Diagnostic effect of shear wave elastography imaging for differentiation of malignant liver lesions: a meta-analysis

Ultrasound tissue scatterer distribution imaging: An adjunctive diagnostic tool for shear wave elastography in characterizing focal liver lesions

OBJECTIVES

Focal liver lesion (FLL) is a prevalent finding in cross-sectional imaging, and distinguishing between benign and malignant FLLs is crucial for liver health management. While shear wave elastography (SWE) serves as a conventional quantitative ultrasound tool for evaluating FLLs, ultrasound tissue scatterer distribution imaging (TSI) emerges as a novel technique, employing the Nakagami statistical distribution parameter to estimate backscattered statistics for tissue characterization. In this prospective study, we explored the potential of TSI in characterizing FLLs and evaluated its diagnostic efficacy with that of SWE.

METHODS

A total of 235 participants (265 FLLs; the study group) were enrolled to undergo abdominal examinations, which included data acquisition from B-mode, SWE, and raw radiofrequency data for TSI construction. The area under the receiver operating characteristic curve (AUROC) was used to evaluate performance. A dataset of 20 patients (20 FLLs; the validation group) was additionally acquired to further evaluate the efficacy of the TSI cutoff value in FLL characterization.

RESULTS

In the study group, our findings revealed that while SWE achieved a success rate of 49.43 % in FLL measurements, TSI boasted a success rate of 100 %. In cases where SWE was effectively implemented, the AUROCs for characterizing FLLs using SWE and TSI stood at 0.84 and 0.83, respectively. For instances where SWE imaging failed, TSI achieved an AUROC of 0.78. Considering all cases, TSI presented an overall AUROC of 0.81. There was no statistically significant difference in AUROC values between TSI and SWE (p > 0.05). In the validation group, using a TSI cutoff value of 0.67, the AUROC for characterizing FLLs was 0.80.

CONCLUSIONS

In conclusion, ultrasound TSI holds promise as a supplementary diagnostic tool to SWE for characterizing FLLs.

The Clinical Value of Multimodal Ultrasound for the Differential Diagnosis of Hepatocellular Carcinoma from Other Liver Tumors in Relation to Histopathology

Recent advances in the field of ultrasonography offer promising tools for the evaluation of liver tumors. We aim to assess the value of multimodal ultrasound in differentiating hepatocellular carcinomas (HCCs) from other liver lesions. We prospectively included 66 patients with 72 liver tumors. The histological analysis was the reference standard for the diagnosis of malignant liver lesions, and partially for benign tumors. All liver lesions were assessed by multiparametric ultrasound: standard ultrasound, contrast-enhanced ultrasound (CEUS), the point shear wave elastography (pSWE) using shear wave measurement (SWM) method and real-time tissue elastography (RTE). To diagnose HCCs, CEUS achieved a sensitivity, specificity, accuracy and positive predictive value (PPV) of 69.05%, 92.86%, 78.57% and 93.55%, respectively. The mean shear-wave velocity (Vs) value in HCCs was 1.59 ± 0.29 m/s, which was lower than non-HCC malignancies (p < 0.05). Using a cut-off value of 1.58 m/s, SWM achieved a sensitivity of 54.76%, and 82.35% specificity, for differentiating HCCs from other malignant lesions. The combination of SWM and CEUS showed higher sensitivity (79.55%) compared with each technique alone, while maintaining a high specificity (89.29%). In RTE, most HCCs (61.53%) had a mosaic pattern with dominant blue areas corresponding to type "c" elasticity. Elasticity type "c" was 70.59% predictive for HCCs. In conclusion, combining B-mode ultrasound, CEUS, pSWE and RTE can provide complementary diagnostic information and potentially decrease the requirements for other imaging modalities.

Primary hepatic epithelioid hemangioendothelioma masquerading as metastases: A rare case report

Epithelioid hemangioendothelioma (EHE) of the liver is an extremely rare malignant tumor of vascular origin, representing less than 1 % of all vascular tumors. Nearly 260 cases have been reported in English literature. Radiologically it is seen as multifocal lesions. It can be seen at different sites like lungs, bones, lymph nodes, breasts, and soft tissue. Often it is misdiagnosed with metastases, cholangiocarcinoma, or angiosarcoma. No definite treatment protocol is available due to its rarity, however, these malignancies are treated by radical resection of the tumor or liver transplant and/or chemotherapy. Here we present a primary hepatic epithelioid hemangioendothelioma (HEHE) which was mimicking metastases in a 42-year-old male who was treated with chemotherapy and radiotherapy. Sadly the patient expired after 1 year of complete course of treatment. Imaging features can help to improve the diagnostic accuracy of this tumor.

Shear wave elastography as a quantitative biomarker of diabetic peripheral neuropathy: A systematic review and meta-analysis

Background

Diabetic peripheral neuropathy (DPN) is one of the most common chronic complications of diabetes and the strongest initiating risk factor for diabetic foot ulceration. Early diagnosis of DPN through screening measures is, therefore, of great importance for diabetic patients. Recently, shear wave elastography (SWE) has been used as a method that is complementary to neuroelectrophysiological examination in the diagnosis of DPN. We aimed to conduct a meta-analysis based on currently available data to evaluate the performance of tibial nerve stiffness on SWE for diagnosing DPN.

Methods

Both PubMed, EMBASE, the Cochrane Library, and Web of Science were searched for studies that investigated the diagnostic performance of SWE for DPN up to March 1th, 2022. Three measures of diagnostic test performance, including the summary area under receiver operating characteristics curve (AUROC), the summary sensitivity and specificity, and the summary diagnostic odds ratios were used to assess the diagnostic accuracy of SWE. All included studies were published between 2017 and 2021.

Results

Six eligible studies (with 170 DPN patients, 28 clinically defined DPN patients, 168 non-DPN patients, and 154 control participants) that evaluated tibial nerve stiffness were included for meta-analysis. The summary sensitivity and specificity of SWE for tibial nerve stiffness were 75% (95% confidence interval [CI]: 68–80%) and 86% (95% CI: 80–90%), respectively, and the summary AUROC was 0.84 (95% CI: 0.81–0.87), for diagnosing DPN. A subgroup analysis of five two-dimensional SWE studies revealed similar diagnostic performance, showing the summary sensitivity and specificity of 77% (95% CI: 69–83%) and 86% (95% CI: 79–91%), respectively, and a summary AUROC value of 0.86 (95% CI: 0.83–0.89).

Conclusions

SWE is found to have good diagnostic accuracy for detecting DPN and has considerable potential as an important and noninvasive adjunctive tool in the management of patients with DPN.

Development of a Robotic Shear Wave Elastography System for Noninvasive Staging of Liver Disease in Murine Models

Shear wave elastography (SWE) is an ultrasound-based stiffness quantification technology that is used for noninvasive liver fibrosis assessment. However, despite widescale clinical adoption, SWE is largely unused by preclinical researchers and drug developers for studies of liver disease progression in small animal models due to significant experimental, technical, and reproducibility challenges. Therefore, the aim of this work was to develop a tool designed specifically for assessing liver stiffness and echogenicity in small animals to better enable longitudinal preclinical studies. A high-frequency linear array transducer (12-24 MHz) was integrated into a robotic small animal ultrasound system (Vega; SonoVol, Inc., Durham, NC) to perform liver stiffness and echogenicity measurements in three dimensions. The instrument was validated with tissue-mimicking phantoms and a mouse model of nonalcoholic steatohepatitis. Female C57BL/6J mice (n = 40) were placed on choline-deficient, L-amino acid-defined, high-fat diet and imaged longitudinally for 15 weeks. A subset was sacrificed after each imaging timepoint (n = 5) for histological validation, and analyses of receiver operating characteristic (ROC) curves were performed. Results demonstrated that robotic measurements of echogenicity and stiffness were most strongly correlated with macrovesicular steatosis (R²  = 0.891) and fibrosis (R²  = 0.839), respectively. For diagnostic classification of fibrosis (Ishak score), areas under ROC (AUROCs) curves were 0.969 for ≥Ishak1, 0.984 for ≥Ishak2, 0.980 for ≥Ishak3, and 0.969 for ≥Ishak4. For classification of macrovesicular steatosis (S-score), AUROCs were 1.00 for ≥S2 and 0.997 for ≥S3. Average scanning and analysis time was <5 minutes/liver. Conclusion: Robotic SWE in small animals is feasible and sensitive to small changes in liver disease state, facilitating in vivo staging of rodent liver disease with minimal sonographic expertise.

Accuracy of ultrasound elastography for predicting breast cancer response to neoadjuvant chemotherapy: A systematic review and meta-analysis

BACKGROUND

Several studies have reported the prognostic value of ultrasound elastography (UE) in patients receiving neoadjuvant chemotherapy (NACT) for breast cancer. However, the assessment of parameters differed between shear-wave elastography and strain elastography in terms of measured elasticity parameter and mode of imaging. It is important, therefore, to assess the accuracy of the two modes of elastography.

AIM

To assess the accuracy of UE for predicting the pathologic complete response (pCR) in breast cancer patients following NACT.

METHODS

A comprehensive and systematic search was performed in the databases of MEDLINE, EMBASE, SCOPUS, PubMed Central, CINAHL, Web of Science and Cochrane library from inception until December 2020. Meta-analysis was performed using STATA software “Midas” package.

RESULTS

A total of 14 studies with 989 patients were included. The pooled sensitivities were 86% [95% confidence interval (CI): 76%-92%] for UE, 77% (95%CI: 68%-84%) for shear-wave elastography, and 92% (95%CI: 73%-98%) for strain-wave elastography. The pooled score specificities were 86% (95%CI: 80%-90%) for UE, 84% (95%CI: 72%-91%) for shear-wave elasticity, and 87% (95%CI: 81%-92%) for strain-wave elastography. A significant heterogeneity was found among studies based on the chi-square test results and an I² statistic > 75%.

CONCLUSION

Strain-wave type of UE can accurately predict the pCR following NACT amongst breast cancer patients. Studies exploring its accuracy in different ethnic populations are required to strengthen the evidence.

Differentiation of benign and malignant superficial soft tissue lesions using real-time strain elastography

Background/aim

To evaluate benign and malignant cutaneous-subcutaneous lesions using real-time strain elastography (RTSE) and to compare the findings with histopathologic results.

Materials and methods

Over a period of 10 months, 72 patients (38 with benign and 34 with malignant cutaneous and subcutaneous lesions) were prospectively included in this study. Elasticity patterns and strain ratios were examined for each lesion. Lesions were evaluated in 4 groups as yellow-red (soft; pattern-1), green-yellow (moderate; pattern-2), blue-green (hard; pattern-3) and blue (hardest; pattern-4). The stiffness of the lesions was displayed with strain ratios by comparing of a nearby reference tissue. The recorded images were compared with histopathologic findings.

Results

On sonoelastograms, considering patterns 1-2 as benign and patterns 3-4 as malignant, the sensitivity, specificity, and positive and negative predictive values for the differentiation of malignant from benign lesions were 100%, 68.5%, 74%, and 100%, respectively. Considering a cut-off value of the strain ratio as > 3.05, the sensitivity, specificity, and positive and negative predictive values were 91%, 89%, 88%, and 92%, respectively. The area under the curve (AUC: 0.972) showed the excellent ability of strain elastography to differentiate benign and malignant lesions.

Conclusion

RTSE is an important imaging tool to differentiate benign and malignant superficial soft tissue lesions. Our results suggest that RTSE can be used to predict malignancy since malignant lesions are more confidentially diagnosed than benign superficial soft tissue lesions on elastograms.

Diagnostic value of shear wave velocity in polycystic ovarian syndrome

Aim: In polycystic ovarian syndrome, the ovaries become stiffer due to chronic anovulation. We aimed to compare tissue elasticity in terms of shear wave velocities measured using acoustic radiation force impulse imaging technique between the ovaries of polycystic ovarian syndrome women and non-polycystic ovarian syndrome women. Material and methods: The study was designed as a retrospective data analysis of women who underwent transvaginal ultrasound and acoustic radiation force impulse imaging in a university hospital between July 2014 and March 2015, for various reasons. There were 32 polycystic ovarian syndrome patients and 32 patients without a diagnosis of polycystic ovarian syndrome. Age, body mass index, fasting glucose levels, cycle day 3 follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, prolactin, antimullerian hormone levels, and menstrual patterns with clinical hyperandrogenism were evaluated. On the menstrual cycle days 2-4, by performing a transvaginal ultrasound scan, the ovarian volumes and antral follicle counts in both ovaries were recorded for each woman. The ultrasound system was converted into the elastography mode, and acoustic radiation force impulse imaging was performed. Shear wave velocity (m/sec) was measured at least 5 times for each ovary, and the mean value was calculated for each polycystic ovarian syndrome and non-polycystic ovarian syndrome woman. Results: Age, body mass index, fasting glucose levels, cycle day 3 follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, and prolactin levels were similar between the groups (p >0,05). Antimullerian hormone levels, antral follicle counts, and mean ovarian volumes were statistically different between the groups (p <0,05). Mean shear wave velocity values for both ovaries were 2.12 ± 0.82 (0.78-4.9) m/sec in the polycystic ovarian syndrome group, and 1.18 ± 0.41 (0.77-2.0) m/sec in the non-polycystic ovarian syndrome group, which was statistically significantly different (p = 0.016). Conclusion: In our study, we found significantly higher shear wave velocity levels in polycystic ovarian syndrome women than non-polycystic ovarian syndrome women, which indicates an impact of the condition on shear wave velocity. The increased acoustic frequencies cause a decreased response in time to transition, and motion becomes out of phase; in other words, scattered waves are faster in stiffer ovaries. Our results are thus compatible with the pathophysiology of the disease. Shear wave velocity is a beneficial tool for evaluating ovarian elasticity in polycystic ovarian syndrome patients in whom the levels are found to be significantly higher than non-polycystic ovarian syndrome women. In light of these findings, shear wave velocity is expected to be slower than polycystic ovarian syndrome levels in ovulatory women.

Refraction artifact on abdominal sonogram

Ultrasonography (US) is the first-line diagnostic tool for observing the whole abdomen. Unfortunately, a wide spectrum of refraction-related artefactual images is very frequently encountered in routine US examinations. In addition, most practitioners currently perform abdominal US examinations without sufficient knowledge of refraction artifacts (RAs). This review article was designed to present many representative RA images seen in the clinical setting, with a brief explanation of the mechanism of these images, in certain cases through an analyzed and reconstructed method using computer simulation that supports clinical observations. RAs are encountered not only with B-mode US but also with Doppler US, contrast-enhanced US, and shear wave elastography. RAs change their appearance according to the situation, but they always have a significant effect on detailed interpretation of abdominal US images. Correct diagnosis of abdominal US relies on a deep understanding of each characteristic artifactual finding, which necessitates knowledge of basic US physics. When analyzing mass lesions, computer simulation analysis helps to reveal the global images of RAs around a lesion.

Hepatocellular Carcinoma and Non-Alcoholic Fatty Liver Disease: A Step Forward for Better Evaluation Using Ultrasound Elastography

Simple Summary

Non-alcoholic fatty liver disease (NAFLD) attracts a lot of attention, due to the increasing prevalence and progression to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Consequently, new non-invasive, cost-effective diagnostic methods are needed. This review aims to explore the diagnostic performance of ultrasound (US) elastography in NAFLD and NAFLD-related HCC, adding a new dimension to the conventional US examination—the liver stiffness quantification. The vibration controlled transient elastography (VCTE), and 2D-Shear wave elastography (2D-SWE) are effective in staging liver fibrosis in NAFLD. VCTE presents the upside of assessing steatosis through the controlled attenuation parameter. Hereby, we critically reviewed the elastography techniques for the quantitative characterization of focal liver lesions (FLLs), focusing on HCC: Point shear wave elastography and 2D-SWE. 2D-SWE presents a great potential to differentiate malignant from benign FLLs, guiding the clinician towards the next diagnostic steps. As a disease-specific surveillance tool, US elastography presents prognostic capability, improving the NAFLD-related HCC monitoring.

Abstract

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) in the general population prompts for a quick response from physicians. As NAFLD can progress to liver fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC), new non-invasive, rapid, cost-effective diagnostic methods are needed. In this review, we explore the diagnostic performance of ultrasound elastography for non-invasive assessment of NAFLD and NAFLD-related HCC. Elastography provides a new dimension to the conventional ultrasound examination, by adding the liver stiffness quantification in the diagnostic algorithm. Whilst the most efficient elastographic techniques in staging liver fibrosis in NAFLD are vibration controlled transient elastography (VCTE) and 2D-Shear wave elastography (2D-SWE), VCTE presents the upside of assessing steatosis through the controlled attenuation parameter (CAP). Hereby, we have also critically reviewed the most important elastographic techniques for the quantitative characterization of focal liver lesions (FLLs), focusing on HCC: Point shear wave elastography (pSWE) and 2D-SWE. As our paper shows, elastography should not be considered as a substitute for FLL biopsy because of the stiffness values overlap. Furthermore, by using non-invasive, disease-specific surveillance tools, such as US elastography, a subset of the non-cirrhotic NAFLD patients at risk for developing HCC can be detected early, leading to a better outcome. A recent ultrasomics study exemplified the wide potential of 2D-SWE to differentiate benign FLLs from malignant ones, guiding the clinician towards the next steps of diagnosis and contributing to better long-term disease surveillance.

Elastography for characterization of focal liver lesions: current evidence and future perspectives

Focal liver lesions (FLLs) are a common finding during routine abdominal ultrasound (US). The differential diagnosis between diverse types of FLLs, especially between benign and malignant ones, is extremely important and can often be particularly challenging. Radiological techniques with contrast administration and/or liver biopsy are mostly necessary for establishing diagnosis, but they have several contraindications or complications. Due to limitations of these tools, there is urgent and still unmet need to develop a first line, non-invasive and simple method to diagnose FLLs. Elastography is an US-based imaging modality that provides information about the physical parameter corresponding to the tissue stiffness and can be considered a virtual biopsy. Several elastographic approaches have been developed, such as transient elastography, strain imaging and share wave imaging, which include point shear wave elastography and 2D shear wave elastography. These tools are already in use for evaluating liver fibrosis and in the assessment of focal lesions in other organs, like breast and thyroid gland. This review aims to assess the current evidence of different techniques based on elastography in the setting of FLLs, in order to evaluate accuracy, limitations and future perspectives. In particular, we focused on two contexts: the ability of discriminating between benign and malignant lesions, especially hepatocellular carcinoma and liver metastasis, and the surveillance after percutaneous therapy. This could have a high clinical impact making elastography crucial to identify the appropriate management of FLLs.

Diagnostic problems in two-dimensional shear wave elastography of the liver

Two-dimensional shear wave elastography (2D-SWE) is used in the clinical setting for observation of the liver. Unfortunately, a wide spectrum of artifactual images are frequently encountered in 2D-SWE, the precise mechanisms of which remain incompletely understood. This review was designed to present many of the artifactual images seen in 2D-SWE of the liver and to analyze them by computer simulation models that support clinical observations. Our computer simulations yielded the following suggestions: (1) When performing 2D-SWE in patients with chronic hepatic disease, especially liver cirrhosis, it is recommended to measure shear wave values through the least irregular hepatic surface; (2) The most useful 2D-SWE in patients with focal lesion will detect lesions that are poorly visible on B-mode ultrasound and will differentiate true tumors from pseudo-tumors (e.g., irregular fatty change); and (3) Measurement of shear wave values in the area posterior to a focal lesion must be avoided.