Original Contribution
A Set of Shear Wave Elastography Quantitative Parameters Combined with Ultrasound BI-RADS to Assess Benign and Malignant Breast Lesions

https://doi.org/10.1016/j.ultrasmedbio.2014.11.014Get rights and content

Abstract

The goal of this study was to determine whether a combination of shear wave elastography (SWE) quantitative parameters could improve the accuracy of ultrasonography in the differentiation of benign and malignant breast lesions. Two hundred seventy-nine breast lesions in 251 women were evaluated with ultrasonography and SWE; pathologic results of all lesions were available. Each lesion was classified according to the Breast Imaging Reporting and Data System (BI-RADS) for ultrasound. SWE quantitative parameters, including maximum elastic value (Emax), mean elastic value (Emean), standard deviation (SD) and ratio of Emean of the lesion to Emean of the surrounding parenchyma (Eratio), were recorded. A receiver operating characteristic curve was used to determine their cutoff values. When any of the four parameters was equal to or higher than the cutoff value, the set of SWE parameters was counted as positive. When both BI-RADS and the set were positive, lesions were evaluated as positive for malignancy. We compared the performance of this combination with use of BI-RADS, Emax, Emean, SD or Eratio alone and also with the combination of BI-RADS and Emax for benign/malignant differentiation. The combination of Emax, Emean, SD, or Eratio with BI-RADS had a sensitivity, specificity, positive predictive value, negative predictive value, accuracy and Youden index of 0.967, 0.912, 0.908, 0.969, 0.938 and 0.879, respectively. The accuracy was the highest (p < 0.01) without loss of sensitivity. Combining a set of SWE quantitative parameters (Emax, Emean, SD and Eratio) could improve the accuracy of ultrasonography in differentiation of benign from malignant breast lesions, without loss of sensitivity.

Introduction

Ultrasonography (US) is a widely used tool for assessing the malignant potential of breast lesions. Ultrasound is used for breast cancer screening in China. The Breast Imaging Reporting and Data System (BI-RADS) for ultrasound provides standardized terminology to describe features, assessments and recommendations for breast lesions visible on US (American College of Radiology 2003). In BI-RADS, breast lesions are classified into categories 0 to 6, with increasing likelihood of malignancy. Studies indicate that BI-RADS is very sensitive but not specific enough to distinguish between benign and malignant lesions (Costantini et al., 2007, Kim et al., 2008, Kwak et al., 2006, Raza et al., 2008).

Breast elastography is a method for measuring tissue stiffness. The elasticity imaging concept was proposed for the first time in 1991 (Ophir et al. 1991). It has been proven to be very efficient in the evaluation of benign and malignant breast lesions (Barr et al., 2012, Itoh et al., 2006). The recently developed shear wave elastography (SWE) technique uses the acoustic radiation force induced by the ultrasound beam itself. This force induces shear waves that propagate transversely in tissue. The velocity of the shear waves is dependent on tissue elasticity. By measuring the different velocities and displaying the data using a color scale, SWE is able to provide quantitative elastic information expressed as the Young's modulus in real time. Quantitative elasticity values such as the maximum (Emax), mean (Emean), standard deviation (SD) and ratio of Emean of a lesion to Emean of surrounding parenchyma (Eratio) have proven to be useful parameters in several studies (Athanasiou et al., 2010, Chang et al., 2011, Cosgrove et al., 2012, Evans et al., 2010, Tanter et al., 2008, Wang et al., 2013).

Furthermore, several studies have reported the performance of combinations of BI-RADS and SWE features in the assessment of breast lesions (Berg et al., 2012, Chang et al., 2011, Evans et al., 2012, Youk et al., 2013). These studies reported that the combinations were helpful in assessing breast lesions, but used different SWE quantitative parameters. Chang et al. (2011) and Evans et al. (2012) reported on the combination of conventional US and Emean, Berg et al. (2012) on the combination of Emax and BI-RADS feature analysis, and Youk et al. (2013) on the combination of Eratio and BI-RADS. According to these articles, several SWE quantitative parameters, combined with ultrasound BI-RADS criteria, were valuable in assessing the malignant potential of breast lesions. Clinically, however, the optimal combination of SWE parameters for use by sonographers has not been elucidated. In this study, we evaluated different combinations of SWE parameters and concluded that using a set of all four parameters, where the positivity of any one parameter counted as a “positive” examination result, serially interpreted with ultrasound BI-RADS, had the highest sensitivity and specificity.

Section snippets

Patients and lesions

From March 2011 to September 2013, 251 consecutive patients in whom breast lesions were found on screening ultrasound or palpation underwent SWE before US-guided core needle biopsy, vacuum-assisted biopsy or surgical excision. Patients who were pregnant or lactating, had breast implants, had a scar adjacent to the lesion in question, were receiving radiotherapy or chemotherapy for cancer or had already undergone needle biopsy before the ultrasound were not included in this study. The enrolled

Results

According to BI-RADS, 114 lesions were classified as category 3, 79 lesions were classified as category 4 and 86 lesions were classified as category 5. Of the 279 lesions, 150 (53.8%) were benign and 129 (46.2%) were malignant. Benign lesions included fibroadenoma (n = 96), adenosis (n = 35), adenoma (n = 7) and papilloma (n = 12). Malignant lesions included invasive ductal carcinoma (n = 120), invasive lobular carcinoma (n = 2), ductal carcinoma in situ (n = 5), lobular carcinoma in situ

Discussion

Emax, Emean, SD and Eratio all performed well when assessed individually. Compared with BI-RADS, the four parameters had lower sensitivity and higher specificity. We hypothesized that together, the four parameters had the potential to increase the specificity above that of BI-RADS alone. As expected, when we combined BI-RADS with the set of Emax, Emean, SD and Eratio, the specificity and accuracy for differentiation of benign from malignant breast lesions improved significantly, without loss of

Conclusions

Serial interpretation of a set of SWE quantitative parameters (Emax, Emean, SD and Eratio) with ultrasound BI-RADS criteria, with a positive SWE (at least one abnormal parameter) and a high BI-RADS score being counted as “malignant,” seems to improve the accuracy of US in differentiation of benign from malignant breast lesions, without loss of sensitivity.

Acknowledgments

This research was supported by Special Funds of the National Natural Science Foundation of China (Grant 81241055).

References (22)

  • J. Ophir et al.

    Elastography: A quantitative method for imaging the elasticity of biological tissues

    Ultrason Imaging

    (1991)
  • M. Tanter et al.

    Quantitative assessment of breast lesion viscoelasticity: Initial clinical results using supersonic shear imaging

    Ultrasound Med Biol

    (2008)
  • American College of Radiology

    Breast Imaging Reporting and Data System (BI-RADS)—Ultrasound

    (2003)
  • A. Athanasiou et al.

    Breast lesions: Quantitative elastography with supersonic shear imaging—Preliminary results

    Radiology

    (2010)
  • R.G. Barr et al.

    Evaluation of breast lesions using sonographic elasticity imaging: A multicenter trial

    J Ultrasound Med

    (2012)
  • W.A. Berg et al.

    BE1 Investigators. Shear-wave elastography improves the specificity of breast US: The BE1 multinational study of 939 masses

    Radiology

    (2012)
  • D. Çebi Olgun et al.

    Use of shear wave elastography to differentiate benign and malignant breast lesions

    Diagn Interv Radiol

    (2014)
  • J.M. Chang et al.

    Clinical application of shear wave elastography (SWE) in the diagnosis of benign and malignant breast disease

    Breast Cancer Res Treat

    (2011)
  • D.O. Cosgrove et al.

    BE1 Study Group. Shear wave elastography for breast masses is highly reproducible

    Eur Radiol

    (2012)
  • M. Costantini et al.

    Solid breast mass characterisation: Use of the sonographic BI-RADS classification

    Radiol Med

    (2007)
  • A. Evans et al.

    Quantitative shear wave ultrasound elastography: Initial experience in solid breast masses

    Breast Cancer Res

    (2010)
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