Elastography of the Breast

Abstract

The use of ultrasound in addition to mammography in breast screening has been shown to increase the detection rate of breast cancer, especially in women with dense breast parenchyma, to 4.2 cancers per 1000 women screened. However, its low specificity and low positive predictive value (PPV) remain an unavoidable limitation of this method [1, 2]. Besides interpretive criteria that take into account factors like mass margins, shape, orientation and effects on the surrounding, colour Doppler sonography and strain elastography, also known as strain elastography, have been introduced to further characterize masses of the breast. Colour Doppler sonography has shown a sensitivity of 68.0–91.2 % and a specificity of 92.7–95.0 % in differentiating malignant breast masses from benign lesions by visualizing the presence and morphology of blood vessels [3–7]. Strain elastography, which is an imaging modality that measures tissue stiffness, shows better specificity in distinguishing benign from malignant solid breast lesions (41.0–98.5 %) than B-mode sonography alone and has become a routine tool during the last years. Three different modes of elastography are currently available. Free-hand ultrasound elastography, also known as strain elastography, which is based on comparison of signals acquired before and after tissue displacement due to manual compression, is the most common method to date, whereas more recent elastography techniques such as acoustic radiation force imaging (ARFI) and shear wave elastography (SWE) offer the possibility of an objective and operator-independent quantitative measurement of tissue elasticity. Additionally, the possibility of differentiation between solid masses and cystic lesions has been shown in several studies [7–14].