Acoustic radiation force impulse (ARFI) imaging with Virtual Touch Tissue Quantification in liver disease associated with cystic fibrosis in children

WFUMB Guideline/Guidance on Liver Multiparametric Ultrasound: Part 1. Update to 2018 Guidelines on Liver Ultrasound Elastography

The World Federation for Ultrasound in Medicine and Biology (WFUMB) endorsed the development of this document on multiparametric ultrasound. Part 1 is an update to the WFUMB Liver Elastography Guidelines Update released in 2018 and provides new evidence on the role of ultrasound elastography in chronic liver disease. The recommendations in this update were made and graded using the Oxford classification, including level of evidence (LoE), grade of recommendation (GoR) and proportion of agreement (Oxford Centre for Evidence-Based Medicine [OCEBM] 2009). The guidelines are clinically oriented, and the role of shear wave elastography in both fibrosis staging and prognostication in different etiologies of liver disease is discussed, highlighting advantages and limitations. A comprehensive section is devoted to the assessment of portal hypertension, with specific recommendations for the interpretation of liver and spleen stiffness measurements in this setting.

Towards a Standardized Classification of the Hepatobiliary Manifestations in Cystic Fibrosis (CFHBI): A Joint ESPGHAN/NASPGHAN Position Paper

The broad spectrum of hepatobiliary involvement in cystic fibrosis (CF) has been commonly referred to as cystic fibrosis liver disease (CFLD). However, differences in the definitions of CFLD have led to variations in reported prevalence, incidence rates, and standardized recommendations for diagnosis and therapies. Harmonizing the description of the spectrum of hepatobiliary involvement in all people with CF (pwCF) is deemed essential for providing a reliable account of the natural history, which in turn supports the development of meaningful clinical outcomes in patient care and research. Recognizing this necessity, The European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) commissioned and tasked a committee to develop and propose a systematic classification of the CF hepatobiliary manifestations to increase uniformity, accuracy, and comparability for clinical, registry, and research purposes. This report describes the committee's combined expert position statement on hepatobiliary involvement in CF, which has been endorsed by NASPGHAN and ESPGHAN. We recommend using CFHBI (Cystic Fibrosis Hepato-Biliary Involvement) as the updated term to describe and classify all hepatobiliary manifestations in all pwCF. CFHBI encompasses the current extensive spectrum of phenotypical, clinical, or diagnostic expressions of liver involvement observed in pwCF. We present a schematic categorization of CFHBI, which may also be used to track and classify the changes and development of CFHBI in pwCF over time. The proposed classification for CFHBI is based on expert consensus and has not been validated for clinical practice and research purposes. Achieving validation should be an important aim for future research.

Cystic fibrosis and noninvasive liver fibrosis assessment methods in children

BACKGROUND

Noninvasive assessments of liver fibrosis are currently used to evaluate cystic fibrosis (CF)-related liver disease. However, there is scarce data regarding their repeatability and reproducibility, especially in children with CF. The present study aimed to evaluate the repeatability and reproducibility of transient elastography (TE) (FibroScan®) and point shear-wave elastography using virtual touch quantification (pSWE VTQ) in children with CF.

METHODS

TE and pSWE VTQ were performed in 56 children with CF by two different operators. Analysis of repeatability and reproducibility was available in 33 patients for TE and 46 patients for pSWE VTQ. Intra- and interobserver agreement were assessed using the intraclass correlation coefficient (ICC) and their 95% confidence interval (CI), and Bland and Altman graphs.

RESULTS

For TE, ICC was 0.91 (0.83-0.95) for intraobserver agreement and 0.92 (95% CI: 0.86-0.96) for interobserver agreement. For pSWE VTQ, ICC was 0.83 (0.72-0.90) for intraobserver agreement and 0.67 (0.48-0.80) for interobserver agreement.

CONCLUSIONS

Both technics can be proposed in the follow-up of patients, according to their availability in CF centers.

IMPACT

This study shows that TE and pSWE VTQ are reliable methods to evaluate liver fibrosis in children with CF. This study shows for the first time that TE and pSWE VTQ are both repeatable and reproducible in children with CF. These data indicate that both TE and pSWE VTQ can be proposed for the follow-up of patients with CF, according to their availability in each CF center.

Non-invasive tools for detection of liver disease in children and adolescents with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a multi-organ genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene which encodes the CFTR protein. CF-associated liver disease (CFLD) is a common complication; diagnosis is based on clinical, laboratory findings and abdominal imaging. However, non-invasive diagnostic approaches are needed to early detect CFLD, its progression and severity. Recent studies demonstrate a possible role of point shear wave elastography (p-SWE) with liver stiffness measurement (LSM) as a tool for CFLD diagnosis also in children. This non-invasive technique measures liver stiffness to assess liver fibrosis and is suggested to be less operator-dependent compared to ultrasonography. Aim of our prospective observational study is to investigate the role of p-SWE with LSM for CFLD diagnosis in children and adolescents with CF and to compare this finding with aspartate aminotransferase to platelet ratio index (APRI), fibrosis index based on four factors (FIB-4) and gamma-glutamyl-transpeptidase to platelet ratio (GPR) indices.

METHODS

Fifty-nine children with CF, who had routinely undergone abdominal imaging, were consecutively enrolled. Laboratory findings and clinical data were recorded, as abdominal ultrasound and shear wave elastography at baseline. The cases were divided into two groups based on collected data and classified as CFLD and CFnoLD (without liver disease) according to Debray criteria. APRI, FIB-4 and GPR fibrosis indices were also evaluated.

RESULTS

Twenty-four/59 (40.7%) were defined as CFLD. LSM test is superior to the APRI (P<0.001), the FIB-4 test (P=0.001) and the GPR test for early detection of liver fibrosis. LSM had an area under receiver operating characteristic (ROC) curve =0.818 (95% CI: 0.702-0.934) compared with APRI (0.571, 95% CI: 0.421-0.722), FIB-4 (0.656, 95% CI: 0.511-0.801) and GPR (0.632, 95% CI: 0.485-0.779). At a cut-off of ≥6.2 LSM show a sensitivity of 75.0% and a specificity of 88.6%.

CONCLUSIONS

LSM by transient p-SWE is a non-invasive, highly accessible, reliable, and reproducible test that can be used to assess early detection of liver fibrosis and its severity in children and adolescents with CF, limiting the use of liver biopsy. These preliminary observations point to the need of larger study population to confirm our data.

Diagnosis of Acute Rejection of Liver Grafts in Young Children Using Acoustic Radiation Force Impulse Imaging

OBJECTIVE. Frequency of acute rejection (AR) after pediatric liver transplant remains high despite progress in immunosuppression. Liver biopsy (LB) is the reference standard for the diagnosis of AR despite its potential for morbidity. The purpose of our study was to evaluate the ability of acoustic radiation force impulse (ARFI) imaging to distinguish AR from other causes of short- and medium-term liver dysfunction and to identify liver transplant cases with normal liver function. MATERIALS AND METHODS. ARFI imaging was used to evaluate shear wave velocity (SWV) after liver transplant in young children. All pediatric liver grafts that had LB and ARFI examination between January 2014 and December 2017 were included in this retrospective study. Results of LB were compared with those of SWV. Collected data included age at biopsy and transplant, sex, weight, height, body mass index, interval between liver transplant and shear wave elastography and LB, kind of graft, type of donor, and diagnosis at transplant. ROC curve analysis was performed to assess the diagnostic performance of SWV. Optimal cutoff of SWV using ARFI imaging in predicting AR was identified using the Youden index. RESULTS. Statistical analysis was performed on 54 children; six of the original 60 were excluded because of confounding alterations or changes in outcome. Median SWV was higher in patients with AR (2.03 m/s; interquartile range [IQR], 1.80-2.45 m/s) compared with those with idiopathic hepatitis (1.33 m/s; IQR, 1.12-1.53 m/s), portal hypertension (1.42 m/s; IQR, 1.32-1.72 m/s), cholangitis (1.56 m/s; IQR, 1.07-1.62 m/s) or normal liver function (1.23 m/s; IQR 1.12-1.29 m/s) at protocol biopsies (all comparisons, p < 0.01). SWV higher than 1.73 m/s was predictive for AR (AUC, 0.966). SWV also showed good diagnostic accuracy in normal liver function (AUC, 0.791). ARFI imaging was not predictive for hepatitis (AUC, 0.402), portal hypertension (AUC, 0.556), or cholangitis (AUC, 0.420). CONCLUSION. ARFI imaging could be routinely used in place of LB in pediatric patients with liver dysfunction after liver transplant, restricting indication and risks of biopsy to selected cases.

Molecular Heterogeneity in Cystic Fibrosis

We aimed to evaluate type, frequency, and variety of pathogenic variants according to clinical and demographic features of children diagnosed with cystic fibrosis (CF). Twenty-five CF patients were evaluated retrospectively. Patients' demographics, physical examination, imaging, laboratory, and molecular pathogenic variant analysis findings were evaluated. Phe508del was the most frequently (33.3%) detected pathogenic variant, followed by point pathogenic variants E92K, 1898 + lGA/7T/7T, and 2789 + 5GA, respectively. Statistically higher rates of pathogenic variants were detected in male patients. The most frequently detected pathogenic variant was Phe508del. The identification of nine additional pathogenic variants of Phe508del revealed the heterogeneous nature of the CF.

Normal values of shear wave velocity in liver tissue of healthy children measured using the latest acoustic radiation force impulse technology

BACKGROUND

Several studies have demonstrated the feasibility and effectiveness of using ultrasound elastography to assess liver tissue stiffness. Virtual touch imaging quantification (VTIQ) based on acoustic radiation force impulse imaging has been developed as a latest and noninvasive method for assessing liver stiffness in children.

AIM

To determine the standard value in healthy children, and to identify possible factors that might influence the VTIQ measurement.

METHODS

With the ethical approval, 202 children between 1 month and 15 years old were included in this study. None of them had any liver or systematic diseases. All children had a normal ultrasound scan and normal body mass index (BMI) range. The subjects were divided into four age and BMI groups. The effects of gender, age, liver lobe, measurement depth, and BMI on liver elasticity were investigated.

RESULTS

A significant correlation was found between age and shear wave velocity (SWV) value. At measurement depths of 1.5 cm and 2.0 cm in the left lobe, there were significant differences among the age groups. SWV values were significantly negatively correlated with the measurement depth. Gender, liver lobe, and BMI showed no significant effect on the SWV values. Age and BMI may influence the quality of the elastogram.

CONCLUSION

VTIQ is a noninvasive technique that is feasible to measure liver stiffness in children. The afore-mentioned velocity value obtained utilizing VTIQ method could be used as reference value for normal liver stiffness in children.

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.

Point shear wave elastography of the pancreas in patients with cystic fibrosis: a comparison with healthy controls

PURPOSE

Manifestations of cystic fibrosis in the pancreas are gaining in clinical importance as patients live longer. Conventional ultrasonography and point shear wave elastography (pSWE) imaging are non-invasive and readily available diagnostic methods that are easy to perform. The aim of this study was to perform conventional ultrasonography and obtain pSWE values in the pancreases of patients with cystic fibrosis and to compare the findings with those of healthy controls.

METHODS

27 patients with cystic fibrosis (13 women/14 men; mean age 27.7 ± 13.7 years; range 9-58 years) and 60 healthy control subjects (30 women/30 men; mean age 30.3 ± 10.0 years; range 22-55 years) underwent examinations of the pancreas with conventional ultrasound and pSWE imaging.

RESULTS

Patients with cystic fibrosis have an echogenic pancreatic parenchyma. We found cystic lesions of the pancreas in six patients. pSWE imaging of the pancreatic parenchyma gave significantly lower shear wave velocities in patients with cystic fibrosis than in the control group (1.01 m/s vs 1.30 m/s; p < 0.001).

CONCLUSIONS

Using pSWE imaging in vivo, we have shown that the pancreas is considerably softer in patients with cystic fibrosis than in a healthy control population.

Diagnosis, follow-up and treatment of cystic fibrosis-related liver disease

PURPOSE OF REVIEW

To provide an insight and overview of the challenges in the diagnosis, follow-up and treatment of cystic fibrosis-related liver disease (CFLD).

RECENT FINDINGS

The variable pathophysiology of CFLD complicates its diagnosis and treatment. A 'gold standard' for CFLD diagnosis is lacking. Over the past years, new techniques to diagnose features of CFLD, such as transient elastography, have been investigated. Although most of these tests confirm cystic fibrosis-related liver involvement (CFLI), they are, however, not suitable to distinguish various phenotypical presentations or predict progression to clinically relevant cirrhosis or portal hypertension. A combined initiative from the European and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition has been started, aimed to obtain consensus on CFLD criteria and definitions. Currently, only ursodeoxycholic acid is used in CFLD treatment, although it has not been convincingly demonstrated to change the natural course of the disease. Drugs that directly target cystic fibrosis transmembrane conductance regulator protein dysfunction show promising results; however, more long-term follow-up and validation studies are needed.

SUMMARY

CFLD is an umbrella term referring to a wide variety of liver manifestations with variable clinical needs and consequences. CFLD with portal hypertension is the most severe form of CFLD due to its significant implications on morbidity and mortality. The clinical relevance of other CFLI is uncertain. Consensus on CFLD definitions is essential to validate new diagnostic tools and therapeutic outcome measures.

Assessment of Liver Disease Progression in Cystic Fibrosis Using Transient Elastography

OBJECTIVES

Cystic fibrosis-related liver disease (CFLD) can develop silently in early life and approximately 10% of children with cystic fibrosis (CF) become cirrhotic before adulthood. Clinical, biological, and ultrasound criteria used to define CFLD often reveal liver involvement at an advanced stage. The aim of this retrospective study was to assess the progression of liver stiffness measurement (LSM) in pediatric patients with CF.

METHODS

The change of LSM, expressed as kPa/year and %/year, was measured using transient elastography (Fibroscan) in 82 children with CF (median age: 6.8 years, interquartile range [IQR]: 5.8). Mean time interval between the 2 LSM was 3.5 years.

RESULTS

Median initial liver stiffness was 3.7 kPa (IQR: 1.3), and then progressed by 0.23 kPa/year, that is, 6%/year. The 7 patients who developed CFLD had a higher initial level of alanine aminotransferase (50 [IQR: 15] vs 30 [IQR: 18], P = 0.0001) and presented a more rapid progression of LSM (0.94 vs 0.23 kPa/year, P = 0.02).

CONCLUSIONS

The present study shows that the slope of worsening of liver stiffness is greater in patients who will develop CFLD, suggesting that annual transient elastography may be useful to detect risk of severe liver disease at an earlier stage.

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.

Ultrasound Elastography Is Useful for Evaluation of Liver Fibrosis in Children-A Systematic Review

OBJECTIVES

Adult studies have proven ultrasound elastography as a validated measure of liver fibrosis. The present study aimed to review the available literature on ultrasound elastography in children to evaluate the ability of the method to distinguish healthy from fibrotic liver tissue and investigate whether cutoff values for liver fibrosis in children have been established.

METHODS

A literature search was performed in MEDLINE, EMBASE, the Cochrane Library, and Web of Science to identify studies on ultrasound elastography of the liver in children. Only original research articles in English concerning ultrasound elastography in children with and without liver disease, younger than 18 years, were included. All reference lists of the included articles were hand-searched for further references.

RESULTS

Twenty-seven articles were included. Elastography in children without liver disease was investigated in 14 studies and were comparable to those existing for adults. Twelve studies compared elastography with liver biopsy in children with liver disease and found that cirrhosis was correctly diagnosed, whereas it was more difficult to assess severe fibrosis correctly. For the distinction between no, mild, and moderate fibrosis in children with liver disease the method was less accurate. Ultrasound elastography was able to differentiate between children with and without liver fibrosis. In children without liver disease ultrasound, elastography showed consistent liver stiffness values comparable to those found in adults. No fibrosis-specific cutoffs were proposed.

CONCLUSIONS

Ultrasound elastography was able to diagnose cirrhosis, distinguish healthy from fibrotic liver tissue, and showed consistent liver stiffness values in children without liver disease.

Ultrasound and Point Shear Wave Elastography in Livers of Patients with Primary Sclerosing Cholangitis

Point shear wave elastography (pSWE) is an ultrasound-based method for non-invasive quantification of liver fibrosis. The objective of this study was to explore liver pSWE in patients with primary sclerosing cholangitis (PSC) for assessment of fibrosis. Fifty-five non-transplant patients with PSC (38 males, 17 females; mean age: 46.4 y) were included and compared with 24 matched controls. Median (range) PSC duration was 8.1 (0-33) y. Ultrasonographic scanning followed by liver stiffness measurement by pSWE was performed using a conventional ultrasound system (Philips iU22). Signs of liver fibrosis on B-mode were identified in 21 patients (38%). Splenomegaly was found in 19 patients (35%) and ascites in two patients (4%). Successful pSWE measurements were achieved in the right liver lobe of all individuals and in the left liver lobe of 36 patients (65.5%). PSC patients had significantly higher median shear wave velocity (SWV) than controls in the right liver (median [range] SWV 1.26 [0.73-2.57] m/s vs. 1.09 [0.88-1.25] m/s, p < 0.001). SWV measured in the left liver lobe and spleen did not differ between PSC patients and controls. Our findings indicate that PSC patients have increased median SWV, indicating more fibrosis compared with controls; however, a wide range of SWV values were obtained among PSC patients, possibly reflecting the various stages in disease development.

Hepatic and Splenic Acoustic Radiation Force Impulse Shear Wave Velocity Elastography in Children with Liver Disease Associated with Cystic Fibrosis

BACKGROUND

Liver disease associated with cystic fibrosis (CFLD) is the second cause of mortality in these patients. The diagnosis is difficult because none of the available tests are specific enough. Noninvasive elastographic techniques have been proven to be useful to diagnose hepatic fibrosis. Acoustic radiation force impulse (ARFI) imaging is an elastography imaging system. The purpose of the work was to study the utility of liver and spleen ARFI Imaging in the detection of CFLD. Method. 72 patients with cystic fibrosis (CF) were studied and received ARFI imaging in the liver and in the spleen. SWV values were compared with the values of 60 healthy controls. Results. Comparing the SWV values of CFLD with the control healthy group, values in the right lobe were higher in patients with CFLD. We found a SWV RHL cut-off value to detect CFLD of 1.27 m/s with a sensitivity of 56.5% and a specificity of 90.5%. CF patients were found to have higher SWC spleen values than the control group. Conclusions. ARFI shear wave elastography in the right hepatic lobe is a noninvasive technique useful to detect CFLD in our sample of patients. Splenic SWV values are higher in CF patients, without any clinical consequence.

Ultrasound shear wave speed measurements correlate with liver fibrosis in children

BACKGROUND

Little published research has shown the relationship between noninvasive US shear wave speed (SWS) measurements and degree of liver fibrosis as established by percutaneous biopsy in children.

OBJECTIVE

To assess the relationship between liver US shear wave speed (SWS) measurements and parenchymal fibrosis in children.

MATERIALS AND METHODS

Sixty-two children (0-18 years old) with known or suspected liver disease underwent same-day US shear wave elastography (SWE) and clinically ordered percutaneous core needle biopsy. SWE was performed just before the liver biopsy in the area targeted for sampling, using an Acuson S3000 US system with a 9L4 transducer; six SWS measurements were acquired using Virtual Touch Quantification (VTQ) and Virtual Touch IQ (VTIQ) modes. Biopsy specimens were scored for histological fibrosis and inflammation. Bivariate relationships were assessed using Pearson correlation, while multiple linear regression analysis was used to establish the relationship between SWS and predictor variables. Receiver operating characteristic (ROC) curves were created to assess the abilities of VTQ and VTIQ to discern low vs. high liver fibrosis (histological fibrosis scores 0-2 vs. 3-6).

RESULTS

There were significant positive correlations between liver histological fibrosis score and VTQ (n = 49) and VTIQ (n = 48) mean shear wave speed measurements (r = 0.68 and r = 0.73; P-values <0.0001). There also were significant positive correlations between liver histological inflammation score and VTQ and VTIQ mean shear wave speed measurements (r = 0.47 and r = 0.44, and P = 0.0006 and P = 0.0016, respectively). For VTQ, both histological fibrosis (P < 0.0001) and inflammation (P = 0.04) scores were significant predictors of shear wave speed (model adjusted R (2) = 0.49). For VTIQ, only histological fibrosis score (P < 0.0001) was a significant predictor of shear wave speed (model adjusted R (2) = 0.56). ROC areas under the curve were 0.84 and 0.86 for VTQ and VTIQ, respectively.

CONCLUSION

Liver US shear wave speed measurements increase with increasing parenchymal fibrosis in children.

Noninvasive methods, including transient elastography, for the detection of liver disease in adults with cystic fibrosis

BACKGROUND

Liver disease is the third leading cause of mortality in patients with cystic fibrosis (CF). However, detection of CF-associated liver disease (CFLD) is challenging.

OBJECTIVE

To evaluate the diagnostic performance of noninvasive methods for the detection of CFLD with a focus on transient elastography (TE).

METHODS

Patients at the Adult CF Clinic of Calgary and Southern Alberta (n=127) underwent liver stiffness measurement (LSM) by TE using the FibroScan (FS, Ecosens, France) M probe; aspartate aminotransferase to platelet ratio index (APRI) and FibroTest (FT) scores were also calculated. The diagnostic performance of these tools for the detection of CFLD (defined as two or more the following criteria: abnormal liver biochemistry, hepatomegaly or sonographic abnormalities other than steatosis) were compared using the area under ROC curves.

RESULTS

Forty-seven percent of the cohort was male. The median age was 27 years (interquartile range [IQR] 22 to 37 years) and body mass index 21 kg⁄m(2) (IQR 19 kg⁄m(2) to 23 kg⁄m(2)); 25% of patients were on ursodeoxycholic acid and 12% had undergone lung transplantation. The prevalence of CFLD was 14% (n=18). FS was successful in all patients; one (0.8%) patient had poorly reliable results (IQR⁄M >30% and LSM ≥7.1 kPa). Compared with patients without CFLD (n=109), individuals with CFLD had higher median LSM according to FS (3.9 kPa [IQR 3.4 to 4.9 kPa] versus 6.4 kPa [IQR 4.4 to 8.0 kPa]), APRI (0.24 [IQR 0.17 to 0.31] versus 0.50 [IQR 0.22 to 1.18]) and FT scores (0.08 [IQR 0.05 to 1.5] versus 0.18 [IQR 0.11 to 0.35]; all P<0.05). Area under ROC curve for FS, APRI and FT for the detection of CFLD were 0.78 (95% CI 0.65 to 0.92), 0.72 (95% CI 0.56 to 0.87) and 0.76 (95% CI 0.62 to 0.90) (P not significant). At a threshold of >5.2 kPa, the sensitivity, specificity, positive and negative predictive values of LSM according to FS for detecting CFLD were 67%, 83%, 40% and 94%, respectively.

CONCLUSIONS

FS, APRI and FT were useful noninvasive methods for detecting CFLD in adults.

Acoustic radiation force impulse (ARFI) elastography for detection of renal damage in children

BACKGROUND

Acoustic radiation force impulse (ARFI) imaging is a promising method for noninvasive evaluation of the renal parenchyma.

OBJECTIVE

To investigate the contribution of ARFI quantitative US elastography for the detection of renal damage in kidneys with and without vesicoureteral reflux (VUR).

MATERIALS AND METHODS

One hundred seventy-six kidneys of 88 children (46 male, 42 female) who had been referred for voiding cystourethrography and 20 healthy controls were prospectively investigated. Patients were assessed according to severity of renal damage on dimercaptosuccinic acid (DMSA) scintigraphy. Ninety-eight age- and gender-matched healthy children constituted the control group. Quantitative shear wave velocity (SWV) measurements were performed in the upper and lower poles and in the interpolar region of each kidney. DMSA scintigraphy was performed in 62 children (124 kidneys). Comparisons of SWV values of kidneys with and without renal damage and/or VUR were done.

RESULTS

Significantly higher SWV values were found in non-damaged kidneys. Severely damaged kidneys had the lowest SWV values (P < 0.001). High-grade (grade V-IV) refluxing kidneys had the lowest SWV values, while non-refluxing kidneys had the highest values (P < 0.05). Significant negative correlations were found between the mean quantitative US elastography values and DMSA scarring score (r = -0.788, P < 0.001) and VUR grade (r = -0.634, P < 0.001). SWV values of the control kidneys were significantly higher than those of damaged kidneys (P < 0.05).

CONCLUSION

Our findings suggest decreasing SWV of renal units with increasing grades of vesicoureteric reflux, increasing DMSA-assessed renal damage and decreasing DMSA-assessed differential function.

Cystic fibrosis related liver disease--another black box in hepatology

Due to improved medical care, life expectancy in patients with cystic fibrosis (CF) has veritably improved over the last decades. Importantly, cystic fibrosis related liver disease (CFLD) has become one of the leading causes of morbidity and mortality in CF patients. However, CFLD might be largely underdiagnosed and diagnostic criteria need to be refined. The underlying pathomechanisms are largely unknown, and treatment strategies with proven efficacy are lacking. This review focuses on current invasive and non-invasive diagnostic standards, the current knowledge on the pathophysiology of CFLD, treatment strategies, and possible future developments.

Normal values of liver shear wave velocity in healthy children assessed by acoustic radiation force impulse imaging using a convex probe and a linear probe

Acoustic radiation force impulse (ARFI) is an image-guided ultrasound elastography method that allows quantification of liver stiffness by measurement of shear wave velocity. One purpose of the work described in this article was to determine the normal liver stiffness values of healthy children using ARFI with two different probes, 4 C1 and 9 L4. Another purpose was to evaluate the effects of site of measurement, age, gender and body mass index on liver stiffness values. This prospective study included 60 healthy children (newborn to 14 y) divided into four age groups. One thousand two hundred ARFI measurements were performed, that is, 20 measurements per patient (5 measurements in each lobe, with each probe). Means, standard deviations (SD) and confidence intervals for velocity were calculated for each hepatic lobe and each probe in each age group and for the whole group. Mean shear wave velocity measured in the right lobe was 1.19 ± 0.04 m/s (SD = 0.13) with the 4 C1 transducer and 1.15 ± 0.04 m/s (SD = 0.15) with the 9 L4 transducer. Age had a small effect on shear wave measurements. Body mass index and sex had no significant effects on ARFI values, whereas site of measurement had a significant effect, with lower ARFI values in the right hepatic lobe. ARFI is a non-invasive technique that is feasible to perform in children with both the 4 C1 and 9 L4 probes. The aforementioned velocity values obtained in the right lobe may be used as reference values for normal liver stiffness in children.

Acoustic radiation force impulse (ARFI) in the evaluation of the renal parenchymal stiffness in paediatric patients with vesicoureteral reflux: preliminary results

OBJECTIVES

To prospectively evaluate acoustic radiation force impulse (ARFI) imaging of the kidneys in children with and without chronic renal disease.

METHODS

Twenty-eight children (age range 9-16 years) with primary or secondary vesicoureteral reflux (≥ grade III) underwent scintigraphy and ultrasound with ARFI. Kidneys were divided-according to scintigraphy-into "affected" and "contralateral"; the results were compared with 16 age-matched healthy subjects. An ARFI value, expressed as speed (m/s) of wave propagation through the tissue, was calculated for each kidney through the mean of the values obtained at the upper, middle and lower third. The Wilcoxon test was used; P values <0.05 were considered statistically significant.

RESULTS

The mean ARFI values obtained in the "affected" kidneys (5.70 ± 1.71 m/s) were significantly higher than those measured in both "contralateral" (4.09 ± 0.97, P < 0.0001) and "healthy" kidneys (3.13 ± 0.09, P < 0.0001). The difference between values in the "contralateral" kidneys and "healthy" ones was significant (P < 0.0001). The "affected" kidneys with secondary reflux had mean ARFI values (6.59 ± 1.45) significantly higher than those with primary reflux (5.35 ± 1.72).

CONCLUSIONS

ARFI values decrease from kidneys with secondary vesicoureteral reflux to kidneys with primary reflux to unaffected kidneys contralateral to reflux to normal kidneys.