Clinical value of dual-energy CT parameters-based nomogram in predicting large-volume central lymph node metastases of papillary thyroid carcinoma
Objective To explore the application value of a dual-energy CT parameters-based nomogram in preoperative prediction of large-volume central lymph node metastasis(CLNM)of papillary thyroid carcinoma(PTC).Methods The clinical and imaging data of 274 patients with PTC who underwent surgical resection and received dual-energy CT examination before surgery in the Fifth Affiliated Hospital of Wenzhou Medical University from September 2017 to December 2022 were retrospectively analyzed.According to the results of central neck lymph node dissection,the patients were divided into the small-volume CLNM group(n=198)and large-volume CLNM group(n=76).Patients were randomly divided into the training set(n=192)and validation set(n=82)with a ratio of 7:3.The clinical and conventional CT features(age,gender,maximum tumor diameter,tumor location,extracapsular invasion and calcification),dual energy CT parameters[normalized iodine concentration(NIC),slope of the spectral Hounsfield unit curve(λHU),and normalized effective atomic number(nzeff)in the arterial phase and venous phase]in the two groups were analyzed.Multivariate logistic analysis was used to analyze the risk factors correlated with the large-volume CLNM,and a nomogram was constructed.The diagnostic performance of the nomogram was evaluated with ROC curve.Results There were significant differences in age,maximum tumor diameter and extracapsular invasion between the two groups(all P<0.05).The NIC,λHU,nzeff in the arterial phase and NIC in the venous phase in the large-volume CLNM group were significantly higher than those in the small-volume CLNM group(all P<0.05).Multivariate logistic regression results showed that maximum tumor diameter,extracapsular invasion,NIC in arterial phase,λHU in arterial phase,and nZeff in arterial phase were independent risk factors for predicting large-volume CLNM in PTC patients(all P<0.05).The nomogram established based on the above indicators showed good prediction performance,the area under ROC curve(AUC)of the nomogram in training set was 0.936 with a sensitivity of 0.887 and a specificity of 0.871;those of the validation set were 0.912,0.871 and 0.808,respectively.Conclusion The nomogram based on dual-energy CT parameters has good clinical value for preoperative evaluation of the large-volume CLNM in PTC patients.