Calcification and Echogenic Foci of Thyroid Nodules

Abstract

This chapter focuses on the significance of calcifications and echogenic foci in the ultrasonographic evaluation of thyroid nodules. Echogenic foci are hyperechoic foci within or surrounding a nodule. Calcifications are dense deposits of calcium and can be classified based on size and presence or absence of acoustic shadowing. Microcalcifications are punctate (1 mm or less in size) hyperechoic spots without acoustic shadowing that are associated with a higher likelihood of malignancy. Macrocalcifications are larger flecks of calcium (greater than 1 mm at longest diameter) accompanied by acoustic shadowing, with a nonspecific clinical significance and should be evaluated in combination with other suspicious ultrasound features. Correct identification of ultrasound features will help differentiate benign from malignant nodules and estimate the risk of malignancy to determine whether a biopsy is indicated.