Development of a method for measuring spleen stiffness by transient elastography using a new device and ultrasound-fusion method

WFUMB Guideline/Guidance on Liver Multiparametric Ultrasound: Part 1. Update to 2018 Guidelines on Liver Ultrasound Elastography

The World Federation for Ultrasound in Medicine and Biology (WFUMB) endorsed the development of this document on multiparametric ultrasound. Part 1 is an update to the WFUMB Liver Elastography Guidelines Update released in 2018 and provides new evidence on the role of ultrasound elastography in chronic liver disease. The recommendations in this update were made and graded using the Oxford classification, including level of evidence (LoE), grade of recommendation (GoR) and proportion of agreement (Oxford Centre for Evidence-Based Medicine [OCEBM] 2009). The guidelines are clinically oriented, and the role of shear wave elastography in both fibrosis staging and prognostication in different etiologies of liver disease is discussed, highlighting advantages and limitations. A comprehensive section is devoted to the assessment of portal hypertension, with specific recommendations for the interpretation of liver and spleen stiffness measurements in this setting.

iATT liver fat quantification for steatosis grading by referring to MRI proton density fat fraction: a multicenter study

BACKGROUND

Several preliminary reports have suggested the utility of ultrasound attenuation coefficient measurements based on B-mode ultrasound, such as iATT, for diagnosing steatotic liver disease. Nonetheless, evidence supporting such utility is lacking. This prospective study aimed to investigate whether iATT is highly concordant with magnetic resonance imaging (MRI)-based proton density fat fraction (MRI-PDFF) and could well distinguish between steatosis grades.

METHODS

A cohort of 846 individuals underwent both iATT and MRI-PDFF assessments. Steatosis grade was defined as grade 0 with MRI-PDFF < 5.2%, grade 1 with 5.2% MRI-PDFF < 11.3%, grade 2 with 11.3% MRI-PDFF < 17.1%, and grade 3 with MRI-PDFF of 17.1%. The reproducibility of iATT and MRI-PDFF was evaluated using the Bland-Altman analysis and intraclass correlation coefficients, whereas the diagnostic performance of each steatosis grade was examined using receiver operating characteristic analysis.

RESULTS

The Bland-Altman analysis indicated excellent reproducibility with minimal fixed bias between iATT and MRI-PDFF. The area under the curve for distinguishing steatosis grades 1, 2, and 3 were 0.887, 0.882, and 0.867, respectively. A skin-to-capsula distance of ≥ 25 mm was identified as the only significant factor causing the discrepancy. No interaction between MRI-logPDFF and MRE-LSM on iATT values was observed.

CONCLUSIONS

Compared to MRI-PDFF, iATT showed excellent diagnostic accuracy in grading steatosis. iATT could be used as a diagnostic tool instead of MRI in clinical practice and trials. Trial registration This study was registered in the UMIN Clinical Trials Registry (UMIN000047411).

B-mode shear wave elastography can be an alternative method to vibration-controlled transient elastography according to a moderate-scale population study

PURPOSE

We aimed to compare vibration-controlled transient elastography (VCTE) with shear wave elastography (SWE) without previous analysis and generate regression equations between VCTE and new point SWE using combination-elastography.

METHODS

Overall, 829 patients with chronic liver disease were enrolled in this study. Patients with a skin-liver capsule distance > 25 mm were excluded. The reproducibility of VCTE and SWE was confirmed in a phantom study and a clinical study. Considering that combination-elastography allows measurement based on strain elastography, a similar analysis was performed for the liver fibrosis index (LFI), which is a quantitative value for evaluation of liver fibrosis calculated using strain elastography image features. Regression equations between the VCTE and SWE values were obtained based on linear regression analysis.

RESULTS

In the phantom study and clinical study, there was a strong correlation between VCTE and SWE [r = 0.995 (p < 0.001) and r = 0.747 (p < 0.001), respectively). The regression equation between VCTE and SWE was VCTE (kPa) = 1.09 × point SWE (kPa) - 0.17. The Bland-Altman plots revealed no statistically significant bias. Meanwhile, there was no correlation between VCTE and LFI (r = 0.279). There was a statistically significant bias between VCTE and LFI in the Bland-Altman plots. The inter-operator reliability showed a good intraclass correlation coefficient of 0.760 (95% confidence interval: 0.720-0.779).

CONCLUSION

Liver stiffness measured using point SWE was comparable to that measured using VCTE.

Accuracy of spleen stiffness measurement for the diagnosis of clinically significant portal hypertension in patients with compensated advanced chronic liver disease: a systematic review and individual patient data meta-analysis

BACKGROUND

The diagnosis of clinically significant portal hypertension is crucial for prognosis and treatment guidance in patients with compensated advanced chronic liver disease (ACLD). Spleen stiffness measurement (SSM) might improve the non-invasive diagnosis of clinically significant portal hypertension, but previous studies have reported heterogeneous SSM cutoffs. We aimed to evaluate the accuracy of SSM and SSM-based algorithms in this setting.

METHODS

In this systematic review and individual patient data meta-analysis, we searched PubMed, Embase, Scopus, Web of Science, and the Cochrane Library from database inception to Dec 31, 2022, for articles, abstracts, and letters, with no restrictions on language. Cross-sectional studies reporting hepatic venous pressure gradient and SSM by different techniques (transient elastography; two-dimensional shear-wave elastography [2D-SWE]; point shear-wave elastography [p-SWE]) in adults (≥18 years) with compensated ACLD were eligible for inclusion. The main outcome was the diagnostic performance of two SSM-based algorithms, with the Baveno VII model as a reference, evaluating sensitivity and specificity, as well as summary negative predictive values (NPVs) and positive predictive values (PPVs). In the Baveno VII model, clinically significant portal hypertension was ruled out if patients had a liver stiffness measurement (LSM) of 15 kPa or less and a platelet count of 150 × 109 platelets per L or higher and ruled in if they had an LSM of greater than 25 kPa. The two SSM-based models combined these same cutoffs with additional criteria. In the Baveno VII-SSM single cutoff model, clinically significant portal hypertension was ruled out if at least two of the following were present: LSM of 15 kPa or less, platelet count of 150 × 109 platelets per L or higher, and SSM of 40 kPa or less; and ruled in if at least two were present: LSM of greater than 25 kPa, platelet count of less than 150 × 109 platelets per L, and SSM of greater than 40 kPa. The Baveno VII-SSM dual cutoff model used the same criteria, but with a cutoff of SSM of less than 21 kPa to rule out, and greater than 50 kPa to rule in, clinically significant portal hypertension. This study is registered with PROSPERO, CRD42019127164.

FINDINGS

Of the 44 records assessed for eligibility, 17 studies (with 1245 patients) were included in the meta-analysis. In the transient elastography cohort (n=600), the Baveno VII algorithm was validated for both ruling out (NPV 100%, 95% CI 64-100; sensitivity 100%, 95% CI 70-100) and ruling in (PPV 95%, 85-98; specificity 94%, 95% CI 87-97) clinically significant portal hypertension, but the proportion of patients with indeterminate results (grey zone) was 48% (95% CI 44-52); 57% (95% CI 52-62) of patients with clinically significant portal hypertension were included in the rule-in zone. The Baveno VII-SSM dual cutoff model had adequate NPV (98%, 95% CI 58-100; sensitivity 100%, 95% CI 91-100) and PPV (93%, 95% CI 84-97; specificity 89%, 95% CI 84-93), with 32% (95% CI 28-36) of patients in the grey zone; 76% (95% CI 72-80) of the patients with clinically significant portal hypertension were in the rule-in zone. The Baveno VII-SSM single cutoff model had a sensitivity of 93% (95% CI 85-97) and a NPV of 85% (95% CI 60-96) for ruling out, and a specificity of 86% (95% CI 80-91) and a PPV of 92% (95% CI 83-95) for ruling in, clinically significant portal hypertension. 88% (95% CI 84-91) of patients with clinically significant portal hypertension were included in the rule-in zone and 9% (95% CI 7-12) of patients were in the grey zone. In the 2D-SWE cohort (n=225), all three algorithms could safely rule in clinically significant portal hypertension with adequate PPV (≥90%), but NPV was inadequate for ruling out clinically significant portal hypertension. Insufficient data were available to evaluate the performance of SSM assessed by p-SWE. Heterogeneity was low (I2<25%) for most estimates.

INTERPRETATION

Algorithms combining Baveno VII criteria with SSM showed good performance and reduced the diagnostic grey zone for clinically significant portal hypertension compared with Baveno VII criteria alone. Future studies should evaluate whether SSM-based diagnosis allows for the identification of patients who would benefit from non-selective β-blocker treatment.

FUNDING

None.

Spleen stiffness in patients with chronic liver disease evaluated by 2-D shear wave elastography with ultrasound multiparametric imaging

BACKGROUND

The novel 2-D shear wave elastography (2D-SWE) can measure two ultrasound parameters: shear wave dispersion (SWD) and shear wave speed (SWS). We investigated the ability of 2D-SWE in measuring spleen stiffness using ultrasound multiparametric imaging.

METHODS

This cross-sectional study included patients with chronic liver disease who underwent esophagogastroduodenoscopy and ultrasonographic examinations of the spleen between September 2018 and December 2021. In total, 157 patients were enrolled in this study: 81 and 67 patients were included in the pilot set for hepatic venous pressure gradient (HVPG) measurements and validation cohort without HVPG measurements, respectively. To confirm reproducibility between the two examiners, an additional 30 patients were enrolled.

RESULTS

The Bland-Altman plots revealed no significant bias in the SWD as measured by two examiners. The splenic SWS (r = 0.752) and SWD (r = 0.444) were correlated with the HVPG. Regarding high-risk varices, as per the Youden index, the cut-off value for splenic SWS was 3.30 m/s, with a sensitivity of 85.7%, specificity of 92.5%, positive predictive value of 85.7%, and negative predictive value of 92.4% in the pilot set. In the validation set, good diagnostic performance by the splenic SWS was observed. However, SWD did not perform as well as SWS.

CONCLUSIONS

The splenic SWS, measured using ultrasound multiparametric imaging, was closely correlated with the HVPG. Thus, SWS is a useful predictive marker for high-risk varices.

A Combined Baveno VII and Spleen Stiffness Algorithm to Improve the Noninvasive Diagnosis of Clinically Significant Portal Hypertension in Patients With Compensated Advanced Chronic Liver Disease

INTRODUCTION

A noninvasive diagnosis of clinically significant portal hypertension (CSPH) has important prognostic and therapeutic implications for patients with compensated advanced chronic liver disease. We aimed to validate and improve the available algorithms for the CSPH diagnosis by evaluating spleen stiffness measurement (SSM) in patients with compensated advanced chronic liver disease.

METHODS

This is a retrospective study including patients with liver stiffness measurement (LSM) ≥10 kPa, no previous decompensation, and available measurements of hepatic venous pressure gradient, LSM, and SSM by transient elastography referring to our center in Bologna. The diagnostic algorithms were adequate if negative and positive predictive values were >90% when ruling out and ruling in CSPH, respectively; these models were validated in a cohort from Verona. The 5-year decompensation rate was reported.

RESULTS

One hundred fourteen patients were included in the derivation cohort. The Baveno VII diagnostic algorithm (LSM ≤15 kPa + platelet count ≥150 × 10 9 /L to rule out CSPH and LSM >25 kPa to rule in CSPH) was validated; however, 40%-60% of the patients remained in the gray zone. The addition of SSM (40 kPa) to the model significantly reduced the gray zone to 7%-15%, maintaining adequate negative and positive predictive values. The diagnostic algorithms were validated in a cohort of 81 patients from Verona. All first decompensation events occurred in the "rule-in" zone of the model including SSM.

DISCUSSION

The addition of SSM significantly improves the clinical applicability of the algorithm based on LSM and platelet count for CSPH diagnosis. Our models can be used to noninvasively identify candidates for nonselective beta-blocker treatment and patients at a high risk of decompensation.

Efficacy of B-mode ultrasound-based attenuation for the diagnosis of hepatic steatosis: a systematic review/meta-analysis

The accuracy of attenuation coefficients and B-mode ultrasound for distinguishing between S0 (healthy, < 5% fat) and S1-3 (steatosis ≥ 5%) livers compared to a controlled attenuation parameter is unclear. This meta-analysis aimed to comprehensively assess the diagnostic performance of B-mode ultrasound imaging for evaluating steatosis of ≥ 5%. We searched the PubMed, Embase, and Web of Science databases for studies on the accuracy of B-mode ultrasound for differentiating S0 from S1-3 in adults with chronic liver disease. A bivariate random-effects model was performed to estimate the pooled sensitivity, specificity, positive (PLR) and negative likelihood ratios (NLR), and diagnostic odds ratios (DORs). Subgroup analyses by attenuation coefficient, conventional B-mode ultrasound findings, and B-mode ultrasound findings without semi-quantification methods were performed. Liver steatosis was scored as follows: S0, < 5%; S1, 5-33%; S2, 33-66%; and S3, > 66%. Nineteen studies involving 3240 patients were analyzed. The pooled sensitivity and specificity of B-mode ultrasound for detecting S1 were 0.70 (95% confidence interval [CI], 0.63-0.77) and 0.86 (95% CI 0.82-0.89), respectively. The pooled PLR, NLR, and DOR were 4.90 (95% CI 3.69-6.51), 0.35 (95% CI 0.27- 0.44), and 14.1 (95% CI 8.7-23.0), respectively. The diagnostic accuracy was better in patients with attenuation coefficients (area under the curve [AUC], 0.89; sensitivity, 0.75; specificity, 0.86) than in those with conventional B-mode findings (AUC, 0.80; sensitivity, 0.59; specificity, 0.83). In particular, the diagnostic value was better when the attenuation coefficient guided by B-mode ultrasound was utilized. To screen patients with steatosis of ≥ 5%, attenuation coefficient should be used.

Measurement of multiple spleen lengths is not necessary for non-invasive prediction of high-risk esophagogastric varices

AIM

To validate an appropriate spleen size measurement technique for the prediction of high-risk esophagogastric varices.

METHODS

This retrospective cross-sectional study included 369 patients who underwent ultrasonography and computed tomography (CT) of the spleen and esophagogastroduodenoscopy between January 2018 and December 2020. Maximum spleen length, width, and craniocaudal length were measured in a longitudinal view. The two-dimensional (2D) spleen index (maximum length × maximum width in the longitudinal view) was calculated. A three-dimensional (3D) spleen index was then defined as follows: 2D spleen index × maximum length in the transverse view. The similarity in spleen volume measured by CT and ultrasonography (spleen index) was assessed by the correlation coefficient. The diagnostic accuracies of the spleen index, platelet/spleen length, and platelet/spleen index were calculated to determine the overall diagnostic accuracy.

RESULTS

Compared to the other spleen indices, our 3D spleen index was significantly better correlated with spleen volume on CT (r = 0.91, 95% confidence interval 0.89-0.92, p < 0.001). Receiver-operating characteristic curve analyses revealed no significant difference between the 3D and 2D indices (p = 0.228) but did show a significant difference between the 3D and one-dimensional indices (p = 0.020). Although the area under the curve for the platelet count combined with the spleen index or length was higher than that for our 3D index, there was no significant difference between platelet count and spleen index or length (p = 0.078).

CONCLUSIONS

Platelet/spleen length has a reasonable ability to predict high-risk esophagogastric varices, even though measurement of two or three factors can be correlated with spleen volume.

Accurate reflection of hepatic venous pressure gradient by spleen stiffness measurement in patients with low controlled attenuation parameter values

Background and Aim

Spleen stiffness measurement (SSM) is useful for assessing portal hypertension. It is unclear whether SSM values are appropriate because vibration‐controlled transient elastography (VCTE) does not generate B‐mode images. This study aimed to confirm whether the controlled attenuation parameter (CAP) measured in the spleen can predict the accuracy of SSM.

Methods

This retrospective study enrolled 349 patients who underwent SSM using VCTE from January 2012 to December 2020. Consecutive patients were classified into the pilot set (SSM and hepatic venous pressure gradient [HVPG] were measured) and the validation set (SSM was measured without HVPG). In the pilot set, scatter plots with a nonparametric contour line were created. Logistic regression analysis was performed to predict outliers outside the 50% contour line.

Results

The values of CAP could distinguish the outliers in scatter plots between the HPVG and SSM in both univariate and multivariate analyses (cutoff, 118 dB/m). The correlation of SSM with HVPG (r = 0.718; P < 0.001) was significantly better in the low CAP (≤118 dB/m) group than in the high CAP (>118 dB/m) group (r = 0.330; P < 0.001). The area under the receiver operating characteristic curve of SSM in predicting high‐risk varices was better in the low CAP group than in all patients or in the high CAP group in the pilot set (0.881, 0.854, and 0.843, respectively) and in the validation set (0.893, 0.821, and 0.814, respectively).

Conclusion

For patients with CAP <118 dB/m, SSM is a feasible predictor of HVPG.

Approaches to the Diagnosis of Portal Hypertension: Non-Invasive or Invasive Tests?

Portal hypertension is the main driver of complications in patients with advanced chronic liver disease (ACLD) and is defined by values of hepatic venous pressure gradient measurement (HVPG) >5 mmHg. Values of HVPG ≥10 mmHg determine the presence of clinically significant portal hypertension (CSPH), the main predictor of the risk of variceal bleeding, hepatic decompensation, and mortality. However, its measurement is invasive and requires high expertise, so its routine use outside third level centers or clinical trials is limited. In the last decades, several non-invasive tests (NITs) have been developed and validated for the diagnosis of portal hypertension. Among these, liver (LSM) and spleen stiffness measurement (SSM) are the most promising tools available, as they have been proven accurate to predict CSPH, high-risk esophageal varices, decompensation, and mortality in patients with ACLD. In the last Baveno VI Consensus proceedings, LSM evaluation was recommended for the first time for diagnosis of CSPH (LSM >20-25 kPa) and the screening of patients with a low probability of having high-risk varices (LSM <20 kPa and platelet count >150.000/mm³). In this review, we aimed to summarize the growing evidence supporting the use of non-invasive tests for the evaluation of portal hypertension in patients with chronic liver disease.