RPS 601b - Elastography

Purpose:

To assess the diagnostic performance of two-dimensional shear wave elastography (2D SWE) for detecting significant liver fibrosis in patients with chronic hepatitis B (CHB).

Methods and materials:

A systematic literature search of the PubMed, EMBASE, Cochrane Library databases, and Web of Science was conducted. Bivariate modelling and summary receiver-operating-characteristic modelling were constructed to summarise the diagnostic performance of 2D SWE. Subgroup analyses were performed to explore the source of heterogeneity.

Results:

11 eligible studies with 2623 patients were included. 2D SWE showed a summary sensitivity of 88% (95% CI: 83–91), specificity of 83% (95% CI: 78–88), and summary AUC of 0.92 (95% CI: 0.89-0.94) for detecting significant liver fibrosis in CHB patients. Subgroup analysis revealed that sensitivity was significantly higher for prospective studies than retrospective studies (89% vs 82%, p <0.01) and for studies excluding patients receiving antiviral therapies than studies without excluding patients with antiviral treatment (89% vs 82%, p <0.01). Specificity was significantly higher for studies with larger populations (≥110) than those with smaller sample size (<110) (85% vs 75%, p <0.05). In particular, the cutoff values in studies exclusively including antiviral treatment-naïve CHB patients were generally lower than studies without excluding patients receiving antiviral treatment, with an average of 7.15 kPa and 8.87 kPa, respectively (p <0.01).

Conclusion:

2D SWE is an excellent modality for the prediction of significant liver fibrosis in CHB populations. Further work is required to establish the cutoff values that account for antiviral treatment as a potential confounding factor.

Limitations:

A small number of studies were included in our research.

Ethics committee approval

n/a

Funding:

This work was supported by the National Natural Science Foundation of China (No. 81771797).

Purpose:

Non-alcoholic fatty liver disease (NAFLD) is an epidemic and a common radiological finding. However, the background of liver stiffness assessed with the ultrasound based noninvasive shear wave elasticity imaging (SWEI) method is still sparse. Our aim was to determinate whether the SWEI based liver stiffness has a heritable component or if it is determinated by the environment.

Methods and materials:

160 Hungarian twins (97 monozygotic, MZ, 62 dizygotic, DZ; mean age 50.6±14.7 years) recruited from the Hungarian Twin Registry underwent a cross sectional ultrasonographic SWEI between 2016 and 2018. Patients with cirrhosis or a history of oncologic disease were excluded. Heritability was calculated using univariate ACE model.

Results:

Men had higher Young-modulus values than the women (8.47±3.52 vs. 6.83±3.09, p=0.01). Young-modulus values were higher in patients with ultrasound based steatosis (6.36±2.55 vs. 8.42±3.57, p=0.001) which was confirmed by increasing mild and moderate steatosis compared to healthy patients without NAFLD. In MZ twins, there was a lower intrapair correlation for the Young-modulus (r=0.32, 95% CI, 0.011 to 0.569) than in DZ twins (r=0.507, 95% CI, 0.172 to 0.734), which demonstrated no additive genetic component, a high unique environmental (E=0.609, 95% CI, 0.427 to 0.831), and moderately common environmental effect (C=0.391, 95% CI, 0.169 to 0.573), respectively.

Conclusion:

SWEI assessed liver stiffness is elevated in men and in patients with NAFLD and demonstrates no heritability. Our results might stimulate further studies to understand the environmental factors determining the liver stiffness.

Limitations:

Relatively low number of DZ twins compared to MZ twins might slightly bias the heritability results.

Ethics committee approval

The local ethical committee approved the study (approval number: 189-1/2014). All participants gave informed consent.

Funding:

No funding was received for this work.

Purpose:

To evaluate whether 2D-shear wave elastography (SWE) could predict post-hepatectomy liver failure (PHLF) in patients who underwent resection for liver tumours in comparison with transient elastography (TE).

Methods and materials:

Between July 2018 and March 2019, we prospectively enrolled 49 patients who underwent surgical resection for liver tumours. After liver resection, development of PHLF was assessed using criteria proposed by an international study group of liver surgery. Association between liver stiffness values obtained by TE/SWE and development of PHLF was assessed using ROC analysis.

Results:

After liver resection, 15 patients (15/49, 30.1%) experienced PHLF. Mean liver stiffness value obtained from TE in 15 patients with PHLF was higher than in 34 patients without PHLF, but there was no statistically significant difference (9.3 kPa vs. 10.5 kPa, P=0.086). The area under the curve (AUC) of TE for prediction of PHLF was 0.655 (P=0.082, 95% confidence interval [CI]; 0.505-0.785). Regarding liver stiffness value obtained 2D-SWE, 15 patients with PHLF had significantly higher liver stiffness value compared to 34 patients without PHLF (8.1 kPa vs. 10.6 kPa, P=0.011). The AUC of 2D-SWE for prediction of PHLF was 0.729 (P=0.006, 95% CI; 0.584-0.846), which was not significantly different from TE (P=0.275). The estimated sensitivity and specificity of 2D-SWE for detecting PHLF was 80.0% and 73.5% when the cut-off value was set at 7.8 kPa.

Conclusion:

2D-SWE with propagation map could have a potential to predict PHLF in patients who underwent resection for liver tumour.

Limitations:

Small number of partcipants.

Ethics committee approval

Our institutional review board approved this prospective study.

Funding:

Canon medical system supported this study. Whole data was collected and analysed by the authors.

Purpose:

To investigate the relationship between the histologic stage of liver fibrosis and the spatial variability of liver shear stiffness (kPa) as measured by 2D magnetic elastography (MRE) in adults with known/suspected non-alcoholic fatty liver disease (NAFLD). Secondarily, to explore possible confounders (age, sex, and body mass index (BMI)).

Methods and materials:

We retrospectively identified 156 adult patients with known or suspected NAFLD who underwent research 2D MRE exams (4 slices per patient) at 3T between 2014 and 2015 and for whom the following was available: age, sex, BMI, and liver biopsies performed within 180 days before or after MRE. Analysts placed regions of interest (ROI) on each of the four slices in areas of liver parenchyma with planar wave propagation. Number of pixels, mean stiffness, and standard deviation (SD) of stiffness was computed across the four ROIs. Stiffness SD was used as a metric of spatial variability. An expert pathologist scored liver fibrosis stage for each patient using the NASH CRN system. Stiffness SD was correlated with fibrosis stage (Spearman correlation). A multivariable linear regression was used to model stiffness SD as a function of fibrosis stage and possible confounders (stiffness mean, age, sex, and BMI).

Results:

Stiffness SD positively correlated fibrosis stage. In multivariable analysis, the strongest predictor of stiffness SD was stiffness mean. Sex and fibrosis stage had trend-wise significant association with stiffness SD, while BMI and age did not.

Conclusion:

Spatial variability of liver stiffness increases with fibrosis stage. Further research is needed to determine whether spatial variability of stiffness reflects the spatial variability in fibrosis or other factors.

Limitations:

Stiffness measured by MRE comes from only within the ROI.

Ethics committee approval

All patients gave informed consent.

Funding:

NIH grant and in part from GE.

Purpose:

To compare the diagnostic performance of T1-mapping and MR-elastography (MRE) for staging of hepatic fibrosis with histopathology as standard of reference.

Methods and materials:

48 patients who underwent liver biopsy for suspected fibrosis or were diagnosed with alcohol-toxic cirrhosis prospectively underwent look-locker inversion recovery T1-mapping and MRE. T1 relaxation time and liver stiffness (LS) were measured in the right and left liver lobe by two readers. Hepatic fibrosis was histopathologically staged according to a standardised fibrosis score (F0-F4). For statistical analysis independent t-test, Mann-Whitney-U-Test and ROC analysis were performed. ROC analysis was performed to determine accuracy of T1-mapping and MRE for fibrosis staging.

Results:

Histopathological analysis diagnosed 3 patients with F0 (6%), 14 with F1 (29%), 13 with F2 (27%), 7 with F3 (15%), and 11 with F4 (23%, including previously diagnosed cirrhotic patients). T1-mapping and MRE both showed significantly higher values for patients with significant fibrosis (F0-1 vs. F2-4; T1-mapping p=0.001, MRE p<0.0001) as well as for patients with severe fibrosis or cirrhosis (F0-2 vs. F3-4; T1-mapping p=0.010, MRE p<0.0001). The diagnostic performance of T1-mapping and MRE was similarly high for significant fibrosis (F2-4) (AUC 0.798 vs. 0.868, p=0.39), but was significantly higher for MRE for severe fibrosis (F3/4) (AUC 0.952 vs. 0.745, p=0.02).

Conclusion:

T1-mapping may be used as an alternative to MRE for diagnosing fibrosis in patients with different liver diseases, especially for the detection of clinically significant fibrosis.

Limitations:

T1-maps were not fat-corrected, which might have influenced the results and should be a target of further studies.

Ethics committee approval

The local ethics committee approved this prospective study and all patients gave written informed consent.

Funding:

No funding was received for this work.