Application Value Of ACR TI-RADS Classification Combined With Superb Micro-vascular Imagingtechnique In The Diagnosis Of Thyroid Nodules

Objective:To evaluate the value of the American radiological society thyroid imaging report and data system(ACR TI-RADS)combined with superb micro-vascular imagine technique(SMI)in the diagnosis of benign and malignant thyroid nodules.Methods: The subjects of this study were 66 patients with thyroid nodules who went to the first affiliated hospital of guangxi medical university for medical treatment from June 2018 to December 2018.A total of 68 thyroid nodules were included.All nodules obtained pathological results through puncture biopsy or(and)surgical treatment.All nodules were graded according to the 2017 ACR TI-RADS classification criteria,and the blood flow pattern and vascular morphological characteristics of each nodule were evaluated and compared by CDFI and SMI.Spectral doppler(SPE)was activated in CDFI and SMI modes respectively,and the maximum value of blood flow resistance index(RI)in nodules was measured and recorded for analysis,and RI mean differencesin different modes were compared.Taking pathological results as the gold standard,the receiver operating characteristic curve(ROC)was described to calculate the best diagnostic point for the diagnosis of benign and malignant thyroid nodules through ACR TI-RADS,SMI single mode and ACR TI-RADS+SMI combined mode.Therefore,the diagnostic performance of each thyroid nodule diagnostic mode was calculated and compared.Results:Using the 2017 ACR TI-RADS model as the classification standard,a total of 16 thyroid nodules in this study were TR3,with a malignant rate of6.2%.Fifteen nodules were TR4,and the malignant rate was 66.6%.Thirty-seven nodules were TR5,and the malignant rate was 86.4%.Compared with CDFI,SMI showed a higher proportion of peripheral blood flow in benign thyroid nodules and a significantly higher display rate of central blood flow in malignant thyroid nodules than CDFI(P<0.05).In addition,SMI had advantages over CDFI in displaying the morphological characteristics of microvessels inside nodules and the details of distal branch vessels.In the SMI model,it was found that the blood flow signal distribution at the edge of benign nodules was dominated by annular blood flow,while convergent blood flow was the most common blood flow signal distribution pattern at the edge of malignant nodules,and the difference was statistically significant(P<0.01).In the comparison of nodule resistance index(RI)measured by CDFI and SMI,the RI mean of SMI mode was higher than that of CDFI mode(0.68±0.15 VS 0.62±0.13,P<0.01).According to the pathological results,nodules were divided into benign group and malignant group,and only in the malignant group,the mean value of RI obtained by SMI mode was higher than that obtained by CDFI mode(0.73±0.11 VS 0.66±0.12,P<0.01),and the mean value of RI in the benign group was not different between the two modes(0.60±0.16 VS 0.55±0.10,P>0.05).In the SMI pattern,there was a significant difference in RI between the benign and malignant group(0.60±0.16 VS0.73±0.11,P<0.01).Benign and malignant thyroid nodules were evaluated using ACR TI-RADS,SMI single mode and ACR TI-RADS+SMI combined mode,respectively.The area under the corresponding ROC curve was 0.880,0.814,0.903,and the yoden index was0.713,0.570,and 0.786.Compared with the single ACR TI-RADS mode,the combined ACR TI-RADS+SMI mode showed slightly lower sensitivity(0.906 vs 0.953,P<0.01)and significantly higher specificity(0.880 vs 0.760,P<0.01).Conclusion: The 2017 ACR TI-RADS classification standard has high clinical value in the differential diagnosis of benign and malignant thyroid nodules.Compared with CDFI,SMI can more effectively observe the tiny blood vessels inside the thyroid nodule and display the low-speed blood flow,which is more advantageous to the display of the blood flow distribution pattern inside and around the nodule.Compared with CDFI,the RI value of blood flow in nodules detected by SPE in SMI mode is more real and accurate,which is mainly reflected in malignant nodules.Therefore,the application of SMI technology can improve the value of SPE in the identification of malignant thyroid nodules.The combined diagnosis model of ACR TI-RADS+SMI can help improve the accuracy of thyroid nodule diagnosis and provide more effective basis for clinicians’ medical decisions.