Evaluation Of Dual Energy CT Iodiogram Combined With Clinical Features In Predicting Central Lymph Node Metastasis Of Thyroid Micropapillary Carcinoma

Objectives:To investigate the value of preoperative dual-energy CT iodiogram combined with clinical features in predicting central lymph node metastasis(CLNM)of micropapillary thyroid carcinoma(PTMC),in order to provide useful information for clinical surgeons whether to perform central lymph node dissection.Methods:A total of 165 patients who received preoperative dual-energy CT scan of the neck and were diagnosed as PTMC by disease examination and all underwent CLNM dissection in Yunnan Cancer Hospital from July 2019 to June 2020 were collected.Patients were divided into CLNM group and no CLNM group according to the results of disease examination as the "gold standard".Patients were divided into CLNM group(79 cases)and non-CLNM group(86 cases)according to whether they had cervical CLNM.Clinical features(gender,age,BMI,combined with Hashimoto’s thyroiditis),CT morphological features of primary lesions(multiple lesions,maximum diameter of nodules,irregular shape,marginal thyroid contact,microcalcification,blurred boundary after enhancement)and central lymph node metastasis were analyzed in PTMC patients.Iodine concentration(IC)and CT values of the parenchymic components of PTMC and the internal carotid artery at the same level were measured in the arterial and venous phases.Standardized iodine concentration(NIC)and standardized CT values(NCT values)of the lesions in the arteriovenous phase were calculated.The differences of IC,CT values,NIC and NCT values in the arteriovenous phase were compared between the two groups.ROC curves were drawn for different clinical features,CT morphological signs and dual-energy quantitative parameters,and the area under the curve(AUC)was calculated.Binary Logistics regression combined with ROC curve analysis was used to obtain clinical characteristics combined with morphology and dual energy CT quantitative parameters to predict the diagnostic efficacy of CLNM.Results:1.Clinical characteristics,distribution and diagnostic efficacy of CLNM in PTMCIn the basic clinical data,there were statistical differences in gender and age(P<0.05),but the diagnostic efficacy of the two was low,with AUC value of about 0.584 and 0.562,respectively.BMI and Hashimoto’s thyroiditis had no statistical difference.2.Morphological signs of primary PTMC,distribution of CLNM and diagnostic efficiencyCLNM was associated with multiple lesions,maximum diameter of nodules,irregular morphology,and thyroid marginal contact,and the AUC values were,in order,0.695>and 0.625>and 0.586>and 0.564,respectively.It was not related to microcalcification or blurred boundary after enhancement.3.The relationship between the quantitative parameters of iodine graph and CLNM in the primary lesions of PTMC and the diagnostic efficiency Comparison of quantitative parameters of iodiogram in arterial phase and venous phase between CLNM group and non-CLNM group showed no statistical significance in IC of PTMC lesions(P>0.05).The differences of NIC and NCT in the arteriovenous period were statistically significant(P<0.05),and the NIC and NCT in the CLNM group were higher than those in the non-CLNM group.Among them,the diagnostic efficiency of arterial NIC was the highest(AUC was 0.822),the specificity of arterial NIC was the best(90%),and the sensitivity of venous NIC was the highest(71%).When the arterial NIC>was 0.36,it suggested that the enlarged lymph nodes in the neck were more likely to develop CLNM.4.Clinical characteristics of PTMC combined with morphological characteristics and quantitative parameters of primary foci can predict the efficacy of CLNMThe AUC of CLNM was 0.908,sensitivity was 86.7%,specificity was 75.1%,gender,age,multiple lesions,maximum diameter of nodules,irregular shape,thyroid marginal contact combined with the value of NIC and NCT in the arteriovenous and venous phases.Conclusions:1.Men,aged<55 years,multiple lesions,larger maximum diameter of nodules,irregular shape,and thyroid marginal contact are more likely to develop CLNM,but it is not recommended to be used as a single indicator for predicting CLNM.2.Both arterial and venous NIC and NCT can be used as predictors of CLNM in PTMC,and the specificity of NIC in arterial phase is high.NIC>0.36 indicates a high possibility of CLNM in enlarged lymph nodes in the neck.3.Clinical characteristics(male,age<55 years of age),the lesion on CT morphology(multiple lesions,nodal maximum diameter,shape is irregular,thyroid edge contact)joint dual-energy CT quantitative parameter iodine maps(arteries and veins NIC and NCT)predict CLNM diagnostic performance of the optimal,CLNM transfer probability is the largest,whether for clinical surgeons were performed to provide important basis for lymph node in central region.