Abstract：ObjectiveTo investigate the value of contrast-enhanced ultrasonography(CEUS) in the diagnosis of thyroid nodules under Thyroid Imaging Reporting and Data System (TI-RADS) classification.MethodsTotally 295 patients were enrolled,387 thyroid nodules underwent conventional ultrasonic TI-RADS classification CEUS.In order to observe the microcirculation perfusion characteristics of thyroid nodules,the time intensity curve was obtained by CAP SonoLiver software and compare with postoperative pathologic results.The quantitative parameters of the intensity curves were analyzed,and the two TI-RADS classification were performed.The sensitivity,specificity,accuracy,positive predictive value and negative predictive value of diagnosis of thyroid malignant nodules were calculated by conventional ultrasonic TI-RADS as well as the two TI-RADS classification.Meanwhile the TI-RADS (ROC) curves were plotted,and the area under the ROC curve was calculated.ResultsThree hundred and eight-seven conventional classification of TI-RADS 2～5 classes of thyroid nodules in 295 patients′ postoperative pathology were analyzed,121 cases in 82 patients were malignant and 213 cases in 266 patients were benign.The sensitivity,specificity,accuracy,positive predictive value and negative predictive value of conventional ultrasound TI-RADS classification for diagnosis of malignant nodules were 63.64% (77/121),73.87% (229/310),79.07% (306/387),45.83% (77/168),and 83.88% (229/273),while the two TIRADS classification for diagnosis of malignant nodules were 85.95% (104/121),92.93% (263/283),94.83% (263/387),83.87% (104/124),and 93.93% (263/280).The sensitivity,specificity,accuracy,positive predictive value,positive predictive value and negative predictive value of the two TI-RADS classification of thyroid malignant nodules were higher than those of conventional ultrasound（χ2=5.92，4.38，7.31，7.45，3.13；P＜0.05）.The area under the ROC curve of conventional ultrasonic and the two TI-RADS classification of thyroid malignant nodules were 0.753 and 0.834,respectively.Among cases that TI-RADS was classified as malignant thyroid nodules by CEUS,they exhibited the following features under ultrasound contrastenhanced mode:solid nodules (≥1cm) exhibited early rapid heterogeneous enhancement pattern together with perfusion defects,and solid nodules (<1cm) also exhibited heterogeneous enhancement pattern.For cases that TI-RADS was classified as benign thyroid nodules by CEUS,nodules and their annular surroundings exhibited homogenous enhancement pattern.The differences in the features between malignant group and benign group were statistically significant （χ2=43.86，12.54；P＜0.05）.The differences between malignant group and benign group were statistically significant （χ2=51.48，17.91，47.25，8.92，3.37，4.05；P＜0.05） in enhancement level,enhancement border,arrival to peak-time characteristics,quantitative parameters mean transit time(MTT),peak intensing(PI) and arrival intensing(AI),（χ2=51.48，17.91，47.25，8.92，3.37，4.05；P＜0.05），but not statistically significant in enhancement value range,quantitative parameters rise time(RT) and peak time(PT) （χ2=2.87，0.95，0.88；P＞0.05）.ConclusionCEUS can improve accuracy in TI-RADS classification of thyroid nodules.
