To explore the qualitative evaluation of contrast-enhanced ultrasound (CEUS) in the differential diagnosis between benign and malignant thyroid nodules (TNs).

Totally 110 outpatients with 132 TNs underwent CEUS were enrolled in this study in Jinling Hospitall Medical School of Nanjing University (Nanjing General Hospital of Nanjing Military). Nanjing General Hospital of Nanjing Military All the nodules underwent ultrasound guided fine needle aspiration biopsy (FNAB). 113 TNs were histologically diagnosed. the characteristics of enhancement for each noudle were scored. The characteristics of enhancement between benign and malignant TNs were compared by chi-square test. The receiver operating characteristic (ROC) curve analysis were conducted to determine the diagnostic values of thyroid CEUS.

Contrast-enhanced patterns were significantly different between benign and malignant TNs in the degree, homogeneity of enhancement, enhanced ring and boundary, shape and size of the enhanced lesions (χ²=23.85, P<0.001; χ²=7.43, P=0.04; χ²=34.54, P<0.001; χ²=25.7, P<0.001; χ²=53.10, P<0.001; χ²=22.78, P<0.001; χ²=30.90, P<0.001). Contrast-enhanced patterns were not significantly different between benign and malignant TNs in the process and completeness of enhancement. Malignant lesions had concentric (79.5%), inhomogeneous (89.0%) and low (71.1%) enhanced with irregular (79.5%) and unclear (64.4%) boundary and bigger size (63.0%). The typical CEUS feature of benign nodules was peripheral ring hyperenhancement (34.7%). According to ROC curve, the cut off value was 3.5 points. The area under the ROC curve (AUC) for CEUS was 0.862 (95%CI: 0.797-0.927).The sensitivity, specificity and accuracy for CEUS were 80.8%, 79.6%, 80.3% respectively.

The pattern of CEUS may assist in differential diagnosis of benign and malignant TNs.