False positive or negative results of shear-wave elastography in differentiating benign from malignant breast masses: analysis of clinical and ultrasonographic characteristics

Comparison of ultrasound elastography, magnetic resonance elastography and finite element model to quantify nonlinear shear modulus

Objective. The aim of this study is to validate the estimation of the nonlinear shear modulus (A) from the acoustoelasticity theory with two experimental methods, ultrasound (US) elastography and magnetic resonance elastography (MRE), and a finite element method.Approach. Experiments were performed on agar (2%)-gelatin (8%) phantom considered as homogeneous, elastic and isotropic. Two specific setups were built to ensure a uniaxial stress step by step on the phantom, one for US and a nonmagnetic version for MRE. The stress was controlled identically in both imaging techniques, with a water tank placed on the top of the phantom and filled with increasing masses of water during the experiment. In US, the supersonic shear wave elastography was implemented on an ultrafast US device, driving a 6 MHz linear array to measure shear wave speed. In MRE, a gradient-echo sequence was used in which the three spatial directions of a 40 Hz continuous wave displacement generated with an external driver were encoded successively. Numerically, a finite element method was developed to simulate the propagation of the shear wave in a uniaxially stressed soft medium.Main results. Similar shear moduli were estimated at zero stress using experimental methods,μ0US= 12.3 ± 0.3 kPa andμ0MRE= 11.5 ± 0.7 kPa. Numerical simulations were set with a shear modulus of 12 kPa and the resulting nonlinear shear modulus was found to be -58.1 ± 0.7 kPa. A very good agreement between the finite element model and the experimental models (AUS= -58.9 ± 9.9 kPa andAMRE= -52.8 ± 6.5 kPa) was obtained.Significance. These results show the validity of such nonlinear shear modulus measurement quantification in shear wave elastography. This work paves the way to develop nonlinear elastography technique to get a new biomarker for medical diagnosis.

Comparison of diagnostic potential of shear wave elastography between breast mass lesions and non-mass-like lesions

BACKGROUND

Shear wave elastography (SWE) can improve the specificity of B-mode ultrasound (US) without reducing the sensitivity for breast cancer diagnosis. Existing research on SWE includes both mass lesions and non‑mass‑like (NML) lesions or only NML lesions; however, there are no studies comparing the diagnostic potential of SWE in the detection of mass and NML lesions in the same trial.

OBJECTIVE

This study aimed to compare the diagnostic performance of SWE in detecting mass lesions and NML lesions and determine the different individualised thresholds of the SWE parameters according to the lesion type.

METHODS

This Study included 623 breast lesions of 562 consecutive women, who were scheduled for conventional US and SWE between January 2021 and December 2021. The diagnostic performances of conventional US and each quantitative SWE parameter (maximum elastic modulus [Emax], mean elastic modulus [Emean], and elastic modulus standard deviation [Esd]) were assessed. Histological diagnosis for all Breast Imaging Reporting and Database System (BI-RADS) category 4/5 patients and some BI-RADS category 3 patients and the follow-up results of other BI-RADS category 3 patients were used as the reference standard.

RESULTS

In this study, 281 benign lesions and 342 malignant lesions were identified. The diagnostic performance of conventional US and SWE was better in the mass lesion group than in the NML lesion group. Every SWE parameter had a different threshold in each group, and the thresholds of the SWE parameters were higher in the mass lesion group than in the NML lesion group. In the mass lesion group, Esd had the highest Az value, whereas in the NML lesion group, Emax had the highest Az value. In both the mass and NML lesion groups, the diagnostic specificity of the combination of conventional US and SWE was significantly higher than that of conventional US alone (P < 0.05), without a significantly decrease in the diagnosticsensitivity.

CONCLUSIONS

SWE could increase the confidence of breast ultrasound diagnosis, especially for NML lesions. NML lesions had lower thresholds of SWE parameters than did the mass lesions.

Nonlinear Characterization of Tissue Viscoelasticity With Acoustoelastic Attenuation of Shear Waves

Shear-wave elastography (SWE) measures shear-wave speed (SWS), which is related to the underlying shear modulus of soft tissue. SWS in soft tissue changes depending on the amount of external strain that soft tissue is subjected to due to the acoustoelastic (AE) phenomenon. In the literature, variations of SWS as a function of applied uniaxial strain were used for nonlinear characterization, assuming soft tissues to be elastic, although soft tissues are indeed viscoelastic in nature. Hence, nonlinear characterization using SWS alone is insufficient. In this work, we use SWS together with shear-wave attenuation (SWA) during incremental quasi-static compressions in order to derive biomechanical characterization based on the AE theory in terms of well-defined storage and loss moduli. As part of this study, we also quantify the effect of applied strain on measurements of SWS and SWA since such confounding effects need to be taken into account when using SWS and/or SWA, e.g., for staging a disease state, while such effects can also serve as an additional imaging biomarker. Our results from tissue-mimicking phantoms with varying oil percentages and ex vivo porcine liver experiments demonstrate the feasibility of our proposed methods. In both experiments, SWA was observed to decrease with applied strain. For 10% compression in ex vivo livers, shear-wave attenuation decreased, on average, by 28% (93 Np/m), while SWS increased, on average, by 20% (0.26 m/s).

The development of breast radiology: the Acta Radiologica perspective

The encouraging results of modern breast cancer care builds on tremendous improvements in diagnostics and therapy during the 20th century. Scandinavian countries have made important footprints in the development of breast diagnostics regarding technical development of imaging, cell and tissue sampling methods and, not least, population screening with mammography. The multimodality approach in combination with multidisciplinary clinical work in breast cancer serve as a role model for the management of many cancer types worldwide. The development of breast radiology is well represented in the research published in this journal and this historical review will describe the most important steps.

Highlights of the development in ultrasound during the last 70 years: A historical review

This review looks at highlights of the development in ultrasound, ranging from interventional ultrasound and Doppler to the newest techniques like contrast-enhanced ultrasound and elastography, and gives reference to some of the valuable articles in Acta Radiologica. Ultrasound equipment is now available in any size and for any purpose, ranging from handheld devices to high-end devices, and the scientific societies include ultrasound professionals of all disciplines publishing guidelines and recommendations. Interventional ultrasound is expanding the field of use of ultrasound-guided interventions into nearly all specialties of medicine, from ultrasound guidance in minimally invasive robotic procedures to simple ultrasound-guided punctures performed by general practitioners. Each medical specialty is urged to define minimum requirements for equipment, education, training, and maintenance of skills, also for medical students. The clinical application of contrast-enhanced ultrasound and elastography is a topic often seen in current research settings.

Diagnostic utility of strain and shear wave ultrasound elastography in differentiation of benign and malignant solid breast lesions

Background

The purpose of our study was to assess diagnostic performance and comparison of strain and shear wave ultrasound elastography for differentiation of benign and malignant breast lesions compared to histopathological diagnosis as a reference standard. Our single center study involved 100 female patients with 132 solid breast masses. All patients underwent supervision of medical history, clinical examination, conventional B-mode ultrasound which was evaluated according to the BIRADS (Breast Imaging Reporting and Data System), and strain and shear wave ultrasound elastography. Strain ratio for strain elastography, mean elasticity value, and stiff ratio for shear wave elastography were calculated. All breast lesions were biopsied. Comparison of the elastography results with the histopathological diagnoses was done.

Results

There was no statistically significant difference as regard the AUCs for calculated values of strain and shear wave ultrasound elastography (strain ratio, 0.916; mean elasticity, 0.884; and stiff ratio, 0.872; P > 0.05). The AUCs for the combined use of B-mode US and elastography techniques were improved as the following: B-mode + strain, 0.920; B-mode + shear wave 0.952 with a significant P value < 0.001. Higher diagnostic accuracy was noted with the combination of strain and shear wave elastography than each single elastographic modality (P = 0.02).

Conclusions

Ultrasound elastography of breast masses is a non-invasive procedure with high sensitivity. Strain and shear wave elastography had almost similar diagnostic performance and displayed higher diagnostic performance if combined with B-mode ultrasound which helps in decreasing the number of unneeded breast biopsies.

Comparison of BSGI, MRI, mammography, and ultrasound for the diagnosis of breast lesions and their correlations with specific molecular subtypes in Chinese women

Background

Breast cancer is a leading cause of cancer in females, and is the second leading cancer-related cause of death in this group. Early diagnosis is essential to breast cancer to be effectively treated, and ultrasound, mammography, and magnetic resonance imaging (MRI) represent three key technologies that are utilized for the diagnosis of breast lesions. Breast-specific gamma imaging (BSGI) is an approach to molecular breast imaging that allows for high-resolution radio-imaging that is not adversely impacted by breast tissue density. This study was therefore designed to assess the relative diagnostic efficacy of BSGI, MRI, mammography, and ultrasound in different molecular subtypes of breast cancer among Chinese women.

Methods

Diagnostic findings from 390 patients that had undergone diagnosis and treatment in our breast surgery department were retrospectively reviewed. Patients had been diagnosed via BSGI, mammography, ultrasound, and MRI. The diagnostic efficacy of these different imaging modalities and their associated biological characteristics were compared in the present study.

Results

A total of 229 of these 390 patients (58.7%) were diagnosed with malignant breast cancer, with the remaining 161 (41.3%) cases having been found to be benign. BSGI, MRI, mammography, and ultrasound yielded respective sensitivity values of 91.7, 92.5, 77.3, and 82.1%, while the respective specificity values for these imaging modalities were 80.7, 69.7, 74.5, and 70.8%. For lesions > 1 cm, BSGI offered a sensitivity of 92.5%. For mammographic breast density A, B, C, and D, BSGI offered a sensitivity of 93.3, 94.0, 91.5, and 89.3%, respectively. BSGI also yielded a significantly higher lesion-to-normal lesion ratio (LNR) for malignant lesions relative to benign lesions (2.76 ± 1.32 vs 1.46 ± 0.49).

Conclusions

These findings confirm that BSGI is highly sensitive and is superior to mammography in the detection and diagnosis of ductal carcinomas in situ (DCIS). Such diagnostic efficacy can be further improved by using BSGI as an auxiliary modality to mammography and ultrasound, potentially improving the reliability of breast lesion diagnosis, thereby ensuring that patients receive rapid and effective treatment without the risk of misdiagnosis or unnecessary surgical treatment.

Evaluation of internal and shell stiffness in the differential diagnosis of breast non-mass lesions by shear wave elastography

BACKGROUND

The diagnostic specificity of conventional ultrasound for breast non-mass lesions (NMLs) is low at approximately 21%-43%. Shear wave elastography (SWE) can distinguish benign from malignant lesions by evaluating the internal and peripheral stiffness. SWE has good reproducibility and high diagnostic efficacy. However, there are very few independent studies on the diagnostic value of SWE in breast NMLs.

AIM

To determine the value of SWE in the differential diagnosis of breast NMLs.

METHODS

This study enrolled a total of 118 patients with breast NMLs who underwent SWE examinations in the Beijing Shijitan Hospital Affiliated to Capital Medical University and The Second Hospital of Shandong University from January 2019 to January 2020. The internal elastic parameters of the lesions were recorded, including maximum (Emax), mean (Emean) and minimum elastic values and the standard deviation. The following peripheral parameters were noted: Presence of a “stiff rim” sign; Emax, and Emean elasticity values within 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm from the edge of NMLs. The receiver operating characteristic curve of each parameter was drawn, and the areas under the curve were calculated.

RESULTS

Emax, Emean and elastic values, and the standard deviation of the internal elastic values in malignant NMLs were significantly higher than those in benign NMLs (P < 0.05). The percentage with the “stiff rim” sign in malignant NMLs was significantly higher than that in the benign group (P < 0.05), and Emax and Emean at the shell of 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm in the malignant group were all higher than those in the benign group (P < 0.05). Of the surrounding elasticity values, Emax of the shell at 2.5 mm in malignant NMLs had maximum areas under the curve of 0.900, and the corresponding sensitivity and specificity were 94.57% and 85.86%, respectively.

CONCLUSION

The “stiff rim” sign and multiple quantitative elastic values within and around the lesion had good diagnostic performance in the differential diagnosis of breast NMLs. Emax in peripheral tissue had better diagnostic efficiency than other parameters.

Diagnostic performance of shear wave elastography in discriminating malignant and benign breast lesions : Our experience with QelaXtoTM software

STUDY AIMS

We sought to evaluate the diagnostic performance of quantitative elastography (shear wave elastography) and to establish the optimal cutoff value to differentiate malignant and benign breast lesions using QelaXtoTM software.

METHODS

We conducted a retrospective observational study of adult women with suspicious breast lesions (BIRADS 3, 4 or 5) who underwent programmed ultrasound-guided core biopsies. Breast lesions were assessed using quantitative elastography combined with B-mode ultrasound. Histopathology was used as reference standard. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were estimated, and a ROC curve analysis was conducted. Three elastography cutoff values were considered: 36, 50 and 80 kPa.

RESULTS

We included 143 women (mean age of 56 years) with a total of 145 breast lesions: 68 benign tumors (47.26%) and 77 malignancies (52.74%). Mean elasticity measurements of benign and malignant lesions were significantly different (24.6 kPa, SD 28.47, vs. 101.49 kPa, SD 47.38, [Formula: see text]). Using the 50 kPa cutoff, elastography showed a global sensitivity of 87% to discriminate malignant lesions (AUC = 0.897). Moreover, sensitivity was 90.7% when lesions were located 5-40 mm below the skin surface (optimal elastographic field of view). Our false positive rate was 17.65%, comprised mainly of fibroepithelial neoplasms, fibroadenomas and fibrosis.

CONCLUSIONS

Quantitative elastography can differentiate malignant and benign breast lesions with acceptable to excellent performance. In our sample, the QelaXtoTM software showed a lower optimal cutoff than other ultrasound systems.

Spectral Quantification of Nonlinear Elasticity Using Acoustoelasticity and Shear-Wave Dispersion

Tissue biomechanical properties are known to be sensitive to pathological changes. Accordingly, various techniques have been developed to estimate tissue mechanical properties. Shear-wave elastography (SWE) measures shear-wave speed (SWS) in tissues, which can be related to shear modulus. Although viscosity or stress-strain nonlinearity may act as confounder of SWE, their explicit characterization may also provide additional information about tissue composition as a contrast modality. Viscosity can be related to frequency dispersion of SWS, which can be characterized using multi-frequency measurements, herein called spectral SWE (SSWE). Additionally, nonlinear shear modulus can be quantified and parameterized based on SWS changes with respect to applied stress, a phenomenon called acoustoelasticity (AE). In this work, we characterize the nonlinear parameters of tissue as a function of excitation frequency by utilizing both AE and SSWE together. For this, we apply incremental amounts of quasi-static stress on a medium, while imaging and quantifying SWS dispersion via SSWE. Results from phantom and ex vivo porcine liver experiments demonstrate the feasibility of measuring frequency-dependent nonlinear parameters using the proposed method. SWS propagation in porcine liver tissue was observed to change from 1.8 m/s at 100 Hz to 3.3 m/s at 700 Hz, while increasing by approximately 25% from a strain of 0% to 12% across these frequencies.

Shear wave elastography for the diagnosis of small (≤2 cm) breast lesions: added value and factors associated with false results

OBJECTIVE

We compared the diagnostic performance of B-mode ultrasound, shear wave elastography (SWE), and combined B-mode ultrasound and SWE in small breast lesions (≤ 2 cm), and evaluated the factors associated with false SWE results.

METHODS

A total of 428 small breast lesions (≤ 2 cm) of 415 consecutive patients between August 2013 and February 2017 were included. The diagnostic performance of each set was evaluated using the area under the receiver operating characteristic curve (AUC) analysis. Histologic diagnosis was used as reference standard. Multivariate logistic regression analyses identified the factors associated with false SWE results.

RESULTS

Of 428 lesions, 142 (33.2%) were malignant and 286 (66.8%) were benign. The AUC of the combined modality was higher than that of B-mode ultrasound (0.792 vs 0.572, p < 0.001) and that of SWE was higher than that of B-mode ultrasound (0.718 vs 0.572, p < 0.001). Multivariate analysis showed that the smaller lesion size and in situ cancer were associated with false negative, and patient's age, high-risk lesion, shorter distance from the skin or chest wall, and deeper breast thickness were associated with false positive (all p < 0.05).

CONCLUSIONS

The addition of SWE to B-mode ultrasound could improve the diagnostic performance in ≤ 2 cm lesions. However, ultrasound lesion size, pathology, and lesion location are likely to affect the SWE value and result in false results.

ADVANCES IN KNOWLEDGE

Despite the diagnostic usefulness of SWE in small breast lesions (≤ 2 cm), ultrasound lesion size, pathology, and lesion location were associated with false results.

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.

Comparison and Combination of Strain and Shear Wave Elastography of Breast Masses for Differentiation of Benign and Malignant Lesions by Quantitative Assessment: Preliminary Study

OBJECTIVES

To compare the diagnostic performance of strain and shear wave elastography of breast masses for quantitative assessment in differentiating benign and malignant lesions and to evaluate the diagnostic accuracy of combined strain and shear wave elastography.

METHODS

Between January and February 2016, 37 women with 45 breast masses underwent both strain and shear wave ultrasound (US) elastographic examinations. The American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) final assessment on B-mode US imaging was assessed. We calculated strain ratios for strain elastography and the mean elasticity value and elasticity ratio of the lesion to fat for shear wave elastography. Diagnostic performances were compared by using the area under the receiver operating characteristic curve (AUC).

RESULTS

The 37 women had a mean age of 47.4 years (range, 20-79 years). Of the 45 lesions, 20 were malignant, and 25 were benign. The AUCs for elasticity values on strain and shear wave elastography showed no significant differences (strain ratio, 0.929; mean elasticity, 0.898; and elasticity ratio, 0.868; P > .05). After selectively downgrading BI-RADS category 4a lesions based on strain and shear wave elastographic cutoffs, the AUCs for the combined sets of B-mode US and elastography were improved (B-mode + strain, 0.940; B-mode + shear wave; 0.964; and B-mode, 0.724; P < .001). Combined strain and shear wave elastography showed significantly higher diagnostic accuracy than each individual elastographic modality (P = .031).

CONCLUSIONS

These preliminary results showed that strain and shear wave elastography had similar diagnostic performance. The addition of strain and shear wave elastography to B-mode US improved diagnostic performance. The combination of strain and shear wave elastography results in a higher diagnostic yield than each individual elastographic modality.

Comparison of 3D and 2D shear-wave elastography for differentiating benign and malignant breast masses: focus on the diagnostic performance

AIM

To evaluate the diagnostic performance of three-dimensional (3D) image shear-wave elastography (SWE) for differentiating benign from malignant breast masses compared to two-dimensional (2D) SWE and B-mode ultrasound (US).

MATERIALS AND METHODS

This study consisted of 205 breast lesions from 199 patients who underwent B-mode US and SWE before biopsy from January 2014 to March 2016. Quantitative elasticity values (maximum and mean elasticity, Emax and Emean) obtained from 2D and 3D SWE (axial, sagittal, and coronal images) were reviewed retrospectively, in addition to the histopathological findings including immunohistochemistry profiles (luminal A, luminal B, human epidermal growth factor receptor 2 (HER2)-enriched, and triple-negative breast cancer) in cases of malignancy. Histopathological findings were regarded as the reference standard. The diagnostic performance of each data set was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC) analysis to compare sensitivity and specificity.

RESULTS

Among 205 lesions, 105 (51.22%) were malignant and 100 (48.78%) were benign. Compared to benign masses, malignant masses had higher values of Emax and Emean on both 2D and 3D SWE, the differences of which were statistically significant (p<0.001). The AUCs of 2D, 3D axial, and sagittal SWE were significantly higher than that of 3D coronal SWE (p<0.05). In addition, the sensitivities of axial, sagittal, and coronal 3D SWE were all higher than that of 2D SWE for Emean (81.9%, 87.6%, and 89.5% versus 70.5%, respectively, p<0.05). Conversely, the specificity of 2D and 3D axial SWE was higher than that of 3D sagittal and coronal SWE (Emax, 84%, 83% versus 76%, 73%; Emean, 85%, 81% versus 68%, 50%, respectively, p<0.05). We also assessed changes in Breast Imaging-Reporting and Data System (BI-RADS) category 3 and category 4a lesions by adding each of the parameters for 2D and 3D SWE in B-mode US. The specificity, PPV, and accuracy of combined 2D or combined 3D SWE with B-mode US was statistically higher than that of B-mode US alone for differentiating benign and malignant lesions (p<0.05).

CONCLUSIONS

Among SWE images, 2D SWE, and 3D SWE axial and sagittal images exhibited superior diagnostic performance compared to 3D coronal images. Addition of 3D SWE images to B-mode US improved the diagnostic performance for distinguishing benign from malignant masses.

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.

Shear-Wave Elastography: Could it be Helpful for the Diagnosis of Non-Mass-Like Breast Lesions?

The goal of this study was to analyze the diagnostic performance of shear wave elastography (SWE) in differentiation of benign and malignant non-mass-like (NML) breast lesions. Three hundred sixteen consecutive breast lesions in 305 patients who have been scheduled for ultrasound (US)-guided core needle biopsy or vacuum-assisted biopsy or surgical excision between January 2013 and August 2013 were initially included in this study. Finally, 63 patients with 67 lesions classified as NML lesions comprised our study population. The features of SWE and its diagnostic performance in NML lesions were analyzed. Among the 67 NML lesions, 33 were malignant and 34 were benign. The maximum elastic modulus, mean elastic modulus, minimum elastic modulus, elastic modulus ratio and stiff rim sign of the malignant lesions were all significantly higher than those of benign lesions (p < 0.05). The combination of conventional US with maximum elastic modulus and stiff rim sign got significantly higher diagnostic specificity and positive predictive value (PPV) than conventional US (p < 0.05 for both). In the benign lesions, 23 (67.6%) unnecessary biopsies could have been eliminated after the combination of conventional US and SWE. SWE could increase diagnostic specificity and positive predictive values of NML breast lesions. The combination of conventional US and SWE could reduce unnecessary benign biopsies of NML lesions.

Breast Lesions: Quantitative Diagnosis Using Ultrasound Shear Wave Elastography-A Systematic Review and Meta--Analysis

The aim of this meta-analysis was to estimate the diagnostic performance of shear wave elastography (SWE) in differentiating malignant from benign breast lesions. A literature search of PubMed, Web of Science and Scopus up to November 2014 was conducted. A summary receiver operating characteristic curve was constructed, and pooled weighted estimates of sensitivity and specificity were calculated using a bivariate mixed-effects regression model. Thirty-three studies, which included a total of 5838 lesions (2093 malignant, 3745 benign) from 5397 patients, were finally analyzed. Summary sensitivity and specificity were 0.886 (95% confidence interval [CI], 0.858-0.909) and 0.866 (95% CI, 0.833-0.894), respectively. The pooled diagnostic odds ratio was 50.410 (95% CI, 34.972-72.664). And the area under the receiver operating characteristic curve of SWE was 0.94 (95% CI, 0.91-0.96). No publication bias existed among these studies (p = 0.245). In the subgroup analysis, sensitivity and specificity were 0.862 (95% CI, 0.811-0.901) and 0.875 (95% CI, 0.793-0.928) among 1552 lesions from 1429 patients in the 12 studies using acoustic radiation force impulse imaging and 0.897 (95% CI, 0.863-0.923) and 0.863 (95% CI, 0.831-0.889) among another 4436 lesions from 4097 patients in the 21 studies using supersonic shear imaging. When analysis confined to 9 studies evaluated the diagnostic performance of combination SWE and conventional ultrasound, the area under the curve was 0.96 (95% CI, 0.94-0.97), yielding a sensitivity of 0.971 (95% CI, 0.941-0.986) and specificity of 0.801 (95% CI, 0.733-0.856). SWE seems to be a good quantitative method for differentiating breast lesions, with promise for integration into routine imaging protocols.

In Vivo Quantification of the Nonlinear Shear Modulus in Breast Lesions: Feasibility Study

Breast cancer detection in the early stages is of great importance since the prognosis, and the treatment depends more on this. Multiple techniques relying on the mechanical properties of soft tissues have been developed to help in early detection. In this study, we implemented a technique that measures the nonlinear shear modulus (NLSM) (μ(NL)) in vivo and showed its utility to detect breast lesions from healthy tissue. The technique relies on the acoustoelasticity theory in quasi-incompressible media. In order to recover μ(NL), static elastography and supersonic shear imaging are combined to subsequently register strain maps and shear modulus maps while the medium is compressed. Then, μ(NL) can be recovered from the relationship between the stress, deduced from strain maps, and the shear modulus. For this study, a series of five nonlinear phantoms were built using biological tissue (pork liver) inclusions immersed in an agar-gelatin gel. Furthermore, 11 in vivo acquisitions were performed to characterize the NLSM of breast tissue. The phantom results showed a very good differentiation of the liver inclusions when measuring μ(NL) with a mean value of -114.1 kPa compared to -34.7 kPa for the gelatin. Meanwhile, values for the shear modulus for the liver and the gelatin were very similar, 3.7 and 3.4 kPa, respectively. In vivo NLSM mean value for the healthy breast tissue was of -95 kPa, while mean values of the benign and the malignant lesions were -619 and -806 kPa with a strong v ariability, respectively. This study shows the potential of the acoustoelasticity theory in quasi-incompressible medium to bring a new parameter for breast cancer diagnosis.