Diagnostic Accuracy of Shear-Wave Elastography for Breast Lesion Characterization in Women: A Systematic Review and Meta-Analysis

Diagnostic performance of ultrasound elastography in differentiating malignant from benign breast microcalcifications: a case-control study

OBJECTIVE

To evaluate the sensitivity and specificity of ultrasound elastography in differentiating between malignant and benign breast microcalcifications through a case-control study.

METHODS

A total of 300 female patients were enrolled in this study, equally divided between malignant (n = 150) and benign (n = 150) microcalcification groups. The malignant cases were histologically confirmed as ductal carcinoma in situ or invasive breast cancer, while benign cases were confirmed through histology or follow-up as fibroadenoma, fibrocystic changes, or benign calcifications. Ultrasound elastography parameters, including elastic modulus (kPa), strain ratio, and elasticity scores, were measured and compared between groups. Multiple logistic regression analysis was performed to identify independent predictors, and diagnostic performance was evaluated using ROC curve analysis.

RESULTS

Malignant lesions demonstrated significantly higher mean elasticity values compared to benign lesions (88.3 ± 16.2 kPa vs. 45.7 ± 9.8 kPa, P < 0.001). The strain ratio and elasticity scores were also significantly elevated in the malignant group (both P < 0.001). Multivariate analysis identified elastic modulus (OR = 1.09, 95%CI: 1.06-1.12, P < 0.001) and strain ratio (OR = 2.50, 95%CI: 1.70-3.80, P < 0.001) as independent predictors of malignancy. Using an optimal cutoff value of 62 kPa for elasticity, the diagnostic sensitivity was 88.0% (95%CI: 81.5-92.8%) and specificity was 86.7% (95%CI: 79.5-91.9%), with an accuracy of 89.0%. The area under the ROC curve (AUC) for elasticity alone was 0.95 (95%CI: 0.92-0.98), which improved to 0.97 (95%CI: 0.94-0.99) when combined with strain ratio (P = 0.018). High interobserver agreement was demonstrated (Kappa = 0.84, 95%CI: 0.79-0.88), and Bland-Altman analysis confirmed excellent measurement reliability.

CONCLUSION

Ultrasound elastography demonstrates high diagnostic accuracy in differentiating between malignant and benign breast microcalcifications, with excellent reproducibility and reliability. The combination of elasticity values and strain ratio provides superior diagnostic performance compared to single parameters alone, suggesting its potential as a valuable tool in clinical practice for the evaluation of breast microcalcifications.

Sonographic Glandular Tissue Component: A Potential Imaging Marker for Upgrading BI-RADS 4A Breast Masses

PURPOSE

To investigate whether sonographic glandular tissue component (GTC) can optimize the management of breast imaging reporting and data system (BI-RADS) 4A breast masses.

MATERIALS AND METHODS

We reviewed the patients with BI-RADS 4A breast masses confirmed by ultrasound and pathology reports from January to December 2020. Based on conventional breast ultrasound images, GTC was categorized into GTC-Low and GTC-High. The consistency of the GTC classification between two radiologists was evaluated using a kappa test. Propensity score matching (PSM) was applied to adjust for unbalanced characteristics between the two groups. Logistic regression was used to analyze the relationship between sonographic GTC and the likelihood of BI-RADS 4A masses being benign or malignant.

RESULTS

Of the 319 patients included finally in the study, the agreement between the two radiologists regarding the GTC classification was good (weighted kappa: 0.736/0.716). The malignancy rate in the GTC-High group (32.7%, 16/49) was significantly higher than that in the overall cohort (14.1%, 45/319; P=0.001). After PSM adjustment to balance relevant covariates between the GTC-High and GTC-Low groups, 45 GTC-High patients were matched with 45 GTC-Low patients. After matching, univariate and multivariate logistic regression analyses identified sonographic GTC as an independent variable associated with malignancy in BI-RADS 4A masses (P=0.012). After matching, the malignancy rate in the GTC-High group (35.6%,16/45) was significantly higher (P=0.014) than that in the GTC-Low group (13.3%, 6/45).

CONCLUSION

Sonographic GTC is an independent predictor of malignancy in BI-RADS 4A breast masses. Masses initially classified as BI-RADS 4A may warrant reclassification to BI-RADS 4B when identified as GTC-High.

Unveiling Matrix Metalloproteinase 13's Dynamic Role in Breast Cancer: A Link to Physical Changes and Prognostic Modulation

The biomechanical properties of the extracellular matrix (ECM) including its stiffness, viscoelasticity, collagen architecture, and temperature constitute critical biomechanical cues governing breast cancer progression. Matrix metalloproteinase 13 (MMP13) is an important marker of breast cancer and plays important roles in matrix remodelling and cell metastasis. Emerging evidence highlights MMP13 as a dynamic modulator of the ECM's physical characteristics through dual mechanoregulatory mechanisms. While MMP13-mediated collagen degradation facilitates microenvironmental softening, thus promoting tumour cell invasion, paradoxically, its crosstalk with cancer-associated fibroblasts (CAFs) and tumour-associated macrophages (TAMs) drives pathological stromal stiffening via aberrant matrix deposition and crosslinking. This biomechanical duality is amplified through feedforward loops with an epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) populations, mediated by signalling axes such as TGF-β/Runx2. Intriguingly, MMP13 exhibits context-dependent mechanomodulatory effects, demonstrating anti-fibrotic activity and inhibiting the metastasis of breast cancer. At the same time, angiogenesis and increased metabolism are important mechanisms through which MMP13 promotes a temperature increase in breast cancer. Targeting the spatiotemporal regulation of MMP13's mechanobiological functions may offer novel therapeutic strategies for disrupting the tumour-stroma vicious cycle.

Ultrasound Viscosity Imaging in Breast Lesions: A Multicenter Prospective Study

RATIONALE AND OBJECTIVES

To explore and validate the clinical value of ultrasound (US) viscosity imaging in differentiating breast lesions by combining with BI-RADS, and then comparing the diagnostic performances with BI-RADS alone.

MATERIALS AND METHODS

This multicenter, prospective study enrolled participants with breast lesions from June 2021 to November 2022. A development cohort (DC) and validation cohort (VC) were established. Using histological results as reference standard, the viscosity-related parameter with the highest area under the receiver operating curve (AUC) was selected as the optimal one. Then the original BI-RADS would upgrade or not based on the value of this parameter. Finally, the results were validated in the VC and total cohorts. In the DC, VC and total cohorts, all breast lesions were divided into the large lesion, small lesion and overall groups respectively.

RESULTS

A total of 639 participants (mean age, 46 years ± 14) with 639 breast lesions (372 benign and 267 malignant lesions) were finally enrolled in this study including 392 participants in the DC and 247 in the VC. In the DC, the optimal viscosity-related parameter in differentiating breast lesions was calculated to be A'-S2-Vmax, with the AUC of 0.88 (95% CI: 0.84, 0.91). Using > 9.97 Pa.s as the cutoff value, the BI-RADS was then modified. The AUC of modified BI-RADS significantly increased from 0.85 (95% CI: 0.81, 0.88) to 0.91 (95% CI: 0.87, 0.93), 0.85 (95% CI: 0.80, 0.89) to 0.90 (95% CI: 0.85, 0.93) and 0.85 (95% CI: 0.82, 0.87) to 0.90 (95% CI: 0.88, 0.92) in the DC, VC and total cohorts respectively (P < .05 for all).

CONCLUSION

The quantitative viscous parameters evaluated by US viscosity imaging contribute to breast cancer diagnosis when combined with BI-RADS.

Current status of optoacoustic breast imaging and future trends in clinical application: is it ready for prime time?

Optoacoustic imaging (OAI) is an emerging field with increasing applications in patients and exploratory clinical trials for breast cancer. Optoacoustic imaging (or photoacoustic imaging) employs non-ionizing, laser light to create thermoelastic expansion in tissues and detect the resulting ultrasonic emission. By combining high optical contrast capabilities with the high spatial resolution and anatomic detail of grayscale ultrasound, OAI offers unique opportunities for visualizing biological function of tissues in vivo. Over the past decade, human breast applications of OAI, including benign/malignant mass differentiation, distinguishing cancer molecular subtype, and predicting metastatic potential, have significantly increased. We discuss the current state of optoacoustic breast imaging, as well as future opportunities and clinical application trends. CLINICAL RELEVANCE STATEMENT: Optoacoustic imaging is a novel breast imaging technique that enables the assessment of breast cancer lesions and tumor biology without the risk of ionizing radiation exposure, intravenous contrast, or radionuclide injection. KEY POINTS: • Optoacoustic imaging (OAI) is a safe, non-invasive imaging technique with thriving research and high potential clinical impact. • OAI has been considered a complementary tool to current standard breast imaging techniques. • OAI combines parametric maps of molecules that absorb light and scatter acoustic waves (like hemoglobin, melanin, lipids, and water) with anatomical images, facilitating scalable and real-time molecular evaluation of tissues.

Kidney cortex shear wave motion simulations based on segmented biopsy histology

BACKGROUND AND OBJECTIVE

Biopsy stands as the gold standard for kidney transplant assessment, yet its invasive nature restricts frequent use. Shear wave elastography (SWE) is emerging as a promising alternative for kidney transplant monitoring. A parametric study involving 12 biopsy data sets categorized by standard biopsy scores (3 with normal histology, 3 with interstitial inflammation (i), 3 with interstitial fibrosis (ci), and 3 with tubular atrophy (ct)), was conducted to evaluate the interdependence between microstructural variations triggered by chronic allograft rejection and corresponding alterations in SWE measurements.

METHODS

Heterogeneous shear wave motion simulations from segmented kidney cortex sections were performed employing the staggered-grid finite difference (SGFD) method. The SGFD method allows the mechanical properties to be defined on a pixel-basis for shear wave motion simulation. Segmentation techniques enabled the isolation of four histological constituents: glomeruli, tubules, interstitium, and fluid. Baseline ex vivo Kelvin-Voigt mechanical properties for each constituent were drawn from established literature. The parametric evaluation was then performed by altering the baseline values individually. Shear wave velocity dispersion curves were measured with the generalized Stockwell transform in conjunction with slant frequency-wavenumber analysis (GST-SFK) algorithm. By fitting the curve within the 100-400 Hz range to the Kelvin-Voigt model, the rheological parameters, shear elasticity (µ1) and viscosity (µ2), were estimated. A time-to-peak algorithm was used to estimate the group velocity. The resultant in silico models emulated the heterogeneity of kidney cortex within the shear wave speed (SWS) reconstructions.

RESULTS

The presence of inflammation showed considerable spatial composition disparities compared to normal cases, featuring a 23 % increase in interstitial area and a 19 % increase in glomerular area. Concomitantly, there was a reduction of 12 % and 47 % in tubular and fluid areas, respectively. Consequently, mechanical changes induced by inflammation predominate in terms of rheological differentiation, evidenced by increased elasticity and viscosity. Mild tubular atrophy showed significant elevation in group velocity and µ1. Conversely, mild and moderate fibrosis exhibited negligible alterations across all parameters, compatible with relatively limited morphological impact.

CONCLUSIONS

This proposed model holds promise in enabling patient-specific simulations of the kidney cortex, thus facilitating exploration into how pathologies altering cortical morphology correlates to modifications in SWE-derived rheological measurements. We demonstrated that inflammation caused substantial changes in measured mechanical properties.

Focused Shear Wave Beam Propagation in Tissue-Mimicking Phantoms

OBJECTIVE

Ultrasound transient elastography (TE) technologies for liver stiffness measurement (LSM) utilize vibration of small, flat pistons, which generate shear waves that lack directivity. The most common cause for LSM failure in practice is insufficient shear wave signal at the needed depths. We propose to increase shear wave amplitude by focusing the waves into a directional beam. Here, we demonstrate the generation and propagation of focused shear wave beams (fSWBs) in gelatin.

METHODS

Directional fSWBs are generated by vibration at 200-400 Hz of a concave piston embedded near the surface of gelatin phantoms and measured with high-frame-rate ultrasound imaging. Five phantoms with a range of stiffnesses are employed. Shear wave speeds assessed by fSWBs are compared with those by radiation-force-based methods (2D SWE). fSWB amplitudes are compared to predictions using an analytical model.

RESULTS

fSWB-derived shear wave speeds are in good agreement with 2D SWE. The amplitudes of fSWBs are localized to the LSM region and are significantly greater than unfocused shear waves. Overall agreement with theory is observed, with some discrepancies in the theoretical source condition.

CONCLUSION

Focusing shear waves can increase the signal in the LSM region for TE. Challenges for translation include coupling piston vibration with the patient skin and increased attenuation in vivo compared to the phantoms employed here.

SIGNIFICANCE

Fibrosis is the most predictive measure of patient outcome in non-alcoholic fatty liver disease. Increased shear wave amplitude in the LSM region can reduce fibrosis assessment failure rates by TE, thus reducing the need for invasive methods like biopsy.

Breast Cancer Screening and Diagnosis: Recent Advances in Imaging and Current Limitations

Breast cancer detection has a significant impact on population health. Although there are many breast imaging modalities, mammography is the predominant tool for breast cancer screening. The introduction of digital breast tomosynthesis to mammography has contributed to increased cancer detection rates and decreased recall rates. In average-risk women, starting annual screening mammography at age 40 years has demonstrated the highest mortality reduction. In intermediate- and high-risk women as well as in those with dense breasts, additional modalities, including MRI, ultrasound, and molecular breast imaging, can also be considered for adjunct screening to improve the detection of mammographically occult malignancy.

Best Practice Guideline - DEGUM Recommendations on Breast Ultrasound

Alongside mammography, breast ultrasound is an important and well-established method in assessment of breast lesions. With the "Best Practice Guideline", the DEGUM Breast Ultrasound (in German, "Mammasonografie") working group, intends to describe the additional and optional application modalities for the diagnostic confirmation of breast findings and to express DEGUM recommendations in this Part II, in addition to the current dignity criteria and assessment categories published in Part I, in order to facilitate the differential diagnosis of ambiguous lesions.The present "Best Practice Guideline" has set itself the goal of meeting the requirements for quality assurance and ensuring quality-controlled performance of breast ultrasound. The most important aspects of quality assurance are explained in this Part II of the Best Practice Guideline.

Improved Breast 2D SWE Algorithm to Eliminate False-Negative Cases

OBJECTIVES

Two-dimensional shear wave elastography (SWE) has been limited in breast lesion characterization due to false-negative results from artifacts. The aim of this study was to evaluate an updated Food and Drug Administration-approved breast 2D-SWE algorithm and compare with the standard algorithm (SA).

MATERIALS AND METHODS

This prospective, single-center study was approved by our local institutional review board and Health Insurance Portability and Accountability Act compliant. From April 25, 2019 to May 2, 2022, raw shear wave data were saved on patients having screening or diagnostic breast ultrasound on a Siemens Sequoia US. After removing duplicate images and those without biopsy diagnosis or stability over 2 years, there were 298 patients with 394 lesions with biopsy-proven pathology or >2-year follow-up. Raw data were processed using the SA and a new algorithm (NA). Five-millimeter regions of interest were placed in the highest stiffness in the lesion or adjacent 3 mm on the SA. Stiffness values (shear wave speed, max) in this location from both algorithms were recorded. Statistics were calculated for comparing the 2 algorithms.

RESULTS

The mean patient age was 56.3 ± 16.1 years (range, 21-93 years). The mean benign lesion size was 10.7 ± 8.0 mm (range, 2-46 mm), whereas the mean malignant lesion size was 14.9 ± 7.8 mm (range, 4-36 mm). There were 201 benign (>2-year follow-up) and 193 biopsied lesions (65 benign; 128 malignant). The mean maximum stiffness for benign lesions was 2.37 m/s (SD 1.26 m/s) for SA and 3.51 m/s (SD 2.05 m/s) for NA. For malignant lesions, the mean maximum stiffness was 4.73 m/s (SD, 1.71 m/s) for SA and 8.45 m/s (SD, 1.42 m/s) for NA. The area under the receiver operating characteristic curve was 0.87 SA and 0.95 NA when using the optimal cutoff value. Using a threshold value of 5.0 m/s for NA and comparing to SA, the sensitivity increased from 0.45 to 1.00 and the specificity decreased from 0.94 to 0.81; the positive predictive value was 0.72, the negative predictive value was 1.00, and the negative likelihood ratio was 0.00.

CONCLUSIONS

Using a new breast SWE algorithm significantly improves the sensitivity of the technique with a small decrease in specificity, virtually eliminating the "soft" cancer artifact. The new 2D-SWE algorithm significantly increases the sensitivity and negative predictive value in characterizing breast lesions as benign or malignant and allows for downgrading all BI-RADS 4 lesions.

Clinical applications of shear wave dispersion imaging for breast lesions: a pictorial essay

Shear wave dispersion (SWD) imaging is a newly developed ultrasound technology designed to evaluate the dispersion slope of shear waves, which is related to tissue viscosity. This advanced imaging technique holds potential for distinguishing malignant lesions from benign lesions and normal breast tissue. The SWD slope, as determined by shear wave elastography (SWE), could offer crucial insights into the characterization of breast lesions. This article presents SWE and SWD images of both malignant and benign breast lesions, in addition to normal breast tissue.

Real-Time Elastography versus Shear Wave Elastography on Evaluating the Timely Radiofrequency Ablation Effect of Rabbit Liver: A Preliminary Experimental Study

Purpose: to evaluate and monitor the timely thermal ablation changes of rabbit liver by using two elastographic methods—real-time elastography (RTE) and shear wave elastography (SWE)—as compared to contrast-enhanced ultrasound (CEUS) and physical specimens. Materials and Methods: 20 ablation zones were created in the livers of 20 rabbits using radiofrequency ablation (RFA). After the ablation, RTE and SWE were used to measure the elastic properties of the twenty ablation zones. The consistency of efficacy evaluation for RTE and SWE measurements was analyzed using the Bland–Altman test. The areas of the thermal ablation zones were also measured and compared according to the images provided by RTE, SWE, CEUS, and gross physical specimen measurement. Results: RTE and SWE could clearly display the shape of RFA ablation zones within one hour after the ablation. The average elasticity ratio for the ablation zone measured by RTE was 3.41 ± 0.67 (2.23–4.76); the average elasticity value measured by SWE was 50.7 ± 11.3 kPa (33.2–70.4 kPa). The mean areas of the ablation zones measured with RTE, SWE, gross specimen, and CEUS were 1.089 ± 0.199 cm2, 1.059 ± 0.201 cm2, 1.081 ± 0.201 cm2, and 3.091 ± 0.591 cm2, respectively. The Bland–Altman test showed that RTE and SWE have great consistency. Area measurements by CEUS were significantly larger than those of the other three methods (p < 0.05). Conclusion: RTE and SWE are both able to accurately confirm the range of ablation zones shortly after the ablation for rabbit livers.

Quantitative Assessment of Breast-Tumor Stiffness Using Shear-Wave Elastography Histograms

Purpose: Shear-wave elastography (SWE) measures tissue elasticity using ultrasound waves. This study proposes a histogram-based SWE analysis to improve breast malignancy detection. Methods: N = 22/32 (patients/tumors) benign and n = 51/64 malignant breast tumors with histological ground truth. Colored SWE heatmaps were adjusted to a 0−180 kPa scale. Normalized, 250-binned RGB histograms were used as image descriptors based on skewness and area under curve (AUC). The histogram method was compared to conventional SWE metrics, such as (1) the qualitative 5-point scale classification and (2) average stiffness (SWEavg)/maximal tumor stiffness (SWEmax) within the tumor B-mode boundaries. Results: The SWEavg and SWEmax did not discriminate malignant lesions in this database, p > 0.05, rank sum test. RGB histograms, however, differed between malignant and benign tumors, p < 0.001, Kolmogorov−Smirnoff test. The AUC analysis of histograms revealed the reduction of soft-tissue components as a significant SWE biomarker (p = 0.03, rank sum). The diagnostic accuracy of the suggested method is still low (Se = 0.30 for Se = 0.90) and a subject for improvement in future studies. Conclusions: Histogram-based SWE quantitation improved the diagnostic accuracy for malignancy compared to conventional average SWE metrics. The sensitivity is a subject for improvement in future studies.