Limitations and opportunities of non-invasive liver stiffness measurement in children

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

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

The discriminatory ability of FibroScan liver stiffness measurement, controlled attenuation parameter, and FibroScan-aspartate aminotransferase to predict severity of liver disease in children

Vibration controlled transient elastography (FibroScan) is used to predict the severity of liver fibrosis and steatosis. In pediatrics, few studies have been performed directly comparing liver histologic features with FibroScan liver stiffness measurements (LSMs) and controlled attenuation parameters (CAPs). The FibroScan-aspartate aminotransferase (FAST) score, which predicts liver disease severity in adult nonalcoholic fatty liver disease (NAFLD), has not been analyzed in children. The aims of this study were to determine if LSM and CAP correlated with liver histologic fibrosis stage and steatosis grade, respectively, and to determine the predictive capacity of FAST in pediatric NAFLD. Research participants (n = 216) included those with FibroScan within 90 days of a liver biopsy. The ability of LSM, CAP, and FAST to predict severity of liver disease was analyzed by Spearman correlation, linear regression, and receiver operating characteristic and C statistic. Significant correlations were identified between LSM and Ishak fibrosis stages, with the strongest correlation occurring in the non-NAFLD group (Spearman r = 0.47, p < 0.0001). LSM adequately predicted Ishak stages F0-2 versus F3-F6 (area under the receiver operating characteristic curve [AUROC], 0.73 for all; 0.77 for non-NAFLD). CAP strongly predicted histologic steatosis grade (r = 0.84; p < 0.0001; AUROC, 0.98). FAST had acceptable discriminatory ability for significant liver disease (AUROC, 0.75). A FAST cutoff ≥0.67 had a sensitivity of 89% but a specificity of only 62% at determining significant liver disease. This study encompasses one of the largest pediatric cohorts describing the accuracy of FibroScan LSM and CAP to predict liver histologic fibrosis stage and steatosis grade, respectively. In order to determine specific LSM, CAP, and FAST cut-off values for fibrosis stages, steatosis grades, and significant liver disease, respectively, a much larger cohort is necessary and will likely entail the need for multicentered studies.

Ultrasound elastography in children - nice to have for scientific studies or arrived in clinical routine?

Ultrasound elastography (USE) is a modality that in addition to fundamental B-mode, Doppler, and contrast-enhanced sonography is suitable to make qualitative and quantitative statements about the stiffness of tissues. Introduced more than 20 years ago in adults, USE becomes now a diagnostic tool also in children. The aim of this paper is to describe current available techniques for USE in children. The significance for routine use in children is shown, and further interesting applications are reported.

Noninvasive Pediatric Liver Fibrosis Measurement: Two-Dimensional Shear Wave Elastography Compared With Transient Elastography

OBJECTIVES

Although transient elastography (TE) is the primary noninvasive method for assessing liver fibrosis, its use remains to be validated in children. This study aims to evaluate the agreement between two-dimensional ultrasound shear wave elastography (2D-SWE) and TE to assess pediatric liver stiffness method.

METHODS

During the 18-month study, we prospectively included 101 consecutive children (median age: 8.5 years, range: 1 month to 17 years) who required TE for medical reasons, and in whom 2D-SWE measurement was performed within a 3-month follow-up during a routine ultrasound. Liver elasticity values were classified according to the Metavir score using published pediatric norms for TE and according to the manufacturer's reference values for 2D-SWE. The Spearman's correlation coefficient was used to assess the relationship between the elasticity measured by the two techniques. Concordance was described by the Bland-Altman method.

RESULTS

A strong correlation (rho = 0.70, p < 0.001) was found between 2D-SWE and TE for the elasticity measures. The strength of correlation was higher among patients older than 6 years (rho = 0.79, p < 0.001). Concordance between liver fibrosis stages assessed by these techniques was moderate [weighted kappa = 0.46, (95% CI: 0.35-0.57)]. When considering stages over F2, 2D-SWE diagnostic performances showed a sensitivity of 85% (95% CI: 74-92) and a specificity of 57% (95% CI: 42-70) compared with TE.

CONCLUSION

Measurements of the liver stiffness using 2D-SWE and TE are strongly correlated. The moderate concordance between these techniques for assessing the liver fibrosis stage provides evidence against alternating between these methods during follow-up of patients with the chronic liver diseases.

The evaluation of the use of 2D shear-wave ultrasound elastography in differentiation of clinically insignificant and significant liver fibrosis in pediatric age group

OBJECTIVE

To determine the accuracy of 2D shear-wave elastography (2D-SWE) in pediatric age group patients in differentiating clinically insignificant and significant liver fibrosis using METAVIR fibrosis scoring system as the gold standard.

INTRODUCTION

Liver biopsy has long been the gold standard in liver fibrosis diagnosis. However, due to probable complications and sampling variabilities, the need for more accurate and non-invasive techniques has increased. 2D-SWE is a non-invasive technique used in the evaluation of liver stiffness and utilized more and more in routine clinical practice with recent advances and researches.

MATERIALS AND METHODS

In this retrospective single-center study, we included 46 pediatric age group patients who had a liver parenchymal biopsy and 2D-SWE evaluation regardless of etiology. For 2D-SWE, the LOGIQ E9 system (GE Medical Systems, Wisconsin, USA) and, for histopathological evaluation, METAVIR fibrosis scoring system were utilized. Patients were further subgrouped as clinically insignificant (METAVIR Score F0-1) and significant (METAVIR Score F2-4). The Kolmogorov-Smirnov and Mann-Whitney U tests were employed for statistical analysis. The diagnostic accuracy of 2D-SWE was assessed, and cutoff values were set by ROC curve analysis.

RESULTS

kPa values were statistically different between clinically significant and insignificant fibrosis patient groups (p < 0.001). kPa value of 8.92 was designated as the best cutoff value according to the Youden Index.

CONCLUSION

2D-SWE is one of the non-invasive techniques in the evaluation of liver fibrosis. Our findings suggest that 2D-SWE accurately differentiate clinically insignificant and significant liver fibrosis.

The utility of two-dimensional shear wave elastography and texture analysis for monitoring liver fibrosis in rat model

BACKGROUND

Liver fibrosis is a common pathological change caused by a variety of etiologies. Early diagnosis and timely treatment can reverse or delay disease progression and improve the prognosis. This study aimed to assess the potential utility of two-dimensional shear wave elastography and texture analysis in dynamic monitoring of the progression of liver fibrosis in rat model.

METHODS

Twenty rats were divided into control group (n = 4) and experimental groups (n = 4 per group) with carbon tetrachloride administration for 2, 3, 4, and 6 weeks. The liver stiffness measurement was performed by two-dimensional shear wave elastography, while the optimal texture analysis subsets to distinguish fibrosis stage were generated by MaZda. The results of elastography and texture analysis were validated through comparing with histopathology.

RESULTS

Liver stiffness measurement was 6.09 ± 0.31 kPa in the control group and 7.10 ± 0.41 kPa, 7.80 ± 0.93 kPa, 8.64 ± 0.93 kPa, 9.91 ± 1.13 kPa in the carbon tetrachloride induced groups for 2, 3, 4, 6 weeks, respectively (P < 0.05). By texture analysis, histogram and co-occurrence matrix had the most frequency texture parameters in staging liver fibrosis. Receiver operating characteristic curve of liver elasticity showed that the sensitivity and specificity were 95.0% and 92.5% to discriminate liver fibrosis and non-fibrosis, respectively. In texture analysis, five optimal parameters were selected to classify liver fibrosis and non-fibrosis.

CONCLUSIONS

Two-dimensional shear wave elastography showed potential applications for noninvasive monitoring of the progression of hepatic fibrosis, even in mild fibrosis. Texture analysis can further extract and quantify the texture features in ultrasonic image, which was a supplementary to further visual information and acquired high diagnostic accuracy for severe fibrosis.

[Abdominal manifestations in cystic fibrosis : Clinical review]

Cystic fibrosis (CF) is the most common fatal autosomal recessive disease in the Caucasian population. A mutation in the cystic fibrosis transmembrane regulator protein (CFTR) gene leads to the production of abnormally viscous mucus and secretions in the lungs of these patients. A similar pathology also occurs in other organs. In the abdomen, among others the gastrointestinal tract, the pancreas, and the hepatobiliary system are affected. The involvement of the pancreas leads to its exocrine and endocrine insufficiency. Hepatic manifestations include hepatic steatosis, focal biliary and multilobular cirrhosis, and portal hypertension. Biliary complications include cholelithiasis, microgallbladder, and sclerosing cholangitis. In the gastrointestinal tract, complications such as the distal intestinal obstruction syndrome, invaginations, chronic constipation, wall thickening, and fibrosis in the colon may occur. An important renal manifestation is nephrolithiasis. With currently rapidly increasing life expectancy of patients with cystic fibrosis, complications of extrapulmonary cystic fibrosis manifestations including hepatic and gastrointestinal malignancy could be an increasing cause of morbidity and mortality of these patients. It is therefore important for radiologists to know and recognize these clinical patterns and to monitor these manifestations in follow-up exams. Previous therapy of extrapulmonary manifestations has been largely symptomatic. Fortunately, the new CFTR modulators seem to represent an effective causal therapeutic approach here.

Advanced liver disease in Russian children and adolescents with chronic hepatitis C

Russia has one of the highest prevalences of paediatric chronic hepatitis C infection (CHC). Our aim was to provide a detailed characterization of children and adolescents with CHC including treatment outcomes. Thus, an observational study of children with CHC aged <18 years was conducted in three hepatology centres from November 2014 to May 2017. Of 301 children (52% male), 196 (65%) acquired HCV vertically, 70 (23%) had a history of blood transfusion or invasive procedures, 1 injecting drug use and 34 (11%) had no known risk factors. Median age at HCV diagnosis was 3.1 [interquartile range, IQR 1.1, 8.2] and 10.8 [7.4, 14.7] at last follow-up. The most common genotype was 1b (51%), followed by 3 (37%). Over a quarter of patients (84, 28%) had raised liver transaminases. Of 92 with liver biopsy, 38 (41%) had bridging fibrosis (median age 10.4 [7.1, 14.1]). Of 223 evaluated by transient elastography, 67 (30%) had liver stiffness ≥5.0 kPa. For each year, increase in age mean stiffness increased by 0.09 kPa (95% CI 0.05, 0.13, P < 0.001). There was significant correlation between liver stiffness and biopsy results (Tau-b = 0.29, P = 0.042). Of 205 treated with IFN-based regimens, 100 (49%) had SVR24. Most children (191, 93%) experienced adverse reactions, leading to treatment discontinuation in 6 (3%). In conclusion, a third of children acquired HCV via nonvertical routes and a substantial proportion of those with liver biopsy had advanced liver disease. Only half of children achieved SVR24 with IFN-based regimens highlighting the need for more effective and better-tolerated treatments with direct-acting antivirals. Further studies are warranted in Russia on causes and prevention of nonvertical transmission of HCV in children.

Usefulness of serum Wisteria floribunda agglutinin-positive Mac-2 binding protein in children with primary sclerosing cholangitis

BACKGROUND

Wisteria floribunda agglutinin-positive Mac-2 binding protein (WFA⁺ -M2BP) is a novel serum marker of hepatic fibrosis in adults with chronic hepatitis C. However, it remains unclear whether serum WFA⁺ -M2BP levels are associated with the progression of liver histology in primary sclerosing cholangitis (PSC).

METHODS

Twenty-eight children and adolescents with pediatric-onset PSC (male : female patient ratio, 20:8; median age at diagnosis, 9 years) were enrolled in this study. The relation between serum WFA⁺ -M2BP levels and clinical characteristics was retrospectively evaluated. Moreover, receiver operating characteristic (ROC) analysis was used to determine whether serum WFA⁺ -M2BP levels could be a reliable marker to identify PSC patients with advanced liver histology.

RESULTS

According to the Ludwig classification of liver histological stage, 28 patients were classified into the four stages. The WFA⁺ -M2BP level, aspartate aminotransferase (AST) to platelet ratio index (APRI), and hyaluronic acid correlated significantly with liver histological stage. Moreover, WFA⁺ -M2BP showed a significant positive correlation (P < 0.05) with autoimmune hepatitis overlap, AST, alanine aminotransferase (ALT), γ-glutamyltransferase, total bilirubin, immunoglobulin G, APRI, and hyaluronic acid. A ROC analysis was undertaken to distinguish the patients with advanced stage disease (stage 3-4) from those with early stage disease (stage 0-2). It showed that WFA⁺ -M2BP yielded the highest area under the ROC curve value (0.898) among four surrogate makers (APRI, 0.850; Fibrosis-4 index, 0.806; and AST/ALT ratio, 0.802). Moreover, WFA⁺ -M2BP yielded the highest sensitivity, specificity, positive predictive value, and negative predictive value among the four markers.

CONCLUSIONS

Serum WFA⁺ -M2BP levels are useful to identify patients with advanced liver histology in pediatric PSC.