Diagnostic value of contrast-enhanced ultrasound in preoperative evaluation of lymph node metastasis and thyroid nodules in papillary thyroid carcinoma: a single-center retrospective study

Background The contrast-enhanced ultrasound (CEUS) has been recently used for the assessment of cervical lymph node metastasis to guide the surgical operation in the patient with papillary thyroid carcinoma (PTC). However, the specificity and sensitivity of CEUS reported from previous studies is not consistent. The objective of this study was to evaluate the diagnostic value of CEUS to the metastasis of cervical lymph node in PTC patients based on the data from one regional central hospital. Methods The diagnostic value of CEUS in preoperative LNM of PTC patients was concluded by comparing the results of CEUS on lymph node status with postoperative pathology examination. In addition, this study conducted hierarchical analysis of PTC patients to explore whether tumor size, different lymph node regions, and hashimoto's thyroiditis have an influence on the assessment of CEUS. Results This research enrolled 965 PTC patients finally, including 266 male and 699 female patients with a mean age of 42.27±11.34 years. 527 patients were supposed to be clinical-node negative and 438 were clinical-node positive before surgery. The specificity, sensitivity, PPV, NPV and accuracy of CEUS in the assessment of LNM in PTC patients were 56.00%, 71.00%, 57.06%, 69.76% and 62.59% respectively. For central and lateral lymph node, the accuracy of CEUS in PTC patients were 49.43% and 54.30%, respectively. Besides, it was showed that the accuracy of CEUS in PTC patients with HT slightly dropped to 58.44%, and the accuracy of CEUS in PTC patients with non-HT in turns increased to 64.17%. The accuracy of CEUS in non-PTMC and PTMC patients were 65.68% and 61.24%, respectively. The accuracy of CEUS in predicting central lymph node metastases was statistically different in PTC patients with or without Hashimoto's thyroiditis(P＜0.001) in this study, but not in lateral lymph nodes (P=0.114). Conclusion The accuracy of CEUS on the assessment of LNM in PTC is not consistently satisfactory, especially for central lymph nodes, small tumor diameter, or the patient with HT. More diagnostic technologies for abnormal lymph node should be considered in PTC patients.