agreement and minimal-to-moderate intra-reader agreement. The median inter-reader difference in SWE measurements ranged from 0.66 to 0.96 kPa. The median intra-reader difference ranged from 0.43 to 0.55 kPa.

CONCLUSIONS

Our study shows that the ingestion of water has no effect on hepatic SWE measurements in healthy participants. The postprandial state had a significant effect on SWE measurements at 1 hour after ingestion but not at 3 hours. The inter-reader and intra-reader agreements were variable and moderate at best.

Feasibility and Reliability of Two-Dimensional Shear-Wave Elastography of the Liver of Clinically Healthy Cats

Given the broad overlap of normal and abnormal liver tissue in the subjective evaluation of the liver in conventional B-mode ultrasonography, there is a need for a non-invasive and quantitative method for the diagnosis of liver disease. Novel two-dimensional shear-wave elastography (2-D SWE) can measure tissue stiffness by propagation of the shear wave induced using acoustic radiation force impulse in real time. To the best of our knowledge, two-dimensional shear-wave measurement of the liver in cats has not been reported to date. This study assessed the feasibility, reliability, normal values, and related influencing factors of 2-D SWE for assessment of the feline liver without anesthesia and breath-holding. Two-dimensional shear-wave ultrasonography was performed by two evaluators at the right and left sides of the liver. Twenty-nine client-owned clinically healthy adult cats were included. The means and standard deviations for the shear-wave speed and stiffness in the right liver were 1.52 ± 0.13 m/s and 6.94 ± 1.26 kPa, respectively, and those for the left liver were 1.61 ± 0.15 m/s and 7.90 ± 1.47 kPa, respectively. Shear-wave speed (P = 0.005) and stiffness (P = 0.002) were significantly lower in the right liver when compared to the left. The intraclass correlation value for liver stiffness was 0.835 and 0.901 for the right and left liver, respectively, indicating high interobserver agreement. Age, weight, body condition score (BCS), gabapentin administration, and measurement depths were not significantly correlated with liver stiffness or elastography measurements (P > 0.05). Our findings suggest that 2-D SWE measurements of the liver are not influenced significantly by age, weight, or BCS and can be reliably performed without anesthesia and breath-holding in cats. The values determined here can help form the basis for reference elastography values for evaluation of the feline liver.

Deep learning networks on chronic liver disease assessment with fine-tuning of shear wave elastography image sequences

Chronic liver disease (CLD) is currently one of the major causes of death worldwide. If not treated, it may lead to cirrhosis, hepatic carcinoma and death. Ultrasound (US) shear wave elastography (SWE) is a relatively new, popular, non-invasive technique among radiologists. Although many studies have been published validating the SWE technique either in a clinical setting, or by applying machine learning on SWE elastograms, minimal work has been done on comparing the performance of popular pre-trained deep learning networks on CLD assessment. Currently available literature reports suggest technical advancements on specific deep learning structures, with specific inputs and usually on a limited CLD fibrosis stage class group, with limited comparison on competitive deep learning schemes fed with different input types. The aim of the present study is to compare some popular deep learning pre-trained networks using temporally stable and full elastograms, with or without augmentation as well as propose suitable deep learning schemes for CLD diagnosis and progress assessment. 200 liver biopsy validated patients with CLD, underwent US SWE examination. Four images from the same liver area were saved to extract elastograms and processed to exclude areas that were temporally unstable. Then, full and temporally stable masked elastograms for each patient were separately fed into GoogLeNet, AlexNet, VGG16, ResNet50 and DenseNet201 with and without augmentation. The networks were tested for differentiation of CLD stages in seven classification schemes over 30 repetitions using liver biopsy as the reference. All networks achieved maximum mean accuracies ranging from 87.2%-97.4% and area under the receiver operating characteristic curves (AUCs) ranging from 0.979-0.990 while the radiologists had AUCs ranging from 0.800-0.870. ResNet50 and DenseNet201 had better average performance than the other networks. The use of the temporal stability mask led to improved performance on about 50% of inputs and network combinations while augmentation led to lower performance for all networks. These findings can provide potential networks with higher accuracy and better setting in the CLD diagnosis and progress assessment. A larger data set would help identify the best network and settings for CLD assessment in clinical practice.

Ultrasound-based liver elastography: current results and future perspectives

Chronic liver disease affects 185 million population worldwide. It encompasses a heterogenous disease spectrum, but all can lead to the development of liver fibrosis. The degree of liver fibrosis is not only a prognosticator, but has also been used to guide the treatment strategy and to evaluate treatment response. Traditionally, staging of liver fibrosis is determined on histological analysis using samples obtained from an invasive liver biopsy. Ultrasound-based liver elastography is a non-invasive method of assessing diffuse liver disease in patients with known chronic liver disease. The use of liver elastography has led to a significant reduction in the number of liver biopsies performed to assess the severity of liver fibrosis and a liver biopsy is now reserved for only select sub-groups of patients. The aim of this review article is to discuss the key findings and current evidence for ultrasound-based elastography in diffuse liver disease as well as the technical challenges and to evaluate the potential research direction.

A digital viscoelastic liver phantom for investigation of elastographic measurements

To develop elastography imaging technologies and implement image reconstruction algorithms, testing is done with phantoms. Although the validation step is usually taken using real data and physical phantoms, their geometry as well as composition, biomechanical parameters, and details of applying stress cannot be modified readily. Such considerations have gained increasing importance with the growth of elastography techniques as one of the non-invasive medical imaging modalities, which can map the elastic properties and stiffness of soft tissues. In this article, we develop a digital viscoelastic phantom using computed tomography (CT) imaging data and several application software tools based on illustrations of normal liver anatomy so as to investigate the biomechanics of elastography via finite element modeling (FEM). Here we discuss how to create this phantom step by step, demonstrate typical shear wave elastography (SWE) experiments of applying transient stress to the liver model, and calculate quantitative measurements. In particular, shear wave velocities are investigated through a parametric study designed based on tissue stiffness and distance from the applied stress. According to the results of FEM analysis, low errors were obtained for shear wave velocity estimation for both mechanical stress (~2-5%) and acoustic radiation force (~3-7%). Results show that our model is a powerful framework and benchmark for simulating and implementing different algorithms in shear wave elastography, which can serve as a guide for upcoming researches and assist scientists to optimize their subsequent experiments in terms of design.

Liver Elastography in Primary Sclerosing Cholangitis Patients Using Three Different Scanner Systems

The aim of the study described here was to characterize three different liver elastography methods in primary sclerosing cholangitis (PSC) patients, for the first time exploring 2-D shear wave elastography (2-D-SWE) in PSC patients and its putative advantages over point shear wave elastography (pSWE). Sixty-six adult PSC patients (51 males, 77%) underwent liver elastography: Transient elastography (TE), pSWE and 2-D-SWE were applied head-to-head after B-mode ultrasonography and blood tests. Liver stiffness measurements (LSMs) by pSWE yielded lower values than those by TE; 2-D-SWE had less steep slope but was overall not significantly different from TE. Correlation between LSMs by pSWE and TE was excellent (intraclass correlation coefficient = 0.92); correlation for 2-D-SWE with either pSWE or TE was moderate but improved with exclusion of overweight individuals. LSMs correlated with the Enhanced Liver Fibrosis test (ELF) across all scanner systems. Our study indicates that LSM by different systems is feasible in PSC patients and that 2-D-SWE tends to underestimate stiffness compared with TE.

Evaluation of the effectiveness of ultrasound shear elastography and liver steatometry

Detection of liver fibrosis and steatosis at early stages is a difficult task for clinical practice, due to the lack of early signs in routine radiation diagnostics. Aim. To evaluate the efficacy of ultrasound shear elastography and ultrasound steatometry of the liver with the use of domestic ultrasonic diagnostic system Angiodin-Sono/N-Ultra. Materials and methods. 264 people held ultrasound elastography and ultrasound steatometry. 38 patients underwent percutaneous puncture liver biopsy and subsequent pathophysiological examination. Results. High correlation of fibrosis obtained at the Angiodin-Sono/N-Ultra and the leading ultrasonic systems with shear elastography was revealed. Cross-sectional comparative analysis of elasticity with the results of liver steatometry was conducted. Conclusions. Results obtained in all groups correlate with the data obtained in studies on Fibroscan. When working with system Angiodin we got a simultaneous comparative analysis of elasticity with the results of liver steatosis. Results appear to be much more stable and compact than those obtained in studies on the Fibroscan. A new diagnostic criterion was revealed the phenomenon of independence of fibrosis and steatosis indices.

Profiles of advanced hepatic fibrosis evaluated by FIB-4 index and shear wave elastography in health checkup examinees

AIM

Advanced hepatic fibrosis is seen in individuals with potential hepatocellular carcinoma and cardiovascular disease. Hepatic fibrosis can be assessed using a combination of the FIB-4 index and imaging modalities, including shear wave elastography. We aimed to investigate the prevalence of advanced fibrosis in the general population and the profiles associated with advanced fibrosis using a data-mining analysis.

METHODS

We enrolled 1155 health checkup examinees (median age 53 years, 685 women, 470 male). Advanced fibrosis was defined by FIB-4 index ≥1.3 and liver stiffness ≥8.07 kPa using shear wave elastography. Participants were classified as normal-mild fibrosis (n = 1035) or advanced fibrosis (n = 120). Factors associated with advanced fibrosis were analyzed by logistic regression and decision-tree analyses.

RESULTS

Advanced fibrosis was observed in 10.4% of participants (120/1155). In the logistic regression analysis, independent factors for advanced fibrosis were age (≥75 years; OR 2.12, 95% CI 1.021-4.415; P = 0.0419) and the presence of metabolic syndrome (OR 2.51, 95% CI 1.416-4.462; P = 0.0017). The decision-tree analysis showed two profiles associated with advanced fibrosis: profile 1 - individuals aged ≥65 years with metabolic syndrome and mild-to-moderate alcohol consumption (prevalence of advanced fibrosis 73.3%); and profile 2 - individuals without metabolic syndrome, aged ≥75 years, with no exercise habit (prevalence of advanced fibrosis 56.3%).

CONCLUSIONS

Advanced fibrosis was observed in 10.4% of health checkup examinees. Furthermore, we showed that aging, metabolic syndrome with mild-to-moderate alcohol consumption, and physical inactivity were associated with advanced fibrosis. Thus, prevention of metabolic syndrome and alcohol withdrawal, as well as exercise habits, might inhibit the progression of hepatic fibrosis.

Inter- and intra-reader reproducibility of shear wave elastography measurements for musculoskeletal soft tissue masses

OBJECTIVE

To determine inter- and intra-reader reproducibility of shear wave elastography measurements for musculoskeletal soft tissue masses.

MATERIALS AND METHODS

In all, 64 patients with musculoskeletal soft tissue masses were scanned by two readers prior to biopsy; each taking five measurements of shear wave velocity (m/s) and stiffness (kPa). A single lesion per patient was scanned in transverse and cranio-caudal planes. Depth measurements (cm) and volume (cm³) were recorded for each lesion, for each reader. Linear mixed modelling was performed to assess limits of agreement (LOA), inter- and intra-reader repeatability, including analyses for measured depth and volume.

RESULTS

Of the 64 lesions scanned, 24 (38%) were malignant. Bland-Altman plots demonstrated negligible bias with wide LOA for all measurements. Transverse velocity was the most reliable measure-intraclass correlation (95% CI) = 0.917 (0.886, 1)-though reader 1 measures could be between 38% lower and 57% higher than reader 2 [ratio-scale bias (95% LOA) = 0.99 (0.64, 1.55)]. Repeatability coefficients indicated most disagreement resulted from poor within-reader reproducibility. LOA between readers calculated from means of five repeated measurements were narrower-transverse velocity ratio-scale bias (95% LOA) = 1.00 (0.74, 1.35). Depth affected both estimated velocity and repeatability; volume also affected repeatability.

CONCLUSION

This study found poor repeatability of measurements with wide LOA due mostly to intra-reader variability. Transverse velocity was the most reliable measure; variability may be affected by lesion depth. At least five measurements should be reported with LOA to assist future comparability between shear wave elastography systems in evaluating soft tissue masses.

2D shear wave elastography: measurement acquisition and reliability criteria in noninvasive assessment of liver fibrosis

PURPOSE

The objective was to evaluate the accuracy of 2D shear wave elastography (SWE) in predicting stages of liver fibrosis using five individual versus grouped measurements and different reliability criteria.

MATERIALS AND METHODS

This is a prospective study of 109 patients who underwent hepatic 2D SWE (Canon Aplio 500) prior to liver biopsy for varied indications. Liver fibrosis was staged using the METAVIR scoring system (F = 0-4). Propagation mapping was used to guide ten SWE measurements from the liver parenchyma: five individual measurements and five grouped measurements. IQR/median, SD/median, and SD/mean were examined as quality criteria for patient inclusion at various thresholds (IQR/median ≤ 0.15, 0.2, 0.3, 0.4, 0.5; SD/median ≤ 0.15, 0.2, 0.3; SD/mean ≤ 0.2, 0.3, 0.5). Threshold for clinically significant fibrosis (F ≥ 2) was determined with receiver operating characteristic (ROC) analysis.

RESULTS

There was high agreement between individual and grouped measurements without statistically significant differences (intraclass correlation coefficient = 0.82; p = 0.26-0.96). When no quality criterion was used (n = 103), the optimal threshold was 11.3 kPa [AUROC 0.78, 95% CI (0.69, 0.88)] with sensitivity and specificity of 80% and 66%, respectively. All quality criteria were associated with equal or higher AUROC ranging from 0.78 to 0.87. IQR/median ≤ 0.5 (n = 88) achieved the highest sensitivity of 85% and only excluded a small subset of patients. The AUROC and specificity were 0.83 [95% CI (0.74, 0.92)] and 72%, respectively.

SIGNIFICANCE

Quality criterion IQR/median ≤ 0.5 increases sensitivity and specificity in prediction of clinically significant liver fibrosis while excluding only a small subset of patients. Grouped measurements are comparable to individual measurements and may help increase procedural efficiency.

Normal Liver Stiffness Values in Children: A Comparison of Three Different Elastography Methods

OBJECTIVES

Noninvasive tests for the evaluation of liver fibrosis are particularly helpful in children to avoid general anesthesia and potential complications of invasive tests. We aimed to establish reference values for 2 different elastography methods in a head-to-head comparison for children and adolescents 4 to 17 years, using transient elastography as common reference in a subset.

METHODS

A total of 243 healthy participants aged 4 to 17 years were examined by a single observer with a full liver B-mode scan before elastography, following a minimum of 3 hours fasting. Liver stiffness measurements (LSMs) using 2-dimensional shear wave elastography (2D-SWE, GE Logiq E9) and point shear wave elastography (pSWE, Samsung RS80A with Prestige) were performed in all participants, and compared to transient elastography (TE, FibroScan) in a subset (n = 87). Interobserver agreement was evaluated in 50 children aged 4 to 17 years.

RESULTS

Valid measurements were obtained in 242 of 243 (99.6%) subjects for 2D-SWE, 238 of 243 (97.9%) for pSWE, and in 83 of 87 (95.4%) for TE. Median liver stiffness overall was 3.3 (interquartile range [IQR] 2.7-4.3), 4.1 (IQR 3.6-4.7), and 4.1 kPa (IQR 3.5-4.6) for 2D-SWE, pSWE, and TE, respectively. Intraclass correlation coefficients between observers were 0.84 and 0.83 for 2D-SWE and pSWE, respectively. LSM values were significantly lower for 2D-SWE compared to pSWE and TE, and increased with advancing age. Higher LSM values in males were observed in adolescents.

CONCLUSIONS

All methods showed excellent feasibility. 2D-SWE showed significantly lower LSM values than pSWE and TE, and lower failure rate compared to TE. Our results further indicate an age and sex effect on LSM values.