Ultrasound is one of the primary methods for imaging of the thyroid gland. Using ultrasound, we can measure reliably the size of the thyroid gland lobes, the thickness of the isthmus and evaluate the gland for diffuse or focal pathology.

Color Doppler allows us to evaluate the thyroid gland for abnormal vascularity.

Thyroid storm - greatly increased vascularity of the thyroid gland in a patient with thyroiditis.

Ultrasound is used to direct our biopsy needle in ultrasound-guided Fine Needle Aspiration FNA of the thyroid gland. Even very small non-palpable nodules can be selectively targeted.

Benign thyroid nodule - Impalpable, it grew in size despite treatment. FNA demonstrated its benign nature.

In biopsy of larger nodules the advantages of ultrasound-guided biopsy include selection of the area of tissue sampling to include the more solid parts of the tumor and avoiding areas of cystic degeneration that might produce non-diagnostic samples. Color Doppler also allows us to avoid major blood vessels during biopsy minimizing the risk of complications (hematoma formation).

Thyroid gland ultrasound scan, sagittal section. Benign nodule in the lower pole of the thyroid lobe of a 51 year-old patient. Power Doppler examination revealed increased vascularity surrounding the nodule and allowed us to avoid major vessels during FNA. Cytology was negative for malignancy.

Finally, FNA will differentiate the malignant nodule from the multitude of benign lesions common in the thyroid, providing us with a diagnosis of great clinical significance.

	Thyroid carcinoma in a 19-year old patient. Clinically there was suspicious palpable hardness. Note irregular, infiltrative contour of the lesion. FNA provided the correct diagnosis.
	Thyroid carcinoma (same patient) - Increased, tortuous vascularity inside the tumour during examination with Color Doppler (Power Doppler).