Prospective Comparison of Liver Stiffness Measurements between Two Point Shear Wave Elastography Methods: Virtual Touch Quantification and Elastography Point Quantification

Validation of a screening algorithm for hepatic fibrosis by Doppler ultrasound and elastography in a general population

BACKGROUND

Early detection can prevent the initial stages of fibrosis from progressing to cirrhosis.

PURPOSE

To evaluate an algorithm combining three echographic indicators and elastographic measurements to screen for hepatic fibrosis in an unselected population.

MATERIAL AND METHODS

From May 2017 to June 2018, all patients with no history and no known chronic liver disease who were referred for an ultrasound (US) were prospectively included in eight hospitals. The indicators being sought were liver surface irregularity, demodulation of hepatic veins, and spleen length >110 mm. Patients presenting at least one of these underwent elastography measurements with virtual touch quantification (VTQ) or supersonic shear imaging (SSI). If elastography was positive, patients were referred to hepatologist for fibrosis evaluation. Reference standard was obtained by FibroMeter^VCTE or biopsy. A FibroMeter^VCTE result >0.384 indicated a "necessary referral" to a hepatologist.

RESULTS

Of the 1501 patients included, 504 (33.6%) were positive for at least one US indicator. All of them underwent US elastography, with 85 being positive. Of the patients, 58 (3.6%) had a consultation with a liver specialist: 21 had positive FibroMeter^VCTE and nine had an indication of biopsy for suspicion of fibrosis. This screening algorithm made it possible to diagnose 1.6% of patients in our population with unknown fibrosis. Of the patients, 50% referred to the liver specialist were "necessary referrals."

CONCLUSION

Our study suggests that three simple US indicators with no systematic elastographic measurement could be applied in day-to-day practice to look for hepatic fibrosis in an unsuspected population allowing relevant referrals to a hepatologist.

Intra-individual comparison of twodimensional shear wave elastography techniques using plane wave imaging and the multi-beam technique: are they interchangeable in measuring liver fibrosis?

PURPOSE

This study compared two different two-dimensional shear wave elastography techniques-plane wave imaging (PWI) and multi-beam (MB) imaging-from the same vendor to evaluate liver fibrosis.

METHODS

In this prospective study, 42 patients with chronic liver disease who had recently undergone magnetic resonance elastography (<3 months) were enrolled, and their liver stiffness (LS) values were measured using PWI or MB. The LS values (kPa) were compared using the Wilcoxon rank-sum test. Inter-technique reproducibility and intra-observer repeatability were assessed using Bland-Altman analysis with 95% limits of agreement (LOA) and coefficients of variation (CVs). The cutoff values for predicting severe fibrosis (≥F3) were estimated using receiver operating characteristic curve (ROC) analysis, with magnetic resonance elastography as the reference standard.

RESULTS

PWI exhibited technical failure in four patients. Therefore, 38 patients underwent both examinations. The LS values showed moderate agreement between PWI and MB (CV, 22.5%) and 95% LOA of -3.71 to 7.44 kPa. The MB technique showed good intra-observer agreement (CV, 8.1%), while PWI showed moderate agreement (CV, 11.0%). The cutoff values of PWI and MB for diagnosing ≥F3 were 12.3 kPa and 13.8 kPa, respectively, with areas under the ROC curve of 0.89 and 0.95 (sensitivity, 100% and 100%; specificity, 65.6% and 85.7%).

CONCLUSION

The LS values significantly differed between PWI and MB, hindering their interchangeable use in longitudinal follow-up. Considering its low technical failure rate and better repeatability, the MB technique may be preferable for evaluating liver fibrosis in chronic liver disease patients.

Comparison of point-shear wave elastography (ElastPQ) and transient elastography (FibroScan) for liver fibrosis staging in patients with non-alcoholic fatty liver disease

BACKGROUND AND AIMS

ElastPQ is a point shear wave elastography technique used to non-invasively assess liver fibrosis. We compared liver stiffness measurements (LSM) by ElastPQ and fibroscan transient elastography (F-TE) in a cohort of patients with non-alcoholic fatty liver disease (NAFLD). We further evaluated the performance of ElastPQ in a subgroup of patients with available liver histology.

MATERIALS AND METHODS

We included patients with NAFLD who presented in a dedicated multidisciplinary clinic. Anthropometric parameters, blood tests and elastography measurements were obtained using F-TE and ElastPQ as part of routine clinical care.

RESULTS

We enrolled 671 patients with NAFLD, mean age 55.8 ± 13 years, body mass index (BMI) 31.5 ± 5.7 kg/m² , 56.6% males, 41% diabetes, 53.7% hypertension, 68% dyslipidaemia. ElastPQ showed an excellent correlation with F-TE (Spearman's r = 0.80, p < .001), which was better for mild/moderate stages of fibrosis. Independent predictors of a >2 kPa discrepancy between the two techniques were a larger waist circumference and F-TE ≥10 kPa. In the subgroup of 159 patients with available histology, ElastPQ showed similar diagnostic accuracy with F-TE in staging liver fibrosis (ElastPQ area under the curves 0.84, 0.83, 0.86 and 0.95, for F ≥ 1, F ≥ 2, F ≥ 3 and F = 4 respectively). Optimal cut-off values of ElastPQ for individual fibrosis stages were lower than those of F-TE.

CONCLUSIONS

ElastPQ shows an excellent correlation with F-TE in patients with NAFLD, which was better for lower LSM. The optimal cut-off values of ElastPQ are lower than those of F-TE for individual stages of fibrosis. ElastPQ has similar diagnostic accuracy to F-TE for all stages of fibrosis.

Optimization of Point-Shear Wave Elastography by Skin-to-Liver Distance to Assess Liver Fibrosis in Patients Undergoing Bariatric Surgery

Background: Obesity is a primary limiting factor in liver stiffness measurement (LSM). The impact of obesity has always been evaluated in terms of body mass index (BMI), without studying the effects of skin-to-liver distance (SLD) on LSM. We studied the impact of SLD on LSM in a cohort of obese patients undergoing bariatric surgery and intra-operatory liver biopsy. Materials and Methods: 299 patients underwent LSM by point-shear wave elastography (ElastPQ protocol), with two different ultrasound machines. SLD was measured as the distance between the skin and the liver capsule, perpendicular to where the region of interest (ROI) was positioned. We used the following arbitrary cut-offs: <5.7 kPa, F0–1; 5.7–7.99 kPa, F2; ≥8 kPa, F3–4. Results: We developed two logistic regression models using elastography–histology agreement (EHA) as the dependent variable and SLD as the independent variable. The model based on the second machine showed strongly more performant discriminative and calibration metrics (AIC 38.5, BIC 44.2, Nagelkerke Pseudo-R2 0.894, AUROC 0.90). The SLD cut-off value of 34.5 mm allowed a correct EHA with a sensitivity of 100%, a specificity of 93%, negative predictive value of 100%, positive predictive value of 87%, an accuracy of 96%, and positive likelihood ratio of 3.56. Conclusion: The impact of SLD is machine-dependent and should be taken into consideration when interpreting LSM. We believe that our findings may serve as a reference point for appropriate fibrosis stratification by liver elastography in obese patients.

Validation of a New Point Shear-Wave Elastography Method for Noninvasive Assessment of Liver Fibrosis: A Prospective Multicenter Study

Objective

To validate the diagnostic value of a new point shear-wave elastography method, S-shearwave elastography (S-SWE; Samsung Medison Co., Ltd.), in noninvasive assessment of liver fibrosis.

Materials and Methods

In this prospective multicenter study, liver stiffness (LS) measurements for 600 participants were obtained with both S-SWE and transient elastography (TE). The rates of unsuccessful LS measurements in S-SWE and TE were compared, and correlations between S-SWE and TE measurements were assessed. In 107 patients with histologic reference data, the optimal LS cut-off values for predicting severe fibrosis and cirrhosis on S-SWE were determined using receiver operating characteristic (ROC) curve analysis. The LS cut-off values in S-SWE were then validated in 463 patients without histologic reference data by using TE values as the reference standard, and the sensitivity and specificity of the cut-off values for predicting severe fibrosis and cirrhosis were calculated.

Results

The frequency of unsuccessful LS measurements on TE (4.5%, 27/600) was significantly higher than that (0.7%, 4/600) on S-SWE (p < 0.001). LS measurements on S-SWE showed a significant correlation with TE values (r = 0.880, p < 0.001). In 107 patients with histological reference data, the areas under the ROC curves on S-SWE were 0.845 and 0.850, with optimal cut-offs of 7.0 kilopascals (kPa) and 9.7 kPa, for the diagnosis of severe fibrosis and cirrhosis, respectively. Using these cut-off values, S-SWE showed sensitivities of 92.9% and 97.4% and specificities of 89.5% and 83.1% in TE-based evaluations of severe fibrosis and cirrhosis, respectively.

Conclusion

LS measurements on S-SWE were well correlated with those on TE. In addition, S-SWE provided good diagnostic performance for staging of hepatic fibrosis, with a lower rate of unsuccessful LS measurements compared with TE.

Impact of respiratory motion on liver stiffness measurements according to different shear wave elastography techniques and region of interest methods: a phantom study

Purpose

This study quantified the impact of respiratory motion on liver stiffness measurements according to different shear wave elastography (SWE) techniques and region of interest (ROI) methods, using liver fibrosis phantoms.

Methods

Three operators measured stiffness values in four phantoms with different stiffness on a moving platform with two SWE techniques (point-SWE [pSWE] and 2-dimensional SWE [2D-SWE]), three types of motion (static mode and moving mode at low and high speeds), and four ROI methods in 2D-SWE (circle, point, box, and multiple). The circular ROI method was used to compare the two SWE techniques. The occurrence of technical failure and unreliable measurements, stiffness values, and measurement time were evaluated.

Results

Technical failure was observed only in moving mode for pSWE and 2D-SWE (n=1 for both). Unreliable measurements were also only observed in moving mode and were significantly less common in 2D-SWE (n=1) than in pSWE (n=12) (P<0.001). No statistically significant differences in the technical failure rate or stiffness values were noted between the static and moving modes for both SWE techniques. The technical failure and unreliable measurement rates were not significantly different among the ROI methods for 2D-SWE. Stiffness values did not differ significantly according to the ROI method used in any moving mode. However, the multiple ROI method had significantly shorter measurement times than the circular ROI method for all moving modes.

Conclusion

2D-SWE may be preferable for evaluating liver fibrosis in patients with poor breath-hold. Furthermore, 2D-SWE with multiple ROIs enables rapid measurements, without affecting liver stiffness values.

Comparison of point and 2-dimensional shear wave elastography for the evaluation of liver fibrosis

PURPOSE

This study aimed to assess the technical performance of ElastQ Imaging compared with ElastPQ and to investigate the correlation between liver stiffness (LS) values obtained using these two techniques.

METHODS

This retrospective study included 249 patients who underwent LS measurements using both ElastPQ and ElastQ Imaging equipped on the same machine. The applicability, repeatability (coefficient of variation [CV]), acquisition time, and LS values were compared using the chi-square or Wilcoxon signed-rank tests. In the development group, the correlation between the LS values obtained by the two techniques was assessed with Spearman correlation coefficients and linear regression analysis. In the validation group, the agreement between the estimated and real LS values was evaluated using a Bland-Altman plot.

RESULTS

ElastQ Imaging had higher applicability (94.0% vs. 78.3%, P<0.001) and higher repeatability, with a lower median CV (0.127 vs. 0.164, P<0.001) than did ElastPQ. The median acquisition time of ElastQ Imaging was significantly shorter than that of ElastPQ (45.5 seconds vs. 96.5 seconds, P<0.001). The median LS value obtained using ElastQ Imaging was significantly higher than that obtained using ElastPQ (5.60 kPa vs. 5.23 kPa, P<0.001). The LS values between the two techniques exhibited a strong positive correlation (r=0.851, P<0.001) in the development group. The mean difference and 95% limits of agreement were 0.0 kPa (-3.9 to 3.9 kPa) in the validation group.

CONCLUSION

ElastQ Imaging may be more reliable and faster than ElastPQ, with strongly correlated LS measurements.

Ultrasound-based liver elastography in the assessment of fibrosis

Ultrasound-based elastography has rapidly replaced the need for liver biopsy in most patients with chronic liver disease in recent years. The technique is now widely supported by many manufacturers. This review will introduce various current ultrasound-based elastography techniques, review the physics and scanning techniques, discuss potential cofounding factors as well as summarising the evidence for its use in staging liver fibrosis using shear-wave elastography among different disease aetiologies. Future challenges and directions will be also be discussed.

Interobserver agreement and diagnostic accuracy of shearwave elastography for the staging of hepatitis C virus-associated liver fibrosis

PURPOSE

Our study aimed to evaluate the technical success rate, interobserver reproducibility, and accuracy of shearwave elastography (SWE) in the staging of hepatitis C virus (HCV)-associated liver fibrosis.

METHODS

A total of 10 healthy controls and 49 patients with chronic liver disease were enrolled prospectively. Two examiners performed point shearwave elastography (pSWE) and two-dimensional shearwave elastography (2D-SWE) measurements with an RS85A ultrasound scanner using the S-Shearwave application (Samsung Medison, Hongcheon, Korea). The performance of S-Shearwave in the staging (METAVIR F0-F4) of liver fibrosis was compared with prior transient elastography (TE) with receiver operating characteristic (ROC) curve analysis.

RESULTS

The interobserver reproducibility was excellent with pSWE (ICC = 0.92, 95% CI: 0.86-0.95, P < .001). A very good agreement was found between pSWE and TE measurements (ICC =0.85, 95% CI: 0.78-0.89, P < .001). The ROC analysis determined the optimal cut-off values of pSWE for the staging of chronic hepatitis C-associated fibrosis (F2, 1.46 m/s; F3, 1.63 m/s; F4, 1.95 m/s). Both observers achieved excellent diagnostic accuracy (AUROC: 94% vs 97%) in the detection of significant (≥F2) liver fibrosis.

CONCLUSION

The interobserver agreement is excellent with S-Shearwave pSWE, and observers can diagnose significant liver fibrosis with a comparable accuracy to TE.

Non-invasive assessment of hepatic fibrosis: comparison of MR elastography to transient elastography and intravoxel incoherent motion diffusion-weighted MRI

OBJECTIVE

To compare the ability of MR elastography (MRE) with transient elastography (TE) and intravoxel incoherent motion (IVIM) diffusion-weighted MRI in staging hepatic fibrosis (HF).

MATERIALS AND METHODS

100 patients with chronic liver disease and 25 healthy volunteers underwent preoperative MRE, IVIM on a 3T MRI unit, and ultrasound-based TE. Liver stiffness measurement from MRE (LSM-MRE) and liver stiffness measurement from TE (LSM-TE) were measured; four diffusion parameters including the true diffusion coefficient (D_t), pseudo-diffusion coefficient, perfusion fraction (f), and apparent diffusion coefficient (ADC) were calculated. Receiver operating characteristic (ROC) curves were performed for significant parameters to compare the diagnosis performance for detecting HF.

RESULTS

LSM-MRE and LSM-TE values showed positive correlation with the fibrosis stage (r = 0.910 and 0.813, P < 0.001). D_t, f, and ADC values showed negative correlation with the fibrosis stage (r = - 0.727, - 0.503, and - 0.601, all P < 0.001). The area under the ROC curve (AUC) of LSM-MRE (AUC = 0.965, 0.957, 0.983) was significantly higher than that of LSM-TE (AUC = 0.906, 0.913, 0.931) and D_t (AUC = 0.875, 0.879, 0.861) in discriminating significant HF (≥ F2), advanced HF (≥ F3), or cirrhosis (F4) (all P < 0.05). Although LSM-TE showed higher AUCs than D_t in detecting fibrosis stages, there were no significant differences between LSM-TE and D_t (P > 0.05) except for detecting F4 (P < 0.05).

CONCLUSION

MRE shows excellent diagnostic performance for predicting significant fibrosis, advanced fibrosis compared with TE and IVIM, while TE and IVIM have comparable diagnostic performance.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Inter-platform reproducibility of liver stiffness measured with two different point shear wave elastography techniques and 2-dimensional shear wave elastography using the comb-push technique

PURPOSE

The purpose of this study was to compare the technical success rate and reliability of measurements made using three shear wave elastography (SWE) techniques and to assess the inter-platform reproducibility of the resultant liver stiffness measurements.

METHODS

This prospective study included 54 patients with liver disease. Liver stiffness (LS) measurements were obtained using 2-point SWE techniques (Virtual Touch Quantification and S-Shearwave) and 2-dimensional (2D) SWE, with transient elastography (TE) serving as the reference standard. The technical success rates and measurement reliability of the three techniques were compared. LS values measured using the three SWE techniques and TE were compared using Spearman correlation coefficients and 95% Bland-Altman limits of agreement. Intra-class correlation coefficients (ICC) were used to analyze the inter-platform reproducibility of LS measurements.

RESULTS

The three SWE techniques and TE showed similar technical success rates (P=0.682) but demonstrated significant differences in the reliability of LS measurements (P=0.006) and mean LS measurements (P<0.001). Despite strong correlations (r=0.73-0.94) between SWE systems, various degrees of inter-platform reproducibility (ICC, 0.58-0.92) were observed for the three SWE techniques. The best agreement was observed between S-Shearwave and TE (ICC, 0.92), and the worst agreement was observed between 2D-SWE and TE (ICC, 0.58). In the BlandAltman analysis, a tendency toward lower LS values with the three SWE techniques than with TE in patients with F3 and F4 disease was observed.

CONCLUSION

Significant inter-system variability was observed in LS measurements made using the three SWE techniques. Therefore, LS values measured using different SWE techniques should not be used interchangeably for longitudinal follow-up.

Diagnostic performance of a point shear wave elastography (pSWE) for hepatic fibrosis in patients with autoimmune liver disease

BACKGROUND & AIMS

Elastography point quantification is a convenient method for measuring liver stiffness. It can be performed simultaneously with conventional ultrasonography. This study aimed to evaluate its diagnostic performance for assessing hepatic fibrosis in patients with autoimmune liver disease (AILD), including autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC).

METHODS

The diagnostic performance of elastography point quantification (ElastPQ) was evaluated and compared with that of serum fibrosis markers, including the aspartate aminotransferase to platelet ratio index (APRI) and fibrosis-4 (FIB-4), using the receiver operating characteristics analysis with histologic evaluation as the reference standard.

RESULTS

In 49 AIH patients, sensitivity and specificity of ElastPQ were 93.6% and 44.4%, respectively, for significant fibrosis (≥ F2, cutoff 4.47 kPa), and 63.6% and 86.8% for cirrhosis (F4, cutoff 9.28 kPa). In 41 PBC patients, they were 81.8% and 73.3%, respectively, for significant fibrosis (≥ F2, cutoff 5.56 kPa), and 100% and 81.6%, respectively, for advanced fibrosis (≥ F3, cutoff 6.04 kPa). The areas under the receiver operating characteristic curves of ElastPQ for significant fibrosis (0.77, 95% CI 0.67-0.86) and cirrhosis (0.81, 95% CI 0.65-0.96) were higher than those of APRI and FIB-4 in AILD patients. According to the multivariable analysis, histological activity, steatosis, and body max index (BMI) were not significant factors that influenced the result of ElastPQ.

CONCLUSIONS

ElastPQ exhibited better diagnostic performance-without the influence of confounding factors-for assessing hepatic fibrosis in AILD patients than serum fibrosis markers.

Evaluation of accuracy of elastography point quantification versus other noninvasive modalities in staging of fibrosis in chronic hepatitis C virus patients

BACKGROUND

Elastography point quantification (ElastPQ) is a newly noninvasive method incorporated into a conventional ultrasound system for staging of liver fibrosis in patients with chronic liver diseases.

AIM

The aim was to evaluate ElastPQ reproducibility and its accuracy in staging of liver fibrosis in hepatitis C virus (HCV) patients in comparison with transient elastography (TE) and fibrosis scores [FIB-4 and aspartate aminotransferase-to-platelet ratio index (APRI)] using liver biopsy as a reference standard and also to predict the sensitivity and specificity of ElastPQ as well as proposing a cut-off for advanced fibrosis.

PATIENTS AND METHODS

A single-center, cross-sectional study enrolled 72 chronic HCV patients. Baseline demographic and laboratory data were recorded. ElastPQ and TE were performed. Fibrosis scores were calculated. The performance of ElastPQ was compared with that of TE and noninvasive methods (FIB-4, APRI) using liver biopsy as a reference standard using receiver operating characteristic curve analysis.

RESULTS

ElastPQ is a valuable diagnostic tool for the diagnosis of F≥1, F≥2, and F≥3, with area under the receiver operating characteristic curve of 0.79, 0.74, and 0.83, respectively. The best cut-off values for ElastPQ were 4.9, 6.6, and 10.7 kPa for mild fibrosis, significant fibrosis, and advanced fibrosis, respectively. ElastPQ correlated positively with all other fibrosis indices (TE, APRI, and FIB-4) as well as liver biopsy. Area under the curve for the diagnosis of advanced fibrosis (F3/F4) using ElastPQ was 0.83 at a cut-off value of 10.7 kPa (P<0.01).

CONCLUSION

ElastPQ is a promising noninvasive US-based method for assessing liver fibrosis in HCV-related chronic liver disease patients with good diagnostic performance comparable to that of liver biopsy and TE.

Non-invasive Assessment of Liver Fibrosis with ElastPQ: Comparison with Transient Elastography and Serologic Fibrosis Marker Tests, and Correlation with Liver Pathology Results

We investigated the feasibility of using ultrasound shear wave elastography point quantification (ElastPQ) for liver fibrosis staging and compared it with other non-invasive tools with respect to efficacy in liver stiffness measurement. A total of 106 patients who underwent liver stiffness measurements, using ElastPQ and biochemical investigations, before parenchymal liver biopsy or surgery were included. Among these, 51 also underwent transient elastography (TE). Correlations of ElastPQ, TE and aspartate aminotransferase-to-platelet ratio index (APRI) with histopathological findings (as the reference standard) were determined using Spearman's correlation coefficient. The diagnostic performance of ElastPQ, TE and APRI was evaluated using receiver operating characteristic (ROC) curve analysis. ElastPQ had good diagnostic accuracy in identifying each liver fibrosis stage, with an area under the ROC curve (AUC) of 0.810 to 0.864. Stiffness values obtained using ElastPQ, TE and APRI were significantly positively correlated (r = 0.686, r = 0.732 and r = 0.454, respectively) with histologic fibrosis staging (p < 0.001). According to the AUC for the diagnosis of significant fibrosis (≥F2) and cirrhosis (=F4), ElastPQ had better diagnostic accuracy (AUC = 0.929 and 0.834, respectively) than APRI (AUC = 0.656 and 0.618, respectively) (p < 0.05), and was similar to TE (AUC = 0.915 and 0.879, respectively). ElastPQ is a promising ultrasound-based imaging technique for evaluation of liver fibrosis, with a diagnostic accuracy comparable to that of TE.

Selection and Reporting of Statistical Methods to Assess Reliability of a Diagnostic Test: Conformity to Recommended Methods in a Peer-Reviewed Journal

Objective

To evaluate the frequency and adequacy of statistical analyses in a general radiology journal when reporting a reliability analysis for a diagnostic test.

Materials and Methods

Sixty-three studies of diagnostic test accuracy (DTA) and 36 studies reporting reliability analyses published in the Korean Journal of Radiology between 2012 and 2016 were analyzed. Studies were judged using the methodological guidelines of the Radiological Society of North America-Quantitative Imaging Biomarkers Alliance (RSNA-QIBA), and COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) initiative. DTA studies were evaluated by nine editorial board members of the journal. Reliability studies were evaluated by study reviewers experienced with reliability analysis.

Results

Thirty-one (49.2%) of the 63 DTA studies did not include a reliability analysis when deemed necessary. Among the 36 reliability studies, proper statistical methods were used in all (5/5) studies dealing with dichotomous/nominal data, 46.7% (7/15) of studies dealing with ordinal data, and 95.2% (20/21) of studies dealing with continuous data. Statistical methods were described in sufficient detail regarding weighted kappa in 28.6% (2/7) of studies and regarding the model and assumptions of intraclass correlation coefficient in 35.3% (6/17) and 29.4% (5/17) of studies, respectively. Reliability parameters were used as if they were agreement parameters in 23.1% (3/13) of studies. Reproducibility and repeatability were used incorrectly in 20% (3/15) of studies.

Conclusion

Greater attention to the importance of reporting reliability, thorough description of the related statistical methods, efforts not to neglect agreement parameters, and better use of relevant terminology is necessary.

Impact of Liver Fibrosis and Fatty Liver on T1rho Measurements: A Prospective Study

OBJECTIVE

To investigate the liver T1rho values for detecting fibrosis, and the potential impact of fatty liver on T1rho measurements.

MATERIALS AND METHODS

This study included 18 healthy subjects, 18 patients with fatty liver, and 18 patients with liver fibrosis, who underwent T1rho MRI and mDIXON collections. Liver T1rho, proton density fat fraction (PDFF) and T2* values were measured and compared among the three groups. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the T1rho values for detecting liver fibrosis. Liver T1rho values were correlated with PDFF, T2* values and clinical data.

RESULTS

Liver T1rho and PDFF values were significantly different (p < 0.001), whereas the T2* (p = 0.766) values were similar, among the three groups. Mean liver T1rho values in the fibrotic group (52.6 ± 6.8 ms) were significantly higher than those of healthy subjects (44.9 ± 2.8 ms, p < 0.001) and fatty liver group (45.0 ± 3.5 ms, p < 0.001). Mean liver T1rho values were similar between healthy subjects and fatty liver group (p = 0.999). PDFF values in the fatty liver group (16.07 ± 10.59%) were significantly higher than those of healthy subjects (1.43 ± 1.36%, p < 0.001) and fibrosis group (1.07 ± 1.06%, p < 0.001). PDFF values were similar in healthy subjects and fibrosis group (p = 0.984). Mean T1rho values performed well to detect fibrosis at a threshold of 49.5 ms (area under the ROC curve, 0.855), had a moderate correlation with liver stiffness (r = 0.671, p = 0.012), and no correlation with PDFF, T2* values, subject age, or body mass index (p > 0.05).

CONCLUSION

T1rho MRI is useful for noninvasive detection of liver fibrosis, and may not be affected with the presence of fatty liver.

Prospective Validation of Intra- and Interobserver Reproducibility of a New Point Shear Wave Elastographic Technique for Assessing Liver Stiffness in Patients with Chronic Liver Disease

Objective

To assess intra- and inter-observer reproducibility of a new point shear wave elastography technique (pSWE, S-Shearwave, Samsung Medison) and compare its accuracy in assessing liver stiffness (LS) with an established pSWE technique (Virtual Touch Quantification, VTQ).

Materials and Methods

Thirty-three patients were enrolled in this Institutional Review Board-approved prospective study. LS values were measured by VTQ on an Acuson S2000 system (Siemens Healthineer) and S-Shearwave on an RS-80A (Samsung Medison) in the same session, followed by two further S-Shearwave sessions for inter- and intra-observer variation at 8-hour intervals. The technical success rate (SR) and reliability of the measurements of both pSWE techniques were compared. The intra- and inter-observer reproducibility of S-Shearwave was determined by intraclass correlation coefficients (ICCs). LS values were measured by both methods of pSWE. The diagnostic performance in severe fibrosis (F ≥ 3) and cirrhosis (F = 4) was evaluated using the receiver operating characteristics curve analysis and the Obuchowski measure with the LS values of transient elastography as the referenced standard.

Results

The VTQ (100%, 33/33) and S-Shearwave (96.9%, 32/33) techniques did not display a significant difference in technical SR (p = 0.63) or reliability of LS measurements (96.9%, 32/33; 93.9%, 30/32, respectively, p = 0.61). The inter- and intra-observer agreement for LS measurements using the S-Shearwave technique was excellent (ICC = 0.98 and 0.99, respectively). The mean LS values of both pSWE techniques were not significantly different and exhibited a good correlation (r = 0.78). To detect F ≥ 3 and F = 4, VTQ and S-Shearwave showed comparable diagnostic accuracy as indicated by the following outcomes: areas under receiver operating characteristics curve (AUROC) = 0.87 (95% confidence intervals [CI] 0.70–0.96), 0.89 for VTQ (95% CI 0.74–0.97), respectively; and AUROC = 0.84 (95% CI 0.67–0.94), 0.94 (95% CI 0.80–0.99) for S-Shearwave (p > 0.48), respectively. The Obuchowski measures were similarly high for S-Shearwave and VTQ (0.94 vs. 0.95).

Conclusion

S-Shearwave shows excellent inter- and intra-observer agreement and diagnostic effectiveness comparable to VTQ in detecting LS.

Quantitative Measurement of Hepatic Fibrosis with Gadoxetic Acid-Enhanced Magnetic Resonance Imaging in Patients with Chronic Hepatitis B Infection: A Comparative Study on Aspartate Aminotransferase to Platelet Ratio Index and Fibrosis-4 Index

Objective

To quantitatively measure hepatic fibrosis on gadoxetic acid-enhanced magnetic resonance (MR) in chronic hepatitis B (CHB) patients and identify the correlations with aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) values.

Materials and Methods

This study on gadoxetic acid-enhanced 3T MR imaging included 81 patients with CHB infection. To quantitatively measure hepatic fibrosis, MR images were analyzed with an aim to identify inhomogeneous signal intensities calculated from a coefficient of variation (CV) map in the liver parenchyma. We also carried out a comparative analysis between APRI and FIB-4 based on metaregression results. The diagnostic performance of the CV map was evaluated using a receiver-operating characteristic (ROC) curve.

Results

In the MR images, the mean CV values in control, groups I, II, and III based on APRI were 4.08 ± 0.92, 4.24 ± 0.80, 5.64 ± 1.11, and 5.73 ± 1.28, respectively (p < 0.001). In CHB patients grouped by FIB-4, the mean CV values of groups A, B, and C were 4.22 ± 0.95, 5.40 ± 1.19, and 5.71 ± 1.17, respectively (p < 0.001). The mean CV values correlated well with APRI (r = 0.392, p < 0.001) and FIB-4 (r = 0.294, p < 0.001). In significant fibrosis group, ROC curve analysis yielded an area under the curve of 0.875 using APRI and 0.831 using FIB-4 in HB, respectively.

Conclusion

Gadoxetic acid-enhanced MR imaging for calculating a CV map showed moderate correlation with APRI and FIB-4 values and could be employed to quantitatively measure hepatic fibrosis in patients with CHB.