Ultrasound shear wave elastography: does it add value to gray-scale ultrasound imaging in differentiating biliary atresia from other causes of neonatal jaundice?

Quantitative Liver Imaging in Children

ABSTRACT

In children and adults, quantitative imaging examinations determine the effectiveness of treatment for liver disease. However, pediatric liver disease differs in presentation from liver disease in adults. Children also needed to be followed for a longer period from onset and have less control of their bodies, showing more movement than adults during imaging examinations, which leads to a greater need for sedation. Thus, it is essential to appropriately tailor and accurately perform noninvasive imaging tests in these younger patients. This article is an overview of updated imaging techniques used to assess liver disease quantitatively in children. The common initial imaging study for diffuse liver disease in pediatric patients is ultrasound. In addition to preexisting echo analysis, newly developed attenuation imaging techniques have been introduced to evaluate fatty liver. Ultrasound elastography is also now actively used to evaluate liver conditions, and the broad age spectrum of the pediatric population requires caution to be taken even in the selection of probes. Magnetic resonance imaging (MRI) is another important imaging tool used to evaluate liver disease despite requiring sedation or anesthesia in young children because it allows quantitative analysis with sequences such as fat analysis and MR elastography. In addition to ultrasound and MRI, we review quantitative imaging methods specifically for fatty liver, Wilson disease, biliary atresia, hepatic fibrosis, Fontan-associated liver disease, autoimmune hepatitis, sinusoidal obstruction syndrome, and the transplanted liver. Lastly, concerns such as growth and motion that need to be addressed specifically for children are summarized.

Serum matrix metalloproteinase-7 for discriminating biliary atresia: a diagnostic accuracy and validation study

BACKGROUND

Prompt and precise differential diagnosis of biliary atresia (BA) among cholestatic patients is of great importance. Matrix metalloproteinase-7 (MMP-7) holds great promise as a diagnostic marker for BA. This study aimed to investigate the accuracy of age-specific serum MMP-7 for discriminating BA from other cholestatic pediatric patients.

METHODS

This was a single center diagnostic accuracy and validation study including both retrospective and prospective cohorts. Serum MMP-7 concentrations were measured using an ELISA kit, the trajectory of which with age was investigated in a healthy infants cohort aged 0 to 365 days without hepatobiliary diseases (n = 284). Clinical BA diagnosis was based on intraoperative cholangiography and subsequent histological examinations. The diagnostic accuracy of age-specific cutoffs of serum MMP-7 were assessed in a retrospective cohort of cholestatic patients (n = 318, with 172 BA) and validated in a prospective cohort (n = 687, including 395 BA).

RESULTS

The MMP-7 concentration declines non-linearly with age, showing higher levels in healthy neonates as well as higher cutoff value in neonatal cholestasis. The area under the ROC curve (AUROC) was 0.967 (95% confidence interval [CI]: 0.946-0.988) for the retrospective cohort, and the cutoff of 18 ng/mL yielded 93.0% (95%CI: 88.1-96.3%), 93.8% (95%CI: 88.6-97.1%), 94.7% (95%CI: 90.1-97.5%), and 91.9% (95%CI: 86.4-95.8%) for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), respectively. The performance of MMP-7 was successfully validated in the larger prospective cohort, resulting in a diagnostic sensitivity of 95.9% (379/395; 95% CI: 93.5-97.7%), a specificity of 87.3% (255/292; 95% CI: 83.0-90.9%), a PPV of 91.1% (379/416; 95% CI: 87.9-93.7%), and a NPV of 94.1% (255/271; 95% CI: 90.6-96.6%), respectively. Besides, higher cutoff value of 28.1 ng/mL achieved the best sensitivity, specificity, PPV, and NPV for infants aged 0-30 days, which was 86.4% (95% CI: 75.0-94.0%), 95.5% (95% CI: 77.2-99.9%), 98.1% (95% CI: 89.7-100%), and 72.4% (95% CI: 52.8-87.3%), respectively.

CONCLUSIONS

The serum MMP-7 is accurate and reliable in differentiating BA from non-BA cholestasis, showing its potential application in the diagnostic algorithm for BA and significant role in the future research regarding pathogenesis of BA.

Comparison for the diagnostic performance of early diagnostic methods for biliary atresia: a systematic review and network meta-analysis

BACKGROUND

Biliary atresia (BA), a progressive condition affecting canalicular-bile duct function/anatomy, requires prompt surgical intervention for favorable outcomes. Therefore, we conducted a network meta-analysis of common diagnostic methods to assess their performance and provide evidence-based support for clinical decision-making.

METHODS

We reviewed literature in PubMed, EMBASE, and Cochrane for BA diagnostics. The search included gamma-glutamyl transferase (GGT), direct/combined bilirubin, matrix metalloproteinase 7 (MMP-7), ultrasonic triangular cord sign (TCS), hepatic scintigraphy (HS), and percutaneous cholangiocholangiography/percutaneous transhepatic cholecysto-cholangiography (PCC/PTCC). QUADAS-2 assessed study quality. Heterogeneity and threshold effect were evaluated using I2 and Spearman's correlation. We combined effect estimates, constructed SROC models, and conducted a network meta-analysis based on the ANOVA model, along with meta-regression and subgroup analysis, to obtain precise diagnostic performance assessments for BA.

RESULTS

A total of 40 studies were included in our analysis. GGT demonstrated high diagnostic accuracy for BA with a sensitivity of 81.5% (95% CI 0.792-0.836) and specificity of 72.1% (95% CI 0.693-0.748). Direct bilirubin/conjugated bilirubin showed a sensitivity of 87.6% (95% CI 0.833-0.911) but lower specificity of 59.4% (95% CI 0.549-0.638). MMP-7 exhibited a total sensitivity of 91.5% (95% CI 0.893-0.934) and a specificity of 84.3% (95% CI 0.820-0.863). TCS exhibited a sensitivity of 58.1% (95% CI 0.549-0.613) and high specificity of 92.9% (95% CI 0.911-0.944). HS had a high sensitivity of 98.4% (95% CI 0.968-0.994) and moderate specificity of 79.0% (95% CI 0.762-0.816). PCC/PTCC exhibited excellent diagnostic performance with a sensitivity of 100% (95% CI 0.900-1.000) and specificity of 87.0% (95% CI 0.767-0.939). Based on the ANOVA model, the network meta-analysis revealed that MMP-7 ranked second overall, with PCC/PTCC ranking first, both exhibiting superior diagnostic accuracy compared to other techniques. Our analysis showed no significant bias in most methodologies, but MMP-7 and hepatobiliary scintigraphy exhibited biases, with p values of 0.023 and 0.002, respectively.

CONCLUSION

MMP-7 and ultrasound-guided PCC/PTCC show diagnostic potential in the early diagnosis of BA, but their clinical application is restricted due to practical limitations. Currently, the cutoff value of MMP-7 is unclear, and further evidence-based medical research is needed to firmly establish its diagnostic value. Until more evidence is available, MMP-7 is not suitable for widespread diagnostic use. Therefore, considering cost and operational simplicity, liver function tests combined with ultrasound remain the most clinically valuable non-invasive diagnostic methods for BA.

Interpretable artificial intelligence-based app assists inexperienced radiologists in diagnosing biliary atresia from sonographic gallbladder images

BACKGROUND

A previously trained deep learning-based smartphone app provides an artificial intelligence solution to help diagnose biliary atresia from sonographic gallbladder images, but it might be impractical to launch it in real clinical settings. This study aimed to redevelop a new model using original sonographic images and their derived smartphone photos and then test the new model's performance in assisting radiologists with different experiences to detect biliary atresia in real-world mimic settings.

METHODS

A new model was first trained retrospectively using 3659 original sonographic gallbladder images and their derived 51,226 smartphone photos and tested on 11,410 external validation smartphone photos. Afterward, the new model was tested in 333 prospectively collected sonographic gallbladder videos from 207 infants by 14 inexperienced radiologists (9 juniors and 5 seniors) and 4 experienced pediatric radiologists in real-world mimic settings. Diagnostic performance was expressed as the area under the receiver operating characteristic curve (AUC).

RESULTS

The new model outperformed the previously published model in diagnosing BA on the external validation set (AUC 0.924 vs 0.908, P = 0.004) with higher consistency (kappa value 0.708 vs 0.609). When tested in real-world mimic settings using 333 sonographic gallbladder videos, the new model performed comparable to experienced pediatric radiologists (average AUC 0.860 vs 0.876) and outperformed junior radiologists (average AUC 0.838 vs 0.773) and senior radiologists (average AUC 0.829 vs 0.749). Furthermore, the new model could aid both junior and senior radiologists to improve their diagnostic performances, with the average AUC increasing from 0.773 to 0.835 for junior radiologists and from 0.749 to 0.805 for senior radiologists.

CONCLUSIONS

The interpretable app-based model showed robust and satisfactory performance in diagnosing biliary atresia, and it could aid radiologists with limited experiences to improve their diagnostic performances in real-world mimic settings.

Measurement of MMP-7 in micro-volume peripheral blood: development of dried blood spot approach

Purpose

Serum matrix metalloproteinase-7 (MMP-7) is significant in differentiating biliary atresia (BA). This study aims to develop a new peripheral blood quantitative collection device to detect MMP-7 levels via dried blood spot (DBS).

Methods

This is a diagnostic accuracy test. Serum and DBS MMP-7 concentrations were measured using an ELISA kit. Intraoperative cholangiography and subsequent histological examinations were used to confirm BA diagnoses.

Results

A total of 241 infants with obstructive jaundice were enrolled, among whom 168 were BA. Linear regression showed DBS MMP-7 correlated well with serum MMP-7 (R = 0.93, P < 0.001). The best cut-off value of serum MMP-7 for BA was 25.9 ng/ml, achieving the area under the ROC curve (AUC) of 0.962 (95% CI: 0.941, 0.983), and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 86.9%, 94.5%, 97.3% and 75.8%, respectively. The best cut-off value of DBS MMP-7 for BA was 12.5 ng/ml, achieving the AUC of 0.922 (95% CI: 0.888, 0.956), and the sensitivity, specificity, PPV, and NPV were 86.9%, 89.0%, 94.8%, and 74.7%, respectively. The dried blood spots were intervened under different storage conditions, including 1-5 days at room temperature, 2 or 3 days at 30 °C and 2 or 3 days at 37 °C. The DBS MMP-7 concentration under different storage conditions had good correlation and consistency with that at -80 °C.

Conclusions

Serum and DBS MMP-7 correlate well, both of which have high accuracy in the diagnosis of BA, while the requirements for the storage of DBS are low.

Pre- and Immediate Post-Kasai Portoenterostomy Shear Wave Elastography for Predicting Hepatic Fibrosis and Native Liver Outcomes in Patients With Biliary Atresia

OBJECTIVE

To evaluate the feasibility of ultrasound shear wave elastography (SWE) for predicting hepatic fibrosis and native liver outcomes in patients with biliary atresia.

MATERIALS AND METHODS

This prospective study included 33 consecutive patients with biliary atresia (median age, 8 weeks [interquartile range, 6-10 weeks]; male:female ratio, 15:18) from Severance Children's Hospital between May 2019 and February 2022. Preoperative (within 1 week from surgery) and immediate postoperative (on postoperative days [PODs] 3, 5, and 7) ultrasonographic findings were obtained and analyzed, including the SWE of the liver and spleen. Hepatic fibrosis, according to the METAVIR score at the time of Kasai portoenterostomy and native liver outcomes during postsurgical follow-up, were compared and correlated with imaging and laboratory findings. Poor outcomes were defined as intractable cholangitis or liver transplantation. The diagnostic performance of SWE in predicting METAVIR F3-F4 and poor hepatic outcomes was analyzed using receiver operating characteristic (ROC) analyses.

RESULTS

All patients were analyzed without exclusion. Perioperative advanced hepatic fibrosis (F3-F4) was associated with older age and higher preoperative direct bilirubin and SWE values in the liver and spleen. Preoperative liver SWE showed a ROC area of 0.806 and 63.6% (7/11) sensitivity and 86.4% (19/22) specificity at a cutoff of 17.5 kPa for diagnosing F3-F4. The poor outcome group included five patients with intractable cholangitis and three undergoing liver transplantation who showed high postoperative liver SWE values. Liver SWE on PODs 3-7 showed ROC areas of 0.783-0.891 for predicting poor outcomes, and a cutoff value of 10.3 kPa for SWE on POD 3 had 100% (8/8) sensitivity and 73.9% (17/23) specificity.

CONCLUSION

Preoperative liver SWE can predict advanced hepatic fibrosis, and immediate postoperative liver SWE can predict poor native liver outcomes in patients with biliary atresia.

Diagnostic Efficacy of Advanced Ultrasonography Imaging Techniques in Infants with Biliary Atresia (BA): A Systematic Review and Meta-Analysis

The early diagnosis of biliary atresia (BA) in cholestatic infants is critical to the success of the treatment. Intraoperative cholangiography (IOC), an invasive imaging technique, is the current strategy for the diagnosis of BA. Ultrasonography has advanced over recent years and emerging techniques such as shear wave elastography (SWE) have the potential to improve BA diagnosis. This review sought to evaluate the diagnostic efficacy of advanced ultrasonography techniques in the diagnosis of BA. Six databases (CINAHL, Medline, PubMed, Google Scholar, Web of Science (core collection), and Embase) were searched for studies assessing the diagnostic performance of advanced ultrasonography techniques in differentiating BA from non-BA causes of infantile cholestasis. The meta-analysis was performed using Meta-DiSc 1.4 and Comprehensive Meta-analysis v3 software. Quality Assessment of Diagnostic Accuracy Studies tool version 2 (QUADAS-2) assessed the risk of bias. Fifteen studies consisting of 2185 patients (BA = 1105; non-BA = 1080) met the inclusion criteria. SWE was the only advanced ultrasonography technique reported and had a good pooled diagnostic performance (sensitivity = 83%; specificity = 77%; AUC = 0.896). Liver stiffness indicators were significantly higher in BA compared to non-BA patients (p < 0.000). SWE could be a useful tool in differentiating BA from non-BA causes of infantile cholestasis. Future studies to assess the utility of other advanced ultrasonography techniques are recommended.

The diagnostic performance of ultrasound elastography for biliary atresia: A meta-analysis

Background

Biliary atresia (BA) is a severe inflammatory obliterative cholangiopathy of infancy that requires early diagnosis and prompt surgical intervention. In this study, we aimed to obtain comprehensive evidence on the diagnostic performance of liver stiffness measurement by ultrasound elastography in the detection of BA through a meta-analysis.

Methods

The PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched for studies that investigated the diagnostic performance of ultrasound elastography in the detection of BA up to January 10, 2022. In this study, in order to summarize the diagnostic performance of ultrasound elastography, the summary receiver operating characteristic (SROC) modeling was constructed. Heterogeneity was estimated with the I ² statistic. Multiple subgroup analyses were also performed.

Results

Fourteen studies from eleven articles, including 774 BA patients, 850 non-BA patients, and 173 controls were included in the present meta-analysis. The summary sensitivity and specificity of ultrasound elastography for liver stiffness were 85% [95% confidence interval (CI): 79-89%] and 82% (95% CI: 73-88%) with the I ² value of 82.90 and 84.33%, respectively. The area under the SROC curve (AUROC) using ultrasound elastography for diagnosing BA was 0.90 (95% CI: 0.87-0.92). In addition, a subgroup analysis of 9 two-dimensional shear wave elastography studies was also performed. Subgroup analysis revealed that the summary sensitivity and specificity were 85% (95% CI: 77-91%) and 79% (95% CI: 71-86%), respectively, and the summary AUROC was 0.89 (95% CI: 0.86-0.92).

Conclusions

Ultrasound elastography exhibits good diagnostic accuracy for BA and can be served as a non-invasive tool to facilitate the differential diagnosis of BA.

Development and validation of a novel nomogram and risk score for biliary atresia in patients with cholestasis

BACKGROUND

Timely discriminating biliary atresia (BA) from other causes of cholestasis is important but challenging.

AIMS

To develop a useful diagnostic nomogram and a simplified scoring system to diagnosing BA.

STUDY DESIGN

All medical records of the patients who were consecutively admitted to our institution with cholestasis from March 2016 to December 2020 were retrospectively searched. The patients were allocated to the derivation cohort (n = 343) and the validation cohort (n = 246). Multivariable logistic regression models were used to construct the nomogram. The nomogram was validated in both cohorts. The simplified risk score was derived from the nomogram.

RESULTS

The nomogram was constructed based on presence of clay stool, gallbladder length, gallbladder emptying index, shear wave elastography value, and gamma-glutamyl transferase level. This model showed good calibration and discrimination ability, with the C-index of 0.968 (95% CI: 0.951-0.984). The discriminating ability is most prominent in the 61-90 days group, with AUC of 0.982 (95% CI: 0.955-1.000). The simplified risk score identified most patients with very high or low risk of BA, and was capable of exempting 64.3% non-BA patients from intraoperative cholangiogram procedure.

CONCLUSIONS

This novel diagnostic nomogram had good discrimination and calibration abilities. The simplified scoring system showed significant clinical utility.

Ultrasound elastography in the diagnosis of biliary atresia in pediatric surgery: a systematic review and meta-analysis of diagnostic test

BACKGROUND

Biliary atresia (BA) is one of the most fatal hepatobiliary diseases in infants and young children, and is easy to cause obstructive jaundice in infants and children, and liver transplantation in children. BA and infantile hepatitis syndrome are the main causes of cholestatic jaundice. The early clinical manifestations are extremely similar, and timely identification is difficult. Therefore, early and differential diagnosis of BA is crucial. At present, there are many imaging diagnosis methods for BA, such as ultrasound examination and nuclear magnetic resonance. Ultrasound elastography (USE) is the most popular method. However, the application of USE in BA is still in the exploratory stage.

METHODS

PubMed, Web of Science, Embase, Cochrane Library, and other databases were searched for articles on USE diagnosis of pediatric surgical BA. Later, the articles were screened, and the included articles should meet the following requirements: the research objects were children with BA; the intervention measures were USE diagnosis; the control group was diagnosed by other methods than USE. RevMan5.3 was adopted for quality assessment, and forest maps and summary receiver operating characteristic (SROC) curves were constructed.

RESULTS

Finally, seven articles covering 490 patients were included. There were 120 patients in the control group. The included articles showed good quality and there was no obvious bias. The area under the SROC curve (AUC) for USE diagnosis of BA was 0.93, the sensitivity was 0.93 (95% CI: 0.72-1.00), and the specificity was 0.95 (95% CI: 0.74-1.00).

DISCUSSION

USE showed high diagnostic value for pediatric surgical biliary tract closure.

Comparison of Two Kinds of Two-Dimensional Shear Wave Elastography Techniques in the Evaluation of Jaundiced Infants Suspected of Biliary Atresia

Purpose: To compare the reliability and performance of Supersonic shear wave elastography (S-SWE) and Toshiba shear wave elastography (T-SWE) in the diagnosis of biliary atresia (BA) and assessment of liver fibrosis among jaundiced infants suspected of BA. Material and Methods: A total of 35 patients with suspected BA who underwent both S-SWE and T-SWE examinations were prospectively included. Diagnostic performances of S-SWE and T-SWE in identifying BA were evaluated. The correlation between two types of SWE values and histological liver fibrosis stages by Metavir scores were investigated in 21 patients with pathology results. The intraclass correlation coefficients (ICCs) were calculated in 16 patients for inter- and intra-observer agreement. The area under the receiver operating characteristic curve (AUC) analysis was compared using a DeLong test. Results: There were 22 patients with BA and 13 patients without BA. The diagnostic performance of S-SWE was comparable to that of T-SWE (AUC 0.895 vs. 0.822, p = 0.071) in diagnosing BA. The AUCs of S-SWE in predicting liver fibrosis stages were from 0.676 to 1.000 and showed no statistical differences from that of T-SWE (from 0.704 to 1.000, all p > 0.05). T-SWE provided higher inter-operator agreement (ICC 0.990) and intra-operator agreement (ICCs 0.966−0.993), compared with that of S-SWE in a previous study (ICC 0.980 for inter-operator and 0.930−0.960 for intra-operator). Conclusions: For infants suspected of BA, T-SWE had good performances in the diagnosis of BA and the assessment of liver fibrosis compared with S-SWE. Furthermore, T-SWE showed higher measurement reproducibility than S-SWE.

Ultrasound for the Diagnosis of Biliary Atresia: From Conventional Ultrasound to Artificial Intelligence

Biliary atresia is an aggressive liver disease of infancy and can cause death without timely surgical intervention. Early diagnosis of biliary atresia is critical to the recovery of bile drainage and long-term transplant-free survival. Ultrasound is recommended as the initial imaging strategy for the diagnosis of biliary atresia. Numerous ultrasound features have been proved helpful for the diagnosis of biliary atresia. In recent years, with the help of new technologies such as elastography ultrasound, contrast-enhanced ultrasound and artificial intelligence, the diagnostic performance of ultrasound has been significantly improved. In this review, various ultrasound features in the diagnosis of biliary atresia are summarized. A diagnostic decision flow chart for biliary atresia is proposed on the basis of the hybrid technologies, combining conventional ultrasound, elastography and contrast-enhanced ultrasound. In addition, the application of artificial intelligence in the diagnosis of biliary atresia with ultrasound images is also introduced.

Recent advances in the use of ultrasound and related techniques in diagnosing and predicting outcomes in biliary atresia

PURPOSE OF REVIEW

Biliary atresia (BA) is the leading cause of chronic liver disease and the most common indication for pediatric liver transplantation. The use of ultrasound (US) and related techniques continues to evolve to help diagnose BA as well as potentially to help predict outcomes after treatment with the Kasai portoenterostomy (KP).

RECENT FINDINGS

There are no US findings that are definitive for BA; however, signs which are consistent with BA include gallbladder abnormalities, the triangular cord sign, presence of hepatic subcapsular flow, and hilar lymphadenopathy. Elastography techniques to measure liver stiffness may also increase the diagnostic accuracy of detecting BA, particularly in older infants or without other US findings. In addition, both US and elastography are still being studied as potential methods to predict outcomes after KP such as the development of portal hypertension and the need for liver transplant.

SUMMARY

US findings in the diagnosis of BA are well characterized. Future studies will help determine the utility of elastography in diagnosing BA, as well as both US and elastography in monitoring and predicting disease outcomes after KP.