Ultrasound elastography in the evaluation of thyroid nodules for thyroid cancer

摘要

PURPOSE OF REVIEW: High-resolution ultrasonography has become mandatory while evaluating patients with thyroid nodules. Although B-mode and Doppler ultrasonography are highly sensitive for diagnosis of thyroid lesions, they lack specificity in differentiating benign from malignant nodules. Ultrasound elastography has proven valuable in discriminating these lesions. This review discusses recent findings regarding the use of elastography as a tool in the evaluation of thyroid masses as well as the different methods and scoring systems used to determine tissue elasticity. RECENT FINDINGS: There are several methods and scores utilized to evaluate the stiffness of normal tissue and solid thyroid lesions, such as strain elastography, acoustic radiation force impulse, and shear wave elastography. Interpretation of data is usually qualitative and subjective obtained with operator-dependent techniques except for shear wave elastography, in which data acquisition is operator-independent with interpretation quantitative and objective in nature. Various software and scoring systems are applied to produce/interpret data resulting in widely variable sensitivity and specificity in differentiating malignant from benign lesions ranging from 73 to 98% and 71 to 100%, respectively. SUMMARY: Although elastography seems promising in identifying malignant thyroid nodules with acceptable accuracy, further studies are necessary to change the current management of thyroid lesions. Consequently, elastography should be used as an additional tool in the work-up of thyroid nodules instead of a single predictor of which lesions should be followed without fine-needle aspiration cytology. Therefore, this exciting methodology, so far, is inadequate to guide the management of thyroid lesions.