Real-time elastography for diagnosis of liver fibrosis in chronic hepatitis B

The non-invasive serum biomarkers contributes to indicate liver fibrosis staging and evaluate the progress of chronic hepatitis B

BACKGROUND

This study aimed to evaluate the diagnostic abilities of the non-invasive serum biomarkers to predict liver fibrosis staging and evaluate the progress of hepatitis B.

METHODS

We enrolled 433 patients with chronic HBV infection had complete medical data available for the study, who underwent percutaneous liver biopsy. The extent of fibrosis was assessed using the modified METAVIR score. The predictive values of the non-invasive serum biomarkers were evaluated by the areas under the receiving operator characteristics curves (AUROCs) with 95% confidence intervals.

RESULTS

The proportion of males with progressive stages of liver fibrosis was relatively larger, and the average age of patients with cirrhosis stages is older than the non-cirrhotic stages. We found PLT, GGT, ALP, TB, FIB4 and GPR to be significantly associated with liver fibrosis in our cohort. GGT showed a sensitivity of 71.4% and specificity of 76.7% in distinguishing cirrhosis (F4) from non-cirrhotic stages (F1-3), with an AUROC of 0.775 (95%CI 0.711-0.840).The AUROCs of the GPR in distinguishing cirrhosis (F4) from non-cirrhotic stages (F1-3) was 0.794 (95%CI 0.734-0.853), but it had a lower sensitivity of 59.2%. Additionally, GGT, FIB4, and GPR could differentiate advanced fibrosis (F3-4) from non-advanced fibrosis (F1-2) among individuals with chronic hepatitis B, with AUROCs of 0.723 (95%CI 0.668-0.777), 0.729 (95%CI 0.675-0.782), and 0.760 (95%CI: 0.709-0.811) respectively.

CONCLUSIONS

GGT was a better biomarker to distinguish cirrhosis (F4) from non-cirrhotic stages (F1-3), while GPR was a better biomarker to identify advanced fibrosis (F3-4) and non-advanced fibrosis (F1-2) in patients with chronic hepatitis B.

Stiffness estimated by strain elastography reflects canine testicular spermatogenesis and histology

Ultrasound elastography was proposed for the evaluation of testicular focal lesions, but no studies verified the agreement between the whole histological architecture of the testis and the stiffness measured by elastography. The present study explored the use of strain elastography in the evaluation of testis with normal or abnormal spermatogenesis, classified based on epididymal sperm attributes, and the consistency between elastographic parameters and the testicular histological feature. Strain elastography was performed during the routine andrological examination in 22 dogs presented for elective orchiectomy. Epididymal sperm attributes and testicular histology were analyzed after orchiectomy. Based on the epididymal sperm characteristics, testes were classified according to normal or abnormal spermatogenesis, and strain elastographic attributes were compared between groups. Possible correlations between strain elastography and histological features were also explored. Consistent with the literature in humans, testes with abnormal spermatogenesis were stiffer (mean strain elastographic index 3.6 ± 0.6) compared with normal testes (mean strain elastographic index 1.9 ± 0.2; P < 0.01). The strain elastographic index was negatively correlated with the area occupied by seminiferous tubules (Pearson's rho = -0.716; P = 0.0003), the mean diameter (Pearson's rho = -0.742; P = 0.0002), and thickness of the seminiferous tubule (Pearson's rho = -0.728; P = 0.0002). Surprisingly, no correlations were found between the area occupied by connective tissue in histological sections and elastographic attributes, suggesting that the increased stiffness was not related to the increased amount of connective tissue. This study demonstrated that strain elastography could be used to support the andrological examination, but measurements should be acquired in specific regions to be reliable.

[Experimental studies for noninvasive assessment of portal vein pressure based on contrast enhanced subharmonic sonographic imaging]

Portal hypertension (PHT) is a common complication of liver cirrhosis, which could be measured by the means of portal vein pressure (PVP). However, there is no report about an effective and reliable way to achieve noninvasive assessment of PVP so far. In this study, firstly, we collected ultrasound images and echo signals of different ultrasound contrast agent (UCA) concentrations and different pressure ranges in a low-pressure environment based on an in vitro simulation device. Then, the amplitudes of the subharmonics in the echo signal were obtained by ultrasound grayscale image construction and fast Fourier transform (FFT). Finally, we analyzed the relationship between subharmonic amplitude (SA) and bionic portal vein pressure (BPVP) through linear regression. As a result, in the pressure range of 7.5-45 mm Hg and 8-20 mm Hg, the linear correlation coefficients (LCC) between SA and BPVP were 0.927 and 0.913 respectively when the UCA concentration was 1∶3 000, and LCC were 0.737 and 0.568 respectively when the UCA concentration was 1∶6 000. Particularly, LCC was increased to 0.968 and 0.916 respectively while the SAs of two UCA concentrations were used as the features of BPVP. Therefore, the results show a good performance on the linear relationship between SA and BPVP, and the LCC will be improved by using SAs obtained at different UCA concentrations as the features of BPVP. The proposed method provides reliable experimental verification for noninvasive evaluation of PVP through SA in clinical practice, which could be a guidance for improving the accuracy of PVP assessment.

The liver fibrosis index is superior to the APRI and FIB-4 for predicting liver fibrosis in chronic hepatitis B patients in China

BACKGROUND

The purpose of this study was to prospectively investigate the value of real-time ultrasound elastography (RTE) for the diagnosis of liver fibrosis (LF) in patients with chronic hepatitis B (CHB), to correlate the elastography findings with the histologic stage of LF and to compare RTE findings with those from noninvasive tests of LF calculated using laboratory blood parameters.

METHODS

Liver biopsies, laboratory blood testing, and RTE were performed in 91 patients with CHB. The LF index (LFI) was calculated using a multiple linear regression equation involving 11 parameters, which represented the degree of LF. The higher the LFI is, the greater the degree of LF.

RESULTS

The mean aspartate aminotransferase-to-platelet ratio index (APRI) and the mean fibrosis index based on four factors (FIB-4) were significantly different for the 5 stages of LF, respectively. The APRI (r = 0.43, P = 0.006), FIB-4 (r = 0.51, P = 0.012) and LFI (r = 0.562, P = 0.004) were correlated with the stages of LF. For discriminating stage F0 from F1, only the LFI had significant power (P = 0.026) for predicting stage F1. For discriminating stage F4 from F3, only the LFI had statistically significant power (P = 0.024) in predicting stage F4. The areas under the receiver operating characteristic curves (AUCs) of the LFI for diagnosing significant, advanced LF and liver cirrhosis were significantly higher than those of the APRI and FIB-4, and the LFI had better sensitivity and specificity.

CONCLUSIONS

The LFI calculated by RTE is reliable for the assessment of LF in patients with CHB and has better discrimination power than the APRI and FIB-4.

Strain elastography for noninvasive assessment of liver fibrosis: A prospective study with histological comparison

The aim of this study was to prospectively evaluate the diagnostic performance of strain elastography for the assessment of liver fibrosis in patients with chronic liver disease using Ishak (0-6) histology stage as a reference standard. Ninety-eight consecutive patients with suspected chronic liver disease scheduled for liver biopsy (n = 78) or histologically confirmed cirrhosis (n = 20) were enrolled. Liver fibrosis Index (LF Index) calculated by strain elastography, liver stiffness by transient elastography and serum fibrosis markers (aspartate aminotransferase-to-platelet ratio index and King's Score) were measured. Spearman's correlation coefficient between the LF Index, liver stiffness, serum fibrosis markers and fibrosis stage were calculated and compared using areas under the receiver-operating characteristics (AUROCs) curves. Among 73 patients who underwent strain elastography, there was weak correlation between fibrosis stage and the LF Index (Spearman's: ρ = 0.385 for Ishak score; P = 0.001). Among 52 patients who underwent strain elastography and transient elastography, the AUROC values using LF Index, transient elastography, aspartate aminotransferase-to-platelet ratio index and King's Score for diagnosing significant fibrosis (Ishak score ≥ 3) were 0.79, 0.87, 0.86 and 0.85, respectively (P < 0.0001) and for diagnosing severe fibrosis/cirrhosis (Ishak score ≥ 5) were 0.83, 0.94, 0.92 and 0.92, respectively (P < 0.0001). When comparing the diagnostic performance using LF Index, transient elastography, aspartate aminotransferase-to-platelet ratio index and King's Score, transient elastography shows a significantly higher AUROC value than LF Index in detecting severe fibrosis (P = 0.0149). The diagnostic performance of LF Index calculated by strain elastography was not statistically significantly different to the other noninvasive tests for the assessment of significant liver fibrosis but inferior to transient elastography for the assessment of severe fibrosis/cirrhosis.

Real-Time Elastography: Noninvasive Diagnostic Tool in the Evaluation of Liver Stiffness in Patients with Chronic Viral Hepatitis, Correlation with Histological Examination

PURPOSE

To determine the value of real-time elastography (RTE) in the assessment of liver stiffness in patients with chronic viral hepatitis, correlating RTE data with the extent of fibrosis based on biopsy findings (Ishak score).

METHODS

We evaluated 98 patients (45-75 years) with chronic viral hepatitis (51 HCV, 47 HBV) by using ultrasonography (US) study combined with RTE analysis. In the RTE images, relative tissue stiffness is expressed, according to color scale, with soft areas represented in green/red colors and hard areas in blue. We divided the patients into 2 groups based on the fibrosis degree: soft degree (D1, corresponding to F1-F3 Ishak score) and hard degree (D2, corresponding to F4-F6). Before RTE, all patients underwent a US-guided percutaneous liver biopsy (right lobe).

RESULTS

Quantitative RTE data were compared with liver biopsy by using the Spearman correlation coefficient in order to assess the correlation between the RTE (D) and fibrosis, according to Ishak score (F) at histology. At RTE, out of 98 patients 55 had degree D1 and 43 had degree D2; at histological analysis, we observed the following: 15 patients with F1, 28 with F2, 17 with F3, 16 with F4, 12 with F5, and 10 with F6. The Spearman's coefficient showed significant correlation between D and F degree, obtaining rho = 0.573, p = 0.003.

CONCLUSIONS

RTE analysis showed high diagnostic accuracy in the assessment of fibrosis, and it appears to be a useful diagnostic tool for noninvasive quantification of fibrosis in patients with chronic viral hepatitis.

Real-time elastography (RTE): a valuable sonography-based non-invasive method for the assessment of liver fibrosis in chronic hepatitis B

PURPOSE

To investigate the diagnostic usefulness of real-time elastography (RTE) for liver fibrosis in chronic hepatitis B (CHB).

METHODS

89 CHB patients were enrolled in the cross-sectional study. Ultrasound-guided percutaneous liver biopsies, RTE, and blood testing were performed in all patients. Areas under receiver operating characteristic curves (AUROC) were used to examine the diagnostic performance of liver fibrosis index (LFI) for the assessment of liver fibrosis.

RESULTS

LFI differed significantly across histologic fibrosis stages (P < 0.05), except the comparison between S0 and S1 (P = 0.298). There was a strong positive correlation between LFI and histologic liver fibrosis stage (Spearman r = 0.831, P < 0.001). The cutoff LFI value of >2.74 indicated a sensitivity of 0.766 and a specificity of 0.872 for predicting significant liver fibrosis (S ≥ 2), and the cutoff LFI value of >3.61 indicated a sensitivity of 0.833 and a specificity of 0.878 for predicting early liver cirrhosis (S = 4). LFI showed higher AUROC for discriminating significant liver fibrosis (0.873 vs. 0.614) and early liver cirrhosis (0.923 vs. 0.769) than aspartate aminotransferase-to-platelet ratio index (APRI).

CONCLUSIONS

RTE is a valuable sonography-based non-invasive method for assessment of liver fibrosis and has better discrimination power for significant liver fibrosis and early liver cirrhosis than APRI in CHB.

Value of the Strain Ratio on Ultrasonic Elastography for Differentiation of Benign and Malignant Soft Tissue Tumors

OBJECTIVES

The purpose of this study was to evaluate whether the strain ratio provides additional value to conventional visual elasticity scores in the differentiation of benign and malignant soft tissue tumors by ultrasonic elastography.

METHODS

The Institutional Review Board approved the protocol of this retrospective review. Seventy-three patients who underwent elastography and had a soft tissue mass pathologically confirmed by ultrasound-guided core biopsy or surgical excision were enrolled from April 2012 through October 2014. On elastography, elasticity scores were determined with a 5-point visual scale, and the strain ratio to adjacent soft tissue at the same depth was calculated. Tumors were divided into benign and malignant groups according to the pathologic diagnoses. Elasticity scores and strain ratios were compared between benign and malignant groups, and diagnostic performance was evaluated by receiver operating characteristic curves.

RESULTS

Of the 73 patients, 40 had benign tumors, and 33 had malignant tumors. Strain ratios (P = .003) and elasticity scores (P = .048) were significantly different between pathologic results. The areas under the receiver operating characteristic curves were 0.700 (95% confidence interval, 0.581-0.802) for the strain ratio and 0.623 (95% confidence interval, 0.515-0.746) for elastography.

CONCLUSIONS

The strain ratios of malignant soft tissue tumors were lower than those of benign tumors and showed better diagnostic performance than did elasticity scores. The strain ratio can be used as a diagnostic indicator to predict the malignant potential of soft tissue tumors.

Diagnostic value of optimised real-time sonoelastography in the assessment of liver fibrosis in chronic hepatitis B and C

Aim

To optimise the method of real-time elastography (RTE) in the assessment of liver fibrosis using an in-house prepared method for elastogram analysis, as well as a semiquantitative analysis based on newly introduced parameters.

Material and methods

Sonoelastography was performed in 94 patients with various degrees of liver fibrosis and also in 25 healthy volunteers. As a reference method for diagnostic efficacy of sonoelastography-based parameters used for the assessment of fibrosis degree in patients with chronic B and C hepatitis, a liver biopsy was used. Patient’s elastograms were analysed using in-house prepared software, Pixel Count, calculating two semiquantitative parameters: mean stiffness fraction (MSF%) and intrinsic stiffness ratio (ISR).

Results

Statistically significant differences between distributions of the above presented parameters for different degrees of liver fibrosis were revealed. Indices of diagnostic efficacy for detection of significant liver fibrosis (F ≥ 2) using MSF% amounted to: sensitivity – 76%, specificity – 87% and ISR: 81% and 87%, respectively. Sensitivity of both parameters in detection of cirrhosis (F = 4) was equal to 88% and specificity amounted to: for MSF% – 84% and ISR – 86%. Interobserver reproducibility determined for both of the above parameters was high, intraclass correlation coefficients (ICC) were 0.91 for MSF% and 0.93 for ISR.

Conclusions

Real-time elastography applied in this study, using in-house prepared Pixel Count software, provided good reproducibility and diagnostic efficacy, especially specificity, in the assessment of liver fibrosis degree.

Effect of Inflammation on Fibrosis Staging Measured by Quantitative Elasticity Parameters in Rats With Immune Hepatitis

OBJECTIVES

To investigate the effect of inflammation on fibrosis staging measured by quantitative elasticity parameters in rats with immune hepatitis.

METHODS

Fifty-two rats were injected with swine serum as a model group, whereas 8 rats were injected with saline as a control group. Rats were randomly subjected to real-time tissue elastography biweekly. Tissue dispersion quantitative analysis was performed to obtain 12 quantitative elasticity parameters: relative mean value, standard deviation, blue area percentage, complexity, kurtosis, skewness, contrast, entropy, inverse difference moment, angular second moment, correlation, and liver fibrosis index. Subsequently, rats were euthanized, and liver specimens were taken for pathologic examination. The Kruskal-Wallis test was used for comparisons among groups. Spearman rank correlation analysis was used for correlation analysis. Receiver operating characteristic curves were used to optimize cutoff values and evaluate the diagnostic performance of the liver fibrosis index.

RESULTS

Except for complexity, kurtosis, and correlation, the other 9 parameters had statistical differences (P < .05), and among these 9 parameters, the liver fibrosis index had the strongest correlation with fibrosis staging (r = 0.809; P < .05). Except for kurtosis and correlation, the other 10 parameters had statistical differences (P < .05), and among these 10 parameters, the liver fibrosis index had the highest correlation with inflammation grading (r= 0.766; P< .05). The fibrosis index cutoff values were 2.35 for stage S1 or higher (area under the curve [AUC], 0.940; sensitivity, 97.1%; specificity, 73.3%), 2.99 for stage S2 or higher (AUC, 0.865; sensitivity, 78.6%; specificity, 81.0%), 3.48 for stage S3 or higher (AUC, 0.924; sensitivity, 94.4%; specificity, 87.1%), and 4.05 for stage S4 (AUC, 0.933; sensitivity, 87.5%; specificity, 95.1%).

CONCLUSIONS

Real-time elastography could be used to noninvasively evaluate fibrosis staging in rats with immune hepatitis. However, inflammation had an effect on the accuracy of this technique.

Clinical value of real-time elastography quantitative parameters in evaluating the stage of liver fibrosis and cirrhosis

The aim of the present study was to assess the value of real-time elastography (RTE) quantitative parameters, namely the liver fibrosis (LF) index and the ratio of blue area (%AREA), in evaluating the stage of liver fibrosis. RTE quantitative analysis software was used to examine 120 patients with chronic hepatitis in order to obtain the values for 12 quantitative parameters from the elastic images. The diagnostic performance of two such parameters, the LF index and %AREA, were assessed with a receiver operating characteristic (ROC) curve to determine the optimal diagnostic cut-off values for liver cirrhosis and fibrosis. A good correlation was observed between the LF index and %AREA with the fibrosis stage. The areas under the ROC curve for the LF index were 0.985 for the diagnosis of liver cirrhosis and 0.790 for liver fibrosis. With regard to %AREA, the areas under the ROC curve for the diagnosis of liver cirrhosis and fibrosis were 0.963 and 0.770, respectively. An LF index of >3.25 and a %AREA of >28.83 for the diagnosis of cirrhosis stage resulted in sensitivity values of 100 and 100%, specificity values of 88.9 and 85.9% and accuracy values of 90.8 and 88.3%, respectively. The LF index and %AREA parameters exhibited higher reliability in the diagnosis of liver cirrhosis compared with the diagnosis of the liver fibrosis stage. However, the two parameters possessed a similar efficacy in the diagnosis of liver cirrhosis and the stage of liver fibrosis. Therefore, the quantitative RTE parameters of the LF index and %AREA may be clinically applicable as reliable indices for the early diagnosis of liver cirrhosis, without the requirement of an invasive procedure.

Validity and Reliability of Magnetic Resonance Elastography for Staging Hepatic Fibrosis in Patients with Chronic Hepatitis B

PURPOSE

We evaluated the validity and reliability of magnetic resonance elastography (MRE) for staging hepatic fibrosis in patients with chronic hepatitis B.

METHODS

The study included 73 patients with chronic hepatitis B and confirmed stages of pathological fibrosis. Two radiologists measured liver stiffness using MRE in all cases. We compared the area under the receiver operating characteristic (ROC) curve (Az) for distinguishing stages of fibrosis compared with MRE liver stiffness measurements and serum fibrosis markers. We used intraclass correlation coefficients to analyze interobserver agreement for measurements of liver stiffness and 2 one-sided t-tests to test the equivalence of the measurements by the 2 observers.

RESULTS

ROC analyses revealed the significantly superior discrimination abilities of MRE for liver fibrosis staging (Az = 0.945 to 0.978 [Observer 1] and 0.936 to 0.967 [Observer 2]) to those of serum fibrosis markers (0.491 to 0.742) for both observers (P < 0.0004). The intraclass correlation coefficient between the 2 observers was excellent (ρ = 0.971), and the measurements of liver stiffness by the 2 observers were statistically equivalent within a 0.1-kPa difference (P = 0.0157)CONCLUSION: MRE is a valid and reliable technique for discriminating the stage of hepatic fibrosis in patients with chronic hepatitis B.

Performance of real-time elastography for the staging of hepatic fibrosis: a meta-analysis

Background

With the rapid development of real-time elastography (RTE), a variety of measuring methods have been developed for the assessment of hepatic fibrosis. We evaluated the overall performance of four methods based on RTE by performing meta-analysis of published literature.

Methods

Online journal databases and a manual search from April 2000 to April 2014 were used. Studies from different databases that meet inclusion criteria were enrolled. The statistical analysis was performed using a random-effects model and fixed-effects model for the overall effectiveness of RTE. The area under the receiver operating characteristic curve (AUROC) was calculated for various means. Fagan plot analysis was used to estimate the clinical utility of RTE, and the heterogeneity of the studies was explored with meta-regression analysis.

Results

Thirteen studies from published articles were enrolled and analyzed. The combined AUROC of the liver fibrosis index (LFI) for the evaluation of significant fibrosis (F≥2), advanced fibrosis (F≥3), and cirrhosis (F = 4) were 0.79, 0.94, and 0.85, respectively. The AUROC of the elasticity index (EI) ranged from 0.75 to 0.92 for F≥2 and 0.66 to 0.85 for F = 4. The overall AUROC of the elastic ratio of the liver for the intrahepatic venous vessels were 0.94, 0.93, and 0.96, respectively. The AUROC of the elastic ratio of the liver for the intercostal muscle in diagnosing advanced fibrosis and cirrhosis were 0.96 and 0.92, respectively. There was significant heterogeneity in the diagnostic odds ratio (DOR) for F≥2 of LFI mainly due to etiology (p<0.01).

Conclusion

The elastic ratio of the liver for the intrahepatic vein has excellent precision in differentiating each stage of hepatic fibrosis and is recommend to be applied to the clinic.

Comparison of intrahepatic vein-to-liver parenchyma and intercostal muscle-to-liver parenchyma strain ratios in the assessment of liver fibrosis: which one should we use?

PURPOSE

The aims of this study were to investigate whether there is a difference in diagnostic value between vein to parenchyma strain ratio (VPSR) and muscle to parenchyma strain ratio (MPSR).

METHODS

VPSR and MPSR were calculated via sonoelastography, and were recorded for comparison with histopathology. ROC analysis, the Mann-Whitney U test, the Kruskal-Wallis test, and Spearman's rank correlation test were used for statistical analysis.

RESULTS

The study included 59 cases of individuals who underwent biopsy (29 women, 30 men). When the threshold value for VPSR was set at 3.23, the sensitivity was 96.2% and the specificity was 83.3% (p < 0.001, F ≥ 1). When the threshold value was set at 3.01 for MPR, the sensitivity was 88.7% and the specificity was 83.3% (p < 0.001, F ≥ 1). The areas under the curve values were VPSR 0.95 and MPSR 0.92 for F ≥ 1, VPSR 0.94 and MPSR 0.92 for F ≥ 2, and VPSR 1.00 and MPSR 0.76 for F = 3 (p < 0.001). The Spearman's correlation coefficient was 0.75, and a high positive concordance was found between VPSR and MPSR (p < 0.001).

CONCLUSIONS

In this study, a high positive correlation was observed between two strain ratios, and VPSR was found to be more reliable than MPSR in determining liver fibrosis.

Real-time elastography in the assessment of liver fibrosis: a review of qualitative and semi-quantitative methods for elastogram analysis

Despite its invasiveness, liver biopsy is still considered the gold standard for the assessment of hepatic fibrosis. Non-invasive ultrasound-based techniques are increasingly employed to assess parenchymal stiffness and the progression of chronic diffuse liver diseases. Real-time elastography is a rapidly evolving technique that can reveal the elastic properties of tissues. This review examines qualitative and semi-quantitative methods developed for analysis of real-time liver elastograms, to estimate parenchymal stiffness and, indirectly, the stage of fibrosis. Qualitative analysis is the most immediate approach for elastogram analysis, but this method increases intra- and inter-observer variability, which is seen as a major limitation of real-time elastography. Semi-quantitative methods include analysis of the histogram derived from color-coded maps, as well as calculation of the elastic ratio and fibrosis index.

Diagnostic accuracy of real-time tissue elastography for the staging of liver fibrosis: a meta-analysis

OBJECTIVE

To evaluate the overall accuracy of real-time tissue elastography (RTE) for the staging of liver fibrosis.

METHODS

We systematically reviewed 15 studies (1,626 subjects) in which sensitivity and specificity of RTE for liver fibrosis are available. For each cut-off stage of fibrosis, i.e., F ≥ 1, F ≥ 2, F ≥ 3, and F ≥ 4, summary sensitivity and specificity were estimated using a bivariate random-effects model. Publication bias was assessed using funnel plots and Egger's test.

RESULTS

Summary sensitivity and specificity were 0.79 and 0.76 for F ≥ 2, 0.82 and 0.81 for F ≥ 3, and 0.74 and 0.84 for F ≥ 4, respectively. Meta-regressions revealed scoring methods of RTE and liver diseases in the samples might not influence sensitivity and specificity of RTE. However, the estimated accuracy of RTE might be overestimated due to publication bias (p = 0.004 for F ≥ 2, p < 0.001 for F ≥ 3, and p = 0.002 for F ≥ 4).

CONCLUSIONS

RTE is not highly accurate for any cut-off stage of fibrosis. Compared with findings of meta-analyses on Transient Elastography and Acoustic Radiation Force Impulse imaging, the overall accuracy of RTE seems to be nearly identical for the evaluation of significant liver fibrosis, but less accurate for the evaluation of cirrhosis.

KEY POINTS

• Non-invasive methods for evaluating liver fibrosis are necessary to replace liver biopsy. • ARFI is as accurate as TE for evaluating liver fibrosis. • RTE may be as accurate as TE and ARFI for fibrosis. • RTE may be less accurate than TE and ARFI for cirrhosis. • The estimated accuracy of RTE may be overestimated by publication bias.

The usefulness of transient elastography in the assessment of patients with HBeAg-negative chronic hepatitis B virus infection

Histological severity is often mandatory for the management of HBeAg-negative chronic HBV patients. We evaluated the performance of transient elastography (TE) in this setting. We included 357 untreated HBeAg-negative patients with ≥ 1 reliable liver stiffness measurement (LSM-kPa) by TE: 182 inactive carriers with HBV-DNA < 2000 (n = 139) or 2000-19 999 IU/mL (n = 43) and 175 patients with chronic hepatitis B (CHB). In carriers, HBV-DNA > 2000 and/or LSM > 6.5 were considered as biopsy indications. LSMs did not differ between carriers with low and high viremia, but were lower in carriers than in patients with CHB (5.8 ± 1.7 vs 9.0 ± 5.6, P < 0.001) offering moderate differentiation between these two groups (AUROC: 0.705). LSMs did not change significantly in carriers after 16 (12-24) months. In carriers with a liver biopsy, Ishak's staging scores were similar between cased with low and high viremia but higher in cases with LSM > 6.5 than ≤ 6.5 kPa. Moderate fibrosis (stages: 2-3) was detected in 0/10 carriers with only HBV-DNA > 2000 IU/mL, 2/10 (20%) carriers with only LSM > 6.5 and 5/10 (50%) carriers with both HBV-DNA > 2000 and LSM > 6.5 (P = 0.009). In patients with CHB, LSMs correlated significantly with grading and staging scores and offered excellent accuracy for ≥ moderate, ≥ severe fibrosis or cirrhosis (AUROC ≥ 0.919-0.950). TE can be helpful for the noninvasive assessment of HBeAg-negative chronic HBV patients. In conclusion, LSMs offer excellent accuracy for fibrosis severity in HBeAg-negative patients with CHB and can identify carriers with high risk of moderate fibrosis, which may be present in up to 35% of carriers with LSM > 6.5 kPa and 50% of carriers with LSM > 6.5 kPa and HBV-DNA > 2000 IU/mL.

Real-time tissue elastography (RTE) for noninvasive evaluation of fibrosis in liver diseases in children in comparison to liver biopsy

PURPOSE

To determine the value of real-time tissue elastography (RTE) in pediatric liver diseases in comparison to liver biopsy.

METHODS

RTE was performed on 34 patients (♀, n = 17; ♂, n = 17; range 0-21 years) with various acute and chronic liver diseases: autoimmune hepatitis (n = 5), liver transplantation (n = 5), Wilson's disease (n = 4), hepatopathy of unknown origin (n = 4), unclear cholestatic hepatitis (n = 2), thalassemia major (n = 2), glycogenosis (n = 2), hereditary fructose intolerance (n = 1), alpha-1-antitrypsin deficiency (n = 1), diabetes mellitus type 1 (n = 1), chronic intestinal pseudo-obstruction (n = 1), primary sclerosing cholangitis (n = 1), hepatitis B (n = 1), cirrhosis of unknown origin (n = 1), drug-induced hepatopathy (n = 1), unexplained transaminase elevation (n = 1), and nonalcoholic steatohepatitis (n = 1). Included children were biopsied. RTE was performed on a control group (n = 30; ♀, n = 15; ♂, n = 15). The mean value of strain (MEAN) in arbitrary units and the ratio of blue color-coded harder tissue (AREA) were calculated based on an elasticity histogram of the selected region of interest in liver parenchyma. They were compared with the histologically defined grade of liver fibrosis.

RESULTS

In comparison to the scoring systems, a moderate correlation was observed for MEAN and AREA by excluding the F0 patients [MEAN r = -0.575 to -0.645, AREA r = 0.545-0.607 (p < 0.05)]. Differentiation of the control group and low-grade fibrosis (F1) from high-grade fibrosis (F2-4) was significantly possible (p values <0.001 at 5 % significance level).

CONCLUSION

RTE parameters enable a possible differentiation of high fibrosis; however, their correlation with fibrosis stage was moderate. RTE seems to be a promising method in liver fibrosis grading in children.

Accuracy of visual scoring and semi-quantification of ultrasound strain elastography--a phantom study

Purpose

The aim of this study was to evaluate the performance of strain elastography in an elasticity phantom and to assess which factors influenced visual scoring, strain histograms and strain ratios. Furthermore this study aimed to evaluate the effect of observer experience on visual scorings.

Materials and Methods

Two operators examined 20 targets of various stiffness and size (16.7 to 2.5 mm) in an elasticity phantom at a depth of 3.5 cm with a 5–18 MHz transducer. Two pre-settings were used yielding 80 scans. Eight evaluators, four experienced, four inexperienced, performed visual scorings. Cut-offs for semi-quantitative methods were established for prediction of target stiffness. Data was pooled in two categories allowing calculations of sensitivity and specificity. Statistical tests chi-square test and linear regression as relevant.

Results

Strain ratios and strain histograms were superior to visual scorings of both experienced and inexperienced observers (p = 0.025, strain histograms vs. experienced observers, p<0.001, strain histograms vs. inexperienced observers, p = 0.044 strain ratios vs. experienced observers and p = 0.002 strain ratios vs. inexperienced observers). No significant difference in predicting target stiffness between strain ratios and strain histograms (p = 0.83) nor between experienced and inexperienced observers (p = 0.054) was shown when using four categories. When pooling data in two groups (80 kPa/45 kPa vs. 14/8 kPa) the difference between the observers became significant (p<0.001). Target size had a significant influence on strain ratios measurements (p = 0.017) and on visual scorings (p<0.001) but not on the strain histograms(p = 0.358). Observer experience had significant effect on visual scorings(p = 0.003).

Conclusion

Strain ratios and strain histograms are superior to visual scoring in assessing target stiffness in a phantom. Target size had a significant impact on strain ratios and visual scoring, but not on strain histograms. Experience influenced visual scorings but the difference between experienced and inexperienced observers was only significant when looking at two classes of target stiffness.

Diagnostic value of real-time elastography in the assessment of hepatic fibrosis in patients with liver iron overload

OBJECTIVE

The objective of our prospective monocentric work was to determine the diagnostic value of real-time elastography (RTE) in the assessment of liver fibrosis in patients with iron overload, using transient elastography (TE) as reference standard.

METHODS

Sixty-seven consecutive patients with MRI detectable iron overload (T2*<6.3 ms) were enrolled. TE and RTE were performed on the same day as MRI. Elastograms were acquired by an experienced operator and analyzed by calculating the elastic ratio between perihepatic soft tissues and liver parenchyma. An elliptical ROI of 1cm(2) (Z1) was positioned in the liver parenchyma and a smaller elliptical ROI of 2mm(2) (Z2) was positioned in a homogeneously soft (red) region of the diaphragm, which was considered as internal control to calculate the elastic ratio Z2/Z1.

RESULTS

Seven patients were excluded because of invalid TE or RTE examinations. The remaining 60 patients were 57% males and 43% females (mean age: 42 [21-76] years), including 37 homozygous-β-thalassemics, 13 patients with β-thalassemia intermedia, 6 with primary hemochromatosis, and 4 with myelodysplastic syndrome. Increasing elastic ratios were significantly correlated with increasing TE values (r=0.645, 95% CI 0.468-0.772, P<0.0001). The mean elastic ratios for each METAVIR group were as follows: F0/1 = 1.9 ± 0.4; F2 = 2.2 ± 0.4; F3 = 2.9 ± 0.5; F4 = 3.2 ± 0.4. The diagnostic accuracy of RTE for F ≥ 2 evaluated by AUC-ROC analysis was 0.798 (95% CI 0.674-0.890). The diagnostic accuracy of RTE for F ≥ 3 was 0.909 (95% CI 0.806-0.968). At a cut-off ≥ 2.75, RTE showed a sensitivity of 70% (95% CI 45.7-88.1) and a specificity of 97.5% (95% CI 86.8-99.9).

CONCLUSIONS

In patients with MRI-detectable liver iron-overload RTE allows to discriminate between F0/1-F2 and F3-F4 with a reasonable diagnostic accuracy.