Strain Elastosonography of Thyroid Nodules: A New Tool for Malignancy Prediction? Overview of Literature

Ultrasound (US) elastography is a new non-invasive technique that uses ultrasounds to provide quantitative information about tissue stiffness. Two kinds of elastography (strain and shear wave elastography) are currently used in clinical practice. Although fine needle aspiration (FNA) is the most important procedure for the management of thyroid nodules, several studies have used US elastography as an adjunctive tool to conventional US, to differentiate malignant from benign nodules. In these studies malignant nodules are often associated with a greater elasticity scoring compared to benign. The conventional US plays an important role in defining which nodules are suitable for the US elastography because calcified and cystic nodules could be responsible for false positive and negative results respectively. On the other hand, follicular carcinoma gross anatomy and cellular pattern may resemble those of benign follicular adenoma. The histologic examination is often necessary to discover capsular or vascular invasion. Moreover, in contemporary literature there is disagreement about the role of US elastography in thyroid nodules with indeterminate or non-diagnostic cytology.