Objective: To investigate the value of nomogram model based on conventional ultrasound and contrast-enhanced ultrasound in predicting cervical lymph node metastasis of papillary thyroid carcinoma (PTC) before operation. Methods: The characteristics of conventional ultrasound and contrast-enhanced ultrasound of the primary focus of 216 patients with PTC diagnosed pathologically in Wuhu Hospital affiliated to East China Normal University and the Third Hospital of Peking University were analyzed retrospectively. The gold standard was whether there was cervical lymph node metastasis in the pathology after surgery According to whether there is lymph node metastasis

54 patients were divided into metastatic group (LNM group) and non metastatic group (NLNM group). Univariate and multivariate Logistic regression analysis were used to screen independent risk factors for predicting lymph node metastasis.The joint prediction model is constructed based on independent risk factors and displayed in the form of nomogram. Results: The results of single factor Logistic regression analysis showed that there were statistically significant differences between the two groups in nine indicators: gender (male)

multifocal

maximum diameter(≥1cm)

microcalcification

blood flow

enhancement

enhancement mode

superficial capsule

and puncture feel (P<0.05); multivariate Logistic regression analysis identified gender(male)

multifocal

maximum diameterr(≥1cm)

blood flow

enhancement

enhancement mode

and superficial capsule as independent risk factors

The area under the curve (AUC) of the nomogram prediction model was 0.822

which was statistically significant compared with other independent indicators (all P<0.05).Hosmer Lemeshow test showed that the model fitted well(2=8.298

P=0.405). The calibration curve shows that the predicted value is consistent with the measured value

and the clinical decision curve analysis(DCA) shows that the nomogram model has the largest clinical application value among all models.The AUC of five fold cross validation was 0.871 (95% CI: 0.781-0.961)

0.900 (95% CI: 0.840-0.959)

0.707 (95% CI: 0.581-0.834)

0.678 (95% CI: 0.556-0.800)

0.762 (95% CI: 0.654-0.870)

and the average AUC was 0.784. Conclusion: The nomogram model based on the characteristics of conventional ultrasound and contrast-enhanced ultrasound can effectively predict the cervical lymph node metastasis of PTC before operation.