Intra- and Inter-Observer Reproducibility of a 2-D Shear Wave Elastography Technique and the Impact of Ultrasound Experience in Achieving Reliable Data

Assessment of the liver with two-dimensional shear wave elastography following COVID-19 infection: A pilot study

Introduction/Purpose

The coronavirus disease (COVID-19) is a widely spread viral infectious disease, which can impact multiple organs, including the liver. Elevated liver enzymes have been reported in COVID-19 patients; however, potential changes in liver stiffness following the viral infection remain uncertain. The main aim of this pilot study was to determine if there is a significant difference in liver stiffness between individuals who have never been infected with COVID-19 and those who had been infected with COVID-19 <6 months, experiencing only mild symptoms. The secondary aim was to compare the liver stiffness between participants infected with COVID-19 depending on the elapsed time since infection.

Methods

Two-dimensional shear wave elastography (2D-SWE) was performed prospectively on 68 participants. Thirty-four participants had been infected with COVID-19 (all for <6 months) (COVID-19 group), and another 34 had never been infected with COVID-19 (control group). The mean 2D-SWE measurements of both the COVID-19 group and the control group were compared using an independent t-test. The mean 2D-SWE measurements of the COVID-19 subgroups A (<2 months), B (2 to <4 months) and C (4 to <6 months) were compared using a one-way ANOVA test (P < 0.05).

Results

The (mean ± standard deviation) liver stiffness (kPa) of the COVID-19 group (5.26 ± 1.63 kPa) was significantly higher than the control group (4.30 ± 0.96 kPa) (P = 0.005). There was no significant difference in liver stiffness among subgroups A (5.20 ± 1.79 kPa), B (4.70 ± 1.53 kPa) and C (5.96 ± 1.48 kPa) (P = 0.143) respectively.

Discussion

The mean liver stiffness of 4.30  ±  0.96k Pa in the control group showed a high probability of being normal as per guidelines. Conversely, the mean liver stiffness of 5.26  ±  1.63 kPa in the COVID-19 group exhibited a statistically significant increase compared to the control group. However, compensated advanced chronic liver disease was ruled out without other known clinical signs, as per guidelines.

Conclusion

A statistically significant increase in liver stiffness value was observed in the post-COVID-19 infection group compared to the group who had never been infected. This highlights the potential for short-term impact on liver stiffness associated with COVID-19 infection. However, it is unclear if these changes in liver stiffness are associated with liver injury. Further study is warranted to investigate the effects of COVID-19 infection and its long-term impact on the liver.

Artifacts in two-dimensional shear wave elastography of liver

BACKGROUND

Artifacts are common when using two-dimensional shear wave elastography (2-D SWE) to measure liver stiffness (LS), but they are poorly recognized.

AIM

To investigate the presence and influence of artifacts in 2-D SWE of liver.

METHODS

We included 158 patients with chronic liver disease, who underwent 2-D SWE examination by a novice and an expert. A cross line at the center of the elastogram was drawn and was divided it into four locations: top-left, top-right, bottom-left, and bottom-right. The occurrence frequency of artifacts in different locations was compared. The influence of artifacts on the LS measurements was evaluated by comparing the elastogram with the most artifacts (EMA) and the elastogram with the least artifacts (ELA).

RESULTS

The percentage of elastograms with artifacts in the novice (51.7%) was significantly higher than that of the expert (19.6%) (P < 0.001). It was found that both operators had the highest frequency of artifacts at bottom-left, followed by top-left and bottom-right, and top-right had the lowest frequency. The LS values (LSVs) and standard deviation values of EMAs were significantly higher than those of ELAs for both operators. An intraclass correlation coefficient value of 0.96 was found in the LSVs of EMAs of the two operators, and it increased to 0.98 when the LSVs of the ELAs were used. Both operators had lower stability index values for EMAs than ELAs, but the difference was only statistically significant for the novice.

CONCLUSION

Artifacts are common when using 2-D SWE to measure LS, especially for the novice. Artifacts may lead to the overestimation of LS and reduce the repeatability and reliability of LS measurements.

A single-center, retrospective, cross-sectional study comparing the number of non-diagnostic measurements ratio in the pSWE and SSI ultrasound elastography methods

The point shear wave elastography and supersonic shear imaging methods were compared regarding incorrect measurements during the liver examinations. A report-based, single-center, retrospective analysis of 425 liver elastography examinations was performed. A lower success ratio was observed for the point shear wave elastography method, as well as the older and obese patients pre-dominated in non-diagnostic studies. In our center experience, it is easier to obtain diagnostic data using the supersonic shear imaging method. However, further investigation of the subject is needed.

Ultrasound shear wave elastography for patients with sialolithiasis undergoing interventional sialendoscopy

Objective

Ultrasound shear wave elastography is an objective tool to evaluate the stiffness of human tissues. Patients with sialolithiasis could be treated by interventional sialendoscopy with a high success rate. Sialolithiasis could be extracted, and the diseased gland could be preserved and evaluated after treatment. Whether ultrasound shear wave elastography could be used for objective outcome measurement and short-term follow-up of the parenchyma of gland in patients with sialolithiasis remains unclear.

Methods

This retrospective self-controlled study was conducted. Patients with sialolithiasis treated by interventional sialendoscopy and followed by high-resolution ultrasound shear wave elastography were selected between January and September 2017.

Results

Seventeen patients with sialolithiasis (mean age: 39.63 ± 12.49 years), including 10 women and 7 men, were enrolled. Fifteen patients had sialolithiasis in the submandibular gland and two in the parotid gland. The preoperative value of shear wave velocity was significantly higher in the diseased gland than in the contralateral normal gland (p < .001; 95% confidence interval [CI], 0.3915-0.6046). After successful treatment by interventional sialendoscopy surgery, the shear wave velocity of the diseased gland decreased significantly (p = 0.001; 95% CI, -0.38792 to -0.20474). However, there was a significant difference between the diseased and contralateral normal glands (p = 0.001; 95% CI, 0.0423-0.2895) after 1.55 months of surgery.

Conclusion

Ultrasound shear wave elastography could be an adjuvant tool to distinguish sialolithiasis-affected diseased glands from contralateral normal glands and assess the short-term treatment outcome objectively. The changing trend of shear wave velocity could help monitor the healing process of the parenchyma in the diseased gland after treatment.

Level of Evidence

4.

Diagnostic performance of 2D-shear wave elastography and serum fibrosis markers for evaluation of hepatic graft fibrosis in pediatric liver-inclusive transplant recipients: A prospective pilot study

BACKGROUND

Liver biopsy is the gold standard for hepatic fibrosis staging, but it is invasive and has potential severe complications. We aimed to determine the diagnostic performance of 2D-SWE and serum markers to predict significant hepatic graft fibrosis (≥F2) in pediatric liver-inclusive transplant recipients.

METHODS

This prospective, cross-sectional pilot study included children younger than 19 years who had received a LT or LSBT and underwent a liver biopsy performed for clinical indications. LS was measured using 2D-SWE. The AUROC was calculated to evaluate the diagnostic performance of 2D-SWE and biomarkers (AST/ALT ratio, APRI, FIB4) for predicting significant fibrosis.

RESULTS

Twenty-two children (13 males, 8 LSBT) were included. Eighteen (81.8%) children received a whole liver graft. Thirteen (59.1%) patients had hepatic fibrosis (≥F1) and four (18.2%) had significant fibrosis. The AUROCs of AST/ALT ratio, APRI, and FIB4 for predicting significant hepatic graft fibrosis were 0.71 (p = .29), 0.85 (p = .0001), and 0.76 (p = .03), respectively. When FIB4 was calculated using the hepatic graft's age, its AUROC improved to 0.85 (p < .0001). The AUROC of 2D-SWE for predicting significant hepatic graft fibrosis was 0.80 (p = .046). When 2D-SWE was combined with APRI or FIB4, its AUROC improved to 0.82 (p = .08) and 0.87 (p = .002), respectively.

CONCLUSIONS

APRI and FIB4 can accurately predict significant hepatic graft fibrosis. 2D-SWE may serve as a valuable adjunct tool to detect significant graft fibrosis, especially when combined with these serum markers.

Direct Comparison of US and MR Elastography for Staging Liver Fibrosis in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

As alternatives to the expensive liver biopsy for assessing liver fibrosis stage in patients with nonalcoholic fatty liver disease (NAFLD), we directly compared the diagnostic abilities of magnetic resonance elastography (MRE), vibration-controlled transient elastography (VCTE), and two-dimensional shear wave elastography (2D-SWE).

METHODS

Overall, 231 patients with biopsy-proven NAFLD were included. Intra- and inter-observer reproducibility was analyzed using intraclass correlation coefficient in a sub-group of 70 participants, in whom liver stiffness measurement (LSM) was performed by an elastography expert and an ultrasound expert who was an elastography trainee on the same day.

RESULTS

Valid LSMs were obtained for 227, 220, 204, and 201 patients using MRE, VCTE, 2D-SWE, and all three modalities combined, respectively. Although the area under the curve did not differ between the modalities for detecting stage ≥1, ≥2, and ≥3 liver fibrosis, it was higher for MRE than VCTE and 2D-SWE for stage 4. Sex was a significant predictor of discordance between VCTE and liver fibrosis stage. Skin-capsule distance and the ratio of the interquartile range of liver stiffness to the median were significantly associated with discordance between 2D-SWE and liver fibrosis stage. However, no factors were associated with discordance between MRE and liver fibrosis stage. Intra- and inter-observer reproducibility in detecting liver fibrosis was higher for MRE than VCTE and 2D-SWE.

CONCLUSIONS

MRE, VCTE, and 2D-SWE demonstrated excellent diagnostic accuracy in detecting liver fibrosis in patients with NAFLD. MRE demonstrated the highest diagnostic accuracy for stage 4 detection and intra- and inter-observer reproducibility. UMIN Clinical Trials Registry No. UMIN000031491.

Reliability of Performing Multiparametric Ultrasound in Adult Livers

PURPOSE

The aim of the study was to test inter-observer and intra-observer reliability of measuring multiparametric ultrasound in adult livers.

METHODS

We prospectively measured shear wave velocity (SWV, m/s), shear wave dispersion slope (SWD, m/s/kHz), attenuation coefficient (ATI, dB/cm/MHz), normalized local variance (NLV), and echo intensity ratio of liver to kidney (L/K ratio) in 21 adults who underwent liver magnetic resonance imaging-proton density fat fraction (MRI-PDFF). Intraclass correlation coefficient and 95% Bland-Altman limits of agreement (95% LOA) were used to analyze intra- and inter-observer reproducibility.

RESULTS

Based on liver MRI-PDFF, 21 participants (8 men and 13 women, mean age 55 years) were divided into group 1 (11 normal livers, MRI-PDFF <5%) and group 2 (10 steatotic livers, MRI-PDFF ≥5%). ICCs for intra-observer repeatability and inter-observer reproducibility in measuring multiple ultrasound parameters in both normal and steatotic livers were above 0.75. However, 95% confidence interval for measuring SWD in all livers and L/K ratio in normal livers was 0.38-0.90 and 0.47-0.91, respectively. Differences in SWV, SWD, ATI, NLV, L/K ratio, and MRI-PDFF between participants with and without hepatic steatosis were significant (p < .05), whereas serum biomarkers and body mass index were not (p > .05), based on a two-tailed t-test.

CONCLUSIONS

The results suggest that the repeatability and reproducibility for measuring liver SWV, ATI, and NLV are moderate to excellent, while those for SWD and L/K ratio are poor. Standardized machine settings, scanning protocols, and operator training are suggested in performing multiparametric ultrasound of the liver.

Quantification of fluoroscopic fundoplication anatomy: inter- and intraobserver reliability

The etiology of postfundoplication dysphagia remains incompletely understood. Subtle changes of gastroesophageal junction (GEJ) anatomy may be contributory. Barium swallows have potential for standardization to evaluate postsurgical anatomical features. Using structured barium swallows, we aim to identify reproducible, objectively measured postfundoplication anatomical features that will permit future comparison between patients with/without dysphagia. At 6-12 months of postfundoplication, 31 patients underwent structured barium swallow with video-fluoroscopy recording: standing anteroposterior; standing oblique (×2); prone oblique (×2); and prone oblique with continuous free drinking. A primary observer recorded 11 variables of GEJ anatomy for each view, repeated 3 months later, forming two datasets to assess intraobserver consistency. Interobserver reliability was determined using a dataset each from the primary observer and two medical students (after training). Intraclass correlation coefficients (ICC) were based on two-way mixed-effects model (ICC agreement: 0.40-0.59 'fair'; 0.60-0.74 'good'; 0.75-1.00 'excellent'). Interobserver reliability was good-excellent for 47 of 66 measurements. Measures of maximal esophageal diameter cf. wrap opening diameter and posterior esophageal angle showed high interobserver reproducibility on all views (ICC range 0.84-0.91; 0.68-0.80, respectively). Interobserver agreement was good-excellent for 5/6 views when measuring anterior GEJ displacement and axis deviation (ICC range 0.56-0.79; 0.41-0.77, respectively). Measures of wrap length showed lower reproducibility. Prone oblique measurements showed highest reproducibility (good-excellent agreement in 19/22 measurements). Intraobserver consistency was excellent for 98% of measurements (ICC range 0.74-0.99). Objective measurements of postfundoplication GEJ anatomy using structured barium swallow are reproducible and may allow further interrogation of anatomical features contributing to postfundoplication dysphagia.

Diagnosis of liver cirrhosis with two-dimensional shear wave elastography in biliary atresia before Kasai portoenterostomy

PURPOSE

To evaluate the application value of two-dimensional shear wave elastography (2D-SWE) for non-invasive diagnosis of liver cirrhosis (LC) in patients with biliary atresia (BA) before Kasai portoenterostomy (KP), and the cutoff value of liver stiffness measurement (LSM) for diagnosing LC.

METHODS

The clinical data of 51 patients with BA who were diagnosed via surgery and pathological results from May 2017 to December 2018 in the department of general surgery, Beijing Children's Hospital, Capital Medical University, were retrospectively analyzed. The liver tissue specimens obtained during KP were evaluated according to the METAVIR criteria. The LSM was obtained using the 2D-SWE technique before KP.

RESULTS

There was a grade positive correlation between LSM and METAVIR staging, and the Spearman correlation coefficient was 0.432 (P = 0.002). The AUC for 2D-SWE diagnosing LC (METAVIR score S = 4) in patients with BA before KP was 0.843 (95% confidence interval 0.736 ~ 0.950). The best cutoff value was 16.05 kPa, and the corresponding sensitivity was 75.0%, specificity was 83.7%, positive predictive value (PPV) was 46.1%, negative predictive value (NPV) was 94.7%, and the accuracy was 82.4%.

CONCLUSION

2D-SWE can be used to noninvasively diagnose LC in patients with BA before KP, and the cutoff value is 16.05 kPa.

Evaluation of Pre-malignant Lesions of the Uterine Cervix by Shear Wave Elastography: A New Diagnostic Tool

The objective of the study was to evaluate the difference in the stiffness between a healthy cervix (no pre-invasive lesions [NPILs]) and a cervix with a pre-invasive lesion (PIL). In the PIL group, we determined whether there was a difference in stiffness between the cervix with persistent low-grade lesions (>2 y, LSIL-persistent) and that with high-grade lesions (HSILs). Evaluation was performed using 2-D shear-wave elastography (SWE) in the midsagittal-plane of the uterine cervix (UC) at 0.5 cm (cervical canal, anterior and posterior cervical lips). In this prospective observational study (consecutive series), we evaluated 96 non-pregnant women: a group with PIL (LSIL-persistent, 22 cases; HSIL, 26 cases) with indications for cervical conization (48 cases) and a group without UC pathology (NPIL, 48 cases). Although we did not observe statistically significant differences (SSDs) in epidemiological characteristics, we did find an SSD in the speed and stiffness between the PIL versus NPIL groups at all evaluated depths (speed: 4.1 m/s vs 3.0 m/s, stiffness: 58.6 and 34.5kPa in the PIL and NPIL groups, respectively, p < 0.001). An SSD in speed and stiffness (speed: 4.9 m/s vs. 3.2 m/s, and stiffness: 76.1 and 38.0 kPa) between the HSIL (26 cases) and LSIL-persistent (22 cases) groups, respectively, was also detected (p < 0.001). The area under the curve of speed differentiation between a cervix with HSILs and without lesions was 73.4% (95% confidence interval [CI]: 63.1-83.7), and the best cutoff of speed was 3.25 m/s (sensitivity = 62.5%, 95% CI: 47.3-76.0), with a specificity of 75.5% (95% CI: 60.4-87.1).

Reliability of performing ultrasound derived SWE and fat fraction in adult livers

PURPOSE

The aim of the study was to test the reproducibility of performing conventional point shear wave elastography (pSWE), auto-pSWE, and ultrasound derived fat fraction (UDFF) in adult livers.

METHODS

The Institutional Review Board approved the study and all participants provided written informed consent. Conventional pSWE (obtaining 10 measurements through 10 acquisitions), auto-pSWE (automatically obtaining 15 measurements by a single acquisition), and UDFF (one measurement obtained by one acquisition) of the liver were prospectively performed in 21 participants (10 men, 11 women, mean age 63y) by senior and junior operators in February-May 2021. Shear wave velocity (SWV, m/s) of the liver was measured by conventional pSWE and auto-pSWE. Intraclass correlation coefficient (ICC) and Bland-Altman limits of agreement were used to test intra-observer repeatability and inter-observer reproducibility in measuring pSWE, auto-pSWE, and UDFF.

RESULTS

ICC for testing intra-observer repeatability and inter-observer reproducibility in performing pSWE, auto-pSWE, and UDFF was >0.85 (95% confidence interval 0.85-0.99). The mean difference of 95% Bland-Altman limits of agreement was -0.02 (upper 0.09, lower -0.12) and the correlation of SWV measured between conventional pSWE and auto-pSWE methods was strong (r² = 0.87).

CONCLUSION

Our results suggest good repeatability and reproducibility in measuring UDFF and SWV in adult livers. The auto-pSWE has higher reliability, reproducibility and time efficacy in measuring SWV of adult livers when compared to conventional pSWE method.

Liver stiffness assessed by shear-wave elastography declines in parallel with immunoregulatory proteins in patients with chronic HCV infection during DAA therapy

BACKGROUND

A rapid decline of liver stiffness (LS) was detected by non-invasive methods in patients with chronic hepatitis C (HCV) infection during treatment with direct-acting antivirals (DAA).

OBJECTIVE

To investigate the influence of inflammation on LS.

METHODS

We prospectively examined LS by sonographic shear-wave elastography in 217 patients during DAA therapy from treatment initiation (BL) to 12 weeks after end of therapy (SVR12). Demographic data, laboratory findings and serum levels of cytokines were determined.

RESULTS

Values of LS decreased from 1.86 m/s to 1.68 m/s (p = 0.01) which was most pronounced in patients who had F4 fibrosis at BL (3.27 m/s to 2.37 m/s; p <  0.001). Initially elevated values of aminotransferases, ferritin, IgG (p <  0.001 each) and international normalized ratio (p <  0.003) declined, thrombocyte count (p = 0.007) increased. Correlations of these laboratory parameters with BL levels of LS measurement (LSM) were most apparent in patients with F1-F3 fibrosis. Tumor necrosis factor (TNF)-α (p = 0.031), interleukin (IL)-10 (p = 0.005) and interferon y inducible protein (IP)-10 (p <  0.001) decreased in parallel with LSM under DAA therapy and corelated with BL values.

CONCLUSION

Decrease of systemic inflammatory parameters correlated with LSM under DAA therapy. We conclude that regression of LSM is attributable to the decline of inflammation rather than reflecting fibrosis.

Assessing Baveno VI Criteria Using Liver Stiffness Measured with a 2D-Shear Wave Elastography Technique

The present study evaluates the performance of Baveno VI criteria, using liver stiffness (LS) assessed with a 2D-SWE elastography technique, for predicting high-risk varices (HRV) in patients with compensated advanced chronic liver disease (cACLD). A secondary aim was to determine whether the use of spleen stiffness measurements (SSMs), as additional criteria, increases the performance of the 2D-SWE Baveno VI criteria. Data were collected from 208 subjects with cACLD, who underwent abdominal ultrasound, liver and spleen stiffness measurements, and upper digestive endoscopy. HRV were defined as grade 1 esophageal varices (EV) with red wale marks, grade 2/3 EV, and gastric varices. A total of 35.6% (74/208) of the included subjects had HRV. The optimal LS cut-off value for predicting HRV was 12 kPa (AUROC-0.80). Using both LS cut-off value < 12 kPa and a platelet cut-off value > 150 × 109 cells/L as criteria to exclude HRV, 52/208 (25%) subjects were selected, 88.5% (46/52) were without EV, 9.6% (5/52) had grade 1 EV, and 1.9% (1/52) had HRV. Thus 98% of the subjects were correctly classified as having or not having HRV and 25% of the surveillance endoscopies could have been avoided. Using SS < 13.2 kPa and a platelet cut-off value > 150 × 109 cells/L as additional criteria for the patients that were outside the initial ones, 32.7% of the surveillance endoscopies could have been avoided.

Quantitative Evaluation of Neonatal Brain Elasticity Using Shear Wave Elastography

OBJECTIVES

To demonstrate the feasibility of 2-dimensional brain ultrasound shear wave elastography (SWE) and to define the average elasticity values of the gray and white matter in term neonates.

METHODS

This work was a prospective observational single-center study including 55 healthy term neonates consecutively recruited in the maternity ward between the second and third postnatal days. All were successfully evaluated with a cerebral SWE examination performed with a multifrequency 4-9-MHz transducer. Bilateral sagittal planes of the thalamus and corona radiata were used to measure stiffness using a quantitative SWE method. Several elastograms with 5 to 15 nonoverlapping areas were obtained from the 2 different anatomic locations. The 5 most central measurements were averaged as representative values.

RESULTS

The 55 neonates ranged from 37 to 40 weeks' gestation. The estimated mean velocity values of the thalamus (1.17 m/s; 95% confidence interval, 1.13, 1.22 m/s) and corona radiata (1.60 m/s; 95% confidence interval, 1.57, 1.64 m/s) were statistically different (P < .001). There was no significant influence of laterality, gestational age, cephalic perimeter, sex, length, or type of delivery on the stiffness measurements.

CONCLUSIONS

Brain ultrasound SWE is feasible and allows measurements of neonatal brain elasticity. The elasticity of the thalamus and corona radiata at the frontal white matter in healthy term neonates is different. The knowledge of normal SWE ranges in term neonates allows comparative studies under pathologic conditions.

Interobserver and Intraobserver Reliability of Hepatic Shear Wave Elastography and the Influence of Fasted Versus Nonfasted States in Healthy Volunteers

OBJECTIVES

The primary objective of this study was to assess the effect of fasting versus ingestion of food and water on hepatic measurements by shear wave elastography (SWE) in healthy participants. The secondary objective was to assess inter- and intra-reader reliability of hepatic elastography in healthy participants.

METHODS

Twenty healthy participants were enrolled in this prospective study and underwent quantitative SWE under fasting conditions and after the ingestion of water and food and water. Two blinded sonographers each independently performed a total of 6 sessions of hepatic SWE in each participant. Sessions 1 to 3 were performed on day 0 and sessions 4 to 6 on day 7. Statistical tests used included the Wilcoxon signed ranks test, the intraclass correlation coefficient, and Bland-Altman plots.

RESULTS

There were no significant differences in hepatic SWE measurements after the ingestion of water versus the fasting state. Statistical significance was assessed as P < 0.05. The postprandial status had a statistically significant effect on hepatic SWE measurements at 1 hour (P = .04) but not at 3 hours (P = .08). By the intraclass correlation coefficient, there was poor-to-moderate inter-reader agreement and minimal-to-moderate intra-reader agreement. The median inter-reader difference in SWE measurements ranged from 0.66 to 0.96 kPa. The median intra-reader difference ranged from 0.43 to 0.55 kPa.

CONCLUSIONS

Our study shows that the ingestion of water has no effect on hepatic SWE measurements in healthy participants. The postprandial state had a significant effect on SWE measurements at 1 hour after ingestion but not at 3 hours. The inter-reader and intra-reader agreements were variable and moderate at best.

Noninvasive assessment of liver fibrosis in a real-world cohort of patients with known or suspected chronic liver disease using 2D-shear wave elastography

OBJECTIVES

We aimed to investigate the diagnostic accuracy of liver stiffness measurement (LSM) by 2D-shear wave elastography (2D-SWE, GE, Logiq E9) in patients with known or suspected chronic liver disease and to define cutoff values for the different stages of fibrosis.

METHODS

First, we retrospectively enrolled 21 patients in a pilot study and validated the results in a prospective cohort of 70 patients between May 2017 and February 2019. In all patients, LSM and liver biopsy were performed. We analyzed the diagnostic accuracy of LSM for the different fibrosis stages and examined the impact of additional clinical parameters on LSM.

RESULTS

The success rate of LSM was 88.6%. In the prospective cohort, optimal cutoff values for F ≥ 1, F ≥ 2, F ≥ 3 and F = 4 were 6.24, 7.86, 8.05 and 10.74 kPa [area under the receiver operating characteristic curve (AUROC) 0.831, 0.913, 0.996 and 0.954]. In both cohorts and in the subgroup of patients with nonalcoholic fatty liver disease (NAFLD) (n = 35), a cutoff value of 8.05 kPa differentiates patients with advanced fibrosis (F ≥ 3) and patients with no or mild fibrosis (F0-F2) with high diagnostic accuracy (AUROC 0.995-1.000). Parameters such as age, sex, BMI, bilirubin- and alanine aminotransferase-level had no significant impact on LSM.

CONCLUSION

LSM by 2D-SWE is an excellent method to differentiate between patients with advanced fibrosis (F ≥ 3) and patients with no or mild fibrosis (F ≤ 2). We were able to show this also in a subgroup of patients with NAFLD.

Performance of a Noninvasive Time-Harmonic Elastography Technique for Liver Fibrosis Evaluation Using Vibration Controlled Transient Elastography as Reference Method

AIM

This study aimed to evaluate the diagnosis performance of time-harmonic elastography (THE) technique in real life in assessing liver fibrosis, considering vibration-controlled transient elastography (VCTE) as a reference method.

MATERIAL AND METHOD

We prospectively evaluated outpatients from the gastroenterology department. Liver stiffness (LS) was measured by the THE system by dedicated operators, and by VCTE by experienced operators. The diagnostic accuracy of THE in staging liver fibrosis was assessed. We also performed an intra- and interobserver reproducibility sub-analysis on a sub-group of 27 subjects, where liver stiffness measurements (LSM) were performed by a novice, an elastography expert, and an ultrasound expert.

RESULTS

Of the 165 patients, using VCTE cut-off values, 49.6% were F0-F1, 15.7% were F2, 6.6% were F3, and 28.1% were F4. A direct, significant and strong correlation (r = 0.82) was observed between LSM assessed by VCTE and THE, p < 0.0001. The cut-off for ruling out liver cirrhosis (LC) by THE on our study group was <1.61 m/s (7.77 kPa)-AUROC = 0.90 [95% CI (0.82-0.93)], Se = 90.7%, Sp = 66.6%, PPV = 55.7%, NPV = 93.9%. The cut-off for ruling in LC by THE was >1.83 m/s (10 kPa)-AUROC = 0.90 [95% CI (0.82-0.93)], p < 0.0001, Se = 65.1%, Sp = 96.7%, PPV = 90.3%, NPV = 85.7%. The overall agreement between examiners was excellent: 0.94 (95% CI: 0.89-0.97); still, the ICCs were higher for the more experienced elastography examiner: 0.92 (95% CI: 0.82-0.96) vs. 0.94 (95% CI: 0.87-0.97) vs. 0.97 (95% CI: 0.95-0.99).

CONCLUSIONS

THE is a feasible and reproducible elastography technique that can accurately rule in and rule out advanced liver disease.

Combination of liver graft sonographic grading and point shear wave elastography to reduce early allograft dysfunction after liver transplantation

OBJECTIVE

To analyze the performance of a liver graft sonographic grading system and point shear wave elastography (PSWE) in predicting early allograft dysfunction (EAD) after liver transplantation (LT).

METHODS

Successive brain-dead donors and liver recipients in our hospital from March 2017 to May 2018 were retrospectively recruited. All donors underwent PSWE examination, abdominal ultrasonography, and sonographic grading (grade 0 to grade 5). Donors with ≥ 10 valid PSWE examinations and a failure rate of < 60% were included. For all recipients, abdominal ultrasonography and blood tests for biologic parameters were performed preoperatively and daily postoperatively to screen for EAD. The recipients and their grafts were classified into EAD and non-EAD groups. Statistical analyses were performed to analyze the correlations among liver stiffness (LS), liver graft sonographic grading, and EAD.

RESULTS

Thirty-two donors and 32 corresponding liver recipients were enrolled (15 cases in the EAD group; 17 in the non-EAD group). There were no grade 0, 1, or 2 cases in the two groups. For prediction of EAD in recipients after LT, the AUC for PSWE was 0.929 and the AUC for combination of PSWE and sonographic grading system was 0.935.

CONCLUSIONS

Combination of PSWE and sonographic grading system can predict postoperative EAD in LT recipients with high sensitivity. Abnormal results may suggest a need for liver biopsy preoperatively, thus avoiding unnecessary surgical preparation for liver procurement.

KEY POINTS

• Combination of PSWE with new sonographic grading system is useful for preoperative evaluation of liver grafts from brain-dead donors. • EAD is as a criterion for evaluating the diagnostic value of PSWE and sonographic grading system. • Combination of PSWE and sonographic grading system can predict postoperative EAD in LT recipients with high sensitivity.

Prospective comparison of 2D-shearwave elastography in both liver lobes in healthy subjects and in patients with chronic liver disease

Background/aims: 2D-shearwave elastography is an established method for liver stiffness measurement (LSM). However, the success rate of LSM using the recommended standard technique in the right lobe is limited by several factors. We aimed to compare LSM in the right and left liver lobe in order to evaluate whether LSM in the left lobe could be an alternative if measurements in the right lobe are not feasible. Methods: A total of 116 subjects, 58 healthy volunteers and 58 patients with chronic liver disease (CLD), were prospectively included. LSM were performed in the right lobe and in the left lobe, both in neutral and in inspiration position. Results: LSM in the left lobe (8.39(±4.83)kPa) was significantly (p < .001) higher than LSM in the right lobe (6.27(±2.45)kPa). LSM in inspiration position (8.60(±4.33) kPa) was significantly (p = .009) higher than LSM in neutral position (7.70(±3.01)kPa). LSM in the left lobe overestimated the grade of fibrosis in 50.0% of the patients with CLD. However, correlation between LSM values right and left was strong (r = 0.856) and additional use of LSM in the left lobe increased the success rate from 106/116 (91.4%) to 112/116 (96.6%; p = .098). High skin-to-liver-capsule-distance and presence of ascites were independent risk factors for non-successful LSM. Conclusions: Despite significantly higher values, LSM in the left lobe may be an alternative if LSM in the right lobe is not feasible, and cirrhosis can be ruled out with high probability if LSM is within the normal range.

Current Imaging Techniques for Noninvasive Staging of Hepatic Fibrosis

OBJECTIVE. The purpose of this article is to discuss quantitative methods of CT, MRI, and ultrasound (US) for noninvasive staging of hepatic fibrosis. Hepatic fibrosis is the hallmark of chronic liver disease (CLD), and staging by random liver biopsy is invasive and prone to sampling errors and subjectivity. Several noninvasive quantitative imaging methods are under development or in clinical use. The accuracy, precision, technical aspects, advantages, and disadvantages of each method are discussed. CONCLUSION. The most promising methods are the liver surface nodularity score using CT and measurement of liver stiffness using MR elastography or US elastography.

Evaluation of liver stiffness by 2D-SWE in combination with non-invasive parameters as predictors for esophageal varices in patients with advanced chronic liver disease

Background/aims: Esophageal varices (EV) are common complications in patients with advanced chronic liver disease (ACLD). Non-invasive parameters to exclude EV in patients with ACLD would be desirable. The aim of this study was the evaluation of liver stiffness measurement (LSM) using 2D-shear wave elastography (GE Logiq E9) and other non-invasive parameters as predictors for EV. Methods: Hundred patients with ACLD were enrolled. Abdominal sonography, including measurement of gall bladder wall thickness (GBWT), spleen diameter and LSM, gastroscopy and blood test results were evaluated. Statistical analyses were performed for the association between EV and non-invasive parameters. Results: Fifty-one per cent of the patients had EV. The mean LSM (14.6 kPa) and GBWT (3.88 mm) in the group with EV were significantly higher than in the group without EV (10.6 kPa; 2.94 mm; p < .01). Performing area under the receiver operating characteristic curve, LSM has a better diagnostic performance (0.781) than GBWT (0.707), spleen diameter (0.672) and platelet count (0.635). Combining LSM (cut-off 13.58 kPa) and GBWT (cut-off 3.07 mm) resulted in a sensitivity of 86.3% and a specificity of 71.4% for the presence of EV. A sensitivity of 100% (negative predictive value 1.0) was achieved at LSM >9 kPa or GBWT >4 mm. Following these criteria in our current study population, 18% of the gastroscopies could have been avoided. Conclusions: Combining LSM with non-invasive parameters, especially GBWT, improves the diagnostic accuracy for predicting EV. We suggest reconsidering screening gastroscopy in patients with ACLD who show LSM <9 kPa and GBWT <4 mm due to the very low risk of having varices.

Impact of Food Intake on Liver Stiffness Determined by 2-D Shear Wave Elastography: Prospective Interventional Study in 100 Healthy Patients

The aim was to evaluate the influence of food intake on liver stiffness measurement (LSM), performed with 2-D shear wave elastography (Logiq E9, GE Medical Systems, Wauwatosa, WI, USA). One hundred healthy volunteers were prospectively enrolled. Mean age was 25.8 (19-55) y, and mean body mass index was 22.43 (17.3-30.8) kg/m². Patients fasted for at least 3 h and subsequently ingested a liquid meal of 800 kcal. Liver stiffness and portal vein velocity were measured before and after food intake. Food intake resulted in significantly higher LSM values compared with baseline LSM (5.74 ± 0.94 kPa vs. 4.80 ± 0.94 kPa, p < 0.001). On multiple linear regression analysis, body mass index was significantly positively correlated with the LSM increase after food intake (p = 0.01). No correlation between the increase in LSM and the increase in post-prandial portal vein velocity was observed (r = 0.09). In summary, food intake has a significant influence on LSM. There is an 11% risk of misclassifying non-fasting, healthy patients as having significant fibrosis.