Interobserver discrepancy in liver fibrosis using transient elastography

Reproducibility and Repeatability of US Shear-Wave and Transient Elastography in Nonalcoholic Fatty Liver Disease

Background US shear-wave elastography (SWE) and vibration-controlled transient elastography (VCTE) enable assessment of liver stiffness, an indicator of fibrosis severity. However, limited reproducibility data restrict their use in clinical trials. Purpose To estimate SWE and VCTE measurement variability in nonalcoholic fatty liver disease (NAFLD) within and across systems to support clinical trial diagnostic enrichment and clinical interpretation of longitudinal liver stiffness. Materials and Methods This prospective, observational, cross-sectional study (March 2021 to November 2021) enrolled adults with NAFLD, stratified according to the Fibrosis-4 (FIB-4) index (≤1.3, >1.3 and <2.67, ≥2.67), at two sites to assess SWE with five US systems and VCTE with one system. Each participant underwent 12 elastography examinations over two separate days within 1 week, with each day's examinations conducted by a different operator. VCTE and SWE measurements were reported in units of meters per second. The primary end point was the different-day, different-operator reproducibility coefficient (RDCDDDO) pooled across systems for SWE and individually for VCTE. Secondary end points included system-specific RDCDDDO, same-day, same-operator repeatability coefficient (RCSDSO), and between-system same-day, same-operator reproducibility coefficient. The planned sample provided 80% power to detect a pooled RDCDDDO of less than 35%, the prespecified performance threshold. Results A total of 40 participants (mean age, 60 years ± 10 [SD]; 24 women) with low (n = 17), intermediate (n = 15), and high (n = 8) FIB-4 scores were enrolled. RDCDDDO was 30.7% (95% upper bound, 34.4%) for SWE and 35.6% (95% upper bound, 43.9%) for VCTE. SWE system-specific RDCDDDO varied from 24.2% to 34.3%. The RCSDSO was 21.0% for SWE (range, 13.9%-35.0%) and 19.6% for VCTE. The SWE between-system same-day, same-operator reproducibility coefficient was 52.7%. Conclusion SWE met the prespecified threshold, RDCDDDO less than 35%, with VCTE having a higher RDCDDDO. SWE variability was higher between different systems. These estimates advance liver US-based noninvasive test qualification by (a) defining expected variability, (b) establishing that serial examination variability is lower when performed with the same system, and (c) informing clinical trial design. ClinicalTrials.gov Identifier NCT04828551 © RSNA, 2024 Supplemental material is available for this article.

Variability of transient elastography-based spleen stiffness performed at 100 Hz

BACKGROUND

Spleen stiffness measurement (SSM) performed by transient elastography at 100 Hz is a novel technology for the evaluation of portal hypertension in advanced chronic liver disease, but technical aspects are lacking. We aimed to evaluate the intraexamination variability of SSM and to determine the best transient elastography protocol for obtaining robust measurements to be used in clinical practice.

METHODS

We analyzed 253 SSM exams with up to 20 scans for each examination, performed between April 2021 and June 2022. All SSM results were evaluated according to different protocols by dividing data into groups of n measurements (from 2 to 19). Considering as reference the median SSM values across all the 20 measurements, we calculated the distribution of the absolute deviations of each protocol from the reference median. This analysis was repeated 1,000 times by resampling the data. Distributions were also stratified by etiology (chronic liver disease versus clinically significant portal hypertension) and different SSM ranges: < 25 kPa, 25-75, and > 75 kPa.

RESULTS

Overall, we observed that the spleen stiffness exam had less variability if it exceeded 12 measurements, i.e., absolute deviations ≤ 5 kPa at 95% confidence. For exams with higher SSM values (> 75 kPa), as seen in clinically significant portal hypertension, at least 15 measurements are highly recommendable.

CONCLUSIONS

Fifteen scans per examination should be considered for each SSM exam performed at 100 Hz to achieve a low intraexamination variability within a reasonable time in clinical practice.

RELEVANCE STATEMENT

Performing at least 15 scans per examination is recommended for 100 Hz SSM in order to achieve a low intraexamination variability, in particular for values > 75 kPa compatible with clinically significant portal hypertension.

KEY POINTS

• Spleen stiffness measurement by transient elastography is used for stratification in patients with portal hypertension. • At 100 Hz, this method may have intraexamination variability. • A minimum of 15 scans per examination achieves a low intraexamination variability.

Agreement and reliability of hepatic transient elastography in patients with chronic hepatitis C: A cross-sectional test-retest study

Background and Aims

Transient elastography (TE) has largely replaced liver biopsy to evaluate fibrosis stage and cirrhosis in chronic hepatitis C. Previous studies have reported excellent reliability of TE but agreement metrics have not been reported. This study aimed to assess interrater agreement and reliability of repeated TE measurements.

Methods

Two operators performed TE independently, directly after each other. The primary outcome was disagreement, defined as a difference in TE results between operators of ≥33%, as well as the smallest detectable change, SDC95 (i.e., the difference between measurements needed to state with 95% certainty that there is a difference in underlying stiffness). Secondary outcomes included reliability, measured as intraclass correlation (ICC), and patient and examination characteristics associated with the agreement.

Results

In total, 65 patients were included, with a mean liver stiffness of 9.7 kPa. Of these, 21 (32%) had a disagreement in TE results of ≥33% between the two operators. The SDC95 on the log scale was 1.97, indicating that an almost twofold increase or decrease in liver stiffness would be required to confidently represent a change in the underlying fibrosis. Reliability, estimated using the ICC, was acceptable at 0.86. In a post hoc analysis, fasting less than 5 h before TE was associated with a higher degree of disagreement (48% vs. 19%, p = 0.03).

Conclusions

In our clinical setting, interrater agreement in directly repeated TE measurements was surprisingly low. It is essential to further investigate the reliability and agreement of TE to determine its validity and usefulness.

The impact of body position and exercise on the measurement of liver Young's modulus by real-time shear wave elastography

BACKGROUND

In the past ten years, liver biopsies have been used as a method to accurately diagnose the stage of fibrosis.

OBJECTIVE

This study aimed to evaluate whether body position and exercise affect the measurement of liver Young's modulus of healthy volunteers by real-time shear wave elastography (RT-SWE).

METHODS

RT-SWE was used to measure liver Young's modulus in the supine and left lateral positions of 70 healthy volunteers at rest and measure the liver Young's modulus in the lying position before exercise, and at zero, five, and ten minutes of rest after exercise.

RESULTS

The liver Young's modulus in the left lateral position was significantly higher than in the supine position (P< 0.05), and the measured value in the supine position was more stable than the left lateral position. The liver Young's modulus measured at zero minutes after exercise was significantly higher than that measured before exercise (P< 0.05). The liver Young's modulus measured at five minutes after exercise was significantly higher than that measured at zero minutes after exercise (P<0.05) and was not statistically different from the measured value before exercise (P> 0.05). The liver Young's modulus measured at ten minutes after exercise was significantly higher from that measured at zero minutes after exercise (P< 0.05) and was not statistically different from the measured value at five minutes after exercise (P> 0.05).

CONCLUSION

Body position and exercise have a significant impact on the measurement of liver Young's modulus. It is recommended that the examinees take a supine position during the measurement, and measurement should be conducted at least ten minutes after exercise.

Repeatability of transient elastography in children

BACKGROUND

Poorly performing diagnostic tests can impact patient safety. Clinical investigations must have good precision and diagnostic accuracy before widespread use in clinical practice. Transient elastography (TE) measures liver stiffness, a surrogate marker of liver fibrosis in adults and children. Studies to evaluate its repeatability and reproducibility (precision) in children are limited. Our aim was to determine (i) the normal range of TE measurements and (ii) the repeatability and reproducibility of TE in healthy children.

METHODS

TE was performed in 257 healthy children, of whom 235 (91%, mean age 11.7 years, standard deviation (SD) 2.51, 107 were males (45.5%)) had two valid TE measurements performed, at least 24 h apart, by two operators under similar circumstances. High-quality TE images were obtained for each examination.

RESULTS

The normal range of TE was 2.88-6.52 kPa. The mean difference between paired measurements was 0.044 (SD 0.4). The 95% limits of agreement ranged from -0.8 to +0.76 kPa for repeat measurements. There was a difference of >1 kPa between measurements in 61/235 (25.9%) children. The lack of precision was similar across all age groups.

CONCLUSIONS

This study demonstrates that TE does not have acceptable precision in healthy children, because random measurement variation results in the lack of agreement between paired measurements.

IMPACT

The precision and diagnostic accuracy of a new technology must be determined before it is deployed in children in order to ensure that appropriate clinical decisions are made, and healthcare resources are not wasted. TE is widely used to diagnose liver disease in children without adequate evaluation of the precision (repeatability) of TE either in healthy children or children with liver disease. This study demonstrates that TE does not have adequate precision in children. This study was performed in accordance with methods previously published for children. Refinements to the test protocol, such as duration of fasting or probe size, will have to be evaluated for their impact on precision and accuracy before the test is deployed in research studies or clinical practice.

Evaluation of three "beyond Baveno VI" criteria to safely spare endoscopies in compensated advanced chronic liver disease

BACKGROUND

Liver stiffness measurement (LSM) <20 kPa and platelet count >150,000/mm³ exclude varices needing treatment (VNT) in viral compensated advanced chronic liver disease (cACLD), saving-up to 20-25% endoscopies (Baveno VI criteria). Refinements of such criteria to further reduce endoscopies and an approach without LSM (Platelet 150/MELD 6) were later proposed.

AIMS

To assess LSM 25/platelet 125, LSM 25/platelet 110 (Expanded-Baveno VI) and Platelet 150/MELD 6 accuracy versus Baveno VI criteria, and the impact of platelet count variability on criteria accuracy in all-etiologies cACLD.

METHODS

cACLD patients undergoing screening endoscopy with laboratory data within 6 months and LSM within one year.

RESULTS

Of 442 patients, 31% had varices (7% with VNT). Baveno VI criteria had 100% sensitivity (Se) and negative predictive value (NPV) and spared 19.5% endoscopies. "LSM 25/platelet 125" and "Expanded-Baveno VI" criteria maintained such accuracy, sparing 15% and 24% more endoscopies, respectively (p < 0.001). Platelet 150/MELD 6 was less accurate, misclassifying 10% VNT. Platelet count variability exceeded 8% and one VNT patient was misclassified with both "Expanded-Baveno VI" and "LSM 25/platelet 125" criteria considering the previous platelet count.

CONCLUSIONS

Both "Expanded-Baveno VI" and "LSM 25/platelet 125" criteria are accurate in cACLD, but the former are more advantageous. Platelet 150/MELD 6 proved inadequate.

Chronic Hepatitis C Patients with Obesity: Do we Need two Operators for Accurate Evaluation of Liver Stiffness?

INTRODUCTION AND AIM

Transient elastography is gaining popularity as a non-invasive method for predicting liver fibrosis, but inter observer agreement and factors influencing reproducibility have not been adequately assessed.

MATERIAL AND METHODS

This cross-sectional study was conducted at Specialized Medical Hospital and the Egyptian Liver Foundation, Mansoura, Egypt. The inclusion criteria were: age older than 18 years and chronic infection by hepatitis C. The exclusion criteria were the presence of ascites, pacemaker or pregnancy. Three hundred and fifty-six patients participated in the study. Therefore, 356 pairs of exams were done by two operators on the same day.

RESULTS

The overall inter observer agreement ICC was 0.921. The correlation the two operators was excellent (Spearman's value q = 0.808, p < 0.001). Inter-observer reliability values were κ = 0.557 (p < 0.001). A not negligible discordance of fibrosis staging between operators was observed (87 cases, 24.4%). Discordance of at least one stage and for two or more stages of fibrosis occurred in 60 (16.9%) and 27 cases (7.6%) respectively. Obesity (BMI ≥ 30 kg/m2) is the main factor associated with discordance (p = 0.002).

CONCLUSION

Although liver stiffness measurement has had an excellent correlation between the two operators, TE presented an inter-observer variability that may not be negligible.

What we need to know when performing and interpreting US elastography

According to the increasing need for accurate staging of hepatic fibrosis, the ultrasound (US) elastography techniques have evolved significantly over the past two decades. Currently, US elastography is increasingly used in clinical practice. Previously published studies have demonstrated the excellent diagnostic performance of US elastography for the detection and staging of liver fibrosis. Although US elastography may seem easy to perform and interpret, there are many technical and clinical factors which can affect the results of US elastography. Therefore, clinicians who are involved with US elastography should be aware of these factors. The purpose of this article is to present a brief overview of US techniques with the relevant technology, the clinical indications, diagnostic performance, and technical and biological factors which should be considered in order to avoid misinterpretation of US elastography results.

How many times should we repeat measuring liver stiffness using shear wave elastography?: 5-repetition versus 10-repetition protocols

The purpose of this study is to evaluate whether a 5-repetition liver stiffness (LS) measurement as the standard protocol of shear wave elastography (SWE) is comparable to a conventional 10-repetition measurement protocol and to identify factors that influence the reliability of the 5-repetition protocol. A total of 346 patients (mean, 48.0years; range, 15-81years, M:F=192:154) who underwent SWE were enrolled. The median, first quartile, third quartile, and interquartile range divided by the median (IQR/M) of LS measurement were calculated and compared between 5-repetition and 10-repetition protocols. Subgroup analyses were also performed to identify factors associated with measurement reliability. The overall mean LS from the 10-repetition protocol was 7.97kPa, which was not significantly different from the mean LS of the 5-repetition protocol (7.91kPa; p=0.192). However, the third quartile and IQR/M values of the two groups were significantly different from each other (p=0.003 and <0.001). Subgroup analysis revealed that the 5-repetition results were significantly different from the 10-repetition results in the fatty liver and high LS subgroups. Therefore, the 5-repetition SWE measurement protocol can replace the conventional 10-repetition protocol, with the exception of patients with fatty liver disease or an LS value higher than 10kPa.

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.

Critical comparison of elastography methods to assess chronic liver disease

Staging of liver fibrosis and diagnosis, or exclusion, of early compensated liver cirrhosis are important in the treatment decisions and surveillance of patients with chronic liver disease. Good diagnostic accuracy, increased availability and the possibility to perform follow-up examinations led to the implementation of noninvasive methods into clinical practice. Noninvasive tests are increasingly included in national and international guidelines, leaving liver biopsy reserved for patients with unexplained discordance or suspected additional aetiologies of liver disease. In addition to staging of liver fibrosis, data on the prognostic value of these methods have increased in the past few years and are of great importance for patient care. This Review focuses on elastography methods for noninvasive assessment of liver fibrosis, disease severity and prognosis. Although liver elastography started with transient elastography, at present all large ultrasonography companies offer an elastography technique integrated in their machines. The goal of this Review is to summarize the methodological problems of noninvasive tests in general, in addition to providing an overview on currently available techniques and latest developments in liver elastography.

Lymphangiogenesis in Breast Cancer Correlates with Matrix Stiffness on Shear-Wave Elastography

PURPOSE

To correlate tumor stiffness and lymphangiogenesis in breast cancer and to find its clinical implications.

MATERIALS AND METHODS

A total of 140 breast cancer patients were evaluated. Tumor stiffness was quantitatively measured by shear-wave elastography in preoperative ultrasound examination, calculated as mean elasticity value (kPa). Slides of resected breast cancer specimens were reviewed for most fibrotic area associated with tumor. D2-40 immunohistochemical staining was applied for fibrotic areas to detect the lymphatic spaces. Microlymphatic density, tumor stiffness, and clinicopathologic data were analyzed.

RESULTS

Higher elasticity value was associated with invasive size of tumor, microlymphatic density, histologic grade 3, absence of extensive intraductal component, presence of axillary lymph node metastasis, and Ki-67 labeling index (LI) in univariate regression analysis, and associated with Ki-67 LI and axillary lymph node metastasis in multivariate regression analysis. Microlymphatic density was associated histologic grade 3, mean elasticity value, and Ki-67 LI in univariate regression analysis. In multivariate regression analysis, microlymphatic density was correlated with mean elasticity value.

CONCLUSION

In breast cancer, tumor stiffness correlates with lymphangiogenesis and poor prognostic factors.

Learning curve and intra/interobserver agreement of transient elastography in chronic hepatitis C patients with or without HIV co-infection

BACKGROUND AND OBJECTIVES

Liver stiffness measurement (LSM) by transient elastography has been validated as a noninvasive method to stage liver fibrosis. Few studies have evaluated the learning curve of this method and its reproducibility has led to controversy results. We aimed to evaluate the intra- and interobserver agreement of transient elastography as well as its learning curve for definition of an experimented operator.

METHODS

We retrospectively analyzed 922 examinations performed in 544 patients during a training program of transient elastography. Patients with chronic hepatitis C with or without HIV co-infection that had two examinations by the training operator (intraobserver analysis; n=125) or examination by both training and experimented operators (interobserver analysis; n=151) in the same day were included. LSM was converted to METAVIR score: <7.1 as F0F1, 7.1-9.4 as F2, 9.5-12.4, as F3 and >12.4 kPa as F4.

RESULTS

The overall intra- and interobserver intraclass correlation coefficient [ICC 95% CI] were 0.926 (0.901-0.951) and 0.912 (0.885-0.939), respectively. Measurements were correlated [Spearman's] in intra- [0.906, P<0.0001] and interobserver [0.907, P<0.0001] analysis. Reliability values [kappa (SE)] were k=0.74 (0.09) and k=0.85 (0.08) for fibrosis stages F ≥ 2 and k=0.77 (0.09) and k=0.75 (0.08) for cirrhosis in intra- and interobserver analysis, respectively. Agreement was improved when operator's experience was higher than 100 exams. However, it was observed discordance for fibrosis staging between examinations in a quarter of patients.

CONCLUSION

Although there was a considerable discrepancy on fibrosis staging between examinations and a small power, transient elastography had an acceptable reproducibility in our population. Performance of at least 100 examinations should be used to define an experimented operator.

Factors That Could Impact on Liver Fibrosis Staging by Transient Elastography

Transient elastography (TE) based on liver stiffness measurement (LSM) is one of the most validated noninvasive methods for liver fibrosis staging in patients with chronic liver diseases. This method is painless, has no potential complications, is rapid (<10 min), and can be performed at the patient's bedside. However, several points should be considered when interpreting TE results. This review aims to discuss the critical points that might influence liver stiffness and TE results. Spectrum bias and the impact of the prevalence of fibrosis stages should be taken into account when interpreting the studies that validated this method using liver biopsy as a gold-standard. LSM might be influenced by nonfasting status, flare of transaminases, heart failure, extrahepatic cholestasis, presence of steatosis, aetiology of liver disease, type and position of probe, and operator's experience. In addition, interobserver variability can impact on the management of patients with chronic liver diseases. TE should be performed by an experienced operator (>100 exams), in a 3-hour fasting status, and its results should be handled by specialist clinicians that are aware of the limitations of this method.

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

The feasibility and reproducibility of liver stiffness measurements using Supersonic Shear-wave Imaging (SSI) in preterm neonate have not been reported. Our aim was to determine if liver stiffness differs between intra-uterine growth restriction (IUGR) and appropriate for gestational age (AGA) preterm infants with/without cholestasis. We measured liver stiffness (in kPa) in 45 AGA and 18 IUGR preterm infants, and assessed reproducibility in 26 preterms using Intraclass Correlation Coefficients (ICC) and Bland-Altman tests. Liver stiffness values were compared between AGA and IUGR with and without cholestasis and correlated with birth weight. Measurements showed high reproducibility (ICC = 0.94–0.98 for intra-operator, 0.86 for inter-operator) with good agreement (95% limits: -1.24 to 1.24 kPa). During the first postnatal week, liver stiffness was higher in IUGR (7.50 ±1.53 kPa) than in AGA infants (5.11 ±0.80 kPa, p<0.001). After day 8, liver stiffness remained unchanged in AGA but increased progressively in IUGR infants (15.57 ±6.49 kPa after day 21). Liver stiffness was higher in IUGR neonates with cholestasis (19.35 ± 9.80 kPa) than without cholestasis (7.72 ± 1.27 kPa, p<0.001). In conclusion, quantitative liver SSI in preterms is feasible and reproducible. IUGR preterms who will develop cholestasis present high liver stiffness even at birth, before biological cholestasis occurs.

Factors Associated with the Quality of Transient Elastography

BACKGROUND

Transient elastography is a noninvasive method for the evaluation of fibrosis in chronic liver disease. However, its reliability is variable, and the factors associated with its accuracy have not been identified completely.

AIMS

To identify the factors associated with the reliability of transient elastography.

METHODS

A total of 2033 transient elastography measurements were taken from March 2009 to October 2013. Reliability was determined according to the interquartile range/median (IQR/M < 0.30 = reliable; IQR/M < 0.10 = very reliable). Other indicators such as the percentage of successful measurements (>60 %), time of performance, and probe size were recorded. Potential factors that could affect the reliability of the procedure were analyzed using multivariate logistic regression.

RESULTS

Slightly less than 5 % of the measurements were unsuccessful, and 83 % of the successful measurements were found to be reliable. Factors associated with an unsuccessful measurement were female gender, incorrect probe size, and the presence of HCV infection. Unreliable measurements were associated with use of the procedure as part of a clinical study and success rate. Very reliable evaluations were associated with >10 measurements, the presence of chronic hepatic disease, and a success rate of >60 %.

CONCLUSIONS

The operator and clinical and anthropometric characteristics are factors that influence the success and reliability of transient elastography. Improvements in the quality of the procedure are needed to provide better diagnostic accuracy in clinical practice.

Interobserver variability in transient elastography analysis of patients with chronic hepatitis C

BACKGROUND & AIMS

Transient elastography based on liver stiffness measurement is a non-invasive method to assess hepatic fibrosis. However, interobserver variability has led to controversy over its use in fibrosis evaluation. To evaluate the interobserver variation in transient elastography in chronic hepatitis C.

METHODS

We performed a cross-sectional study, analysing findings from two experienced operators who each assessed 195 patients by transient elastography on the same day. Liver stiffness measurement used to define fibrosis stages, based on METAVIR score, was: <7.1 as F0F1, 7.1-9.4 as F2, 9.5-12.4, as F3 and >12.4 kPa as F4. We also assessed interobserver variation in identification of potential oesophageal varices screening based on transient elastography.

RESULTS

The interobserver intraclass correlation coefficient was 0.940 (95% CI 0.863-0.967) and measurements made by operators correlated [Spearman's ρ = 0.924; P < 0.001]. However, the median liver stiffness measurement assessed by first operators was higher (11.5 vs 9.8 kPa; P < 0.001). The discordance between operators was 35% for at least one stage of fibrosis and 5% for two or more stages. Interobserver reliability values were κ = 0.61 for fibrosis stages F ≥ 2 and κ = 0.80 for cirrhosis. Among the 74 patients determined to have cirrhosis by at least one operator, there was considerable discordance in identification of those with indication for oesophageal varices screening (κ values from 0.13 to 0.61) according to several cut-offs.

CONCLUSION

Although a high correlation of liver stiffness measurement between operators, interobserver variability in transient elastography was not negligible. This method should not be used as the only screening tool for oesophageal varices in chronic hepatitis C.

Significant variations in elastometry measurements made within short-term in patients with chronic liver diseases

BACKGROUND & AIMS

Transient elastometry is a noninvasive procedure used to measure fibrosis when patients are diagnosed with liver disease; it might be used to monitor changes over time. We investigated whether there are short-term variations in stiffness measurements that are not attributable to changes in fibrosis by studying patients with stable liver disease.

METHODS

We performed a retrospective analysis of 531 paired liver stiffness measurements made by Fibroscan when the study began (LSM1) and at follow-up (LSM2), more than 1 day and less than 1 year apart, from 432 stable (for body mass index, waist circumference, and alcohol consumption), untreated, immunocompetent patients with chronic liver disease (from January 2006 through March 2009). Variations between the first and follow-up measurements were expressed as absolute (LSM2-LSM1, kPa) or relative ([LSM2-LSM1]/LSM1*100) or as changes in fibrosis stage.

RESULTS

There was >20% variation in 49.7%, >30% in 34.3%, and >50% in 12.2% of paired measurements; this variation was constant across the spectrum of LSM1 values. The variations produced a 1-fibrosis stage difference in 31.5% of pairs and a ≥ 2-stage difference in 9.8% of pairs. Patients with LSM1 >7 kPa had increased probability of having a different stage of fibrosis at LSM2, compared with patients with LSM1 <7 kPa. Factors associated with variation included measurements made by 2 different operators or at least 1 non-senior operator, ratios of interquartile range:median values, significant fibrosis (≥ 7 kPa) at LSM1, baseline body mass index, or a 2-fold difference in level of alanine aminotransferase between measurements. When the analyses were restricted to measurements made by the same operator, the variation was slightly reduced; fibrosis stage differed between measurements for only 34.3% of cases.

CONCLUSIONS

Operator-related and patient-related factors produce significant variations in liver stiffness measurements made by transient elastometry, limiting its use in monitoring patients. These variations are unrelated to disease progression. The lowest levels of variation occur in measurements made in patients with no or early-stage fibrosis or by a single experienced operator.

Egy-score as a noninvasive score for the assessment of hepatic fibrosis in chronic hepatitis C: a preliminary approach

BACKGROUND AND AIMS

Egy-Score is a new noninvasive score for prediction of severe hepatic fibrosis in patients with chronic liver diseases. The aim of this study was to validate Egy-Score as a noninvasive score for predicting stage of hepatic fibrosis in a group of Egyptian chronic hepatitis C patients.

PATIENTS AND METHODS

One hundred Egyptian patients with chronic hepatitis C were enrolled. Mean age was 40.25 ± 9.39 years. They were subjected to CA19-9, alpha-2-macroglobulin, total bilirubin, platelet count and albumin, liver biopsy, and histopathological staging of hepatic fibrosis according to METAVIR scoring system as part of their assessment for treatment. Egy-Score was calculated according to the following formula: Egy-Score = 3.52 + 0.0063 × CA19-9 + 0.0203 × age + 0.4485 × alpha-2-macroglobulin + 0.0303 × bilirubin - 0.0048 × platelet - 0.0462 × albumin. Egy-Score results were correlated to the stage of hepatic fibrosis.

RESULTS

Egy-Score correlates positively with the stage of hepatic fibrosis (F0-F4). Egy-Score was able to differentiate significant hepatic fibrosis, severe hepatic fibrosis, and cirrhosis accurately. Cutoff values of Egy-Score were 2.91850 (for significant fibrosis), 3.28624 (for severe fibrosis), and 3.67570 (for cirrhosis). Sensitivity, specificity, and areas-under-ROC curve (AUROCs) were 75.8%, 68.42%, and 0.776 (for significant fibrosis "≥F2"), 91.67%, 77.63%, and 0.875 (for severe fibrosis "≥F3"), and 81.82%, 86.52%, and 0.874 (for cirrhosis "F4"), respectively.

CONCLUSION

Egy-Score is a useful noninvasive panel of surrogate biomarkers that could accurately predict different stages of hepatic fibrosis in patients with chronic hepatitis C.

Application and limitations of transient liver elastography in children

OBJECTIVES

Transient elastography (TE) using the FibroScan has gained popularity recently for the noninvasive diagnosis of hepatic fibrosis. Data on its use in children younger than 6 years are still scarce, and the influence of technical aspects such as probe choice and site of measurement on FibroScan results is not clear. Our study aims to clarify some technical issues concerning the use of the FibroScan in children and to deliver normal FibroScan values for reference.

METHODS

TE was performed in 527 children (229 girls, ages 0.1-17.8 [median 6.0] years, including 400 healthy controls). Feasibility of different sites of measurements, paired comparison of probe settings, and pre- and postprandial measurements were systematically performed. Sedated versus unsedated measurements were compared in age- and sex-matched cohorts.

RESULTS

Success rate of TE in our population was 90%, but decreased to 83% in children younger than 24 months even in ideal conditions. General anesthesia significantly increased liver stiffness in healthy children (5.4 [3-9.5] vs 4.2 [2.8-8.15] kPa; P < 0.01). Probe choice equally influenced results in paired comparisons (S1 5.5 [3.5-17.9] vs S2 4.8 [2.1-15.4] kPa; P < 0.01), as did food intake (5.9 [3.6-75] vs 5.4 [3.6-63.9] kPa; P = 0.015). Inter- and intraobserver agreements were good. Normal liver stiffness was 4.5 (2.5-8.9) kPa and did not vary significantly with age or sex.

CONCLUSIONS

TE is feasible even in extremely young children, but confounding influences on test results such as probe choice, sedation, or food intake need to be taken into account when interpreting results.