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Breast Imaging

E1047. Breast Elastography: A Review of Strain and Shear Wave Elastography

Saraiya A1,  Barr R.2,3 1. Rhode Island Hospital, Providence, RI; 2. Southwoods Imaging, Youngstown, OH; 3. Northeast Ohio Medical University, Rootstown, OH

Address correspondence to R. Barr (rgbarr@zoominternet.net)

Background Information: Manual palpation has been used for centuries to identify malignant breast lesions. Breast cancers are significantly stiffer than benign breast lesions. There is little overlap of stiffness values between benign and malignant breast lesions. These characteristics make elastography highly accurate in characterizing breast lesions. There are two types of ultrasound elastography presently available clinically, strain elastography (SE) and shear wave elastography (SWE). SE is a qualitative technique comparing the relative stiffness of different tissues in an image; however, a unique characteristic of breast lesions on elastography is that benign lesions appear smaller on b-mode and malignant lesions appear larger. The ratio of the elastography length to the b-mode length (E/B ratio) can be used to characterize breast lesions as benign or malignant, with sensitivities of up to 99% and specificity of 90%. SWE is a quantitative technique with which the stiffness of the lesion can be estimated by the shear wave speed through the lesion in meters per second or can be converted to Young modulus in kilopascals. Both techniques have a learning curve on how to perform an adequate stiffness measurement.

Educational Goals/Teaching Points: The purpose of this exhibit is first to review the SE and SWE findings in a wide range of biopsy-proven benign and malignant breast lesions. Both techniques are provided for each lesion presented. Our second goal is to discuss artifacts in both SE and SWE and their clinical usefulness in diagnosis. Third, we will compare and contrast the findings in SE and SWE of the breast.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: This exhibit will describe SE and SWE, review imaging findings in benign lesions (cystic lesions, mastitis, fat necrosis, fibrocystic change, and fibroadenoma) and malignant lesions (ductal carcinoma in situ, invasive ductal cancer, invasive lobular cancer, lymphoma, and nonbreast metastatic lesions), and summarize the advantages and disadvantages of SE and SWE in characterizing breast pathology findings.

Conclusion: SE and SWE have been shown to improve characterization of breast masses. Appropriate technique is required to acquire high-quality images. With the use of elastography, there is a decreased false biopsy rate and an increased positive biopsy rate. Knowledge of the elastographic features of both benign and malignant lesions is required to have optimal results.