Shear-wave elastography of invasive breast cancer: correlation between quantitative mean elasticity value and immunohistochemical profile

The mechanopathology of the tumor microenvironment: detection techniques, molecular mechanisms and therapeutic opportunities

The mechanical properties of the tumor microenvironment (TME) undergo significant changes during tumor growth, primarily driven by alterations in extracellular (ECM) stiffness and tumor viscoelasticity. These mechanical changes not only promote tumor progression but also hinder therapeutic efficacy by impairing drug delivery and activating mechanotransduction pathways that regulate crucial cellular processes such as migration, proliferation, and resistance to therapy. In this review, we examine the mechanisms through which tumor cells sense and transmit mechanical signals to maintain homeostasis in the biomechanically altered TME. We explore current computational modelling strategies for mechanotransduction pathways, highlighting the need for developing models that incorporate additional components of the mechanosignaling machinery. Furthermore, we review available methods for measuring the mechanical properties of tumors in clinical settings and strategies aiming at restoring the TME and blocking deregulated mechanotransduction pathways. Finally, we propose that proper characterization and a deeper understanding of the mechanical landscape of the TME, both at the tissue and cellular levels, are essential for developing therapeutic strategies that account for the influence of mechanical forces on treatment efficacy.

Magnetic Resonance Elastography of Invasive Breast Cancer: Evaluating Prognostic Factors and Treatment Response

Objectives: To assess the elasticity values in breast tissues using magnetic resonance elastography (MRE) and examine the association between elasticity values of invasive breast cancer with prognostic factors and the pathologic response to neoadjuvant systemic therapy (NST). Methods: A total of 57 patients (mean age, 54.1 years) with invasive breast cancers larger than 2 cm in diameter on ultrasound were prospectively enrolled. The elasticity values (mean, minimum, and maximum) of invasive breast cancers, normal fibroglandular tissues, and normal fat tissues were measured via MRE using a commercially available acoustic driver and compared. Elasticity values of breast cancers were compared according to prognostic factors and pathologic responses in patients who received NST before surgery. Receiver operating curve analysis was performed to evaluate the predictive efficacy of elasticity values in terms of pathological response. Results: Among the 57 patients, the mean elasticity value of invasive breast cancers was significantly higher than that of normal fibroglandular tissue and normal fat tissue (7.90 ± 5.80 kPa vs. 2.54 ± 0.80 kPa vs. 1.32 ± 0.33 kPa, all ps < 0.001). Invasive breast cancers with a large diameter (>4 cm) exhibited significantly higher mean elasticity values relative to tumors with a small diameter (≤4 cm) (11.65 ± 7.22 kPa vs. 5.87 ± 3.58 kPa, p = 0.002). Among 24 patients who received NST, mean, minimum, and maximum elasticity values significantly differed between the pathologic complete response (pCR) and non-pCR groups (all ps < 0.05). For the mean elasticity value, the area under the curve value for distinguishing pCR and non-pCR groups was 0.880 (95% confidence interval, 0.682, 0.976; p < 0.001). Conclusions: The elasticity values of invasive breast cancers measured via breast MRE showed a positive correlation with tumor size and showed potential in predicting the therapeutic response in patients receiving NST.

Diffusion-Weighted MRI-Based Virtual Elastography and Shear-Wave Elastography for the Assessment of Breast Lesions

BACKGROUND

Diffusion-weighted imaging (DWI)-based virtual MR elastography (DWI-vMRE) in the assessment of breast lesions is still in the research stage.

PURPOSE

To investigate the usefulness of elasticity values on DWI-vMRE in the evaluation of breast lesions, and the correlation with the values calculated from shear-wave elastography (SWE).

STUDY TYPE

Prospective.

POPULATION/SUBJECTS

153 patients (mean age ± standard deviation: 55 ± 12 years) with 153 pathological confirmed breast lesions (24 benign and 129 malignant lesions).

FIELD STRENGTH/SEQUENCE

1.5-T MRI, multi-b readout segmented echo planar imaging (b-values of 0, 200, 800, and 1000 sec/mm2).

ASSESSMENT

For DWI-vMRE assessment, lesions were manually segmented using apparent diffusion coefficient (ADC0-1000) map, then the region of interests were copied to the map of shifted-ADC (sADC200-800, sADC 200-1500). For SWE assessment, the shear modulus of the lesions was measured by US elastic modulus (μUSE). Intraclass/interclass kappa coefficients were calculated to measure the consistency.

STATISTICAL TESTS

Pearson's correlation was used to assess the relationship between sADC and μUSE. A receiver operating characteristic analysis with the area under the curve (AUC) was performed to compare the diagnostic accuracy between benign and malignant breast lesions of sADC and μUSE. A P value <0.05 was considered statistically significant.

RESULTS

There were significant differences between benign and malignant breast lesions of μUSE (24.17 ± 10.64 vs. 37.20 ± 12.61), sADC200-800 (1.38 ± 0.31 vs. 0.97 ± 0.18 × 10-3 mm2/sec), and sADC200-1500 (1.14 ± 0.30 vs. 0.78 ± 0.13 × 10-3 mm2/sec). In all breast lesions, a moderate but significant correlation was observed between μUSE and sADC200-800/sADC200-1500 (r = -0.49/-0.44). AUC values to differentiate benign from malignant lesions were as follows: μUSE, 0.78; sADC200-800, 0.89; sADC200-1500, 0.89.

DATA CONCLUSIONS

Both SWE and DWI-vMRE could be used for the differentiation of benign versus malignant breast lesions. Furthermore, DWI-vMRE with the use of sADC show relatively higher AUC values than SWE.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 2.

Correlation of shear-wave elastography stiffness and apparent diffusion coefficient values with tumor characteristics in breast cancer

We aimed to investigate the correlation between shear-wave elastography (SWE) and apparent diffusion coefficient (ADC) values in breast cancer and to identify the associated characteristics. We included 91 breast cancer patients who underwent SWE and breast MRI prior to surgery between January 2016 and November 2017. We measured the lesion's mean (Emean) and maximum (Emax) elasticities of SWE and ADC values. We evaluated the correlation between SWE, ADC values and tumor size. The mean SWE and ADC values were compared for categorical variable of the pathological/imaging characteristics. ADC values showed negative correlation with Emean (r =  - 0.315, p = 0.002) and Emax (r =  - 0.326, p = 0.002). SWE was positively correlated with tumor size (r = 0.343-0.366, p < 0.001). A higher SWE value indicated a tendency towards a higher T stage (p < 0.001). Triple-negative breast cancer showed the highest SWE values (p = 0.02). SWE were significantly higher in breast cancers with posterior enhancement, vascularity, and washout kinetics (p < 0.02). SWE stiffness and ADC values were negatively correlated in breast cancer. SWE values correlated significantly with tumor size, and were higher in triple-negative subtype and aggressive imaging characteristics.

Tumor-Infiltrating Lymphocyte Level Consistently Correlates with Lower Stiffness Measured by Shear-Wave Elastography: Subtype-Specific Analysis of Its Implication in Breast Cancer

Background: We aimed to elucidate the clinical significance of tumor stiffness across breast cancer subtypes and establish its correlation with the tumor-infiltrating lymphocyte (TIL) levels using shear-wave elastography (SWE). Methods: SWE was used to measure tumor stiffness in breast cancer patients from January 2016 to August 2020. The association of tumor stiffness and clinicopathologic parameters, including the TIL levels, was analyzed in three breast cancer subtypes. Results: A total of 803 patients were evaluated. Maximal elasticity (Emax) showed a consistent positive association with an invasive size and the pT stage in all cases, while it negatively correlated with the TIL level. A subgroup-specific analysis revealed that the already known parameters for high stiffness (lymphovascular invasion, lymph node metastasis, Ki67 levels) were significant only in hormone receptor-positive and HER2-negative breast cancer (HR + HER2-BC). In the multivariate logistic regression, an invasive size and low TIL levels were significantly associated with Emax in HR + HER2-BC and HER2 + BC. In triple-negative breast cancer, only TIL levels were significantly associated with low Emax. Linear regression confirmed a consistent negative correlation between TIL and Emax in all subtypes. Conclusions: Breast cancer stiffness presents varying clinical implications dependent on the tumor subtype. Elevated stiffness indicates a more aggressive tumor biology in HR + HER2-BC, but is less significant in other subtypes. High TIL levels consistently correlate with lower tumor stiffness across all subtypes.

Predicting the expansion of the lower pole of the breast following smooth breast implant augmentation: A novel shear wave elastography study

OBJECTIVES

This study aimed to educate and demonstrate how the use of shear wave elastography (SWE) can be used to determine the elasticity of patient tissues preoperatively, which can then be used to predict the level of lower pole expansion postoperatively, following breast augmentation surgery.

MATERIALS AND METHODS

This study evaluated 60 breasts in 30 patients that were divided in 3 equal groups (n = 20) according to their predefined elastography criteria measured via SWE (loose, moderate, and tight tissue elasticity). All measurements were taken under maximum stretch between the inferior border of the nipple alveolar complex (NAC) and inframammary fold (IMF) using a measuring tape in millimetres (mm). The follow-up appointments for routine assessments and measurements were done at 3, 6, 12, 18, and 24 months.

RESULTS

The study engaged 38 patients over 4 years, but only 10 patients in each group attended all the appointments. Statistical analysis showed the elastic skin types (loose, moderate, and tight) had significantly different rates of lower pole expansion, and the rate of expansion increased significantly after 6 months postoperatively, whereas prior to 6 months, the rates were comparable (p < 0.05).

DISCUSSION

The results showed that increasingly elastic skin types have a greater rate of lower pole expansion. This is important for the operating surgeon to be aware of as looser skin types will be more prone to lower pole expansion, and thus, a higher surgical IMF suture may be advised to manage patient expectations.

CONCLUSION

This study can be used as a guideline for surgeons, which will allow for a more predictable surgical planning system that will ultimately lead to fewer revisions and risks for patients worldwide.

Correlation of shear-wave elastography parameters with the molecular subtype and axillary lymph node status in breast cancer

PURPOSE

To examine correlations between shear-wave elastography (SWE) parameters with molecular subtype and axillary lymph node (LN) status of breast cancer.

METHODS

We retrospectively analyzed 545 consecutive women (mean age, 52.7 ± 10.7 years; range, 26-83) with breast cancer who underwent preoperative breast ultrasound with SWE between December 2019 and January 2021. SWE parameters (E_max, E_mean, and E_ratio) and the histopathologic information from surgical specimens including histologic type, histologic grade, size of invasive cancer, hormone receptor and HER2 status, Ki-67 proliferation index, and axillary LN status were analyzed. The relationships between SWE parameters and histopathologic findings were analyzed using an independent sample t-test, one-way ANOVA test with Tukey's post hoc test, and logistic regression analyses.

RESULTS

Higher stiffness values of SWE were associated with larger lesion size (>20 mm) on ultrasound, high histologic grade, larger invasive cancer size (>20 mm), high Ki-67, and axillary LN metastasis. E_max and E_mean were the lowest in the luminal A-like subtype, and all three parameters were the highest in the triple-negative subtype. Lower value of E_max was independently associated with the luminal A-like subtype (P = 0.04). Higher value of E_mean was independently associated with axillary LN metastasis for tumors ≤ 20 mm (P = 0.03).

CONCLUSION

Increases in the tumor stiffness values on SWE were significantly associated with aggressive histopathologic features of breast cancer. Lower stiffness values were associated with the luminal A-like subtype, and tumors with higher stiffness values were associated with axillary LN metastasis in small breast cancers.

The Utility of Quantitative Parameters of Shear-Wave Elastography to Predict Prognostic Histologic Features of Breast Cancer

ABSTRACT

In this study, we aimed to investigate the correlation of stiffness values of shear-wave elastography (SWE) and histopathological prognostic factors in patients with breast cancer. Between January 2021 and June 2022, SWE images of 138 core-biopsy proven breast cancer lesions from 132 patients were retrospectively reviewed. Histopathogic prognostic factors, including tumor size, histologic grade, histologic type, hormone receptor positivity, human epidermal growth factor receptor (HER2) status, immunohistochemical subtype and Ki-67 index were documented. Elasticity values including mean and maximum elasticity ( Emean and Emax ) and lesion-to-fat ratio ( Eratio ) were recorded. The association between histopathological prognostic factors and elasticity values were assessed using Mann-Whitney U and Kruskal-Wallis test, and multiple linear regression analysis. Tumor size, histological grade, and Ki-67 index were significantly associated with the Eratio ( P < 0.05). Larger tumor size and higher Ki-67 index also showed significantly higher Emean and Emax values ( P < 0.05). However, hormone receptor positivity, HER2 status, and immunohistochemical subtype were not significantly associated with elasticity values ( P > 0.05). Multivariate logistic regression analysis revealed that tumor size was significantly associated with Emean , Emax , and Eratio values ( P < 0.05). A high Ki-67 index was also significantly associated with high Eratio values. Larger tumor size and higher Ki-67 index are independently associated with high Eratio values. Preoperative SWE may improve the performance of conventional ultrasound in predicting prognosis and treatment planning.

Correlation analysis between shear-wave elastography and pathological profiles in breast cancer

PURPOSE

To explore the correlation between shear-wave elastography (SWE) parameters and pathological profiles of invasive breast cancer.

METHODS

A total of 197 invasive breast cancers undergoing preoperative SWE and primary surgical treatment were included. Maximum elastic modulus (Emax), mean elastic modulus (Emean), and elastic modulus standard deviation (Esd) were calculated by SWE. Pathological profile was gold standard according to postoperative pathology. The relationship between SWE parameters and pathological factors were analyzed using univariate and multivariate analysis.

RESULTS

In univariate analysis, large cancers showed significantly higher Emax, Emean and Esd (all P < 0.001). Emax and Esd in the group of histological grade III were higher than those in the group of grade I (both P < 0.05). Invasive lobular carcinomas (ILC) showed higher Emean than invasive ductal carcinoma (IDC) (P < 0.001). Lymphovascular invasion (LVI) group showed higher Emax values than negative group (P < 0.05). Emax, Emean and Esd of the Ki-67 positive group presented higher values than negative group (all P < 0.05). Androgen receptor (AR) positive lesions had lower Esd than AR negative lesions (P < 0.05). In multivariate analysis, invasive size independently influenced Emax (P < 0.001). Invasive size and pathological type both independently influenced Emean (both P < 0.001). Invasive size and AR status were both independently influenced Esd (both P < 0.05).

CONCLUSION

SWE parameters correlated with pathological profiles of invasive breast cancer.In particular, AR positive group showed significantly low Esd than negative group.

Clinical Significance of Ultrasound Elastography and Fibrotic Focus and Their Association in Breast Cancer

(1) Background: Ultrasound (US) elastography is an imaging technology that reveals tissue stiffness. This study aimed to investigate whether fibrotic focus (FF) affects elastographic findings in breast cancer, and to evaluate the clinical significance of US elastography and FF in breast cancer. (2) Methods: In this study, 151 patients with breast cancer who underwent surgery were included. Strain elastography was performed and an elasticity scoring system was used to assess the findings. The elasticity scores were classified as negative, equivocal, or positive. FF was evaluated in the surgical specimens. Medical records were reviewed for all patients. (3) Results: Elastographic findings were equivocal in 30 patients (19.9%) and positive in 121 patients (80.1%). FF was present in 68 patients (46.9%). There was no correlation between elastographic findings and FF. Older age, larger tumor size, lymph node metastasis, and higher tumor stage were associated with positive elastographic results. FF showed a positive correlation with age, postmenopausal status, tumor size, lymphovascular invasion, lymph node metastasis, tumor stage, and intratumoral and peritumoral inflammation. (4) Conclusions: Our study showed that positive elastographic results and FF were associated with poor prognostic factors for breast cancer. FF did not affect the elastographic findings of this study.

Correlation of Shear-Wave Elastography and Apparent Diffusion Coefficient Values in Breast Cancer and Their Relationship with the Prognostic Factors

Background: Diffusion-weighted imaging and elastography are widely accepted methods in the evaluation of breast masses, however, there is very limited data comparing the two methods. The apparent diffusion coefficient is a measure of the diffusion of water molecules obtained by diffusion-weighted imaging as a part of breast MRI. Breast elastography is an adjunct to conventional ultrasonography, which provides a noninvasive evaluation of the stiffness of the lesion. Theoretically, increased tissue density and stiffness are related to each other. The purpose of this study is to compare MRI ADC values of the breast masses with quantitative elastography based on ultrasound shear wave measurements and to investigate their possible relation with the prognostic factors and molecular subtypes. Methods: We retrospectively evaluated histopathologically proven 147 breast lesions. The molecular classification of malignant lesions was made according to the prognostic factors. Shear wave elastography was measured in kiloPascal (kPa) units which is a quantitative measure of tissue stiffness. DWI was obtained using a 1.5-T MRI system. Results: ADC values were strongly inversely correlated with elasticity (r = −0.662, p < 0.01) according to Pearson Correlation. In our study, the cut-off value of ADC was 1.00 × 10−3 cm2/s to achieve a sensitivity of 84.6% and specificity of 75.4%, and the cut-off value of elasticity was 105.5 kPa to achieve the sensitivity of 96.3% and specificity 76.9% to discriminate between the malignant and benign breast lesions. The status of prognostic factors was not correlated with the ADC values and elasticity. Conclusions: Elasticity and ADC values are correlated. Both cannot predict the status of prognostic factors and differentiate between molecular subtypes.

Correlation of Yes-Associated Protein 1 with Stroma Type and Tumor Stiffness in Hormone-Receptor Positive Breast Cancer

Simple Summary

YAP1 is an oncogene that can be activated by matrix stiffness, as it can act as a mechanotransducer. So far, only in vitro studies regarding YAP1 activation and matrix stiffness are present. We confirmed the activation of YAP1 in breast cancer using human breast cancer tissue and immunohistochemistry. Tumor stiffness was quantified by shear-wave elastography. Nuclear localization of YAP1 showed correlation with tumor stiffness in hormone-receptor positive (HR+) breast cancer. Also, tumors with non-collagen-type stroma showed an association between YAP1 expression and tumor stiffness. YAP1 expression, along with tumor stiffness, may serve as a prognostic candidate in HR+ breast cancer.

Abstract

(1) Background: Yes-associated protein 1 (YAP1) is an oncogene activated under the dysregulated Hippo pathway. YAP1 is also a mechanotransducer that is activated by matrix stiffness. So far, there are no in vivo studies on YAP1 expression related to stiffness. We aimed to investigate the association between YAP1 activation and tumor stiffness in human breast cancer samples, using immunohistochemistry and shear-wave elastography (SWE). (2) Methods: We included 488 patients with treatment-naïve breast cancer. Tumor stiffness was measured and the mean, maximal, and minimal elasticity values and elasticity ratios were recorded. Nuclear YAP1 expression was evaluated by immunohistochemistry and tumor-infiltrating lymphocytes (TILs); tumor-stroma ratio (TSR) and stroma type of tumors were also evaluated. (3) Results: Tumor stiffness was higher in tumors with YAP1 positivity, low TILs, and high TSR and was correlated with nuclear YAP1 expression; this correlation was observed in hormone receptor positive (HR+) tumors, as well as in tumors with non-collagen-type stroma. (4) Conclusions: We confirmed the correlation between nuclear YAP1 expression and tumor stiffness, and nuclear YAP1 expression was deemed a prognostic candidate in HR+ tumors combined with SWE-measured tumor stiffness.

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.

Comprehensive Risk System Based on Shear Wave Elastography and BI-RADS Categories in Assessing Axillary Lymph Node Metastasis of Invasive Breast Cancer-A Multicenter Study

PURPOSE

To develop a risk stratification system that can predict axillary lymph node (LN) metastasis in invasive breast cancer based on the combination of shear wave elastography (SWE) and conventional ultrasound.

MATERIALS AND METHODS

A total of 619 participants pathologically diagnosed with invasive breast cancer underwent breast ultrasound examinations were recruited from a multicenter of 17 hospitals in China from August 2016 to August 2017. Conventional ultrasound and SWE features were compared between positive and negative LN metastasis groups. The regression equation, the weighting, and the counting methods were used to predict axillary LN metastasis. The sensitivity, specificity, and the areas under the receiver operating characteristic curve (AUC) were calculated.

RESULTS

A significant difference was found in the Breast Imaging Reporting and Data System (BI-RADS) category, the "stiff rim" sign, minimum elastic modulus of the internal tumor and peritumor region of 3 mm between positive and negative LN groups (p < 0.05 for all). There was no significant difference in the diagnostic performance of the regression equation, the weighting, and the counting methods (p > 0.05 for all). Using the counting method, a 0-4 grade risk stratification system based on the four characteristics was established, which yielded an AUC of 0.656 (95% CI, 0.617-0.693, p < 0.001), a sensitivity of 54.60% (95% CI, 46.9%-62.1%), and a specificity of 68.99% (95% CI, 64.5%-73.3%) in predicting axillary LN metastasis.

CONCLUSION

A 0-4 grade risk stratification system was developed based on SWE characteristics and BI-RADS categories, and this system has the potential to predict axillary LN metastases in invasive breast cancer.

Stiffness Could be a Predictor of AJCC Prognostic Stage Groups in Preoperative Invasive Ductal Carcinoma

OBJECTIVES

This study aimed to evaluate the stiffness of 2-dimensional (2D) shear wave elastography (SWE) in preoperatively predicting the prognostic stage groups of invasive ductal carcinoma (IDC).

METHODS

Eighty-six newly diagnosed lesions on 83 patients with IDCs were analyzed. All parameters from conventional ultrasound and stiffness to virtual touch tissue imaging and quantification were collected, and mean shear wave velocity (SWVmean) was calculated. Data on maximum diameter, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), histologic grading system and Tumor Node Metastasis (TNM) stages were collected. The levels of maximum shear wave velocity (SWVmax), minimum shear wave velocity (SWVmin) and SWVmean were compared. In receiver operating characteristic (ROC) curves analysis, the diagnostic efficacy was found in area under the curve (AUC). Parallel mode was used to improve the predictive value of sensitivity.

RESULTS

The median stiffness of SWVmax and SWVmean for IDCs were 9.38 and 6.32 m/s for late stage (stages II, III, IV) and 6.39 m/s and 4.72 m/s for early stage (stage I) of the prognostic stage groups, respectively. The median stiffness values in the late stage were significantly higher than those in the early stage (P = .003, P = .005). The optimal cutoff stiffness of SWVmax and SWVmean were 8.62 and 6.13 m/s, respectively. In ROC curves analysis, the AUC for SWVmax was 0.742, and it showed a better diagnostic value than SWVmean (0.725). In predictive diagnosis, the sensitivity for SWVmax and SWVmean were both 62.50%. The parallel mode improved the prediction power of sensitivity to 68.75%.

CONCLUSIONS

Preoperative SWV level may serve as a promising prognostic imaging indicator for breast IDCs.

Tumor stiffness measured by shear-wave elastography: association with disease-free survival in women with early-stage breast cancer

OBJECTIVE

To determine whether shear-wave elastography (SWE)-measured tumor stiffness is associated with disease-free survival in females with early-stage invasive breast cancer.

METHODS

This retrospective study included 202 consecutive females (mean age, 52.9 years; range, 25-84 years) with newly diagnosed T1-two breast cancer who underwent preoperative SWE between April 2015 and January 2016. Tumor stiffness was assessed and quantitative SWE features of each breast lesion were obtained by a breast radiologist. Cox proportional hazard models were used to identify associations between SWE features and disease-free survival after adjusting for clinicopathologic factors.

RESULTS

Fifteen (7.4%) patients exhibited recurrence after a median follow-up of 56 months. Mean (Emean), minimum, and maximum elasticity values were higher in females with recurrence than in those without recurrence (184.4, 138.3, and 210.5 kPa vs 134.9, 101.7, and 159.8 kPa, respectively; p = 0.005, p = 0.005, and p = 0.012, respectively). Receiver operating characteristics curve analysis for prediction of recurrence showed that Emean yielded the largest area under the curve (0.717) among the quantitative SWE parameters, and the optimal cut-off value was 121.7 kPa. Multivariable Cox proportional hazards analysis revealed that higher Emean (>121.7 kPa) [adjusted hazard ratio (HR), 10.01; 95% CI: 1.31-76.33; p = 0.026] and lymphovascular invasion (adjusted HR, 7.72; 95% CI: 1.74-34.26; p = 0.007) were associated with worse disease-free survival outcomes.

CONCLUSION

Higher SWE-measured Emean was associated with worse disease-free survival in females with early-stage invasive breast cancer.

ADVANCES IN KNOWLEDGE

Tumor stiffness assessed with shear-wave elastography might serve as a quantitative imaging biomarker of disease-free survival in females with T1-two breast cancer.

Characterization of Suspicious Microcalcifications on Mammography Using 2D Shear-Wave Elastography

Our aim was to investigate the correlations between the findings of two-dimensional shear-wave elastography (2D-SWE) and the histopathologic results of microcalcifications (MCs) visualized using ultrasonography (USG). Fifty people with suspicious MCs without accompanying mass were evaluated. They underwent USG and 2D-SWE before USG-guided tru-cut biopsy. SWE values and histopathologic features were compared statistically. The variables between groups were analyzed using the Mann-Whitney U test. Receiver operating characteristic analysis was performed and cut-off values determined to discriminate malignancy, invasiveness and high grade. Pathology confirmed 27 malignant lesions (18 invasive ductal carcinomas, one invasive lobular and eight ductal carcinomas in situ) and 23 benign ones. There was a statistically significant difference between the SWE values of malignant and benign MCs (p < 0.001). The diagnostic performance of SWE for malignancy, invasiveness and high grade were as follows, repectively: sensitivity (93%, 83%, 88%), specificity (91%, 88%, 53%), positive predictive value (93%, 94%, 44%), negative predictive value (91%, 70%, 90%) and area under the curve (0.952, 0.885, 0.776). Cut-off values were determined as 57 kPa for malignancy, 124 kPa for invasiveness and 124.5 kPa for high grade. In conclusion, SWE is a useful method in clinical practice for characterizing MCs that can be visualized with USG.

Prediction of Invasive Breast Cancer Using Mass Characteristic Frequency and Elasticity in Correlation with Prognostic Histologic Features and Immunohistochemical Biomarkers

This purpose of this study is to correlate a new shear-wave elastography (SWE) parameter, mass characteristic frequency (fmass) and other elasticity measure with the prognostic histological factors and immunohistochemical (IHC) biomarkers for the evaluation of heterogeneous breast carcinomas. The new parameter, fmass, first introduced in this paper, is defined as the ratio of the averaged minimum shear wave speed taken spatially within regions of interest to the largest mass dimension. 264 biopsy-proven breast cancerous masses were included in this study. Mean (Emean), maximum (Emax), minimum (Emin) shear wave elasticity and standard deviation (Esd) of shear wave elasticity were found significantly correlated with tumor size, axillary lymph node (ALN) status, histological subtypes and IHC subtypes. The areas under the curve for the ALN prediction are 0.73 (95% confidence interval [CI]: 0.67-0.80) and 0.75 (95% CI: 0.69-0.81) for the combination of Emean with Breast Imaging Reporting and Data System (BI-RADS) score and Emax with BI-RADS score, respectively. fmass was significantly correlated with the presence of calcifications, ALN status, histological grade, the expressions of IHC biomarkers and IHC subtypes. To conclude, poor prognostic factors were associated with high shear wave elasticity values and low mass characteristic frequency value. Therefore, SWE provides valuable information that may help with prediction of breast cancer invasiveness.

Shear-Wave Elastography-Guided Core Needle Biopsy for the Determination of Breast Cancer Molecular Subtype

OBJECTIVE

To investigate whether shear-wave elastography (SWE) guidance during core-needle biopsy can improve diagnostic accuracy and accurate determination of the molecular subtypes of breast cancer.

METHODS

This controlled, randomized prospective cohort study included 58 patients (mean age: 56.9 ± 16.2) who were referred for image-guided core-needle biopsy between May 2018 and April 2019 for lesions larger than 1 cm. In Group 1, 30 lesions were biopsied without SWE guidance and recorded as Biopsy A. In Group 2, 30 lesions were examined with SWE before biopsy, and then two different parts of the lesions were biopsied; biopsies from the relatively rigid areas of the lesions were recorded as Biopsy B, and biopsies from the less rigid areas of the lesions were recorded as Biopsy C. The histopathological and immunohistochemical results of biopsies were compared with the surgical results.

RESULTS

The sensitivity of Biopsy A, B and C were 96.7%, 100% and 100%, respectively. The benign-malignant concordance rates were 94.7%, 100%, and 90% and the diagnostic concordance rates were 89.5%, 100%, and 90% in Biopsies A, B, and C, respectively. When the 10% differences in the estrogen receptor (ER), progesterone receptor (PR), and Ki67 rates were considered significant, the concordance rate of ER was highest in Biopsy B (77.8%; p = 0.040). The concordance rate of immunohistochemical subtyping was 100% in Biopsy B and 71.4% in Biopsies A and C (p = 0.086).

CONCLUSION

SWE-guided core-needle biopsy of breast lesions increased the sensitivity, diagnostic accuracy, and accuracy of immunohistochemical subtyping to 100%.

TGF-β1: is it related to the stiffness of breast lesions and can it predict axillary lymph node metastasis?

Background

This study aimed to explore whether transforming growth factor β1 (TGF-β1) is correlated with the stiffness of breast lesions and if it can predict axillary lymph node (ALN) metastasis.

Methods

A retrospective analysis was performed in our hospital. A total of 135 breast lesions in 130 patients who were to undergo vacuum-assisted excisional biopsy (VAEB) or surgery were enrolled between April 2018 and October 2018. Ultrasound (US) and shear wave elastography (SWE) examinations were performed for every lesion before VAEB or surgery. Pathology results obtained by VAEB or surgery were regarded as gold criteria. The elastic parameters and TGF-β1 expression level of malignant breast lesions were compared with those of benign lesions; the relationship between TGF-β1 expression level in breast lesions and the elastic parameters was analyzed; the TGF-β1 expression level in breast lesions with or without ALN metastasis were compared; and the efficacy of TGF-β1 expression level in predicting ALN metastasis was analyzed.

Results

The malignant breast lesions were different from benign lesions in the maximum and mean elasticity (Emax, Emean), standard deviation of elasticity (ESD), elastic ratio of the lesions to the peripheral tissue (Eratio), and the occurrence rate of "stiff rim sign" (P<0.001). The expression level of TGF-β1 in benign breast lesions was significantly lower than that in malignant lesions (P<0.001), and the TGF-β1 expression level was positively correlated with Emax, Emean, ESD, and Eratio (r=0.869, 0.840, 0.834, and 0.734, respectively). The expression level of TGF-β1 in breast lesions with or without "stiff rim sign" was significantly different (P<0.001), and the TGF-β1 expression level in malignant breast lesions with ALN metastasis was significantly higher than that in malignant lesions without ALN metastasis (P=0.0009). When TGF-β1 expression level >0.3138 was taken as the cut-off value, its efficacy in predicting ALN metastasis was 0.853, with a sensitivity of 86.67%, and a specificity 83.33%.

Conclusions

The expression level of TGF-β1 was positively correlated with the elastic parameters of breast lesions, and it could be useful for predicting ALN metastasis, especially for negative ALN diagnosis clinically.

Clinical Application of Shear Wave Elastography for Assisting Brain Tumor Resection

Background

The clinical outcomes for brain tumor resection have been shown to be significantly improved with increased extent of resection. To achieve this, neurosurgeons employ different intra-operative tools to improve the extent of resection of brain tumors, including ultrasound, CT, and MRI. Young’s modulus (YM) of brain tumors have been shown to be different from normal brain but the accuracy of SWE in assisting brain tumor resection has not been reported.

Aims

To determine the accuracy of SWE in detecting brain tumor residual using post-operative MRI scan as “gold standard”.

Methods

Thirty-four patients (aged 1–62 years, M:F = 15:20) with brain tumors were recruited into the study. The intraoperative SWE scans were performed using Aixplorer^® (SuperSonic Imagine, France) using a sector transducer (SE12-3) and a linear transducer (SL15-4) with a bandwidth of 3 to 12 MHz and 4 to 15 MHz, respectively, using the SWE mode. The scans were performed prior, during and after brain tumor resection. The presence of residual tumor was determined by the surgeon, ultrasound (US) B-mode and SWE. This was compared with the presence of residual tumor on post-operative MRI scan.

Results

The YM of the brain tumors correlated significantly with surgeons’ findings (ρ = 0.845, p < 0.001). The sensitivities of residual tumor detection by the surgeon, US B-mode and SWE were 36%, 73%, and 94%, respectively, while their specificities were 100%, 63%, and 77%, respectively. There was no significant difference between detection of residual tumor by SWE, US B-mode, and MRI. SWE and MRI were significantly better than the surgeon’s detection of residual tumor (p = 0.001 and p < 0.001, respectively).

Conclusions

SWE had a higher sensitivity in detecting residual tumor than the surgeons (94% vs. 36%). However, the surgeons had a higher specificity than SWE (100% vs. 77%). Therefore, using SWE in combination with surgeon’s opinion may optimize the detection of residual tumor, and hence improve the extent of brain tumor resection.

Shear Wave Elastography of Invasive Ductal Carcinoma: Correlations between Shear Wave Velocity and Histological Prognostic Factors

The correlations between shear wave velocity (SWV) calculated from virtual touch tissue imaging quantification (VTIQ) technique and histological prognostic factors of invasive ductal carcinoma was investigated. A total of 76 breast tumors histologically confirmed as invasive ductal carcinomas were included in this study. SWV values were measured by VTIQ for each lesion preoperatively or prior to breast biopsy. The maximum values were recorded for statistical analysis. Medical records were reviewed to determine tumor size, histological grade, lymph node status and immunohistochemical results. Tumor subtypes were categorized as luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) positive and triple negative. The correlations between SWV and histological prognostic factors were analyzed. It was found that tumor size showed positive association with SWV (r=0.465, P<0.001). Larger tumors had significantly higher SWV than smaller ones (P=0.001). Histological grade 1 tumors had significantly lower SWV values than those with higher histological grade (P=0.015). The Ki67 expression, tumor subtypes and lymph node status showed no statistically significant correlations with SWV, although triple negative tumors and lymph node-positive tumors showed higher SWV values. It was concluded that tumor size was significantly associated with SWV. Higher histological grade was associated with increased SWV. There was no statistically significant correlations between SWV and other histological prognostic factors.

Tumor stiffness measured by shear wave elastography correlates with tumor hypoxia as well as histologic biomarkers in breast cancer

Background

Shear wave elastography (SWE) is an ultrasound technique for the noninvasive quantification of tissue stiffness. The hypoxic tumor microenvironment promotes tumor stiffness and is associated with poor prognosis in cancer. We aimed to investigate the correlation between tumor hypoxia and histologic biomarkers and tumor stiffness measured by SWE in breast cancer.

Methods

From June 2016 to January 2018, 82 women with invasive breast cancer who underwent SWE before treatment were enrolled. Average tumor elasticity (E_average) and tumor-to-fat elasticity ratio (E_ratio) were extracted from SWE. Immunohistochemical staining of glucose transporter 1 (GLUT1) was used to assess tumor hypoxia in breast cancer tissues and automated digital image analysis was performed to assess GLUT1 activities. Spearman correlation and logistic regression analyses were performed to identify associations between GLUT1 expression and SWE values, histologic biomarkers, and molecular subtypes. The Mann–Whitney U test, t test, or Kruskal–Wallis test was used to compare SWE values and histologic features according to the GLUT1 expression (≤the median vs > median).

Results

E_average (r = 0.676) and E_ratio (r = 0.411) correlated significantly with GLUT1 expression (both p <  0.001). E_average was significantly higher in cancers with estrogen receptor (ER)–, progesterone receptor (PR)–, Ki67+, and high-grade (p <  0.05). E_ratio was higher in cancers with Ki67+, lymph node metastasis, and high-grade (p <  0.05). Cancers with high GLUT1 expression (>median) had higher E_average (mean, 85.4 kPa vs 125.5 kPa) and E_ratio (mean, 11.7 vs 17.9), and more frequent ER– (21.7% vs 78.3%), PR– (26.4% vs 73.1%), Ki67+ (31.7%% vs 68.3%), human epidermal growth factor receptor 2 (HER2) + (25.0% vs 75.0%), high-grade (28.6% vs 71.4%), and HER2-overexpressing (25.0% vs 75.0%) and triple-negative (23.1% vs 76.9%) subtypes (p <  0.05). Multivariable analysis showed that E_average was independently associated with GLUT1 expression (p <  0.001).

Conclusions

Tumor stiffness on SWE is significantly correlated with tumor hypoxia as well as histologic biomarkers. In particular, E_average on SWE has independent prognostic significance for tumor hypoxia in the multivariable analysis and can potentially be used as a noninvasive imaging biomarker to predict prognosis and pretreatment risk stratification in breast cancer patients.

Shear-Wave Elastography of the Breast: Added Value of a Quality Map in Diagnosis and Prediction of the Biological Characteristics of Breast Cancer

Objective

To determine the added value of a shear-wave elastography (SWE) quality map (QM) in the diagnosis of breast lesions and in predicting the biological characteristics of invasive breast cancer.

Materials and Methods

Between January 2016 and February 2019, this study included 368 women with 368 pathologically proven breast lesions, which appeared as poor-quality regions in the QM of SWE. To measure shear-wave velocity (SWV), seven regions of interest were placed in each lesion with and without QM guidance. Under QM guidance, poor-quality areas were avoided. Diagnostic performance was calculated for mean SWV (SWV_mean), max SWV (SWV_max), and standard deviation (SD) with QM guidance (SWV_mean + QM, SWV_max + QM, and SD + QM, respectively) and without QM guidance (SWV_mean − QM, SWV_max − QM, and SD − QM, respectively). For invasive cancers, the relationship between SWV findings and biological characteristics was investigated with and without QM guidance.

Results

Of the 368 women (mean age, 47 years; SD, 10.8 years) enrolled, 159 had benign breast lesions and 209 had malignant breast lesions. SWV_mean + QM (3.6 ± 1.39 m/s) and SD + QM (1.02 ± 0.84) were significantly different from SWV_mean − QM (3.29 ± 1.22 m/s) and SD − QM (1.46 ± 1.06), respectively (all p < 0.001). For differential diagnosis of breast lesions, the sensitivity and areas under the receiver operating characteristic curve (AUC) of SWV_mean + QM (sensitivity: 89%; AUC: 0.932) were better than those of SWV_mean − QM (sensitivity, 84.2%; AUC, 0.912) (all p < 0.05). There was no significant difference in sensitivity and specificity between SD + QM and SD − QM (all p = 1.000). Among the biological characteristics of invasive cancers, lymphovascular involvement, axillary lymph node metastasis, negative estrogen receptor status, negative progesterone receptor status, positive human epidermal growth factor receptor status, and aggressive molecular subtypes showed higher SWV_mean + QM (all p < 0.05), while only lymphovascular involvement showed higher SWV_mean − QM (p = 0.036).

Conclusion

The use of QM in SWE might improve the diagnostic performance for breast lesions and facilitate prediction of the biological characteristics of invasive breast cancers.

What shear wave elastography parameter best differentiates breast cancer and predicts its histologic aggressiveness?

Purpose

This study aimed to identify useful shear wave elastography (SWE) parameters for differentiating breast cancer and predicting associated immunohistochemical factors and subtypes.

Methods

From November 2018 to February 2019, a total of 211 breast lesions from 190 patients who underwent conventional breast ultrasonography and SWE were included. The Breast Imaging Reporting and Data System categories and qualitative and quantitative SWE parameters for each lesion were obtained. Pathologic results including immunohistochemical factors were evaluated. The diagnostic performance of each parameter and its correlation with histological characteristics, immunohistochemical factors, and subtypes of breast cancer were analyzed using analysis of variance, the independent t test, the Fisher exact test, logistic regression analysis, and the DeLong method.

Results

Among 211 breast lesions, 82 were malignant, and 129 were benign. Of the SWE parameters, Emax showed the highest area under the curve (AUC) for differentiating malignant from benign lesions (AUC, 0.891; cut-off>50.85). Poor tumor differentiation and progesterone receptor-negativity were correlated with higher SDmean and Emax (P<0.05). Ki-67-positive breast cancer showed higher SDmean and a heterogeneous color distribution (P<0.05). Ki-67 and cytokeratin 5/6-positive breast cancers showed higher Emax/Efat ratios (P<0.05). Luminal B, human epidermal growth factor receptor 2-enriched, and triple-negative (non-basal) subtypes showed somewhat higher SDmean values than the luminal A and triple-negative (basal) subtypes (P=0.028).

Conclusion

Emax is a reliable parameter for differentiating malignancies from benign breast lesions. In addition, high stiffness and SDmean values in tumors measured on SWE could be used to predict poorly differentiated, progesterone receptor-negative, or Ki-67-positive breast cancer.

Can Ultrasonographic Vascular and Elastographic Features of Invasive Ductal Breast Carcinoma Predict Histologic Aggressiveness?

RATIONALE AND OBJECTIVES

To investigate if preoperative ultrasonographic vascular and shear-wave elastographic examinations can predict histologic aggressiveness.

MATERIALS AND METHODS

Preoperative ultrasonographic vascular features and shear-wave elasticities were retrospectively evaluated for 147 invasive ductal carcinomas. Vascular feature was assessed using four-tier vascularity score. Mean and maximum elasticities (Emean and Emax), and the lesion-to-fat ratio (Eratio) were documented. Histologic parameters were reviewed for tumor size, multiplicity, axillary lymph node status, lymphovascular invasion, histologic grade, estrogen receptor, progesterone receptor, human epidermal growth factor receptor2 (HER2), Ki-67, p53, and histologic subtype. Vascularity score and elasticities were correlated with histologic parameters and histologic parameters were compared between the group with low vascularity score and elasticities and the group with high vascularity score and elasticities using ANOVA, chi-squared test, and regression analysis.

RESULTS

Vascularity score was independently associated with tumor size (p = 0.010) and HER2 (p = 0.007). Emean and Emax were associated with tumor size, histologic grade, and lymphovascular invasion, and Eratio was associated with tumor size, histologic grade, estrogen receptor, progesterone receptor, Ki-67, and histologic subtype (p < 0.05). Emean and Emax were independently associated with tumor size (p < 0.001). The group with high vascularity score and Eratio showed large tumor size (p < 0.001) and HER2 positivity (p = 0.039) in comparison to the group with low vascularity score and Eratio.

CONCLUSION

Ultrasonographic vascular features were associated with tumor size and HER2. SWE elasticities were associated with tumor size, histologic grade, hormonal receptor, and histologic subtype. Therefore, preoperative vascular and elastographic examinations could predict histologic aggressiveness of invasive ductal breast carcinoma.

Role of sonoelastography in assessment of axillary lymph nodes in breast cancer: a systematic review and meta-analysis

AIM

To evaluate the effectiveness of shear-wave elastography (SWE) and strain elastography (SE) for axillary lymph nodes (ALNs).

MATERIALS AND METHODS

PubMed, Embase, and Cochrane Library databases were searched until September 2018. Weighted mean difference was calculated for continuous variables. The accuracy of sonoelastography was assessed by calculating pooled sensitivity, specificity, area under the curve (AUC), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). All data were analysed using Stata 12.0.

RESULTS

Ten studies with 1,038 ALNs were included in the meta-analysis. Five studies evaluated the use of SE, and the other five evaluated the SWE. The SWE stiffness values of malignant ALNs were significantly higher than those of benign nodes. Both SE and SWE have relatively high specificity and sensitivity. The max stiffness in SWE showed the highest specificity (0.94; 95% confidence interval [CI], 0.81-0.98), PLR (12.1; 95% CI, 4-36.5), NLR (0.29; 95% CI, 0.12-0.69), AUC (0.94; 95% CI, 0.91-0.96), and DOR (42; 95% CI, 12-154); in contrast, the mean stiffness showed the highest sensitivity (0.80; 95% CI, 0.61-0.91).

CONCLUSION

Sonoelastography demonstrated high sensitivity and specificity for differentiating between malignant and benign ALNs. The max and mean stiffness on SWE appeared to exhibit the highest accuracy. Thus, SWE is an effective accompaniment to sentinel node biopsy, and is appropriate for preoperative assessment of ALNs in the post-Z0011 era.

Value of Elastography in Differentiating Benign from Malignant Breast Lesions Keeping Histopathology as Gold Standard

Background: Breast cancer is the most common cancer in females, both in developed and developing countries. Pakistan has the highest breast cancer incidence rate in Asia. Guidelines recommend screening for detecting breast cancer with mammography and ultrasonography (US). Shear-wave elastography (SWE) is a newer technique that can aid additional characterization of breast lesions. 

Objective: The aim of this study was to determine the diagnostic accuracy of breast ultrasound elastography in differentiating benign from malignant breast lesions using histology diagnosis as the gold standard.

Materials and methods: The study was conducted at the Abbasi Shaheed Hospital and Jinnah Post Graduate Medical Centre, Karachi. All consecutive patients undergoing breast biopsy and elastography of breast lesions were enlisted; 2 x 2 tables were used to measure the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of breast ultrasound elastography for differentiation of benign from malignant breast masses.

Results: A total of 155 female patients were included with a mean age of 45.41 ± 14.24 years (range 20-70 years). On histological evaluation, 115 (74.2%) lesions were malignant and 40 (25.8%) were benign. The overall average mean elastography value was 108.45 kPa ± 52.75. The mean elastography (E_Mean) value for benign breast lesions was 48.96 kPa ± 42.32 and 132.78 kPa ± 42.32 for malignant lesions. The difference in mean elastography values of benign and malignant breast lesions was statistically significant (48.96 kPa ± 42.32 vs 32.78 kPa ± 42.32, P <0.001). The area under the curve (AUC) was 0.952, optimal cutoff E_Mean value of 72 kPa and higher likelihood ratio was 9.41. A cutoff mean elastography (E_Mean) value of ≤ 72 kilopascal (kPa) for benign lesions had sensitivity 92.17%, specificity 90.4%, PPV 96.36%, NPV 80.0% and diagnostic accuracy 91.61%. 

Conclusion: Ultrasound elastography was found to have high sensitivity and specificity and diagnostic accuracy for differentiating benign from malignant breast lesions. Use of shear-wave elastography may increase malignancy detection rate by reducing the need for biopsy in benign breast lesions.

Conventional US and 2-D Shear Wave Elastography of Virtual Touch Tissue Imaging Quantification: Correlation with Immunohistochemical Subtypes of Breast Cancer

Our study aimed to investigate the correlation of the imaging features obtained using conventional ultrasound (US) and elastography (conventional strain elastography of elasticity imaging [EI], virtual touch tissue imaging [VTI] and 2-D shear wave elastography [2-D-SWE] of virtual touch tissue imaging quantification [VTIQ]) with the clinicopathologic features and immunohistochemical (IHC) subtypes of breast cancer. The sample consisted of images from 202 patients with 206 breast lesions that were confirmed as breast cancers. Lesions with HER2 overexpression (luminal B HER2+ or HER2+) had higher mean shear wave velocity (SWV) values than the others. Older patients, lower histologic grade, no lymphovascular invasion and no lymph node metastasis were associated with luminal A (p < 0.001). There were significant differences in SWV values, histologic grade and lymph node status among the different pathologic types. This association may allow the use of 2-D-SWE in the pre-operative prediction of tumor characteristics and biologic activity, which may determine the prognosis in a non-invasive manner.

Simultaneous comparison between strain and shear wave elastography of breast masses for the differentiation of benign and malignant lesions by qualitative and quantitative assessments

PURPOSE

To compare the addition of diagnostic strain elastography (SE) and shear wave elastography (SWE) values to the conventional B-mode ultrasonography in differentiating between benign and malignant breast masses by qualitative and quantitative assessments.

MATERIALS AND METHODS

B-mode ultrasound, SE, and SWE were simultaneously performed using one ultrasound system in 148 breast masses; 88 of them were malignant. The breast imaging reporting and data system category in the B-mode, Tsukuba score (SE_Tsu), Fat-Lesion-Ratio (SE_FLR) in SE, and five-point color assessment (SWE_col) and elasticity values (SWE_ela) in SWE were assessed. The results were compared using the area under the receiver-operating characteristic curve (AUC).

RESULT

The AUC for B-mode and each elastography were similar (B-mode, 0.889; SE_Tsu, 0.885; SE_FLR, 0.875; SWE_col, 0.881; SWE_ela, 0.885; P > 0.05). The combined sets between B-mode and either of the elastography technique showed good diagnostic performance (B-mode + SE_Tsu, 0.903; B-mode + SE_FLR, 0.909; B-mode + SWE_col, 0.919; B-mode + SWE_ela, 0.914). B-mode + SWE_col and B-mode + SWE_ela showed a higher AUC than B-mode alone (P = 0.026 and 0.029), and B-mode + SE_Tsu and B-mode + SE_FLR showed comparable AUC to B-mode alone (P = 0.196 and 0.085). There was no significant difference between qualitative and quantitative assessments for the combined sets of B-mode and elastography (P > 0.05).

CONCLUSION

The addition of both SE and SWE to B-mode ultrasound improved the diagnostic performance with increased AUC, and especially SWE was more useful than SE, and no significant difference was found between qualitative and quantitative assessments.

Diagnostic performance of qualitative and quantitative shear wave elastography in differentiating malignant from benign breast masses, and association with the histological prognostic factors

Background

To determine the diagnostic performance of qualitative and quantitative shear wave elastography (SWE) and the optimal cutoff values of the quantitative SWE parameters in differentiating malignant from benign breast masses, and to evaluate the association between the quantitative SWE parameters and histological prognostic factors.

Methods

A gray scale ultrasound and SWE were prospectively performed on a total of 244 breast masses (148 benign, and 96 malignant) in 228 consecutive patients before an ultrasound-guided needle biopsy. The qualitative SWE and quantitative SWE parameters (the mean elasticity, maximum elasticity, and elasticity ratio) were measured in each mass. The diagnostic performance of SWE and the optimal cutoff values of the quantitative SWE parameters were obtained. An association analysis of the parameters and histological prognostic factors was performed.

Results

The malignant masses had a more heterogeneous pattern on the qualitative SWE than benign masses (P<0.001). The quantitative SWE parameters of the malignant masses were higher than those of the benign masses (P<0.001); the mean elasticity, maximum elasticity, and elasticity ratio of the benign masses were 19.73 kPa, 23.98 kPa, and 2.78, respectively; and the mean elasticity, maximum elasticity, and elasticity ratio of the malignant masses were 88.13 kPa, 98.48 kPa, and 10.64, respectively. The optimal cutoff value of the mean elasticity was 30 kPa, of the maximum elasticity was 36 kPa, and of the elasticity ratio was 4.5. The maximum elasticity had the highest AUC. Combining the three SWE parameters to differentiate between the malignant and benign masses increased the negative predictive value (NPV), which correctly downgraded 72.73% of BI-RADS category 4A masses to BI-RADS category 3. No statistically significant association was found between the quantitative SWE parameters and the tumor grading, tumor types, axillary lymph node statuses, or molecular subtypes of the breast cancers (P>0.05).

Conclusions

The qualitative and quantitative SWE provided good diagnostic performance in differentiating malignant and benign masses. The maximum elasticity of the quantitative SWE parameters had the best diagnostic performance. Adding the three combined quantitative SWE parameters to the BI-RADS category 4A masses potentially downgraded them to BI-RADS category 3 and avoided unnecessary biopsies. No statistically significant association was found between the quantitative SWE parameters and the histological prognostic factors.

Association Between Shear Wave Elastography of Virtual Touch Tissue Imaging Quantification Parameters and the Ki-67 Proliferation Status in Luminal-Type Breast Cancer

OBJECTIVES

To evaluate the association between shear wave elastography parameters using virtual touch tissue imaging quantification (VTIQ) and the Ki-67 index in luminal-type breast cancer.

METHODS

Eighty-one patients with 82 lesions of pathologic confirmed luminal-type breast cancer underwent virtual touch tissue imaging quantification examination before surgery between December 2015 and June 2016. Patients were divided into 2 groups according to the Ki-67 index (≥14% versus < 14%), which is used to define luminal type B and luminal type A, respectively. The mean shear wave velocity (SWV_mean ) and lesion-to-adjacent tissues ratio (SWV ratio) were calculated for each lesion.

RESULTS

The SWV_mean , SWV ratio, histologic grade, axillary lymph node involvement, and lymphovascular invasion showed a significant positive association with a high Ki-67 index (all P < .05). Receiver operating characteristic curve analysis for the differential diagnosis between high (≥14%) and low (<14%) Ki-67 groups displayed that the optimal cutoff value for SWV_mean and SWV ratio were 3.99 meters per second and 2.861, with sensitivity 94% and 72%, specificity 40.6% and 56.2%, and area under the receiver operating characteristic curve of 0.689 and 0.651, respectively. Univariate analysis showed that SWV_mean (P = .005), SWV ratio (P = .029), histologic grade (P = .011), presence of axillary node involvement (P = .004), and lymphovascular invasion (P = .008) were significantly associated with high Ki-67 status. Multivariable analysis displayed that SWV_mean (hazard ratio [HR], 1.459, 95% confidence interval [CI], 1.028-2.072; P = .035), histologic grade (HR, 4.105; 95% CI, 1.142-14.763; P = .031), and presence of axillary node involvement (HR, 3.75; 95% CI, 1.228-11.453; P = .020) maintained significance for predicting high Ki-67 status.

CONCLUSIONS

The SWV_mean using the virtual touch tissue imaging quantification method showed significant correlation with the Ki-67 index, suggesting the potential to assess tumor proliferation status in luminal-type breast cancer with a noninvasive manner.

Correlation between histopathological grading and shear-wave elastography in evaluating invasive carcinoma of no special type

The present study aimed to investigate the correlation between histologic grade and shear-wave elastography in evaluating invasive breast carcinoma of no special type (NST). A total of 84 breast lesions in 80 patients (age range, 32-64 years) were retrospectively evaluated. The patients underwent B-mode ultrasound and virtual touch tissue quantification diagnosis. A semi-quantitative method was then applied in order to determine the histologic grade of the invasive carcinoma of NST according to the grading system published by the World Health Organization. Among the 84 breast lesions, 14 (16.7%) were classified as Grade I, while 29 (34.5%) and 41 (48.8%) were determined to be of Grade II and Grade III, respectively. The size of the breast lesions increased with the increase in histological grade (P<0.001). In addition, 29.3% of the Grade-III breast lesions exhibited acoustic enhancement, while the majority of the Grade-I breast lesions (78.6%) exhibited acoustic shadowing (P=0.002). Furthermore, a higher histopathological grade was closely correlated with a higher mean, minimum and maximum shear-wave velocity value (P<0.05). In conclusion, regarding the evaluation of invasive breast carcinoma of NST, the histologic grade was strongly correlated with tissue stiffness; a higher histologic grade was associated with a harder lesion. Therefore, shear-wave elastography may provide important clinical reference values.

Virtual touch tissue imaging and quantification (VTIQ) in the evaluation of breast lesions: The associated factors leading to misdiagnosis

PURPOSE

To investigate the factors that could cause a misdiagnosis in virtual touch tissue imaging and quantification (VTIQ) when differentiating benign and malignant breast lesions, and to analyze the imaging characteristics of those lesions with incorrect findings.

METHODS

The conventional ultrasound (CUS) features and the VTIQ parameters of 153 benign lesions and 99 malignant lesions were retrospectively analyzed and compared with histopathological and/or core-needle biopsy (CNB)-proven results. Independent variables that led to inaccurate VTIQ results were selected by binary logistic regression analysis.

RESULTS

The maximum shear wave speed (SWS-max), the mean SWS (SWS-mean), the minimum SWS (SWS-min), the lesion-to-fat SWS ratio (SWS-L/F), and the lesion-to-gland SWS ratio (SWS-L/G) in malignant lesions were significantly higher than those in benign lesions (all P < 0.001). The false-positive rate (FPR) of benign lesions and the false-negative rate (FNR) of malignant lesions were 9.8% and 19.2%, respectively, using an SWS-max cut-off value of 4.46 m/s. Diameter, depth, and posterior acoustic features were independent variables related to false-positive VTIQ findings (P: 0.049, 0.010 and 0.032, respectively). The invasive status and the histologic grade of infiltrating carcinoma were significantly associated with false-negative VTIQ findings (P: 0.026 and 0.015).

CONCLUSION

Diameter, depth, posterior acoustic features, invasive status, and histologic grade have a significant influence on the accuracy of VTIQ results, and these characteristics of breast lesions should be taken into account when interpreting the results of VTIQ examinations.

Tumor stiffness measured by quantitative and qualitative shear wave elastography of breast cancer

OBJECTIVE

To correlate clinicoradiologic and pathological features of breast cancer with quantitative and qualitative shear wave elastographic parameters.

METHODS

82 breast cancers in 75 patients examined by B-mode ultrasound and shear wave elastography (SWE) were included. SWE parameters including quantitative factors [maximum elasticity (E_max), mean elasticity (E_mean), elasticity ratio (E_ratio) and standard deviation (SD)] and qualitative factor (color pattern) were correlated with clinicoradiologic and pathological features using univariate and multivariate linear regression analyses.

RESULTS

Presence of symptoms and larger tumor size on ultrasound were significantly associated with higher E_max, E_mean, E_ratio, and SD (all p < 0.05) on univariate analysis. Older age was significantly correlated with higher E_max and E_mean (p = 0.026, 0.018). Lymphovascular invasion and larger pathologic size were significantly associated with higher E_max (p = 0.036, 0.043) and SD (p < 0.001, 0.019). No immunohistochemical biomarkers were significantly correlated with SWE parameters. There was no significant correlation between color pattern and any variable. Multivariate logistic regression analysis showed that the symptom, tumor size on ultrasound and lymphovascular invasion were independent factors that influenced the SWE values.

CONCLUSION

Tumor stiffness as measured by SWE and B-mode ultrasound could help predict cancer prognosis. Advances in knowledge: Clinicoradiologic factors had correlation with quantitative and qualitative SWE parameters. Using SWE parameters and B-mode ultrasound, we can predict breast cancer prognosis.

Ultrasound shear wave elastography of breast lesions: correlation of anisotropy with clinical and histopathological findings

Background

Ultrasound shear-wave elastography (SWE) may increase specificity of breast lesion assessment with ultrasound, but elasticity measurements may change with transducer orientation, defined as anisotropy. In this study, we aimed to observe the anisotropy of SWE of breast lesions, and its correlation with clinical and histopathological findings.

Methods

This retrospective study was approved by institutional review board. From June 2014 to June 2015, a total of 276 women (mean age, 48.75 ± 12.12 years) with 276 breast lesions (174 malignant, 102 benign) were enrolled for conventional ultrasound and SWE before surgical excision. Elasticity modulus in the longest diameter and orthogonal diameter were recorded, including maximum elasticity (Emax), mean elasticity (Emean), standard deviation (Esd) and ratio between mean elasticity of lesion and normal fatty tissue (Eratio). Anisotropy coefficients including anisotropic difference (AD) and anisotropy factors (AF) were calculated, and correlations with malignancy, tumor size, palpability, movability, lesion location and histopathology were analyzed.

Results

The average Emax, Emean, Esd and Eratio of the longest diameter were significantly higher than orthogonal diameter (P < 0.05). AUCs of ADs and AFs were inferior to quantitative parameters (P < 0.001), with AUCs of AFs superior to ADs (P < 0.001). ADs showed no significant correlation with malignancy, palpability, movability, distance from nipple and skin, and histopathological patterns. ADmean was significantly higher in inner half than outer half of the breast (P = 0.034). Higher AFs were significantly correlated with larger lesion size (P = 0.042), palpability (P < 0.05), shorter distance from nipple and skin (P < 0.05) and higher suspicion for malignancy (P < 0.001). AFs were significantly higher in IDC than DCIS (P < 0.05), higher in Grade II/III than Grade I IDC (P < 0.001), and correlated with ER/PR(+) (P < 0.05).

Conclusions

AF of SWE was an indicator for malignancy and more aggressive breast cancer.

Association of conventional ultrasound, elastography and clinicopathological factors with axillary lymph node status in invasive ductal breast carcinoma with sizes > 10 mm

Background

To evaluate whether conventional ultrasound, elastography [conventional strain elastography of elasticity imaging, acoustic radiation force impulse induced strain elastography of virtual touch tissue imaging, and a novel two-dimensional shear wave elastography of virtual touch tissue imaging quantification] and clinicopathological factors are associated with axillary lymph node metastasis in invasive ductal breast carcinoma with sizes > 10 mm.

Materials and Methods

We evaluated 150 breast lesions from 148 patients using the above methods and the clinicopathological factors. Univariate and multivariate logistic regression analysis were performed to determine the axillary lymph node metastasis risk factors. Diagnostic performance was evaluated using receiver operating characteristic curve analysis.

Results

Sixty-three tumors (42%) were node-positive, 87 (58%) were node-negative. Aspect ratio, virtual touch tissue imaging grade, shear wave velocity, pathological invasive tumor size, and histological grade maintained independent significance in predicting nodal involvement. The mean tumor shear wave velocitys (4.60, 6.49, 7.16) increased in proportion to metastatic node number (0, 1-3, ≥ 4, respectively; P < 0.001). For all tumors in this study, the cut-off shear wave velocity was 6.16 m/s and was associated with 64.1% sensitivity, 78.0% specificity and an area under the ROC curve of 0.799 (95% confidence interval, 0.731-0.868).

Conclusions

Aspect ratio, virtual touch tissue imaging grade, shear wave velocity, pathological invasive tumor size and histological grade are independently associated with axillary lymph node metastasis in invasive ductal breast carcinoma with sizes > 10 mm.

Three-dimensional versus two-dimensional shear-wave elastography: Associations of mean elasticity values with prognostic factors and tumor subtypes of breast cancer

PURPOSE

To explore associations between prognostic factors and subtypes of invasive breast cancer (IBC) and elasticity values using three-dimensional (3D) and two-dimensional (2D) shear-wave elastography (SWE).

MATERIALS AND METHODS

Mean elasticity values (kPa) of 121 IBCs were measured using both 3D and 2D SWE. Associations between these values and prognostic factors and subtypes were analyzed using linear regression model.

RESULTS

In both 3D and 2D SWE, larger size and presence of lymphovascular invasion were independent factors influencing higher mean elasticity on multivariate analyses (all p values<0.05).

CONCLUSIONS

Using either 3D or 2D SWE, higher mean elasticity values are associated with poor prognostic factors of IBC.

Evaluation of Antivascular Combretastatin A4 P Efficacy Using Supersonic Shear Imaging Technique of Ectopic Colon Carcinoma CT26

A recent ultrasound imaging technique-shear wave elastography-showed its ability to image and quantify the mechanical properties of biological tissues, such as prostate or liver tissues. In the present study this technique was used to evaluate the relationship among tumor growth, stiffness and reduction of treatment with combretastatin (CA4 P) in allografted colon tumor CT26 in mice. During 12 d, CT26 tumor growth (n = 52) was imaged by ultrasound, and shear modulus was quantified, showing a good correlation between tumor volume and stiffness (r = 0.59). The treatment was initiated at d 12 and monitored every d during 4 d. Following the treatment, the tumor volume had decreased, while the elasticity of the tumor volume remained steady throughout the treatment. After segmentation using the shear modulus map, a detailed analysis showed a decrease in the stiffness after treatment. This reduction in the mechanical properties was shown to correlate with tissue reorganization, particularly, fibrosis and necrosis, assessed by histology.

The value of quantitative shear wave elastography in differentiating the cervical lymph nodes in patients with thyroid nodules

PURPOSE

This study aimed at evaluating the diagnostic performance of quantitative shear wave elastography (SWE) in differentiating metastatic cervical lymph nodes from benign nodes in patients with thyroid nodules.

METHODS

One hundred and forty-one cervical lymph nodes from 39 patients with thyroid nodules that were diagnosed as papillary thyroid cancer had been imaged with SWE. The shear elasticity modulus, which indicates the stiffness of the lymph nodes, was measured in terms of maximum shear elasticity modulus (maxSM), minimum shear elasticity modulus (minSM), mean shear elasticity modulus (meanSM), and standard deviation (SD) of the shear elasticity modulus.

RESULTS

All the patients underwent thyroid surgery, 50 of the suspicious lymph nodes were resected, and 91 lymph nodes were followed up for 6 months. The maxSM value, minSM value, meanSM value, and SD value of the metastatic lymph nodes were significantly higher than those of the benign nodes. The area under the curve of the maxSM value, minSM value, meanSM value, and SD value were 0.918, 0.606, 0.865, and 0.915, respectively.

CONCLUSIONS

SWE can differentiate metastasis from benign cervical lymph nodes in patients with thyroid nodules, and the maxSM, meanSM, and SD may be valuable quantitative indicators for characterizing cervical lymph nodes.

Shear-wave elastography in breast ultrasonography: the state of the art

Shear-wave elastography (SWE) is a recently developed ultrasound technique that can visualize and measure tissue elasticity. In breast ultrasonography, SWE has been shown to be useful for differentiating benign breast lesions from malignant breast lesions, and it has been suggested that SWE enhances the diagnostic performance of ultrasonography, potentially improving the specificity of conventional ultrasonography using the Breast Imaging Reporting and Data System criteria. More recently, not only has SWE been proven useful for the diagnosis of breast cancer, but has also been shown to provide valuable information that can be used as a preoperative predictor of the prognosis or response to chemotherapy.

Breast Lesion Elastography Region of Interest Selection and Quantitative Heterogeneity: A Systematic Review and Meta-Analysis

In this systematic review and meta-analysis, we report measured elasticities of benign and malignant breast pathologies from shear wave elastography (SWE), quantitatively confirm the effect of the selected region of interest (ROI) on these measures and test the hypothesis that a metric of heterogeneity based on the mean and maximum elasticity can improve specificity of diagnosis. The elasticities of benign, malignant and specific pathologic states are reported from 22 publications encompassing 2989 patients, identified from a structured search of the literature from May to September 2015. Twelve articles were included in a meta-analysis that grouped results by the method of ROI selection to discriminate between different pathologies. We observe a significant correlation between the method of selection of ROI for malignant mean (p < 0.001) and maximum (p = 0.027) elasticities, but no correlation with benign measures. We define a quantitative heterogeneity parameter, the "stiffness gradient," computed from the mean and maximum measured elasticities. The stiffness gradient out-performed the current standard maximum elasticity metric in stratifying malignancy risk by a margin of 15% for the partial ROI, and 42% for the maximized ROI. An anecdotal example of improved differentiation using the stiffness gradient on pathology-specific lesions is also provided. These results quantitatively indicate that the method of ROI selection in SWE not only has a significant impact on the resulting mean reported elasticity of a lesion, but may provide some insight into lesion heterogeneity. Our results suggest that further exploration of quantitative heterogeneity is warranted to improve the specificity of diagnosis.

Combination of shear wave elastography and Ki-67 index as a novel predictive modality for the pathological response to neoadjuvant chemotherapy in patients with invasive breast cancer

PURPOSE

This study evaluated shear wave elastography (SWE) and SWE combined with the Ki-67 index as novel predictive modalities for the pathological response of invasive breast cancer to neoadjuvant chemotherapy (NAC).

METHODS

The prospective study recruited 66 eligible patients from July 2014 to November 2015. Tumour stiffness, which corresponds with tumour progression and invasiveness, was assessed by quantitative SWE 1 d before biopsy (time point t0, elasticity E0), 1 d before next NAC cycle (t1-t5, E1-E5), and 1 d before surgery (t6, E6). The relative changes in SWE parameters after the first and second NAC cycles were considered as the variables [ΔE (t1), ΔE (t2)]. The pathological response was classified according to the residual cancer burden (RCB) protocol. Correlations between RCB scores and variables were evaluated. The predictive diagnostic performances of SWE parameters, Ki-67 index, and the predictive RCB (predRCB) score determined by a linear regression model were compared.

RESULTS

Some immunohistochemical and molecular factors and SWE parameters were significantly different among the three RCB groups. The ΔEmean (t2) and Ki-67 had significantly better diagnostic performance than other parameters regarding predicting the pathological response (the RCB-I response and RCB-III resistance). However, the correlation between ΔEmean (t2) and Ki-67 index was significantly weaker as a diagnostic predictor (r = 0.29). We generated a new predictive modality, predRCB, which is a multivariable linear regression model that combines ΔEmean (t2) and the Ki-67 index. The predRCB modality showed better diagnostic performance than SWE parameters and Ki-67 index alone.

CONCLUSION

Our findings highlight the potential utility for adding the Ki-67 index to the SWE results, which may improve the predictive power of SWE and facilitate personalising the treatment regimens of patients with breast cancer. These results should be validated in the future by performing a multicentre prospective study with a larger cohort.

Correlating Tumor Stiffness with Immunohistochemical Subtypes of Breast Cancers: Prognostic Value of Comb-Push Ultrasound Shear Elastography for Differentiating Luminal Subtypes

PURPOSE

The purpose of our study is to correlate quantitatively measured tumor stiffness with immunohistochemical (IHC) subtypes of breast cancer. Additionally, the influence of prognostic histologic features (cancer grade, size, lymph node status, and histological type and grade) to the tumor elasticity and IHC profile relationship will be investigated.

METHODS

Under an institutional review board (IRB) approved protocol, B-mode ultrasound (US) and comb-push ultrasound shear elastography (CUSE) were performed on 157 female patients with suspicious breast lesions. Out of 157 patients 83 breast cancer patients confirmed by pathology were included in this study. The association between CUSE mean stiffness values and the aforementioned prognostic features of the breast cancer tumors were investigated.

RESULTS

Our results demonstrate that the most statistically significant difference (p = 0.0074) with mean elasticity is tumor size. When considering large tumors (size ≥ 8mm), thus minimizing the statistical significance of tumor size, a significant difference (p< 0.05) with mean elasticity is obtained between luminal A of histological grade I and luminal B (Ki-67 > 20%) subtypes.

CONCLUSION

Tumor size is an independent factor influencing mean elasticity. The Ki-67 proliferation index and histological grade were dependent factors influencing mean elasticity for the differentiation between luminal subtypes. Future studies on a larger group of patients may broaden the clinical significance of these findings.