To discuss the predictive value of multiple ultrasonic features combination in diagnosis of thyroid papillary carcinoma (PTC) more than 1.0 cm in diameter.

The ultrasonic features of 258 PTC nodules from 251 patients and 207 nodular goiter (NG) nodules from 190 patients in the First People′s Hospital of Hangzhou were retrospectively analyzed. All the nodules were confirmed by pathological examination after surgery. The ultrasonic features included the shape of nodules, internal echo, anteroposterior/transverse diameter ratio (A/T), and microcalcification. The χ² test was used to analyze the differences of ultrasonic features between PTC and NG. Multi-variate analyses (Logistic regression) was used to analyze the predictive risk ultrasonic features of PTC. The sensitivity and specificity of ultrasonic features were analyzed based on the gold standard of pathological results.

There were significantly differences between 258 PTC nodules and 207 NG nodules in irregular shape, hypoechogenicity, A/T>1 and microcalcification (χ² values were 121.511, 105.411, 41.483, 121.072, all P<0.01). The results of Logistic regression showed that irregular shape, hypoechogenicity, A/T>1 and microcalcification were risk ultrasonic features of PTC. And their OR values were 5.013 (95%CI 2.919-8.610), 5.811 (95%CI 3.411-9.901), 15.399 (95%CI 7.576-31.301), 4.141 (95%CI 1.687-10.164) respectively. The sensitivity and specificity of single ultrasonic feature were 26.0%-79.5% and 71.5%-96.1%; the sensitivity and specificity of two ultrasonographic features combination were 11.2%-57.0% and 92.3%-99.0%; and the sensitivity and specificity of three or four ultrasonographic features combination were 8.1%-31.8% and 99.0%-99.5%.

Irregular shape, hypoechogenicity, A/T>1 and microcalcification of thyroid neoplasm are important ultrasonic features of PTC. Although the sensitivity of single ultrasonic feature in diagnosing PTC is higher than that of multiple features combination, it has a lower specificity. Therefore, combination of multiple ultrasonographic features can improve the specificity in diagnosing PTC and reduce the misdiagnosis of PTC.