Use of ultrasound in the management of thyroid cancer

Abstract

The use of ultrasound for thyroid cancer has evolved dramatically over the last few decades. Since the late 1960s, ultrasound has become essential in the examination of the thyroid gland with the increased availability of high-frequency linear array transducers and computer-enhanced imaging capabilities of modern day portable ultrasound equipment in a clinic- or office-based setting. As a noninvasive, rapid, and easily reproducible imaging study, ultrasound has been demonstrated to have a broadened utility beyond the simple confirmation of thyroid nodules and their sizes. Recently, office-based ultrasound has become an integral part of clinical practice, where it has demonstrated overwhelming benefits to patients being evaluated and treated for thyroid cancer. Ultrasound has become useful in the qualitative characterization of thyroid nodules based on benign or malignant features. On the basis of such classifications and the relative risk for thyroid malignancy, the need for ultrasound-guided fine-needle aspiration, preoperative and intraoperative staging, lymph node mapping, and the extent of surgery can subsequently be determined. Furthermore, ultrasound has additional value in the surveillance of patients treated for thyroid cancer.

Figure 1.

Malignant thyroid nodule. Longitudinal view of the right thyroid lobe. A combination of hypoechogenicity, irregular borders, and microcalcifications in the same solitary thyroid nodule has a strong correlation with thyroid cancer.

Figure 2.

Ultrasound image of a level 3 lymph node containing metastatic cancer. Transverse view of level 3 lymph node. Abnormal lymph nodes appear as hypoechoic and round lesions with calcifications and the absence of a fatty hilus.

Figure 3.

Ultrasound images of a right malignant nodule and level 6 (central) lymph node. Transverse view of right posteriorly located malignant thyroid nodule (A) and enlarged and hypoechoic level 6 lymph node in the same patient ((B), white arrow).