A feasibility study of predictive values of lateral cervical lymph node metastasis from cN1-stage papillary thyroid carcinoma based on dual-energy CT nomogram / 中华放射学杂志

ABSTRACT

Objective:To investigate the feasibility of predicting lateral cervical lymph node metastasis (LLNM) in patients with papillary thyroid carcinoma (PTC) based on the nomogram constructed by dual-energy CT data.Methods:In total 417 patients with PTC confirmed by pathology in Tianjin First Central Hospital from January 2015 to December 2018 were retrospectively analyzed as a training group. Internal validation was conducted, including 139 patients in the LLNM group and 278 patients in the non-LLNM group. A total of 169 PTC patients from January 2019 to June 2020 were included as an external validation group, including 58 patients in the LLNM group and 111 patients in the non-LLNM group. The morphological characteristics of the primary thyroid lesions on dual-energy CT iodine maps were analyzed, including tumor location, maximum diameter, calcification, and extrathyroidal extension (ETE). Iodine concentration (IC) of the PTC parenchyma and the internal carotid artery on the same level in the arterial and venous phases were measured, and normalized iodine concentration (NIC) was calculated. The independent risk factors for LLNM were obtained by univariate and multivariate logistic regression analysis. Base on the results, a prediction model was constructed and expressed in the form of a nomogram. The internal and external validation of the model was carried out using ROC curve.Results:Multivariate binary logistic regression analysis showed that the lesion location in the upper polar of the thyroid, the presence of ETE, IC in arterial phase>2.9 mg/ml, IC in the venous phase>3.2 mg/ml, and NIC in the arterial phase>0.21 were independent risk factors for LLNM prediction. The nomogram based on the above factors was constructed with an area under the ROC curve (AUC) of 0.895 (95%CI 0.862-0.923). With a cut-off value of 0.79, the sensitivity and specificity were 86.3% and 75.2%, respectively. As for the external validation group, the AUC of the model was 0.887 (95%CI 0.830-0.931), with the sensitivity of 82.8%, and the specificity of 81.1%.Conclusion:The application values of the nomogram model based on dual-energy CT data in preoperative evaluation of the possibility of LLNM of PTC patients has been verified. The model constructed in this study might be helpful with the individualized treatment in a certain degree.