Association between papillary thyroid carcinoma and cervical lymph node metastasis based on ultrasonic radio frequency signals

Objective: Papillary thyroid carcinoma (PTC) has a high propensity for cervical lymph node metastasis (CLNM). We evaluated the association between PTC radio frequency (RF) signals and CLNM. Methods: Patients with PTC (n = 170) confirmed by pathology after thyroidectomy between July 2019 and May 2022 were enrolled in this retrospective cohort study. Patients were divided into positive and negative groups according to CLNM. Univariate analysis was performed to predict CLNM and a receiver operating characteristic (ROC) curve was generated to evaluate the diagnostic performance of RF signals and the Thyroid imaging Reporting and Data System. Results: Of 170 patients with 182 nodules included in the study, 11 had multiple nodules. Univariate analysis showed that age, maximum tumor diameter, cross-sectional and longitudinal aspect ratio, RF quantitative parameters (cross-sectional intercept, mid-band, S1, and S4, and longitudinal Higuchi, slope, intercept, mid-band, S1), and echogenic foci were independently associated with CLNM (p < 0.05). The area under the curve (AUC) values of the maximum tumor diameter, longitudinal slope, and echogenic foci were 0.68, 0.61, and 0.62, respectively. Linear regression analysis of maximum tumor diameter, longitudinal slope, and echogenic foci showed that the correlations between longitudinal slope and CLNM were greater than that of echogenic foci (beta = 0.203 vs. beta = 0.154). Conclusion: Longitudinal slope and echogenic foci have similar diagnostic efficacy for predicting the risk of CLNM in PTC, although longitudinal slope has a greater correlation with CLNM.