What we need to know when performing and interpreting US elastography

Shear wave elastography in chronic kidney disease - the physics and clinical application

Chronic kidney disease is a leading public health problem worldwide. The global prevalence of chronic kidney disease is nearly five hundred million people, with almost one million deaths worldwide. Estimated glomerular filtration rate, imaging such as conventional ultrasound, and histopathological findings are necessary as each technique provides specific information which, when taken together, may help to detect and arrest the development of chronic kidney disease, besides managing its adverse outcomes. However, estimated glomerular filtration rate measurements are hampered by substantial error margins while conventional ultrasound involves subjective assessment. Although histopathological assessment is the best tool for evaluating the severity of the renal pathology, it may lead to renal insufficiency and haemorrhage if complications occurred. Ultrasound shear wave elastography, an emerging imaging that quantifies tissue stiffness non-invasively has gained interest recently. This method applies acoustic force pulses to generate shear wave within the tissue that propagate perpendicular to the main ultrasound beam. By measuring the speed of shear wave propagation, the tissue stiffness is estimated. This paper reviews the literature and presents our combined experience and knowledge in renal shear wave elastography research. It discusses and highlights the confounding factors on shear wave elastography, current and future possibilities in ultrasound renal imaging and is not limited to new sophisticated techniques.

Evaluation of the stiffness of normal cervix and its change with different factors using transvaginal two-dimensional shear wave elastography under strict quality control

BACKGROUND

The usefulness of transvaginal two-dimensional shear wave elastography (2D SWE) for cervical lesions is still uncertain. This study was to explore the value of transvaginal 2D SWE in the evaluation of the stiffness of normal cervix and its change with different factors under strict quality control (QC).

METHODS

Two hundred patients with normal cervix were included in this study and were examined using quantitative 2D SWE to evaluate cervical stiffness and its change with different factors under strict QC.

RESULTS

Intra-observer concordance of transvaginal 2D SWE parameters in midsagittal planes were acceptable with intraclass correlation coefficients higher than 0.5. Transvaginal 2D SWE parameters were significantly higher than the corresponding transabdominal parameters. 2D SWE parameters of internal cervical os were significantly higher than the corresponding parameters of external cervical os in a transvaginal midsagittal plane. 2D SWE parameters of external cervical os increased significantly over 50 years old, while these parameters of internal cervical os didn't change significantly with increasing age. 2D SWE parameters of internal cervical os of horizontal position cervix were significantly higher than those of vertical position cervix. SWE parameters of normal cervix did not change according to different menstrual cycles, parities and human papilloma virus test results.

CONCLUSIONS

Transvaginal 2D SWE under strict QC could provide quantitative, repeatable and reliable cervical stiffness information. Internal cervical os was stiffer than external cervical os. Menstrual cycles, parities and human papilloma virus test results wouldn't affect cervical stiffness. However, age and cervical positions should be taken into condition while interpreting 2D SWE results of cervical stiffness.

Diagnostic accuracy of liver stiffness on two-dimensional shear wave elastography for detecting clinically significant portal hypertension: a meta-analysis

PURPOSE

Two-dimensional shear wave elastography (2D-SWE) has recently been proposed to detect clinically significant portal hypertension (CSPH), we aimed to perform a meta-analysis based on the published data to assess the diagnostic accuracy of 2D-SWE for detecting CSPH.

METHOD

Literature databases were searched up until 1 August 2021. The summary area under receiver operating characteristics curve (AUROC), the summary diagnostic odds ratio (DOR), and the summary sensitivity and specificity were used to examine the accuracy of 2D-SWE for evaluating CSPH. Heterogeneity was explored using meta-regression.

RESULTS

Finally 9 studies with 956 patients were included in this study for evaluation and meta-analysis. 2D-SWE showed good diagnostic performance for detecting CSPH with a summary sensitivity of 83% (95% confidence interval [CI]: 76%-88%) and summary specificity of 78% (95% CI: 65%-87%); the summary AUROC was 0.88 (95% CI: 0.84-0.90). Summary positive likelihood ratio (LR), negative LR, and DOR of 2D-SWE for detecting CSPH were 3.7 (95% CI: 2.4-5.9), 0.22 (95% CI: 0.16-0.30), and 17 (95% CI: 10-29), respectively.

CONCLUSIONS

2D-SWE showed good performance in diagnosing CSPH and can be considered as an important and noninvasive adjunctive approach in the management of patients with CSPH.

Clinical application of two dimensional shear wave elastography with a propagation map in evaluating liver fibrosis in patients with liver tumors

OBJECTIVE

This study aimed to evaluate the diagnostic performance of two-dimensional shear wave elastography (2D-SWE) with a propagation map in evaluating the degree of hepatic fibrosis in patients with liver tumors before resection.

METHODS AND MATERIALS

From January 2020 to April 2021, 128 patients with liver tumors were prospectively enrolled, including 20 benign liver tumors and 108 malignant liver tumors. 2D-SWE with a propagation map technology was used to measure the stiffness of liver parenchyma 2 cm away from the tumor. The median value of five measurements was used in this study. The stage of hepatic fibrosis was graded in accordance with Scheuer standard. Spearman correlation was used to analyze the correlation between liver fibrosis stage and the liver stiffness. Univariate and multivariate linear regression analyses were used to determine significant affecting factors for liver stiffness value. The diagnostic performance of 2D-SWE with a propagation map in predicting fibrosis stage was evaluated by receiver operating characteristic curve analysis.

RESULTS

The median liver stiffness value in patients with benign liver tumors was lower than that in patients with malignant liver tumors (6.0 kPa vs. 9.4 kPa, p < 0.05). The median liver stiffness values in patients with primary liver cancer were higher than that in patients with benign liver tumors and other types of malignant liver tumors (9.6 kPa vs. 6.0 kPa, p < 0.05). The liver stiffness measured by 2D-SWE was highly correlated with the fibrosis stage confirmed by postoperative pathology (r = 0.834, p < 0.05). For the liver stiffness value, PLT,TB,ALB and fibrosis stage are significantly associated with liver stiffness. The median liver stiffness values in stages S0-S4 of fibrosis were 6.0, 7.2, 8.0, 9.4, and 12.6 kPa, respectively. The areas under the ROC curve of S≥1, S≥2, S≥3, and S = 4 as predicted by SWE were 0.932, 0.945, 0.945, and 0.916, respectively. According to the Youden index, the optimal critical values for predicting fibrosis S≥1, S≥2, S≥3, and S = 4 were 6.8 (sensitivity of 89.69% and specificity of 93.55%), 7.5 (sensitivity of 87.50 % and specificity of 95.00 %), 8.3 (sensitivity of 87.14 % and specificity of 87.93 %) and 9.8 (sensitivity of 79.55 % and specificity of 86.90 %) kPa.

CONCLUSION

2D-SWE with a propagation map could noninvasively and accurately predict the staging of liver fibrosis in patients with liver tumors before resection.

Alignment of Physician-Stated vs Clinically Derived Reference Fibrosis Score in Patients with Non-Alcoholic Steatohepatitis: A Real-World European Survey

Objective

Stratifying disease severity in patients with non-alcoholic steatohepatitis (NASH) is essential for appropriate treatment and long-term management. Liver biopsy is the reference standard for fibrosis severity in NASH, but less invasive methods are used, eg, Fibrosis-4 Index (FIB-4) and vibration-controlled transient elastography (VCTE), for which reference thresholds for no/early fibrosis and advanced fibrosis are available. We compared subjective physician assessment of NASH fibrosis versus reference thresholds to understand classification in a real-world setting.

Methods

Data were drawn from Adelphi Real World NASH Disease Specific Programme^TM conducted in France, Germany, Italy, Spain and UK in 2018. Physicians (diabetologists, gastroenterologists, hepatologists) completed questionnaires for five consecutive NASH patients presenting for routine care. Physician-stated fibrosis score (PSFS) based on available information was compared with clinically defined reference fibrosis stage (CRFS) determined retrospectively using VCTE and FIB-4 data and eight reference thresholds.

Results

One thousand two hundred and eleven patients had VCTE (n = 1115) and/or FIB-4 (n = 524). Depending on thresholds, physicians underestimated severity in 16-33% (FIB-4) and 27-50% of patients (VCTE). Using VCTE ≥12.2, diabetologists, gastroenterologists and hepatologists underestimated disease severity in 35%, 32%, and 27% of patients, respectively, and overestimated fibrosis in 3%, 4%, and 9%, respectively (p = 0.0083 across specialties). Hepatologists and gastroenterologists had higher liver biopsy rates than diabetologists (52%, 56%, 47%, respectively).

Conclusion

PSFS did not consistently align with CRFS in this NASH real-world setting. Underestimation was more common than overestimation, potentially leading to undertreatment of patients with advanced fibrosis. More guidance on interpreting test results when classifying fibrosis is needed, thereby improving management of NASH.

The diagnostic performance of ultrasound elastography for biliary atresia: A meta-analysis

Background

Biliary atresia (BA) is a severe inflammatory obliterative cholangiopathy of infancy that requires early diagnosis and prompt surgical intervention. In this study, we aimed to obtain comprehensive evidence on the diagnostic performance of liver stiffness measurement by ultrasound elastography in the detection of BA through a meta-analysis.

Methods

The PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched for studies that investigated the diagnostic performance of ultrasound elastography in the detection of BA up to January 10, 2022. In this study, in order to summarize the diagnostic performance of ultrasound elastography, the summary receiver operating characteristic (SROC) modeling was constructed. Heterogeneity was estimated with the I ² statistic. Multiple subgroup analyses were also performed.

Results

Fourteen studies from eleven articles, including 774 BA patients, 850 non-BA patients, and 173 controls were included in the present meta-analysis. The summary sensitivity and specificity of ultrasound elastography for liver stiffness were 85% [95% confidence interval (CI): 79-89%] and 82% (95% CI: 73-88%) with the I ² value of 82.90 and 84.33%, respectively. The area under the SROC curve (AUROC) using ultrasound elastography for diagnosing BA was 0.90 (95% CI: 0.87-0.92). In addition, a subgroup analysis of 9 two-dimensional shear wave elastography studies was also performed. Subgroup analysis revealed that the summary sensitivity and specificity were 85% (95% CI: 77-91%) and 79% (95% CI: 71-86%), respectively, and the summary AUROC was 0.89 (95% CI: 0.86-0.92).

Conclusions

Ultrasound elastography exhibits good diagnostic accuracy for BA and can be served as a non-invasive tool to facilitate the differential diagnosis of BA.

Applications of elastography in operative neurosurgery: A systematic review

Elastography is an imaging technology capable of measuring tissue stiffness and consistency. The technology has achieved widespread use in the workup and management of diseases of the liver, breast, thyroid, and prostate. Although elastography is increasingly being applied in neurosurgery, it has not yet achieved widespread adoption and many clinicians remain unfamiliar with the technology. Therefore, we sought to summarize the range of applications and elastography modalities available for neurosurgery, report its effectiveness in comparison with conventional imaging methods, and offer recommendations. All full-text English-language manuscripts on the use of elastography for neurosurgical procedures were screened using the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, and Web of Science databases. Thirty-two studies were included with 990 patients, including 21 studies on intracranial tumors, 5 on hydrocephalus, 4 on epilepsy, 1 on spinal cord compression, and 1 on adolescent scoliosis. Twenty studies used ultrasound elastography (USE) whereas 12 used magnetic resonance elastography (MRE). MRE studies were mostly used in the preoperative setting for assessment of lesion stiffness, tumor-brain adherence, diagnostic workup, and operative planning. USE studies were performed intraoperatively to guide resection of lesions, determine residual microscopic abnormalities, assess the tumor-brain interface, and study mechanical properties of tumors. Elastography can assist with resection of brain tissue, detection of microscopic lesions, and workup of hydrocephalus, among other applications under investigation. Its sensitivity often exceeds that of conventional MRI and ultrasound for identifying abnormal tissue and lesion margins.

Diagnostic Performance of 2-D Shear Wave Elastography on the Evaluation of Hepatic Fibrosis with Emphasis on Impact of the Different Region-of-Interest Methods

The purpose of this study was to evaluate the impact of the different region-of-interest (ROI) methods of 2-D shear wave elastography (2-D SWE) on hepatic fibrosis diagnosis. In this retrospective study, 83 patients who underwent 2-D SWE with three ROI methods (a circle ROI, a box ROI and multiple ROIs in an elastogram) and transient elastography (TE) were included. Liver stiffness (LS) was measured five times with each ROI method. These LS values were compared, and their correlation with those obtained from TE was evaluated. The LS values obtained using the three different ROI methods differed statistically (p < 0.001). However, the LS values obtained using each ROI method of 2-D SWE were highly correlated with those obtained using TE (r > 0.7, p < 0.001). All three ROI methods of 2-D SWE had high areas under the receiver operating characteristic curve in diagnosing significant fibrosis and cirrhosis (0.841, 0.820 and 0.840, respectively; 0.962, 0.946 and 0.945, respectively). There were no significant differences in area under the receiver operating characteristic curve among the ROI methods of 2-D SWE. Regardless of the ROI method, 2-D SWE had high performance in diagnosing hepatic fibrosis.

Risk assessment of hepatocellular carcinoma and liver-related events using ultrasonography and transient elastography in patients with chronic hepatitis B

Cirrhosis has prognostic value. We investigated whether the combined use of ultrasonography (US) and transient elastography (TE) to diagnose cirrhosis is beneficial for the risk assessment of hepatocellular carcinoma (HCC) and liver-related events in patients with chronic hepatitis B (CHB). A total of 9300 patients with CHB who underwent US and TE in two institutions between 2006 and 2018 were enrolled. TE value ≥13 kPa was set to indicate cirrhosis. Patients were divided into four groups: US(+)TE(+) (cirrhosis by US and TE), US(+)TE(-) (cirrhosis by US, but not by TE), US(-)TE(+) (cirrhosis by TE, but not by US) and US(-)TE(-) (non-cirrhosis by US and TE).The patients were predominantly male (n = 5474, 58.9%) with a mean age of 47.5 years. The proportions of patients with cirrhosis diagnosed by US and TE were 17.2% (n = 1595) and 13.2% (n = 1225), respectively. The proportion of patients with discordant results in diagnosing cirrhosis by US and TE was 18.7% (n = 1740). During follow-up (median: 60.0 months), HCC and liver-related events developed in 481 (5.2%) and 759 (8.2%) patients, respectively. The cumulative incidence rates of HCC and liver-related events were highest in the US(+)TE(+) group, intermediate-high in the US(-)TE(+) group, intermediate-low in the US(+)TE(-) group and lowest in the US(-)TE(-) group (overall p < .001). Cirrhosis assessed using US and TE was a major predictor of HCC and liver-related event development in patients with CHB. Cirrhosis assessed using TE seemed better in predicting HCC or liver-related events than using US, when cirrhosis diagnosis was discordant by US and TE.

Shear Wave Dispersion Predicts Liver Fibrosis and Adverse Outcomes in Patients with Heart Failure

Background: It has been recently reported that liver stiffness assessed by transient elastography reflects right atrial pressure (RAP) and is associated with worse outcomes in patients with heart failure (HF). However, the relationship between shear wave dispersion (SWD, a novel indicator of liver viscosity) determined by abdominal ultrasonography and RAP, and the prognostic impact of SWD on HF patients have not been fully examined. We aimed to clarify the associations of SWD with parameters of liver function test (LFT) and right heart catheterization (RHC), as well as with cardiac events such as cardiac death and worsening HF, in patients with HF. Methods: We performed abdominal ultrasonography, LFT and RHC in HF patients (n = 195), and followed up for cardiac events. We examined associations between SWD and parameters of LFT and RHC. Results: There were significant correlations between SWD and circulating levels of direct bilirubin (R = 0.222, p = 0.002), alkaline phosphatase (R = 0.219, p = 0.002), cholinesterase (R = −0.184, p = 0.011), and 7S domain of collagen type IV (R = 0.177, p = 0.014), but not with RAP (R = 0.054, p = 0.567) or cardiac index (R = −0.015, p = 0.872). In the Kaplan–Meier analysis, cardiac event rate was significantly higher in the high SWD group (SWD ≥ 10.0 (m/s)/kHz, n = 103) than in the low SWD group (SWD < 10.0 (m/s)/kHz, n = 92; log-rank, p = 0.010). In the Cox proportional hazard analysis, high SWD was associated with high cardiac event rates (hazard ratio, 2.841; 95% confidence interval, 1.234–6.541, p = 0.014). In addition, there were no interactions between SWD and all subgroups, according to the subgroup analysis. Conclusions: SWD assessed by abdominal ultrasonography reflects liver fibrosis rather than liver congestion, and is associated with adverse prognosis in HF patients.

Correlation of the grade of hepatic steatosis between controlled attenuation parameter and ultrasound in patients with fatty liver: a multi-center retrospective cohort study

BACKGROUND/AIMS

The controlled attenuation parameter (CAP), based on transient elastography, is widely used for noninvasive assessment of the degree of hepatic steatosis (HS). We investigated the correlation of the degree HS between CAP and ultrasound (US) in patients with HS.

METHODS

In total, 986 patients with US-based HS who underwent transient elastography within 1 month were evaluated. The US-based grade of HS was categorized as mild (grade 1), moderate (grade 2), or severe (grade 3).

RESULTS

The CAP was significantly correlated with the US-based grade of HS (r = 0.458, p < 0.001). The median CAP value of each US-based HS grade showed a positive correlation with grade (271.1, 303.7, and 326.7 dB/m for grades 1, 2, and 3). In a multivariate analysis, the US-based HS grade, body mass index, serum albumin, alanine aminotransferase, and total cholesterol, and liver stiffness were all significantly correlated with the CAP value (all p < 0.05). The areas under the receiver operating characteristic curves for grade 2 to 3 and grade 3 HS were 0.749 (95% confidence interval [CI], 0.714 to 0.784) and 0.738 (95% CI, 0.704 to 0.772). The optimal cut-off CAP values to maximize the sum of the sensitivity and specificity for grade 2 to 3 and grade 3 HS were 284.5 dB/m (sensitivity 78.6%, specificity 61.7%) and 298.5 dB/m (sensitivity 84.6%, specificity 55.6%).

CONCLUSION

The correlation of the degree of HS between CAP and US was significantly high in patients with HS, and the optimal cut-off CAP values for grade 2 to 3 and grade 3 HS were 284.5 and 298.5 dB/m.

Diagnostic Performance of Ultrasound Elastography and Serologic Fibrosis Indices for Evaluation of Hepatic Involvement in Wilson Disease

OBJECTIVES

To investigate the diagnostic value of transient elastography (TE), 2-dimensional (2D) shear wave elastography (SWE), and the serologic fibrosis indices aspartate transaminase-to-platelet ratio index (APRI) and Fibrosis-4 (FIB-4) score for Wilson disease (WD).

METHODS

We retrospectively identified patients with a diagnosis of WD who underwent TE and 2D SWE on the same day. Their APRI and FIB-4 scores were calculated. Hepatic involvement was classified into 5 clinical categories (I-V) based on the laboratory findings, hepatic morphologic characteristics on ultrasound (US) imaging, and clinical symptoms of cirrhosis: I, normal (n = 17); II, only biochemical abnormality (n = 15); III, altered hepatic morphologic characteristics (n = 10); IV, compensated liver cirrhosis (n = 3); and V, decompensated liver cirrhosis (n = 0). We compared the area under the receiver operating characteristic curve (AUROC) data for TE, 2D SWE, the APRI, and the FIB-4 score. A combined assessment of the serologic markers and US elastography was performed, and the AUROCs of the combinations were compared.

RESULTS

Forty-five patients were included in the study (median age, 16.0 years; range, 3-35 years). Transient elastography, 2D SWE, and APRI were comparable in distinguishing the clinical categories (AUROC, 0.799-0.928). The FIB-4 score showed lower diagnostic value in distinguishing clinical category I from the other categories (AUROC, 0.647). Combining the serologic markers and US elastography significantly increased the AUROC value of the FIB-4 score (with TE and 2D SWE, P = .01 and .02).

CONCLUSIONS

Transient elastography and 2D SWE showed excellent diagnostic accuracy for differentiating the clinical categories of hepatic involvement. The APRI showed better diagnostic performance than the FIB-4 score. The assessment of hepatic manifestations in WD can be improved by combining US elastography with serologic indices.

Prognosis of Untreated Minimally Active Chronic Hepatitis B Patients in Comparison With Virological Responders by Antivirals

Serum hepatitis B virus (HBV)-DNA > 2,000 IU/mL is associated with higher risk of disease progression. However, without hepatocellular carcinoma (HCC) or cirrhosis, nucleos(t)ide analogs (NUCs) are recommended only for patients with elevated serum HBV-DNA and alanine aminotransferase ≥2 × upper normal limit.

Two-Dimensional-Shear Wave Elastography with a Propagation Map: Prospective Evaluation of Liver Fibrosis Using Histopathology as the Reference Standard

Objective

The aim of this study was to prospectively evaluate whether liver stiffness (LS) assessments, obtained by two-dimensional (2D)-shear wave elastography (SWE) with a propagation map, can evaluate liver fibrosis stage using histopathology as the reference standard.

Materials and Methods

We prospectively enrolled 123 patients who had undergone percutaneous liver biopsy from two tertiary referral hospitals. All patients underwent 2D-SWE examination prior to biopsy, and LS values (kilopascal [kPa]) were obtained. On histopathologic examination, fibrosis stage (F0–F4) and necroinflammatory activity grade (A0–A4) were assessed. Multivariate linear regression analysis was performed to determine the significant factors affecting the LS value. The diagnostic performance of the LS value for staging fibrosis was assessed using receiver operating characteristic (ROC) analysis, and the optimal cut-off value was determined by the Youden index.

Results

Reliable measurements of LS values were obtained in 114 patients (92.7%, 114/123). LS values obtained from 2D-SWE with the propagation map positively correlated with the progression of liver fibrosis reported from histopathology (p < 0.001). According to the multivariate linear regression analysis, fibrosis stage was the only factor significantly associated with LS (p < 0.001). The area under the ROC curve of LS from 2D-SWE with the propagation map was 0.773, 0.865, 0.946, and 0.950 for detecting F ≥ 1, F ≥ 2, F ≥ 3, and F = 4, respectively. The optimal cut-off LS values were 5.4, 7.8, 9.4, and 12.2 kPa for F ≥ 1, F ≥ 2, F ≥ 3, and F = 4, respectively. The corresponding sensitivity and specificity of the LS value for detecting cirrhosis were 90.9% and 88.4%, respectively.

Conclusion

The LS value obtained from 2D-SWE with a propagation map provides excellent diagnostic performance in evaluating liver fibrosis stage, determined by histopathology.

Mechanical properties of human glioma

Brain gliomas represent some of the most aggressive tumors encountered by modern medicine and, despite major efforts to optimize early diagnosis and treatment, the prognosis remains poor. Due to the complex structure of the brain and the unique mechanical properties of the extracellular matrix, gliomas invade and expand into the brain parenchyma, along white matter tracts and within perivascular spaces, usually sparing normal vessels. Different methods have been developed to study the mechanical properties of gliomas in a wide range of scales, from cells and the microscale to tissues and the macroscale. In this review, the current view on glioma mechanics is presented and the methods used to determine glioma mechanical properties are outlined. Their principles and current state of affairs are discussed.

Imaging in Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome

Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life-threatening complication of hematopoietic cell transplantation. Early diagnosis and, subsequently, earlier intervention have been shown to be beneficial to clinical outcomes. Diagnostic criteria from the European Society for Blood and Marrow Transplantation include recommendations on the use of imaging for diagnosis. This review discusses evidence on the use of imaging in the management of VOD/SOS and how imaging biomarkers can contribute to earlier diagnosis/treatment.

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.

Test-retest repeatability of ultrasonographic shear wave elastography in a rat liver fibrosis model: toward a quantitative biomarker for preclinical trials

PURPOSE

This study evaluated the test-retest repeatability and measurement variability of ultrasonographic shear wave elastography (SWE) for liver stiffness in a rat liver fibrosis model.

METHODS

In 31 Sprague-Dawley rats divided into three groups (high-dose, low-dose, and control), liver fibrosis was induced by intraperitoneal administration of thioacetamide for 8 weeks. A dedicated radiographer performed SWE to measure liver stiffness in kilopascals in two sessions at a 3-day interval. We calculated correlations between liver stiffness and histopathologic results, measurement variability in each session using coefficients of variation (CoVs) and interquartile/median (IQR/M), and test-retest repeatability between both sessions using the repeatability coefficient.

RESULTS

Different levels of liver fibrosis in each group were successfully induced in the animal model. The mean liver stiffness values were 8.88±1.48 kPa in the control group, 11.62±1.70 kPa in the low-dose group, and 11.91±1.73 kPa in the high-dose group. The correlation between collagen areas and liver stiffness values was moderate (r=0.6). In all groups, the second session yielded lower CoVs (i.e., more reliable results) for liver stiffness than the first session, suggesting a training effect for the operator. The mean IQR/M values were also lower in the second session than in the first session, which had four outliers (0.21 vs. 0.12, P<0.001). The test-retest repeatability coefficient was 3.75 kPa and decreased to 2.82 kPa after removing the four outliers.

CONCLUSION

The use of ultrasonographic SWE was confirmed to be feasible and repeatable for evaluating liver fibrosis in preclinical trials. Operator training might reduce variability in liver stiffness measurements.

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.

Comparison of 2-Dimensional Shear Wave Elastographic Measurements Using ElastQ Imaging and SuperSonic Shear Imaging: Phantom Study and Clinical Pilot Study

OBJECTIVES

To compare the feasibility and clinical applicability of ElastQ imaging (Philips Healthcare, Best, the Netherlands) with that of SuperSonic shear imaging (SSI; SuperSonic Imagine, Aix-en-Provence, France) using an elastographic phantom and a pilot study of patients.

METHODS

Two-dimensional shear wave elastography measurement was performed by ElastQ imaging and SSI by 2 radiologists. An elastographic phantom with 5 target elasticities at 2 acquisition depths was used. The coefficients of variation and intraclass correlation coefficients (ICCs) were evaluated for repeatability and interobserver agreement, respectively. The mean elasticities of the systems at each target were compared. The proportions of measurements that were out of the range of expected values and measurement errors were calculated to determine accuracy. Liver stiffness (LS) was measured by both systems in 27 children and young adult patients with various liver diseases.

RESULTS

Both systems provided high repeatability in elasticity measurements of phantom targets (coefficients of variation, 0.69%-15.82%), and there was excellent interobserver agreement (ICC, 0.992). Most (90%) mean elasticities of targets were significantly different between the techniques (P ≤ .002) and acquisition depths (P ≤ .004). ElastQ imaging had significantly lower proportions of out-of-range measurements and measurement errors (P ≤ .003) than SSI. In patients with liver disease, LS measurements of the systems were strongly correlated (ρ = 0.955; P < .001) and had excellent agreement (ICC, 0.951; P < .001).

CONCLUSIONS

ElastQ imaging had comparably good results in terms of repeatability, interobserver agreement, and accuracy in the phantom model compared with SSI. The pilot patient study showed strong correlations in LS values between the systems.

Intraoperative Ultrasonographic Elastography: A Semi-Quantitative Analysis of Brain Tumor Elasticity Patterns and Peritumoral Region

BACKGROUND

Ultrasonographic elastography imaging visualizes the elastic properties of tissues to distinguish pathologic and healthy areas. Real-time elastography measures relative tissue hardness by evaluating changes in local strain in response to external forces.

OBJECTIVE

We aimed to determine the elastographic patterns of different brain tumor types and establish differences between their peritumoral regions.

METHODS

We prospectively enrolled patients undergoing craniotomy along with intraoperative ultrasonographic elastography for supratentorial brain tumors in March 2018-May 2019. The elastograms were semi-quantitatively analyzed offline based on the mean tissue elasticity of the tumors, peritumoral regions, and healthy parenchyma.

RESULTS

We examined 37 lesions in 36 patients. The pathologic diagnoses comprised 11 meningiomas (29.7%), 4 low-grade gliomas (LGGs; 10.8%), 16 high-grade gliomas (HGGs; 43.2%), and 6 metastases (16.2%). The median MTE values observed after manual segmentation of the whole tumor were as follows: meningiomas, 119.9 (36.6); HGGs, 77.9 (18.9); LGGs, 91 (19.5); metastases, 103.9 (35.6); tumor types significantly differed (H = 18.2; P < 0.001). The peritumoral MTE values were as follows: meningiomas, 120.1 (36.3); HGGs, 86.3 (20.9); LGGs, 94.8 (7.38); and metastases, 116.3 (22). The intergroup differences were significant (H = 17.43; P < 0.001). Using receiver operating characteristic curves, we obtained an optimal cutoff point of 92.22 (whole tumors) and 109.6 (peritumoral regions). Values below these cutoff points were correlated with a high probability of being a glioma.

CONCLUSIONS

We objectively describe the elastographic patterns of different types of brain tumors (i.e., gliomas, metastases, and meningiomas). We have identified differences in both the tumors and the peritumoral areas of these histologic types.

Shear-Wave Dispersion Slope from US Shear-Wave Elastography: Detection of Allograft Damage after Liver Transplantation

Background Allograft damage (hepatic parenchymal damage) after liver transplant is associated with the degree of necroinflammation in graft liver. According to a recent animal study, shear-wave dispersion slope obtained at US shear-wave elastography (SWE) is associated with necroinflammatory activity in the liver. Purpose To evaluate the role of shear-wave dispersion slope in detecting allograft damage after liver transplant. Materials and Methods In this prospective study, 104 liver transplant recipients underwent percutaneous liver biopsy for allograft evaluation from December 2017 to November 2018. All participants underwent allograft SWE examination just before liver biopsy, and liver stiffness and shear-wave dispersion slope were obtained. Allograft damage was diagnosed by histopathologic analysis. Clinical and imaging factors related to liver stiffness and shear-wave dispersion slope were determined by multivariable linear regression analysis. Diagnostic performance of each variable in detecting allograft damage was evaluated by comparing area under the receiver operating curve (AUC) values. Results There were 104 study participants (35 women); median age was 56 years (interquartile range, 50-62 years). Allograft damage was found in 46 of 104 (44.2%) of participants. The median liver stiffness (8.2 kPa vs 6.3 kPa; P < .01) and shear-wave dispersion slope (14.4 [m/sec]/kHz vs 10.4 [m/sec]/kHz; P < .01) were higher in participants with allograft damage than in those without damage, respectively. Fibrosis stage was the only determinant factor for liver stiffness (coefficient, 1.8 kPa per fibrosis stage; 95% confidence interval: 0.1, 3.5; P = .03), whereas both fibrosis stage (coefficient, 1.4 [m/sec]/kHz per fibrosis stage; 95% confidence interval: 0.3, 2.6; P = .02) and necroinflammatory activity (coefficient, 1.6 [m/sec]/kHz per necroinflammatory activity grade; 95% confidence interval: 0.5, 2.7; P < .01) affected shear-wave dispersion slope. The AUC for shear-wave dispersion slope in detecting allograft damage was 0.86, which was higher than that of liver stiffness (AUC, 0.75; P < .01). Conclusion Shear-wave dispersion slope determined at US shear-wave elastography may help in detecting allograft damage after liver transplant. © RSNA, 2019 Online supplemental material is available for this article.

Accuracy and precision of ultrasound shear wave elasticity measurements according to target elasticity and acquisition depth: A phantom study

OBJECTIVE

To investigate the accuracy and precision of ultrasound shear wave elasticity measurements as a function of target elasticity and acquisition depth.

MATERIALS AND METHODS

Using five ultrasound systems (VTQ, VTIQ, EPIQ 5, Aixplorer, and Aplio 500), two operators independently measured shear wave elasticities in two phantoms containing five different target elasticities (8±3, 14±4, 25±6, 45±8, and 80±12 kPa) at depths of 15, 30, 35, and 60 mm. Accuracy was assessed by evaluating measurement errors and the proportions of outliers, while factors affecting accuracy were assessed using logistic regression analysis. Measurement errors were defined as differences between the measured values and 1) the margins of the target elasticity, and 2) the median values of the target elasticity. Outliers were defined as measured values outside the margins of the target elasticity. Precision was assessed by calculating the reproducibility of measurements using the within-subject coefficient of variation (wCV).

RESULTS

Mean measurement errors and the proportions of outliers were higher for high than for low target elasticities (p<0.001), but did not differ in relation to acquisition depth, either within an elastography system or across the different systems. Logistic regression analysis showed that target elasticity (p<0.001) significantly affected accuracy, whereas acquisition depth (p>0.05) did not. The wCV for the 80±12 kPa target (31.33%) was significantly higher than that for lower elasticity targets (6.96-10.43 kPa; p<0.001). The wCV did not differ across acquisition depths. The individual elastography systems showed consistent results.

CONCLUSIONS

Targets with high elasticity showed lower accuracy and lower precision than targets with low elasticity, while acquisition depth did not show consistent patterns in either accuracy or precision.

Addition of Reliability Measurement Index to Point Shear Wave Elastography: Prospective Validation via Diagnostic Performance and Reproducibility

The clinical value of the reliability measurement index (RMI), newly added to point shear wave elastography (pSWE), was investigated. Forty-nine patients underwent both pSWE providing RMI (range: 0.0-1.0) and transient elastography (TE) before hepatic surgery. Interclass correlation coefficients (ICCs) between the median of the first two to nine measurements (as categorized by RMI values ≥0.0 (liver stiffness-reliability measurement index [LS-RMI] 0.0), ≥0.4 (LS-RMI 0.4) and ≥0.7 (LS-RMI 0.7) and the median of 10 consecutive measurements (LS-REF) were obtained. Compared with LS-REF, minimums of 7 LS-RMI 0.0, 5 LS-RMI 0.4 and 3 LS-RMI 0.7 measurements were required to obtain an ICC ≥0.95 with high inter-observer agreement (ICC ≥0.90). Diagnostic performance did not differ (p values >0.05) using these reduced numbers of LS measurements. Significant correlations were found between the reduced number of LS measurements and TE or METAVIR (p values <0.001). Therefore, RMI helped to improve reliability and reduce the number of LS measurements while maintaining the diagnostic performance of pSWE.

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.

Diagnostic Performance of Ultrasound Elastography for Evaluating Portal Hypertension in Children: A Systematic Review and Meta-analysis

OBJECTIVES

To assess the diagnostic performance of ultrasound (US) elastography in evaluating portal hypertension in children and compare the liver and spleen stiffness values between the portal hypertension and control groups.

METHODS

Studies in the MEDLINE and Embase databases were selected that investigated the diagnostic performance of US elastography in children with portal hypertension up to December 21, 2017. Pooled sensitivity and specificity data were assessed by hierarchical logistic regression modeling.

RESULTS

Eleven studies were included in the systematic review, and a meta-analysis could be conducted in 7 of these publications to evaluate the diagnostic performance of US elastography. The summary sensitivity and specificity of this method for liver stiffness were 90% (95% confidence interval [CI], 83%-94%) and 79% (95% CI, 73%-84%), respectively, and the area under the hierarchical summary receiver operating characteristic curve was 0.92 (95% CI, 0.90-0.94). A subgroup analysis of 5 transient elastographic studies revealed similar diagnostic performance (sensitivity, 90%; specificity, 78%). In 10 of the 11 studies that investigated liver stiffness and 2 of the 3 studies that also measured spleen stiffness, patients in the portal hypertension group had a significantly higher stiffness value than the control group (P < .05).

CONCLUSIONS

Ultrasound elastography shows good performance in diagnosing portal hypertension and can identify significant differences in liver and spleen stiffness in children with this condition. This method thus has considerable potential as a noninvasive tool for screening portal hypertension-related complications in children with chronic liver disease.

Comparison between chronic hepatitis B patients with untreated immune-tolerant phase vs. those with virological response by antivirals

Routine nucleos(t)ide analogs (NUCs) have not yet been recommended for patients with immune-tolerant (IT) phase in chronic hepatitis B virus (HBV) infection. We aimed to evaluate prognosis of patients in untreated IT-phase (UIT group), compared to those in immune-active phase who achieved virological response by NUCs according to guidelines (VR group). Between 2006 and 2012, patients in UIT or VR groups were included. Cumulative risks of HCC and liver-related events (LREs) development were assessed. Furthermore, propensity-score was calculated based upon age, gender, diabetes and liver stiffness. UIT group (n = 126) showed younger age, lower proportion of male gender and lower LS than VR group (n = 641). UIT group had similar 10-year cumulative risks of HCC (2.7% vs. 2.9%, p = 0.704) and LRE (4.6% vs. 6.1%, p = 0.903) development, compared to VR group. When we re-defined UIT group by the lower ALT cut-offs, 10-year cumulative risks of HCC and LRE development were 2.9% and 4.8%, respectively. Using propensity-score matching and inverse probability treatment weighting analysis, similar results were reproduced. UIT group consistently had similar prognosis compared to VR group. Therefore, further large-scale prospective studies in order to verify rationales of routine NUCs in UIT group are still required.

Technical performance of shear wave elastography for measuring liver stiffness in pediatric and adolescent patients: a systematic review and meta-analysis

OBJECTIVE

To assess the technical performance (proportion of technical failure and unreliable measurements) of shear wave elastography (SWE) for assessing liver stiffness in pediatric and adolescent patients.

METHODS

We searched Ovid-MEDLINE and EMBASE databases for eligible studies and selected original articles investigating transient elastography (TE), point shear wave elastography (pSWE), or two-dimensional SWE (2D-SWE) for measuring liver stiffness in pediatric and adolescent patients. A quantitative synthesis of studies reporting technical failures and/or unreliable measurements of TE, pSWE, or 2D-SWE is presented. Meta-analytic pooling was conducted using the random effects model. Meta-regression analysis was conducted to explore potential causes of heterogeneity.

RESULTS

Forty of 69 studies (58%) provided technical performance information. Technical failure data were reported in 3 TE, 6 pSWE, and 8 2D-SWE studies. Unreliable measurement data were provided in 21 TE, 4 pSWE, and 1 2D-SWE study. The pooled proportion of unreliable measurements of TE was 12.1%. Meta-regression analysis showed that the study population size and readers' blinding to pathologic results affected the study's heterogeneity. The pooled proportions of technical failure during pSWE and 2D-SWE were 4.1% and 2.2%, respectively, demonstrating no significant difference between the techniques.

CONCLUSIONS

We reviewed the technical performance of SWE, especially the rate of unreliable measurements from TE studies and rates of technical failure from pSWE and 2D-SWE studies. Considering the importance of technical performance for clinical validation of SWE, numbers of and reasons for technical failure and unreliable measurements should be reported in future studies. Further efforts are necessary to standardize SWE reliability criteria.

KEY POINTS

• Most TE studies reported rate of unreliable measurements, whereas pSWE and 2D-SWE studies were likely to report rates of technical failure. • The pooled proportion of unreliable measurements of TE was 12.1%. • The pooled proportions of technical failure during pSWE and 2D-SWE were 4.1% and 2.2%, respectively, demonstrating no significant difference between the techniques.

Combination of Transient Elastography and an Enhanced Liver Fibrosis Test to Assess the Degree of Liver Fibrosis in Patients with Chronic Hepatitis B

Background/Aims

Liver stiffness (LS) was assessed using transient elastography, and the enhanced liver fibrosis (ELF) test was performed to accurately assess fibrotic burden. We validated the LS-ELF algorithm and investigated whether the sequential LS-ELF algorithm performs better than concurrent combination of these analyses in chronic hepatitis B (CHB) patients.

Methods

Between 2009 and 2013, 222 CHB patients who underwent liver biopsy (LB), as well as LS measurement and the ELF test, were enrolled.

Results

Advanced fibrosis (≥F3) and cirrhosis (F4) were identified in 141 (63.6%) and 118 (53.2%) patients, respectively. Areas under receiver operating characteristic curve for LS predictions of ≥F3 (0.887 vs 0.703) and F4 (0.853 vs 0.706) were significantly higher than the ELF test (all p＜0.001). Based on the LS-ELF algorithm, 60.4% to 71.6% and 55.7% to 66.3% of patients could have avoided LB to exclude ≥F3 and F4, respectively, whereas 68.0% to 78.7% and 63.5% to 66.1% of patients could have avoided LB to confirm ≥F3 and F4, respectively. When confirmation and exclusion strategies were applied simultaneously, 69.4% to 72.5% and 60.8% to 65.3% of patients could have avoided LB and been diagnosed as ≥F3 and F4, respectively. The proportion of patients who correctly avoided LB for the prediction of ≥F3 (69.4% to 72.5% vs 42.3% to 59.0%) and F4 (60.8% to 65.3% vs 23.9% to 49.5%) based on the sequential LS-ELF algorithm was significantly higher than the concurrent combination (all p＜0.05).

Conclusions

The sequential LS-ELF algorithm conferred a greater probability of avoiding LB in CHB patients to diagnose advanced fibrosis and cirrhosis, and this test performed significantly better than the concurrent combination.

Shear Wave Elastography as a Quantitative Biomarker of Clinically Significant Portal Hypertension: A Systematic Review and Meta-Analysis

OBJECTIVE

To qualify shear wave elastography (SWE) as a biomarker for clinically significant portal hypertension (CSPH) beyond proof of concept, we aimed to accumulate and summarize the current evidence through systematic review and meta-analysis.

MATERIALS AND METHODS

A computerized literature search was performed to identify studies from MEDLINE and EMBASE up to February 9, 2017. Studies on the diagnostic performance of liver stiffness measurements using SWE for CSPH with hepatic venous pressure gradient (HVPG) as the reference standard were included. Various aspects of SWE were comprehensively assessed. The summary diagnostic performance of SWE for the diagnosis of CSPH and the summary correlation coefficient between liver stiffness measured using SWE and HVPG were evaluated through a meta-analysis.

RESULTS

Nine articles (including 746 patients) were retrieved. The diagnostic performance of SWE for the diagnosis of CSPH was fairly good, with a summary sensitivity of 85% (95% CI, 75-91%; I² = 78.56%) and summary specificity of 85% (95% CI, 77-90%; I² = 0%); the area under the ROC curve was 0.88 (95% CI, 0.85-0.91). The summary correlation coefficient between liver stiffness and HVPG measurements was 0.741 (95% CI, 0.658-0.825; I² = 0%). These results support the value of SWE as a diagnostic biomarker for CSPH. However, there was significant heterogeneity in the imaging devices, protocols, liver stiffness measurement methods, and cutoff values used, which suggests that standardization is required.

CONCLUSION

The consistent evidence favoring SWE as a biomarker for CSPH should be considered in the biomarker qualification process and management of patients with CSPH.

Reduced risk of hepatocellular carcinoma by achieving a subcirrhotic liver stiffness through antiviral agents in hepatitis B virus-related advanced fibrosis or cirrhosis

BACKGROUND AND AIM

A subcirrhotic range of liver stiffness (sc-LS), assessed by transient elastography, is associated with better outcomes in patients with chronic hepatitis B (CHB). We investigated whether the achievement of sc-LS by antiviral therapy (AVT) reduced the risk of developing hepatocellular carcinoma (HCC) in patients with CHB-related advanced fibrosis or cirrhosis.

METHODS

In total, 209 patients with CHB-related advanced fibrosis or cirrhosis, who received paired transient elastography examinations during AVT between 2007 and 2012, were enrolled. The cut-off LS value for ultrasonographic cirrhosis was defined as 11.6 kPa.

RESULTS

The median age of the study population was 51 years, with males predominating (n = 138, 66.0%). The median LS value at enrollment was 14.1 kPa (interquartile range: 9.5-24.1 kPa). After 2 years of AVT, 140 (67.0%) patients achieved sc-LS. During the study period, 28 (13.4%) patients developed HCC after 2 years of AVT. On multivariate analysis, the achievement of sc-LS after AVT was independently associated with a decreased risk of HCC development (hazard ratio [HR] = 0.485, P = 0.047), whereas older age (HR = 1.071) and male gender (HR = 3.704) were independently associated with an increased HCC risk (both P < 0.05). Patients with a cirrhotic range of LS value after 2 years of AVT were at a higher risk of HCC development than those with sc-LS (log-rank test, P = 0.020).

CONCLUSIONS

The achievement of sc-LS after AVT can reduce the risk of HCC development in patients with CHB, even when advanced fibrosis or cirrhosis is apparent on starting AVT.

Real-time two-dimensional Shear-wave elastography for liver stiffness in children: Interobserver variation and effect of breathing technique

OBJECTIVES

To evaluate interobserver variation and to assess the effect of the breathing technique on liver stiffness (LS) measurement using real-time two-dimensional shear-wave elastography (2D-SWE) in children.

METHODS

Patients who underwent real-time 2D-SWE by two operators (group 1) and patients who underwent real-time 2D-SWE by one operator using the free-breathing and breath-holding techniques (group 2) were included. In group 1, interobserver agreement was assessed using the intraclass correlation coefficient (ICC) and the 95% limits-of-agreement was analyzed to evaluate the maximum change in the LS values based on Bland-Altman analysis. In group 2, the Bland-Altman plot and the paired t-test were used to determine the effect of breathing technique on LS measurement.

RESULTS

The interobserver agreement of the LS measurement in group 1 (n=63) was excellent (ICC, 0.953), and the 95% limits-of-agreement was 31.8% of the mean LS values. In group 2 (n=45), the free-breathing technique revealed systematically lower LS with a mean difference of -11.1% of the mean LS values, compared to the breath-holding technique (P=0.016).

CONCLUSION

LS measurement assessed by real-time 2D-SWE in children showed excellent interobserver agreement. Changes in LS values less than 31.8% of the mean LS values may represent the measurement error. The free-breathing technique showed lower LS values, compared to the breath-holding technique.

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.

Shear-Wave Elastography for Detection of Prostate Cancer: A Systematic Review and Diagnostic Meta-Analysis

OBJECTIVE

The objective of this study is to review the diagnostic performance of shear-wave elastography (SWE) in the detection of prostate cancer (PCa).

MATERIALS AND METHODS

The MEDLINE, EMBASE, and Cochrane library databases were searched up to December 23, 2016. We included diagnostic accuracy studies that used SWE for PCa detection with prostatectomy or biopsy used as the reference standard. The methodologic quality of the studies was evaluated by two independent reviewers using the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. The sensitivity and specificity of all studies were calculated. Results were pooled and plotted in a hierarchical summary ROC plot with further exploration done using meta-regression analysis and subgroup analysis.

RESULTS

Eight studies (a total of 1028 patients) were evaluated. The pooled sensitivity was 0.83 (95% CI, 0.66-0.92) with a specificity of 0.85 (95% CI, 0.78-0.90) for the detection of PCa. Study design (prospective vs retrospective) was the only significant factor affecting heterogeneity (p < 0.01). At subgroup analysis, the pooled sensitivity and specificity were 0.84 (95% CI, 0.64-0.94) and 0.84 (95% CI, 0.76-0.90), respectively, in studies using shear-wave speed imaging and 0.84 (95% CI, 0.64-0.94) and 0.86 (95% CI, 0.78-0.91), respectively, in studies based on per-lesion analysis.

CONCLUSION

SWE shows good performance for the detection of PCa. However, specific recommendations regarding cutoff value cannot be made because of study heterogeneity.

Liver Stiffness Measured by Shear-wave Elastography for Evaluating Intrahepatic Portal Hypertension in Children

OBJECTIVES

The aim of the study was to correlate liver stiffness (LS) and hepatic venous-pressure gradient (HVPG) and to evaluate the diagnostic performance of shear-wave elastography (SWE) for predicting clinically significant portal hypertension in children with suspected liver diseases, in consideration of the reliability criteria.

METHODS

We identified 33 SWEs from 32 children who underwent HVPG measurement within 2 weeks between June 2012 and October 2015. The correlation between LS and HVPG was assessed. The diagnostic performance for predicting clinically significant portal hypertension (HVPG ≥ 10 mmHg) was assessed using the receiver-operating characteristic curve. Reliable measurement was evaluated based on the coefficient of variation (CV).

RESULTS

LS was significantly correlated with HVPG (r = 0.742, P < 0.001). The area under the receiver-operating characteristic curve for predicting clinically significant portal hypertension was 0.914, and the best cutoff value of 18.4 kPa showed sensitivity of 87.5% and specificity of 84.0%. LS measurements having CV ≤ 0.2 were significantly correlated with HVPG (r = 0.774, P < .001), whereas those having CV > 0.2 did not show a significant correlation with HVPG (r = 0.598, P = 0.089).

CONCLUSIONS

SWE had excellent diagnostic performance for predicting clinically significant portal hypertension in children with suspected liver diseases. LS measurements having CV ≤ 0.2 may possibly be used as a reliability criterion in SWE measurement.