Application of 3D and 2D quantitative shear wave elastography (SWE) to differentiate between benign and malignant breast masses

Extracellular matrix stiffness in endometrial cancer: driving progression and modulating treatment sensitivity via the ROCK1/YAP1 axis

Endometrial cancer (EC) is among the most prevalent gynecological malignancies, with advanced or recurrent cases posing significant treatment challenges due to limited responses to conventional therapies. Growing evidence highlights the critical role of extracellular matrix (ECM) stiffness in driving tumor progression by shaping the tumor microenvironment. In this study, we demonstrate that ECM stiffness is significantly higher in EC tissues compared to normal endometrium, correlating with elevated expression of ROCK1, a mechanosensitive kinase. Using atomic force microscopy (AFM), we quantified ECM stiffness, while polyacrylamide gels with varying stiffness were employed to mimic ECM conditions in vitro. Bioinformatics analyses, immunofluorescence, Western blotting, and co-immunoprecipitation experiments revealed that ROCK1 modulates the phosphorylation of YAP1, promoting its nuclear localization and transcriptional activity, thereby driving aggressive tumor behaviors, including enhanced proliferation, migration, invasion, and reduced apoptosis. Pharmacological inhibition of ROCK1 with Y-27632 mitigated these effects, suppressing tumor growth, restoring apoptosis, and inducing cell cycle arrest. Treatment with Y-27632 improved sensitivity to chemotherapy and radiotherapy, and significantly enhanced macrophage-mediated phagocytosis, thereby boosting anti-tumor immune responses. In hormone-resistant EC cells, ROCK1 inhibition restored sensitivity to progesterone therapy. Notably, in vivo experiments in a xenograft mouse model confirmed the therapeutic potential of Y-27632, as combination therapy with progesterone showed superior tumor-suppressive effects compared to monotherapy. These findings underscore the dual role of ECM stiffness and ROCK1 in driving tumor progression and influencing treatment outcomes. By elucidating the relationship between ECM stiffness, ROCK1/YAP1 signaling, and treatment sensitivity, this study highlights the potential of targeting the ROCK1/YAP1 axis as a therapeutic strategy. ROCK1 serves as both a biomarker for prognosis and a target for improving personalized treatment approaches, offering new avenues to enhance clinical outcomes for EC patients.

3D multiparametric ultrasound of spontaneous murine tumors for non-invasive tumor characterization

Objective.Non-invasive tumor diagnosis and characterization is limited today by the cost and availability of state of the art imaging techniques. Thanks to recent developments, ultrasound (US) imaging can now provide quantitative volumetric maps of different tissue characteristics. This study applied the first fully concurrent 3D ultrasound imaging set-up including B-mode imaging, shear wave elastography (SWE), tissue structure imaging with backscatter tensor imaging (BTI), vascular mapping with ultrasensitive Doppler (uDoppler) and ultrasound localization microscopy (ULM)in-vivo. Subsequent analysis aimed to evaluate its benefits for non-invasive tumor diagnosis.Approach.A total of 26 PyMT-MMTV transgenic mice and 6 control mice were imaged weekly during tumor growth. First-order statistics and radiomic features were extracted from the quantitative maps obtained, and used to build predictive models differentiating healthy from cancerous mammary pads. Imaging features were also compared to histology obtained the last week of imaging.Main results.High quality co-registered quantitative maps were obtained, for which SWE speed, BTI tissue organization, ULM blood vessel count and uDoppler blood vessel density were correlated with histopathology. Significant changes in uDoppler sensitivity and BTI tissue structure were measured during tumor evolution. Predictive models inferring the cancerous state from the multiparametric imaging reached 99% accuracy, and focused mainly on radiomics measures of the BTI maps.Significance.This work indicates the relevance of a multiparametric characterization of lesions, and highlights the strong predictive power of BTI-derived parameters for differentiating tumors from healthy tissue, both before and after the tumor can be detected by palpation.

Shear Wave Elastography: A Non-Invasive Approach for Assessing TGF-β1/MAPK Signaling Molecules and EMT in Breast Cancer

Background

This study investigated the relationship between Shear Wave Elastography (SWE), TGF-β1/MAPK signaling molecules, and epithelial-to-mesenchymal transition (EMT) in breast lesions, exploring the feasibility of SWE in early EMT identification for breast cancer.

Methods

117 breast lesions in 107 patients from July to November 2023 were consecutively enrolled. SWE was performed preoperatively, and elastic parameters were documented. Immunohistochemistry (IHC) assessed the expression levels of TGF-β1, p38 MAPK, p-p38 MAPK, ERK1/2, p-ERK1/2, ERK5, p-ERK5, JNK, p-JNK, E-cadherin, β-catenin, N-cadherin, and Vimentin. Correlations between SWE parameters and biomarkers were analysed, and their diagnostic efficacy for axillary lymph node metastasis (LNM) was evaluated.

Results

Among 117 breast lesions, 53 were classified as benign and 64 as malignant (25 exhibiting axillary LNM). Optimal SWE thresholds for distinguishing benign from malignant lesions were Emax = 106.7 kPa, Emean = 62.9 kPa, Emin = 22.5 kPa, Eratio = 3.4, and Esd = 21.2 kPa. For LNM prediction, cut-offs were Emax = 170.1 kPa, Emean = 118.5 kPa, and Eratio = 10.5. TGF-β1 and E-cadherin showed significant predictive value for LNM (AUCs: 0.774 and 0.704, respectively). E-cadherin negatively correlated with SWE parameters, while TGF-β1 and MAPK molecules (p38 MAPK, p-p38 MAPK) showed positive correlations. Lesions with "stiff rim sign" had significantly lower E-cadherin expression but elevated levels of TGF-β1 (P<0.001). Additionally, Vimentin, p38 MAPK and p-p38 MAPK levels were higher in the occurrence of the "stiff rim sign" (P all <0.05).

Conclusion

TGF-β1, p38 MAPK, and E-cadherin demonstrated strong diagnostic capabilities and correlated with SWE parameters. SWE offers a promising non-invasive approach for assessing prognosis by identifying EMT characteristics at an earlier stage in breast cancer.

Validation of Volumetric Multifrequency Shear Wave Vibro-Elastography With Matrix Array Transducer for the In Vivo Liver

Three-dimensional shear wave absolute vibro-elastography (S-WAVE) is a steady-state, volumetric elastography imaging technique similar to magnetic resonance elastography (MRE), with the additional advantage of multifrequency imaging and a significantly shorter examination time. We present a novel ultrasound matrix array implementation of S-WAVE for high-volume refresh rate acquisition. This new imaging setup is equipped with real-time shear wave monitoring for an improved data collection workflow and image quality. The image processing and elasticity reconstruction pipeline is tailored for high body mass index (BMI) subjects. We characterized this system with tissue phantoms and a human study cohort composed of 7 healthy volunteers and 25 patients with nonalcoholic fatty liver disease. The validation results show that S-WAVE can maintain a high agreement with the liver tissue stiffness measurements obtained with both the 2-D and 3-D MRE techniques, with an average cross correlation >93% and an average , which outperforms the conventional transient elasticity technique. Our findings show that the matrix array-based 3-D S-WAVE is a suitable volumetric elastography imaging solution for delivering a similar assessment of liver fibrosis as MRE in a more accessible, flexible, and cost-effective way.

Evaluating Carotid Plaque Stiffness with Ultrasound 2D Shear-Wave Elastography in Patients Undergoing Coronary Artery Bypass Grafting

Background: Coronary and carotid artery diseases are manifestations of a systemic atherosclerotic process, often coexisting in patients affected by both conditions. This association emphasizes the importance of evaluating both coronary and carotid atherosclerosis in high-risk individuals. Ultrasound 2D shear-wave elastography (2D-SWE) has shown promise as a noninvasive technique for assessing carotid plaque stiffness. This prospective pilot study aimed to assess carotid plaque stiffness in patients undergoing coronary artery bypass grafting (CABG) and those not scheduled for the procedure as a control group. Methods: 32 patients (17 CABG and 15 controls) were recruited, collectively presenting 43 carotid plaques. Bilateral carotid ultrasound was performed using a high-resolution linear transducer. Plaque stiffness was quantified via 2D-SWE, expressed in shear-wave velocity (SWV, m/s) and Young's modulus (YM, kPa). Plaque characteristics, including GSM, were quantified. Intra-observer reproducibility was evaluated with intraclass correlation coefficients (ICCs) and Bland-Altman plots. Statistical differences and correlations were assessed using Mann-Whitney U and Spearman's correlation tests. Results: Carotid plaques in the CABG group exhibited significantly lower stiffness compared to controls (median stiffness SWV: 3.64 m/s vs. 4.91 m/s, p < 0.0001; YM: 20.96 kPa vs. 72.54 kPa, p < 0.0001). ICCs demonstrated excellent reproducibility for stiffness measurements (SWV: ICC = 0.992; YM: ICC = 0.992), with minimal bias in measurements. A positive correlation was observed between 2D-SWE and GSM values (SWV: r = 0.343, p = 0.024; YM: r = 0.340, p = 0.026). Conclusions: Ultrasound 2D-SWE has shown promise as a reliable tool for quantifying carotid plaque stiffness, demonstrating high reproducibility and a significant correlation with GSM. The observed reduction in plaque stiffness among CABG patients highlights its potential as a valuable parameter for identifying high-risk plaques and assessing cerebrovascular risk in patients undergoing CABG.

Shear wave elastography primer for the abdominal radiologist

PURPOSE

Shear wave elastography (SWE) provides a means for adding information about the mechanical properties of tissues to a diagnostic ultrasound examination. It is important to understand the physics and methods by which the measurements are made to aid interpretation of the results as they relate to disease processes.

METHODS

The components of how ultrasound is used to generate shear waves and make measurements of the induced motion are reviewed. The physics of shear wave propagation are briefly described for elastic and viscoelastic tissues. Additionally, shear wave propagation in homogeneous and inhomogeneous cases is addressed.

RESULTS

SWE technology has been implemented by many clinical vendors with different capabilities. Various quality metrics are used to define valid measurements based on aspects of the shear wave signals or wave velocity estimates.

CONCLUSION

There are many uses for SWE in abdominal imaging, but it is important to understand how the measurements are performed to gauge their utility for diagnosis of different conditions. Continued efforts to make the technology robust in complex clinical situations are ongoing, but many applications actively benefit from added information about tissue mechanical properties for a more holistic view of the patient for diagnosis or assessment of prognosis and treatment management.

Deep learning model targeting cancer surrounding tissues for accurate cancer diagnosis based on histopathological images

Accurate and fast histological diagnosis of cancers is crucial for successful treatment. The deep learning-based approaches have assisted pathologists in efficient cancer diagnosis. The remodeled microenvironment and field cancerization may enable the cancer-specific features in the image of non-cancer regions surrounding cancer, which may provide additional information not available in the cancer region to improve cancer diagnosis. Here, we proposed a deep learning framework with fine-tuning target proportion towards cancer surrounding tissues in histological images for gastric cancer diagnosis. Through employing six deep learning-based models targeting region-of-interest (ROI) with different proportions of no-cancer and cancer regions, we uncovered the diagnostic value of non-cancer ROI, and the model performance for cancer diagnosis depended on the proportion. Then, we constructed a model based on MobileNetV2 with the optimized weights targeting non-cancer and cancer ROI to diagnose gastric cancer (DeepNCCNet). In the external validation, the optimized DeepNCCNet demonstrated excellent generalization abilities with an accuracy of 93.96%. In conclusion, we discovered a non-cancer ROI weight-dependent model performance, indicating the diagnostic value of non-cancer regions with potential remodeled microenvironment and field cancerization, which provides a promising image resource for cancer diagnosis. The DeepNCCNet could be readily applied to clinical diagnosis for gastric cancer, which is useful for some clinical settings such as the absence or minimum amount of tumor tissues in the insufficient biopsy.

Assessment of testicular stiffness in fertile dogs with shear wave elastography techniques: a pilot study

Ultrasound of the testes is important in the evaluation of breeding dogs, and recently advanced techniques such as Shear Wave Elastography (SWE) have been developed. This study focused on evaluation of normal testicular stiffness in healthy and fertile male dogs, employing both qualitative (2D-SWE) and quantitative (pSWE, 2D-SWE) techniques. Nineteen dogs of various medium-large breeds aged 3.39 ± 2.15 years, and with a history of successful reproduction were included after clinical, B-mode and Doppler ultrasound of testes and prostate, and semen macro and microscopic evaluations. pSWE involved square regions of interest (ROIs) placed at six different points in the testicular parenchyma, while 2D-SWE depicted stiffness with a color scale ranging from blue (soft) to red (stiff), allowing a subsequent quantification of stiffness by the application of 4 round ROIs. The results showed a mean Shear Wave Speed (SWS) of 2.15 ± 0.39 m/s using pSWE, with lower values above the mediastinum compared to below, and in the center of the testis compared to the cranial and caudal poles. 2D-SWE demonstrated a uniform blue pattern in the parenchyma, and a mean SWS of 1.65 ± 0.15 m/s. No significant differences were found between left and right testes, above and below the mediastinum, or among breeds. No correlations were observed between mean SWS and body condition score, age, testicular and prostatic volume. Weight was positively correlated with mean SWS only by 2D-SWE. By performing semen analysis and enrolling only healthy and fertile adult dogs, we ensured both structural and functional integrity of the testes. This pilot study represents a valuable baseline data for testicular stiffness by both pSWE and 2D-SWE with a Mindray US machine in medium-large sized healthy and fertile dogs, pointing out the potential role of SWE in the non-invasive fertility assessment and management of breeding dogs.

Ultrasonic surface acoustic wave elastography: A review of basic theories, technical developments, and medical applications

Physiological and pathological changes in tissues often cause changes in tissue mechanical properties, making tissue elastography an effective modality in medical imaging. Among the existing elastography methods, ultrasound elastography is of great interest due to the inherent advantages of ultrasound imaging technology, such as low cost, portability, safety, and wide availability. However, most current ultrasound elastography methods are based on the bulk shear wave; they can image deep tissues but cannot image superficial tissues. To address this challenge, ultrasonic elastography methods based on surface acoustic waves have been proposed. In this paper, we present a comprehensive review of ultrasound-based surface acoustic wave elastography techniques, including their theoretical foundations, technical implementations, and existing medical applications. The goal is to provide a concise summary of the state-of-the-art of this field, hoping to offer a reliable reference for the further development of these techniques and foster the expansion of their medical applications.

Three-Dimensional Shear Wave Elastography Using Acoustic Radiation Force and a 2-D Row-Column Addressing (RCA) Array

Acoustic radiation force (ARF)-based shear wave elastography (SWE) is a clinically available ultrasound imaging mode that noninvasively and quantitatively measures tissue stiffness. Current implementations of ARF-SWE are largely limited to 2-D imaging, which does not provide a robust estimation of heterogeneous tissue mechanical properties. Existing 3-D ARF-SWE solutions that are clinically available are based on wobbler probes, which cannot provide true 3-D shear wave motion detection. Although 3-D ARF-SWE based on 2-D matrix arrays have been previously demonstrated, they do not provide a practical solution because of the need for a high channel-count ultrasound system (e.g., 1024-channel) to provide adequate volume rates and the delicate circuitries (e.g., multiplexers) that are vulnerable to the long-duration "push" pulses. To address these issues, here we propose a new 3-D ARF-SWE method based on the 2-D row-column addressing (RCA) array which has a much lower element count (e.g., 256), provides an ultrafast imaging volume rate (e.g., 2000 Hz), and can withstand the push pulses. In this study, we combined the comb-push shear elastography (CUSE) technique with 2-D RCA for enhanced SWE imaging field-of-view (FOV). In vitro phantom studies demonstrated that the proposed method had robust 3-D SWE performance in both homogenous and inclusion phantoms. An in vivo study on a breast cancer patient showed that the proposed method could reconstruct 3-D elasticity maps of the breast lesion, which was validated using a commercial ultrasound scanner. These results demonstrate strong potential for the proposed method to provide a viable and practical solution for clinical 3-D ARF-SWE.

Real-Time Shear Wave Elastography for Determining the Ideal Site of Liver Biopsy in Diffuse Liver Disease

Objectives  The objective of the study was to identify accurate site of liver biopsy under ultrasound and elastography guidance and compare the shear wave elastography (SWE) and transient elastography (TE) diagnostic accuracy with histopathological correlation. Methods  This was a prospective single-center study where patients scheduled for nonfocal liver biopsy were divided into two groups (group U: ultrasound; group E elastography) by sequential nonrandom selection of patients. Elastography was performed before the biopsy and biopsies from the maximum stiffness segment were taken. Results  There was no significant difference of intersegmental liver stiffness with mean velocity; however, biopsy segment velocities show significant difference with mean liver stiffness suggestive of heterogenous distribution of fibrosis. The rho ( r ; Spearman's correlation) value between biopsy segments and mean velocities shows excellent correlation. The diagnostic performance of TE was good for fibrosis stages F2, F3, and F4, while SWE was fair for the diagnosis of fibrosis stages F1 and F2 and fairly equal for the diagnosis stages F2 and F3. Area under the curve (AUC) values in differentiating mild (F1) or no fibrosis from significant fibrosis (≥F2) were 95.5 with cutoff value of at least 1.94 m/s. Conclusions  The diagnostic performance of SWE is comparable with TE in liver fibrosis staging and monitoring. Fibrosis is heterogeneously distributed in different segments of the right lobe liver. Therefore, elastography at the time of biopsy may help in defining the accurate site for biopsy and improve histopathological yield in detecting liver fibrosis in patients with chronic liver disease. Advances in Knowledge  Elastography-guided biopsy is helpful to determine the ideal site of biopsy.

The effect of gel pads on the measurement of breast superficial lesions by shear wave elastography

OBJECTIVE

This study aimed to compare the repeatability and diagnostic efficiency of shear wave elastography (SWE) while using coupling gel and gel pads in the diagnosis of superficial breast lesions.

METHODS

Two experienced sonographers, trained in SWE, used different methods to perform the maximum Young's modulus (Emax) measurement of the lesion while using coupling gel SWE and gel pad SWE at different time points. All 80 lesions were in the superficial layer of the breast. The interclass correlation coefficient (ICC) was calculated to evaluate the intraobserver and interobserver repeatability. Meanwhile, the receiver operating characteristic curve (ROC curve) was used to calculate the sensitivity, specificity and area under the curve of the two methods.

RESULTS

In the 80 breast lesions, the intraobserver and interobserver reproducibility of SWE measurements using coupling gel were considered good, and the ICCs were 0.728 (95% CI: 0.509-0.813) and 0.702 (95% CI: 0.492-0.795), respectively. The intraobserver and interobserver reproducibility of the SWE measured by the gel pad were also considered good, and the ICCs were 0.745 (95% CI: 0.501-0.801) and 0.713 (95% CI: 0.498-0.802), respectively. The sensitivity, specificity and area under the curve were 0.711 and 0.737, 0.929 and 0.905, and 0.873 and 0.878, respectively.

CONCLUSIONS

In the SWE measurement of superficial breast lesions, the use of a gel pad does not affect the repeatability and diagnostic efficiency of the measurement.

Non-invasive Measurement of the Viscoelasticity of the Optic Nerve and Sclera for Assessing Papilledema: A Pilot Clinical Study

OBJECTIVE

The purpose of this study was to evaluate our novel ultrasound vibro-elastography (UVE) technique for assessing patients with papilledema by non-invasively measuring shear wave speed (SWS), elasticity and viscosity properties of the optic nerve and sclera.

METHODS

Shear wave speeds were measured at three frequencies-100, 150 and 200 Hz-on the optic nerve and sclera tissues for assessing patients with papilledema resulting from idiopathic intracranial hypertension (IIH). The method was evaluated in six papilledema patients and six controls on two separate locations for each participant (i.e., optic nerve and posterior sclera). SWSs of the optic nerve and sclera were analyzed by using a 2-D speed map technique within a circular region of interest (ROI) (i.e., the diameter of the ROI was 1.5 mm × 3.0 mm at the optic nerve and sclera, respectively). Elasticity and viscosity were then analyzed using the wave speed dispersion over the three frequencies.

RESULTS

We measured values of SWS at both locations, optic nerve and sclera, of the right eye and left eye at three different frequencies in IIH patients and controls. The SWS (mean ± standard deviation [m/s]) of the right eye was significantly higher at the sclera in IIH patients compared with controls (i.e., patients vs. controls: 5.91 ± 0.54 vs. 3.86 ± 0.56, p < 0.0001 at 100 Hz), but there was no significant difference at the optic nerve (i.e., patients vs. controls: 3.62 ± 0.39 vs. 3.36 ± 0.35, p = 0.1100 at 100Hz). We observed increased elasticity (kPa) in IIH patients, indicating there are significant differences in elasticity between patients and controls at the optic nerve and sclera (i.e., right eye [patients vs. controls]: 14.42 ± 6.59 vs. 6.5 ± 5.71, p = 0.0065 [optic nerve]; 33.04 ± 10.62 vs. 9.16 ± 7.15, p < 0.0001 [sclera]). Viscosity was also (Pa·s) higher in the sclera and optic nerve of the left eye (i.e., left eye [patient vs. control]: 8.89 ± 4.37 vs. 7.27 ± 5.01, p = 0.3790 (optic nerve); 16.05 ± 10.79 vs. 8.49 ± 6.09, p < 0.0194 [sclera]).

CONCLUSION

This research illustrates the feasibility of using our UVE system to evaluate stiffness of different tissues in the eye non-invasively. It suggests that the viscoelasticity of the posterior sclera is higher than that of the optic nerve. We found that the posterior sclera is stiffer than the optic nerve in patients with papilledema resulting from IIH, making UVE a potential non-invasive technique for assessing papilledema.

Immersion ultrasound improves the repeatability of shear-wave elastography for measuring median nerve elasticity

OBJECTIVE

To study the factors that influence the measurement of median nerve elasticity, to provide a more reproducible test for the assessment of median nerve elasticity using shear wave elasticity (SWE), and to reduce operator empirical dependence. To compare the repeatability of the median nerve elasticity measurement using immersion SWE with that using contact SWE, analyze the factors affecting SWE measurement, and provide a more repeatable method for doctors without SWE operation experience.

METHODS

Two doctors without SWE operation experience measured the median nerve mean elastic modulus (Emean) at the same position and at different time points on the right wrist of 58 healthy volunteers using immersion and contact ultrasound methods. The intraobserver and interobserver repeatability of measurements was assessed using the interclass correlation coefficient (ICC), while the repeatability was assessed using the Bland-Altman diagram.

RESULTS

The intraobserver and interobserver repeatability of the median nerve elasticity measured via contact SWE by inexperienced operators were classified as good, with ICCs of 0.633 (95% CI 0.380-0.783) and 0.552 (95% CI 0.243-0.735), respectively. The intraobserver and interobserver repeatability of the median nerve elasticity measured by immersion SWE were very good, with ICCs of 0.975 (95% CI 0.958-0.985) and 0.942 (95% CI 0.902-0.966), respectively. The intraobserver and interobserver Bland-Altman diagram of median nerve elasticity measured by immersion SWE showed that 98% of the points fell within the 95% limits of agreement. The intraobserver and interobserver Bland-Altman diagram of median nerve elasticity measured by contact SWE showed that 94% of the points fell within the 95% limits of agreement.

CONCLUSION

Immersion ultrasound can improve the repeatability of median nerve elasticity measurements by inexperienced operators.

The peritumor microenvironment: physics and immunity

Cancer initiation and progression drastically alter the microenvironment at the interface between healthy and malignant tissue. This site, termed the peritumor, bears unique physical and immune attributes that together further promote tumor progression through interconnected mechanical signaling and immune activity. In this review, we describe the distinct physical features of the peritumoral microenvironment and link their relationship to immune responses. The peritumor is a region rich in biomarkers and therapeutic targets and thus is a key focus for future cancer research as well as clinical outlooks, particularly to understand and overcome novel mechanisms of immunotherapy resistance.

Evaluation of diagnostic efficacy of multimode ultrasound in BI-RADS 4 breast neoplasms and establishment of a predictive model

Objectives

To explore the diagnostic efficacy of ultrasound (US), two-dimensional and three-dimensional shear-wave elastography (2D-SWE and 3D-SWE), and contrast-enhanced ultrasound (CEUS) in breast neoplasms in category 4 based on the Breast Imaging Reporting and Data System (BI-RADS) from the American College of Radiology (ACR) and to develop a risk-prediction nomogram based on the optimal combination to provide a reference for the clinical management of BI-RADS 4 breast neoplasms.

Methods

From September 2021 to April 2022, a total of 104 breast neoplasms categorized as BI-RADS 4 by US were included in this prospective study. There were 78 breast neoplasms randomly assigned to the training cohort; the area under the receiver-operating characteristic curve (AUC), 95% confidence interval (95% CI), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 2D-SWE, 3D-SWE, CEUS, and their combination were analyzed and compared. The optimal combination was selected to develop a risk-prediction nomogram. The performance of the nomogram was assessed by a validation cohort of 26 neoplasms.

Results

Of the 78 neoplasms in the training cohort, 16 were malignant and 62 were benign. Among the 26 neoplasms in the validation cohort, 6 were malignant and 20 were benign. The AUC values of 2D-SWE, 3D-SWE, and CEUS were not significantly different. After a comparison of the different combinations, 2D-SWE+CEUS showed the optimal performance. Least absolute shrinkage and selection operator (LASSO) regression was used to filter the variables in this combination, and the variables included Emax, Eratio, enhancement mode, perfusion defect, and area ratio. Then, a risk-prediction nomogram with BI-RADS was built. The performance of the nomogram was better than that of the radiologists in the training cohort (AUC: 0.974 vs. 0.863). In the validation cohort, there was no significant difference in diagnostic accuracy between the nomogram and the experienced radiologists (AUC: 0.946 vs. 0.842).

Conclusions

US, 2D-SWE, 3D-SWE, CEUS, and their combination could improve the diagnostic efficiency of BI-RADS 4 breast neoplasms. The diagnostic efficacy of US+3D-SWE was not better than US+2D-SWE. US+2D-SWE+CEUS showed the optimal diagnostic performance. The nomogram based on US+2D-SWE+CEUS performs well.

Diagnostic Value of Different 3-D Shear Wave Elastography Sections in the Diagnosis of Thyroid Nodules

The aim of the study was to explore the value of 3-D shear wave elastography (SWE) in differentiating malignant from benign thyroid nodules. A total of 188 patients with 216 nodules who underwent conventional ultrasound, 2-D SWE and 3-D SWE were included in this study. All patients underwent surgical excision, and the pathological results were the gold standard. Receiver operating characteristic (ROC) curves of the American College of Radiology's Thyroid Imaging Reporting and Data System (ACR TI-RADS), 2-D SWE and 3-D SWE were plotted, and the areas under the curves (AUCs) were compared using a Z-test. There were 62 benign thyroid nodules and 154 malignant thyroid nodules in this study. Young's modulus (E_min, E_mean, E_max, E_sd) values of thyroid malignant nodules in different sections of 2-D SWE and 3-D SWE were significantly higher than those of thyroid benign nodules (p < 0.001). The AUC of E_max in 2-D SWE transverse sections was significantly lower than that in 3-D SWE transverse sections and 3-D SWE sagittal sections (0.768 vs. 0.831 and 0.844, p < 0.05). The AUC of 3-D S-E_max combined with ACR TI-RADS was 0.859; the specificity increased from 54.84% to 85.71%, and the diagnostic accuracy increased from 74.54% to 85.19%, compared with ACR TI-RADS. The difference was statistically significant (p < 0.05). Three-dimensional SWE combined with ACR TI-RADS for the diagnosis of thyroid nodules significantly improved the diagnostic ability of ACR TI-RADS, and was significantly better than 2-D SWE combined with ACR TI-RADS.

Which combination of different ultrasonography modalities is more appropriate to diagnose breast cancer?: A network meta-analysis (a PRISMA-compliant article)

BACKGROUND

Abundant amount of literature that analyze the various detection of different ultrasound methods, no comprehensive literature that investigates the diagnostic values of breast cancer (BC) by different ultrasonography modalities through a network meta-analysis (NMA) has been made available. Each imaging diagnostic examination has its own advantages and disadvantages, and any imaging examination is not enough to make an accurate diagnosis of the disease. Thus, this study aimed to compare diagnostic values among different ultrasonography modalities, including the information of 2-dimension, stiffness and blood flow, by a network meta-analysis in the hopes of understanding which imaging methods are better and which combination of different ultrasonography modalities is more appropriate to diagnose BC.

METHODS

We made use of Cochrane Library, PubMed, and Embase in order to obtain literature and papers. The combination analysis of both direct and indirect evidence in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value(NPV) and accuracy was conducted so as to assess the odds ratios (ORs) and surface under the cumulative ranking curve (SUCRA) values of the 8 different ultrasound methods.

RESULTS

A total of 36 eligible diagnostic tests regarding 8 ultrasound methods were included in the study. According to this network meta-analysis, Breast Imaging Reporting and Data System (BI-RADS) 4b exhibited higher specificity, PPV, and accuracy and lower sensitivity and NPV than BI-RADS 4a. Contrast-enhanced ultrasound (CEUS) had the highest sensitivity, PPV, NPV and accuracy and superb microvascular imaging (SMI) had the highest specificity among color Doppler flow imaging (CDFI), power Doppler imaging(PDI), SMI and CEUS. There was no significant difference in diagnostic indexes between SMI and CEUS. Shear wave elastrography (SWE) had higher PPV and accuracy and lower sensitivity, specificity NPV than strain elastography (SE).

CONCLUSION

The results of this network meta-analysis suggested more appropriate combination of different ultrasound modalities is BI-RADS 4b, SMI, and SWE for the diagnosis of breast cancer.

Second-Look Ultrasound Using Shear-Wave Elastography in MRI-Suspected Locoregional Recurrence of Breast Carcinoma

PURPOSE

To investigate if second-look US using shear-wave elastography (SWE) can help to differentiate between benign and malignant changes in the postoperative breast after surgical treatment of breast carcinoma.

MATERIALS AND METHODS

SWE and related sonographic features were reviewed in 90 female patients with a history of surgical treatment of breast carcinoma and a suspicious lesion detected on a follow-up MRI scan. A single experienced radiologist performed all second-look US exams with SWE measurements placing a circular region of interest measuring 2 mm in diameter over the stiffest part of the lesion. Tissue samples for histopathological analysis were obtained during the same US examination via core-needle biopsy.

RESULTS

Out of 90 lesions, 39 were proven malignant on histopathological analysis. 50 % of malignant lesions had El_max values ranging from 128 to 199 kPa, and 50 % of benign lesions had El_max values ranging from 65 to 169 kPa. The cut-off value of 171.2 kPa for El_max shows a sensitivity of 59 % and specificity of 78.4 % for carcinoma recurrence, area under the curve 0.706 (CI95 % 0.6-0.81), P = 0.001. In univariate logistic models, restricted diffusion and stiffness on SWE, El_max > 171.2 kPa, were shown as significant recurrence predictors. In the multivariate model, restricted diffusion remains significant independent recurrence predictor. With a recurrence prevalence of 43 %, the test sensitivity is 95 % (CI95 % 81-99 %) and the specificity is 75 % (CI95 % 60-85 %).

CONCLUSION

Stiffer lesions should be considered suspicious on second-look US in the postoperative breast and SWE can be a helpful tool in identifying malignant lesions, especially if this is related to restricted diffusion on MRI exam. Lesion stiffness, however, should not be considered as an independent predictor of lesion malignancy in the postoperative breast, because of benign changes that can appear stiff on SWE, as well as carcinoma recurrences that may appear soft.

Evaluation of Different Types of Breast Lesions With Apparent Diffusion Coefficient and Shear Wave Elastography Values: Comparison of Shear Wave Elastography and Apparent Diffusion Coefficient in Breast Lesions

Objective:

The aim of this study was to compare the stiffness of different histological types of breast lesions by obtaining shear wave elastography (SWE) and apparent diffusion coefficient (ADC) values, and to determine the contribution of these two methods to the diagnosis.

Materials and Methods:

In total, 70 patients with biopsy-proven breast lesions were included in the study. The mean SWE values of breast lesions were recorded and ADC values of these lesions were calculated. Receiver operating characteristic (ROC) curve analyses and the diagnostic accuracies of SWE-ADC values were determined.

Results:

The mean SWE values were 45.47 ± 25.11 kPa and 3.51 ± 1.04 m/s in benign group, and 161.11 ± 219.34 kPa and 5.96 ± 1.06 m/s in malignant group, respectively. The mean ADC values were 1.38 ± 0.32 (×10–3 mm2/s) in benign group and 0.96 ± 0.22 (×10–3 mm2/s) in malignant group, respectively. When the diagnostic performances of both imaging modalities on mass stiffness are evaluated, statistically significant negative correlations were found between SWE lesion values and ADC lesion values.

Conclusion:

Evaluation of tissue elasticity has recently been used frequently in the diagnosis of breast diseases. SWE-ADC values, which are negatively correlated in the diagnosis of breast masses, may prove to be a powerful alternative diagnostic tool that can be used interchangeably, as appropriate.

Three-Dimensional Multi-Frequency Shear Wave Absolute Vibro-Elastography (3D S-WAVE) With a Matrix Array Transducer: Implementation and Preliminary In Vivo Study of the Liver

Magnetic resonance elastography (MRE) is commonly regarded as the imaging-based gold-standard for liver fibrosis staging, comparable to biopsy. While ultrasound-based elastography methods for liver fibrosis staging have been developed, they are confined to a 1D or a 2D region of interest and to a limited depth. 3D Shear Wave Absolute Vibro-Elastography (S-WAVE) is a steady-state, external excitation, volumetric elastography technique that is similar to MRE, but has the additional advantage of multi-frequency excitation. We present a novel ultrasound matrix array implementation of S-WAVE that takes advantage of 3D imaging. We use a matrix array transducer to sample axial multi-frequency steady-state tissue motion over a volume, using a Color Power Angiography sequence. Tissue motion with the frequency components {40,50,60} and {45,55,65} Hz are acquired over a (90° lateral) × (40° elevational) × (16 cm depth) sector with an acquisition time of 12 seconds. We compute the elasticity map in 3D using local spatial frequency estimation. We characterize this new approach in tissue phantoms against measurements obtained with transient elastography and MRE. Six healthy volunteers and eight patients with chronic liver disease were imaged. Their MRE and S-WAVE volumes were aligned using T1 to B-mode registration for direct comparison in common regions of interest. S-WAVE and MRE results are correlated with R² = 0.92, while MRE and TE results are correlated with R² = 0.71. Our findings show that S-WAVE with matrix array has the potential to deliver a similar assessment of liver fibrosis as MRE in a more accessible, inexpensive way, to a broader set of patients.

Value of multimodality imaging in the diagnosis of breast lesions with calcification: A retrospective study

PURPOSE

To assess the value of conventional ultrasound (US), contrast-enhanced ultrasound (CEUS) and mammography in the diagnosis of breast lesions with calcifications.

METHODS

A total of 87 breast lesions with calcification were subjected to US, CEUS and mammography and divided into 3 groups: Group A (all cases), Group A1 (31 cases who underwent US and CEUS first followed by mammography), and Group A2 (56 cases who underwent mammography first followed by US and CEUS). A receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of different methods in different groups.

RESULTS

In Group A, the area under the ROC curve (AUROC) of CEUS were 0.937, which were significantly higher than that of mammography (p < 0.05). In Group A1, the AUROC of CEUS were 0.842, which were not significantly different from that of US and mammography (p > 0.05). In Group A2, the AUROC of CEUS were 0.987, which were significantly higher than that of mammography and US (p < 0.05).

CONCLUSION

Based on the mammography results, the combination of US and CEUS might improve the diagnostic efficacy in breast lesions with calcification.

Irreversible electroporation ablation against subcutaneously implanted VX2 tumors in rabbits: findings of shearwave ultrasound elastography

PURPOSE

This study aimed to evaluate stiffness changes of rabbit subcutaneous VX₂ tumors before and after irreversible electroporation (IRE) ablationby shearwave ultrasound elastography (SWE).

METHODS

IRE was performed on 20 subcutaneously implanted VX₂ tumors in rabbits (R-SIVX₂). Tumor stiffness was measured by SWE at different time points (before IRE,120minutes after IRE,7 days after IRE and 14 days after IRE).

RESULTS

Before IRE, the mean stiffness (E_mean) of tumors was (10.45 ± 1.07) KPa. 120 minutes after I RE, the E_mean of tumors obviously rose to (70.53 ± 9.87) KPa. 7 days after IRE, the E_mean of tumors decreased to (40.22 ± 9.01) KPa. 14 days after IRE, the E_mean of tumors was (15.17 ± 1.00) KPa. A clear boundary was observed between the ablation area and the normal tissues in the pathological results.

CONCLUSIONS

The stiffness of the VX₂ tumors experienced a first rise process and tend to be normal in the procedure of IRE. SWE could provide tissue stiffness information of different IRE ablation period as a non-invasive method.

Accuracy of real-time shear wave elastography in staging hepatic fibrosis: a meta-analysis

Background

Chronic liver disease (CLD) is an important cause of morbidity and mortality and can lead to hepatic fibrosis. This study was conducted to evaluate the diagnostic value of real-time shear wave elastography (SWE) in the assessment of hepatic fibrosis.

Methods

A systematic search of databases was performed for publications on SWE during the period between 2010 and 2017. The identified studies were analyzed using Meta-disc 1.4 software to integrate and analyze the data.

Results

Eleven studies comprising 1560 patients were included for analysis. The pooled sensitivity, specificity and diagnostic odds ratio were 0.85 (95% CI: 0.82–0.87), 0.79 (95% CI: 0.76–0.82) and 30.81 (95% CI: 16.55–57.34), respectively for patients with a Metavir-score of ≥ F2; 0.87 (95% CI: 0.84–0.91), 0.84 (95% CI: 0.82–0.87), 41.45 (95% CI:18.25–94.45), respectively for patients with ≥ F3; 0.88(95% CI: 0.83–0.91), 0.91 (95% CI: 0.89–0.92), 67.18 (95% CI:30.02–150.31), respectively for patients with ≥ F4. The areas under the receiver operating characteristic curve of the three groups were 0.9147, 0.9223 and 0.9520, respectively.

Conclusions

Our work demonstrates that SWE is highly accurate for detecting and staging hepatic fibrosis.

Shear Wave Elastography of Breast Lesions: Quantitative Analysis of Elastic Heterogeneity Improves Diagnostic Performance

The aim of this study was to evaluate whether quantitative analysis of elastic heterogeneity (EH) could improve the diagnostic performance of shear wave elastography (SWE) in breast lesions. From August 2016 to August 2017, 280 patients were enrolled in this prospective study. All lesions were evaluated with the ultrasound Breast Imaging Reporting and Data System (BI-RADS) and SWE with Virtual Touch tissue imaging quantification. The shear wave velocity (SWV) of the three areas of highest stiffness and lowest stiffness within the lesions were measured to calculate the maximum SWV (SWV_max), mean SWV (SWV_mean) and EH. The EH was determined as the difference between the averaged highest SWV and lowest SWV. The diagnostic performance-including the area under the receiver operating characteristic curve (AUC) and the sensitivity and specificity of BI-RADS, EH, SWV_max and SWV_mean-were analyzed. The AUC of EH, SWV_max and SWV_mean were 0.963, 0.949 and 0.937, respectively. The sensitivity of EH was 93.75%, which was significantly higher than that of SWV_max (84.37%) and SWV_mean (84.37%) (p < 0.001); there was no significant difference in the specificity among EH, SWV_max and SWV_mean (p > 0.05). For category 4A lesions, EH predicted all the malignant lesions, while two cancers were misdiagnosed by SWV_max and SWV_mean, respectively. Quantitative analysis of EH can improve the sensitivity of SWE for the differential diagnosis of breast lesions without loss of specificity.

OCT-elastography-based optical biopsy for breast cancer delineation and express assessment of morphological/molecular subtypes

Application of compressional optical coherence elastography (OCE) for delineation of tumor and peri-tumoral tissue with simultaneous assessment of morphological/molecular subtypes of breast cancer is reported. The approach is based on the ability of OCE to quantitatively visualize stiffness of studied samples and then to perform a kind of OCE-based biopsy by analyzing elastographic B-scans that have sizes ~several millimeters similarly to bioptates used for "gold-standard" histological examinations. The method relies on identification of several main tissue constituents differing in their stiffness in the OCE scans. Initially the specific stiffness ranges for the analyzed tissue components (adipose tissue, fibrous and hyalinized tumor stroma, lymphocytic infiltrate and agglomerates of tumor cells) are determined via comparison of OCE and morphological/molecular data. Then assessment of non-tumor/tumor regions and tumor subtypes is made based on percentage of pixels with different characteristic stiffness ("stiffness spectrum") in the OCE image, also taking into account spatial localization of different-stiffness regions. Examples of high contrast among benign (or non-invasive) and several subtypes of invasive breast tumors in terms of their stiffness spectra are given.

Comparative Diagnostic Accuracy of Contrast-Enhanced Ultrasound and Shear Wave Elastography in Differentiating Benign and Malignant Lesions: A Network Meta-Analysis

Background: We performed a network meta-analysis to compare the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) and shear wave elastography (SWE) in differentiating benign and malignant lesions in different body sites.

Methods: A computerized literature search of Medline, Embase, SCOPUS, and Web of Science was performed using relevant keywords. Following data extraction, we calculated sensitivity, specificity, positive likelihood ratio (LR), negative LR, and diagnostic odds ratio (DOR) for CEUS, and SWE compared to histopathology as a reference standard. Statistical analyses were conducted by MetaDiSc (version 1.4) and R software (version 3.4.3).

Results: One hundred and fourteen studies (15,926 patients) were pooled in the final analyses. Network meta-analysis showed that CEUS had significantly higher DOR than SWE (DOR = 27.14, 95%CI [2.30, 51.97]) in breast cancer detection. However, there were no significant differences between CEUS and SWE in hepatic (DOR = −6.67, 95%CI [−15.08, 1.74]) and thyroid cancer detection (DOR = 3.79, 95%CI [−3.10, 10.68]). Interestingly, ranking analysis showed that CEUS achieved higher DOR in detecting breast and thyroid cancer, while SWE achieved higher DOR in detecting hepatic cancer. The overall DOR for CEUS in detecting renal cancer was 53.44, 95%CI [29.89, 95.56] with an AUROC of 0.95, while the overall DOR for SWE in detecting prostate cancer was 25.35, 95%CI [7.15, 89.89] with an AUROC of 0.89.

Conclusion: Both diagnostic tests showed relatively high sensitivity and specificity in detecting malignant tumors in different organs. Network meta-analysis showed that CEUS had higher diagnostic accuracy than SWE in detecting breast and thyroid cancer, while SWE had higher accuracy in detecting hepatic cancer. However, the results were not statistically significant in hepatic and thyroid malignancies. Further head-to-head comparisons are needed to confirm the optimal imaging technique to differentiate each cancer type.

Future of breast elastography

Both strain elastography and shear wave elastography have been shown to have high sensitivity and specificity for characterizing breast lesions as benign or malignant. Training is important for both strain and shear wave elastography. The unique feature of benign lesions measuring smaller on elastography than B-mode imaging and malignant lesions appearing larger on elastography is an important feature for characterization of breast masses. There are several artifacts which can contain diagnostic information or alert to technique problems. Both strain and shear wave elastography continue to have improvements and new techniques will soon be available for clinical use that may provide additional diagnostic information. This paper reviews the present state of breast elastography and discusses future techniques that are not yet in clinical practice.

Three-Dimensional Shear Wave Elastography for Differentiating Benign From Malignant Thyroid Nodules

OBJECTIVES

To prospectively evaluate the diagnostic performance of 3-dimensional (3D) shear wave elastography (SWE) for assessing thyroid nodules.

METHODS

A total of 176 surgically or cytologically confirmed thyroid nodules (63 malignant and 113 benign) in 176 patients who had undergone conventional ultrasound (US), 2-dimensional (2D) SWE, and 3D SWE examinations were included in this study. Quantitative elasticity values (mean elasticity, maximum elasticity, and standard deviation of elasticity of a large region of interest and mean elasticity of a 2-mm region of interest) were measured on 2D and 3D SWE. Diagnostic performances of conventional US, 2D SWE, and 3D SWE were assessed. The role of 2D and 3D SWE in reducing unnecessary fine-needle aspiration (FNA) for nodules with low suspicion was also evaluated.

RESULTS

The diagnostic performances in terms of the area under the receiver operating characteristic curve were 0.612 for conventional US, 0.836 for 2D SWE (P < .001 in comparison with conventional US), and 0.839 for 3D SWE (P < .001 in comparison with conventional US). The mean elasticity achieved the highest diagnostic performance in 2D SWE, whereas the standard deviation of elasticity achieved the highest performance in 3D SWE, although no significant difference was found between them (P > .05). Three-dimensional SWE increased the specificity in comparison with 2D SWE (88.5% versus 82.3%; P = .039). For the 37 nodules with low suspicion on conventional US imaging, 2D SWE was able to avoid unnecessary FNA in 77.1% (27 of 35) of benign nodules, and 3D SWE further increased the number to 88.6% (31 of 35).

CONCLUSIONS

Three-dimensional SWE is a useful tool for predicting thyroid nodule malignancy and reducing unnecessary FNA procedures in thyroid nodules with low suspicion of malignancy.

Fibrosis imaging: Current concepts and future directions

Fibrosis plays an important role in many different pathologies. It results from tissue injury, chronic inflammation, autoimmune reactions and genetic alterations, and it is characterized by the excessive deposition of extracellular matrix components. Biopsies are routinely employed for fibrosis diagnosis, but they suffer from several drawbacks, including their invasive nature, sampling variability and limited spatial information. To overcome these limitations, multiple different imaging tools and technologies have been evaluated over the years, including X-ray imaging, computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), positron emission tomography (PET) and single-photon emission computed tomography (SPECT). These modalities can provide anatomical, functional and molecular imaging information which is useful for fibrosis diagnosis and staging, and they may also hold potential for the longitudinal assessment of therapy responses. Here, we summarize the use of non-invasive imaging techniques for monitoring fibrosis in systemic autoimmune diseases, in parenchymal organs (such as liver, kidney, lung and heart), and in desmoplastic cancers. We also discuss how imaging biomarkers can be integrated in (pre-) clinical research to individualize and improve anti-fibrotic therapies.