Quantitative Shear-Wave Elastography of the Liver in Preterm Neonates with Intra-Uterine Growth Restriction

Anatomical and functional changes of the fetal adrenal gland in intrauterine growth restriction

OBJECTIVE

The aim of this study was to demonstrate the establishment of adrenal sparing in intrauterine growth restricted (IUGR) human fetuses. IUGR fetuses are a subgroup of small for gestational age (SGA) fetuses that are unable to reach their own growth potential because of chronic hypoxia and undernutrition. We hypothesized that in IUGR fetuses the adrenal gland is relatively larger and secretion of noradrenaline (NA), adrenaline (A), and cortisol is increased.

STUDY DESIGN

This is a prospective observational study including 65 singleton pregnancies (42 IUGR and 23 controls). Using two-dimensional ultrasound, we measured fetal adrenal diameters and adrenal/abdominal circumference (AD/AC) ratio between 25 and 37 weeks. We considered only one measurement per fetus. In 21 pregnancies we also measured NA, A, and cortisol levels in arterial and venous fetal cord blood collected at the time of delivery.

RESULTS

The AD/AC ratio was significantly higher in IUGR fetuses than in controls. Cord NA and A levels were significantly higher in IUGR fetuses than in controls. An increase in cortisol secretion in IUGR fetuses was observed but the difference was not statistically significant.

CONCLUSIONS

Adrenal sparing correlates with a relative increase in adrenal measurements and function.

Postneonatal mortality of severely small for gestational age extremely low birth weight infants

BACKGROUND

Infants born with weights below the 10th percentile of the expected birth weight for gestational age, defined as small for gestational age (SGA), have an increased risk of neonatal mortality and prematurity-related complications. However, the relationship between SGA and postneonatal (28 days to <1 year) mortality among extremely low birth weight infants (ELBWIs) remains uncertain. Hence, this study aimed to investigate the association between birth weight percentiles and postneonatal mortality in ELBWIs.

METHODS

A cohort of ELBWIs with a gestational age greater than 23 weeks who were admitted to Osaka Women's and Children's Hospital between 2008 and 2019 were considered eligible. Infants with major congenital anomalies, those large for their gestational age, or those who died within 28 days of birth were excluded. Baseline characteristics and outcomes of the three groups of ELBWIs-severe SGA (sSGA; birth weight, <3rd percentile), moderate SGA (mSGA; birth weight, 3rd to <10th percentile), and appropriate for gestational age (AGA; birth weight, 10th to <90th percentile)-were compared. Logistic regression analysis was used to identify perinatal factors associated with postneonatal mortality in sSGA infants.

RESULTS

sSGA ELBWIs demonstrated higher incidence of meconium obstruction (25% vs. 8.3% vs. 7.6%, P < 0.001), cholestasis (21% vs. 4.2% vs. 9.7%, P < 0.003), and postneonatal mortality (7.3% vs. 0% vs. 0.7%, P < 0.004) than mSGA and AGA ELBWIs. In the logistic regression analysis, cholestasis (odds ratio, 30.1; 95% confidence interval, 2.98-304) and sepsis (odds ratio, 13.5; 95% confidence interval, 1.06-173) were significantly related to postneonatal mortality among ELBWIs with sSGA. The leading cause of postneonatal mortality in sSGA ELBWIs was liver failure (55.5%).

CONCLUSION

sSGA ELBWIs exhibited a higher rate of postneonatal mortality compared to mSGA and AGA ELBWIs. Therefore, strategies aimed at preventing liver dysfunction in severely cholestatic ELBWIs with sSGA are necessary.

MR and Ultrasound Elastography for Fibrosis Assessment in Children: Practical Implementation and Supporting Evidence-AJR Expert Panel Narrative Review

Quantitative MRI and ultrasound biomarkers of liver fibrosis have become important tools in the diagnosis and clinical management of children with chronic liver disease (CLD). In particular, MR elastography (MRE) is now routinely performed in clinical practice to evaluate the liver for fibrosis. Ultrasound shear-wave elastography has also become widely performed for this purpose, especially in young children. These noninvasive methods are increasingly used to replace liver biopsy for the diagnosis, quantitative staging, and treatment monitoring of patients with CLD. Although ultrasound has advantages of portability and lower equipment cost, available evidence indicates that MRI may have greater reliability and accuracy in liver fibrosis evaluation. In this AJR Expert Panel Narrative Review, we describe how, why, and when to use MRI- and ultrasound-based elastography methods for liver fibrosis assessment in children. Practical approaches are discussed for adapting and optimizing these methods in children, with consideration of clinical indications, patient preparation, equipment requirements, acquisition technique, as well as pitfalls and confounding factors. Guidance is provided for interpretation and reporting, and representative case examples are presented.

Virtual touch IQ elastography in the evaluation of fetal liver and placenta in pregnancies with gestational diabetes mellitus

OBJECTIVES

Elastography is considered a novel technique in the assessment of placenta parenchymal elasticity and very few data present the feasibility of elastography on human fetal tissue. This study aims to investigate the feasibility of fetal liver and placenta elastography and differences in pregnancies with GDM.

METHODS

Fifty-five women with GDM and 40 women with uncomplicated pregnancy as the control group was enrolled prospectively in this case-control study. Fetal liver VTIQ and placenta VTIQ elastography were performed between 25 and 39 weeks of pregnancy.

RESULTS

Mean placenta thickness at the level of umbilical cord insertion was significantly higher in the GDM group than in the control group (p=0.034). VTIQ elastography elasticity velocity (kPa) examinations revealed similar mean placenta and mean fetal liver stiffness in both groups. A weak to moderate correlation was observed between the mean elasticity of the placenta and the mean elasticity of the fetal liver (r=0.310; p=0.004).

CONCLUSIONS

Elastography may provide valuable information of especially on fetal tissue development and pathology. While placenta and fetal liver VTIQ elastography are feasible in pregnancy, the diagnostic value of these examinations in GDM is not certain and it seems to be that significant differences in SWE examinations that reflect structural changes in fetal tissue or placenta are more prominent in more chronic conditions such as type 1 and type 2 diabetes mellitus.

Prenatal quantification of human foetal lung and liver elasticities between 24 and 39 weeks of gestation using 2D shear wave elastography

Objectives

To quantify and model normal foetal lung and liver elasticities between 24 and 39 weeks of gestation (WG) using two-dimensional shear wave elastography (2D-SWE). To assess the impact of the distance between the probe and the target organ on the estimation of elasticity values.

Methods

Measurements of normal foetal lungs and liver elasticity were prospectively repeated monthly between 24 and 39 WG in 72 foetuses using 2D-SWE. Elasticity was quantified in the proximal lung and in the region inside the hepatic portal sinus. The distance between the probe and the target organ was recorded. Trajectories representing foetal lung and liver maturation from at least 3 measurements over time were modelled.

Results

The average elasticity for the lung and liver was significantly different from 24 WG to 36 WG (p < 0.01). Liver elasticity increased during gestation (3.86 kPa at 24 WG versus 4.45 kPa at 39 WG). From 24 WG to 32 WG, lung elasticity gradually increased (4.12kPa at 24 WG, 4.91kPa at 28 WG, 5.03kPa at 32 WG, p < 0.002). After 32 WG, lung elasticity decreased to 4.54kPa at 36 WG and 3.94kPa at 39 WG. The dispersion of the average elasticity values was greater for the lung than for the liver (p < 0.0001). Variation in the elasticity values was less important for the liver than for the lung. The values were considered valid and repeatable except for a probe-lung distance above 8cm.

Conclusion

Foetal lung and liver elasticities evolve differently through gestation. This could reflect the tissue maturation of both organs during gestation.

Trial registration

clinicaltrials.gov identifier: NCT03834805

Key Points

• Prenatal quantification of foetal lung elasticity using 2D shear wave elastography could be a new prenatal parameter for exploring foetal lung maturity.

• Liver elasticity increased progressively from 24 weeks of gestation (WG) to 39 WG, while lung elasticity increased first between 24 and 32 WG and then decreased after 32 WG.

• The values of elasticity are considered valid and repeatable except for a probe-lung distance above 8cm.

Cholestasis after very preterm birth was associated with adverse neonatal outcomes but no significant long-term liver disease: A population-based study

AIM

To describe outcome linked to neonatal cholestasis in a defined cohort of very preterm infants.

METHODS

Population-based retrospective case-control study of preterm infants, gestational age <30 weeks, surviving for 28 days, in Stockholm County. Cholestasis was defined as conjugated bilirubin ≥30 μmol/L exceeding 20% of total level at least twice and graded as high if exceeding 100 μmol/L. Cholestatic cases were matched on gestational week with two non-cholestatic controls.

RESULTS

The incidence rate of cholestasis was 37/250 (14.8%), with increasing rates in lower gestational weeks. Perinatal factors associated with cholestasis were pre-eclampsia and being born small for gestational age. Cholestatic infants had three times more bronchopulmonary dysplasia and eight times more retinopathy of prematurity. The mortality was 13.5% in cholestatic infants versus 2.7% in controls (P = .040). All deceased cholestatic infants had high-grade cholestasis. No surviving infants developed chronic liver disease by 10 years of age.

CONCLUSION

Cholestasis was common in very preterm infants and linked to disease severity and adverse outcome. Cholestasis may be an independent risk factor for bronchopulmonary dysplasia and retinopathy of prematurity and more severe cholestasis associated with increased mortality. Cholestasis was not associated with chronic liver disease later in childhood.

Pterostilbene attenuates liver injury and oxidative stress in intrauterine growth-retarded weanling piglets

OBJECTIVES

The aim of the present study was to investigate the potential of pterostilbene, a beneficial component primarily found in blueberries, to alleviate the intrauterine growth retardation (IUGR)-induced early liver injury and oxidative stress in a porcine model.

METHODS

Thirty-six IUGR piglets and an equal number of normal birth weight (NBW) counterparts received a diet with or without pterostilbene (250 mg/kg diet) during the first week post-weaning. Parameters related to the hepatic injury, oxidative stress, and antioxidant defense mechanisms were analyzed.

RESULTS

Relative to NBW, IUGR induced liver injury, which corresponded to increments in circulating alanine transaminase activity and hepatic apoptotic cell rate, superoxide radical generation, and the accumulation of oxidative damage products (P < 0.05). Administering pterostilbene reduced plasma transaminase activities, decreased hepatocyte apoptosis rate, and prevented the augmented levels of hepatic superoxide anion, 8-hydroxy-2 deoxyguanosine, and 4-hydroxynonenal-modified protein (P < 0.05). In terms of the hepatic antioxidant function, pterostilbene was efficient in improving the superoxide dismutase activity and the metabolic cycle between reduced glutathione and its oxidized form (P < 0.05). The pterostilbene-supplemented diet facilitated the nuclear translocation of nuclear factor erythroid-2-related factor 2 (NRF2) and promoted the expression levels of superoxide dismutase 2 in the liver of IUGR piglets (P < 0.05).

CONCLUSION

This study indicates that pterostilbene treatment has an auxiliary therapeutic potential to ameliorate early liver injury in IUGR neonates, presumably by stimulating the NRF2 signals and the associated antioxidant function.

Shear wave elastography correlates with liver fibrosis scores in pediatric patients with liver disease

BACKGROUND

While liver biopsy remains the gold standard, given the procedure risks and sampling errors, there is a need for reliable noninvasive biomarkers of hepatic fibrosis.

OBJECTIVE

Determine the accuracy of two-dimensional shear wave elastography (2-D SWE) in predicting the histological severity of liver fibrosis in pediatric patients with known or suspected liver disease.

MATERIALS AND METHODS

Subjects 0-18 years old with known or suspected liver disease and liver biopsy within 30 days (n=70) were included. Comparisons by 2-D SWE were made to a control group (n=79). Two-dimensional SWE was performed using the GE LOGIQ E9 system. Liver biopsy specimens were scored according to METAVIR and Ishak scoring systems using Spearman's Rho correlation. Receiver operator characteristic (ROC) analysis, Kruskal-Wallis and Mann-Whitney U tests were conducted.

RESULTS

Control group median 2-D SWE measurements were lower than in subjects with any degree of liver fibrosis (P<0.001). Those with METAVIR F0 and Ishak 0 scores had significantly lower median 2-D SWE measurements (1.35 m/s; 1.36 m/s) than those with more advanced liver disease (F1-F3: 1.49-1.62 m/s; 1-4: 1.45-1.63 m/s) (P<0.05 for all), whereas the 2-D SWE in the higher scores were similar. Results did not differ between METAVIR and Ishak scores for any degree of fibrosis. Fibrosis scores moderately correlated with median 2-D SWE measurements (r_s=0.43). The area under the curve for F1 compared to combined control/F0 was 0.89 (95% confidence interval [CI] 0.83-0.95; P<0.001) with sensitivity of 94.6% and specificity of 78.6%. Results for Ishak score 1 were similar. The ideal cutoff value for identifying fibrosis was determined to be 1.29 m/s.

CONCLUSION

The liver 2-D SWE measurements correlated with the histological liver fibrosis scores, regardless of the histopathological scoring system, although 2-D SWE was better at identifying patients with early fibrosis, not at distinguishing among the individual fibrosis levels. Two-dimensional SWE using the GE LOGIQ US system is useful for identifying pediatric patients at risk for liver fibrosis.

Feasibility of two-dimensional ultrasound shear wave elastography of human fetal lungs and liver: A pilot study

PURPOSE

The first aim was to evaluate feasibility and reproducibility of 2-dimensional ultrasound (2D) shear wave elastography (SWE) of human fetal lungs and liver between 24 and 34weeks of gestation. The second aim was to model fetal lung-to-liver elastography ratio (LLE ratio) and to assess its variations according to gestational age and maternal administration of corticosteroids.

MATERIAL AND METHODS

2D-SWE examinations were prospectively performed in fetuses of women with an uncomplicated pregnancy (group 1) and fetuses of women with a threatened preterm labor requiring administration of corticosteroids (group 2). Two 2D-SWE examinations were performed at "day 0" and "day 2" in group 1; before and 24hours after a course of corticosteroid in group 2. Three operators performed 2 cycles of 3 measurements on the lung (regions A1, A2, A3) and the liver (regions IV, V, VI). Repeatability and reproducibility of measurements were calculated. The fetal LLE ratio was modeled from the most reproducible regions.

RESULTS

Fifty-five women were enrolled in group 1 and 48 in group 2. For the lung, 8.6% of measurements were considered invalid and 6.9% for the liver. The most reproducible region for the lung was A3 [ICC between 0.70 (95% CI: 0.42-0.85) and 0.78 (95% CI: 0.48-0.90)] and region VI for the liver [ICC between 0.70 (95% CI: 0.40-0.85) and 0.84 (95% CI: 0.60-0.94)]. According to gestational age, a moderate positive linear correlation was found for stiffness values of A3 (R=0.56), V (R=0.46) and VI (R=0.44). LLE ratio values at "day 0" were not different between the two groups but decreased at "day 2" in group 2 (0.2; 95% CI: 0.07-0.34; P<0.001).

CONCLUSION

Quantitative fetal lung and liver stiffness measurements are possible with 2D-SWE with acceptable reproducibility.

Technical performance of shear wave elastography for measuring liver stiffness in pediatric and adolescent patients: a systematic review and meta-analysis

OBJECTIVE

To assess the technical performance (proportion of technical failure and unreliable measurements) of shear wave elastography (SWE) for assessing liver stiffness in pediatric and adolescent patients.

METHODS

We searched Ovid-MEDLINE and EMBASE databases for eligible studies and selected original articles investigating transient elastography (TE), point shear wave elastography (pSWE), or two-dimensional SWE (2D-SWE) for measuring liver stiffness in pediatric and adolescent patients. A quantitative synthesis of studies reporting technical failures and/or unreliable measurements of TE, pSWE, or 2D-SWE is presented. Meta-analytic pooling was conducted using the random effects model. Meta-regression analysis was conducted to explore potential causes of heterogeneity.

RESULTS

Forty of 69 studies (58%) provided technical performance information. Technical failure data were reported in 3 TE, 6 pSWE, and 8 2D-SWE studies. Unreliable measurement data were provided in 21 TE, 4 pSWE, and 1 2D-SWE study. The pooled proportion of unreliable measurements of TE was 12.1%. Meta-regression analysis showed that the study population size and readers' blinding to pathologic results affected the study's heterogeneity. The pooled proportions of technical failure during pSWE and 2D-SWE were 4.1% and 2.2%, respectively, demonstrating no significant difference between the techniques.

CONCLUSIONS

We reviewed the technical performance of SWE, especially the rate of unreliable measurements from TE studies and rates of technical failure from pSWE and 2D-SWE studies. Considering the importance of technical performance for clinical validation of SWE, numbers of and reasons for technical failure and unreliable measurements should be reported in future studies. Further efforts are necessary to standardize SWE reliability criteria.

KEY POINTS

• Most TE studies reported rate of unreliable measurements, whereas pSWE and 2D-SWE studies were likely to report rates of technical failure. • The pooled proportion of unreliable measurements of TE was 12.1%. • The pooled proportions of technical failure during pSWE and 2D-SWE were 4.1% and 2.2%, respectively, demonstrating no significant difference between the techniques.

Feasibility of 2-D ultrasound shear wave elastography of fetal lungs in case of threatened preterm labour: a study protocol

INTRODUCTION

2-D ultrasound shear wave elastography (SWE) could be considered as a new noninvasive tool for monitoring fetal lung development based on evaluation of mechanical properties during pregnancy. Interesting results are available concerning the use of SWE on developing organs, especially on premature infants and animal models. The main objective in this study is to evaluate the feasibility of 2-D SWE in human fetal lungs between 24 and 34 weeks of gestation (WG). The secondary objective is to modellise fetal lung-to-liver elastography ratio (LLE ratio) and to assess variations between normal lung and lung surfactant-enriched after a corticosteroids course indicated for a threatened preterm labour (TPL).

METHODS/DESIGN

A prospective case-control study will be performed between 24 and 34 WG. Fetal lungs and liver will be explored by SWE into two groups: fetuses of women with an uncomplicated pregnancy (control group) and fetuses of women with a TPL requiring administration of corticosteroids (cases group). LLE ratio will be defined as the value of the lung elasticity divided by the value of the liver elasticity.Primary judgement criterion is the value of elasticity modulus expressed in kilopascal. Lungs and liver will be explored through three measurements to define the most reproducible regions with the lowest intra- and inter-observer variability. Feasibility will be evaluated by assessing the number of examinations performed and the number of examinations with interpretable results. Intra- and inter-observer reproducibility will be evaluated by means of the intra-class correlation coefficient.

ETHICS AND DISSEMINATION

Approval of the study protocol was obtained from the human ethical research committee (Comité de Protection des Personnes EST II, process number 15/494) and the French National Agency for Medicines and Health Products Safety (process number 2015-A01575-44). All participants will sign a statement of informed consent.

TRIAL REGISTRATION NUMBER

NCT02870608; Recruiting.

Ultrasound measurement of fetal adrenal gland in fetuses with intrauterine growth restriction, an early predictive method for adverse outcomes

OBJECTIVES

Comparing the sonographic measurements of fetal adrenal gland in pregnancies with intrauterine growth restriction (IUGR) versus healthy controls and to assess whether the changes in adrenal gland measurements could predict adverse pregnancy outcomes in IUGR fetuses.

METHODS

This prospective cohort study evaluated 97 pregnant women (48 with IUGR pregnancies and 49 healthy controls) during their third gestational trimester. All mothers underwent two dimensional ultrasonography of the fetal adrenal gland, and the fetal zone in transverse, sagittal, and coronal planes. Adrenal gland volume (AGV) and fetal zone volume (FZV) were calculated and corrected (c) for fetal weight. The mothers were then followed until delivery.

RESULTS

Fetuses in the IUGR group had larger corrected adrenal gland volume (c_AGV) and smaller corrected fetal zone volume (c_FZV) compared to the fetuses in the control groups (p < .001). In the IUGR group, significantly smaller c_AGV and higher fetal/adrenal were detected in IUGR fetuses who had nonreassuring fetal status before delivery, preterm birth, very low birth weight delivery, and also those who required neonatal intensive care unit admission (p < .01 for all).

CONCLUSIONS

Third trimester fetal adrenal gland sonography could potentially be used as an easy noninvasive method for identifying those IUGR fetuses who might have poorer outcomes.

Role of Point Shear Wave Elastography in the Determination of the Severity of Fibrosis in Pediatric Liver Diseases With Pathologic Correlations

OBJECTIVES

Our aims in this study were as follows: (1) to determine the cutoff value that can distinguish between advanced liver fibrosis and normal liver tissue for two different elastographic techniques; (2) to determine the cutoff value that can distinguish mild liver fibrosis from normal liver tissue for the techniques; and (3) to assess tissue stiffness in nonalcoholic fatty liver disease (NAFLD).

METHODS

Seventy-five patients assessed for liver biopsy on the same day were evaluated by point shear wave elastography. Thirty-one healthy children and 11 children with NAFLD were also evaluated. A 9L4 transducer with Virtual Touch quantification (VTQ) and Virtual Touch imaging and quantification (VTIQ) modes (Siemens Medical Solutions, Mountain View, CA) was used for quantification.

RESULTS

The shear wave speed of the patients with NAFLD was higher than that of the control group. The only predictive factor for VTQ and VTIQ was the histologic fibrosis score (model-adjusted R²  = 0.56 for VTQ and 0.75 for VTIQ). Shear wave speed cutoffs were 1.67 m/s for VTQ and 1.56 m/s for VTIQ in detecting fibrosis or inflammation and 2.09 m/s for VTQ and 2.17 m/s for VTIQ in discriminating children with low and high histologic liver fibrosis scores.

CONCLUSIONS

The VTQ and VTIQ values reveal high-grade histopathologic fibrosis and have high success rates when distinguishing high- from low-grade fibrosis. However, they have limited success rates when differentiating low-grade fibrosis from normal liver tissue.