Contrast-enhanced ultrasonography features of papillary thyroid carcinoma for predicting cervical lymph node metastasis.

The present study was performed to evaluate the predictive value of contrast-enhanced ultrasonography (CEUS) for the risk of cervical lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC). Between May 2014 and November 2016, 42 patients who received surgery for suspicious PTCs were enrolled in the present study. Each individual underwent CEUS with conventional ultrasound (US), preoperative US-guided fine needle aspiration and personalized surgery. Subsequently, the microvascular density (MVD) of all surgical specimens was measured. According to the results of surgical histopathology, individuals were divided into two groups: LNM+ (PTCs with LNM), and LNM- (PTCs without LNM). Clinicopathological characteristics, CEUS enhancement patterns, perfusion parameters and measurements of MVD were compared. The correlation between quantitative variables and LNM was analyzed using Spearman's correlation analysis. Compared with that in the LNM- group, patients in the LNM+ group were younger (P<0.05) and had a larger mean tumor size (P<0.05). The incidence ratio of patients who were ≤45 years old (P<0.05), tumors >10 mm in size (P<0.05) and capsular infiltration (P<0.05) were statistically higher in the LNM+ group. Following the use of a novel classification system, the ratio of PTCs with early partial hyper-enhancement was identified to be significantly higher in the LNM+ group (P<0.01). The mean intensity, intensity increase velocity, MVD ratio and mean intensity ratio of intratumoral/peripheral thyroid parenchyma (MIR) were statistically higher in the LNM+ group compared with that in the LNM- group (all P<0.05). MIR was identified to be positive correlated with LNM (P<0.05). A MIR value of 0.86 was the optimal threshold of LNM in PTCs. In conclusion, LNM may rely on the local rich blood supply of PTC lesions. Partial hyper-enhancements of CEUS and higher values of MIR may suggest a high risk for LNM in PTC.