Sonographic Imaging of Thyroid Nodules and Cervical Lymph Nodes

https://doi.org/10.1016/j.ecl.2007.12.003Get rights and content

The initial application of sonography for the evaluation of the neck, more than 30 years ago, was to differentiate cystic and solid thyroid nodules. With improvements in technology, ultrasound has been applied to characterize distinct features in the appearance of thyroid nodules. More recently, its function has been expanded to assess cervical lymph nodes for metastatic thyroid cancer. This article discusses the sonographic features of thyroid nodules associated with malignancy and the role of ultrasound in the management of patients with thyroid cancer.

Section snippets

Ultrasound imaging of thyroid nodules

When examined by ultrasound, rather than by palpation, thyroid nodules are commonly detected with a prevalence of 40% to 50% in the general population [1]. However, only 5% to 10% of thyroid nodules are malignant, even if found incidentally [2], [3]. While fine-needle aspiration (FNA) is the cornerstone of the evaluation of thyroid nodules, ultrasound contributes significantly both to identify and to evaluate thyroid nodules. Multiple reports have examined the sonographic features of thyroid

Lymph nodes

In addition to providing excellent imaging for thyroid nodules, high-frequency (10 to 14 MHz) ultrasound transducers allow for high-resolution imaging of small anatomic structures such as cervical lymph nodes. Of the approximately 800 lymph nodes in the human body, about 300 are located in the neck, varying in size from 3 to 30 mm [22]. Most neck lymph nodes are located superficially and are accessible to ultrasound imaging. Because of the frequent metastatic involvement of these lymph nodes by

Summary

Ultrasound is an important tool for the evaluation of the thyroid nodules and cervical lymph nodes. Certain sonographic features of thyroid nodules can be helpful in identifying those nodules most at risk for malignancy including hypoechogenicity, increased vascularity, microcalcifications, irregular margins, and the absence of a halo. These features alone do not have the sensitivity or specificity to diagnose thyroid cancer and FNA remains the procedure of choice to diagnose thyroid cancer.

Acknowledgments

We are grateful to Mr. Sherard Graham for his expert assistance in manuscript preparation.

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