The value of non-punctate echogenic foci in the ultrasonic diagnosis of thyroid nodules.

Purpose: To evaluate the diagnostic value of different subtypes of non-punctate echogenic foci in thyroid malignancy.

Methods: Retrospective research of 342 thyroid nodules with calcification was performed. The echogenic foci were divided into punctate echogenic foci (type I) and non-punctate echogenic foci (type II), and type II were further divided into four subtypes: macrocalcification (type IIa), continuous peripheral calcification (type IIb), discontinuous peripheral calcification (type IIc) and isolated calcification (type IId). Postoperative histopathological results were used as the gold standard to evaluate the correlation between non-punctate echogenic foci subtypes and thyroid malignancy.

Results: The malignant risk of nodules with echogenic foci was type I (82.1%) > type IIa (66.2%) > type IIc (52.9%) > type IId (16.7%) > type IIb (13.9%), P < 0.001. Type I and type IIa echogenic foci were independent risk factors for thyroid cancer (OR = 16.593, 7.785). Solid, hypoechogenicity/marked hypoechogenicity and a single lesion in a unilateral thyroid lobe were independently associated with malignant thyroid nodules with macrocalcification(OR = 6.825, 40.042, 5.201). Irregular margins and uneven calcification thickness were independent factors for malignant thyroid nodules with peripheral calcification (OR = 5.676, 2.750).

Conclusion: Type IIa echogenic foci could independently predict thyroid malignancy. The diagnostic value of non-punctate echogenic foci depended on the differentiated combination of ultrasound characteristics. Type IIa nodules with solid composition, irregular margins, and a single lesion in a unilateral thyroid lobe implied a higher risk of malignancy; peripheral calcified nodules with irregular margins and uneven calcification thickness suggested an increased risk of malignancy.