【Abstract】　Objective：To investigate the correlation between CEUS quantitative parameters and extrathyroidal extension (ETE) of thyroid papillary carcinoma (PTC). Materials and methods: A retrospective analysis in February 2013 to November 2019 in the affiliated Renmin Hospital

Jiangsu University

of papillary thyroid carcinoma (PTC)

112 cases of patients (157 nodules)

preoperative CEUS in check

for PTC with ETE and without ETE group

internal echo

the size of the edge

blood flow signal

vertical

horizontal diameter ratio

strengthen

uniformity

and enhance the strength of variables do chi-square test or the Mann - Whitney U test

then using Logistic regression analysis of risk factors for the screening of PTC ETE

further drawn half quantitative analysis parameters of the peak down time (time from peak to one half

TPH)

increase the slope (wash in slope

WIS) and tumor size in the diagnosis of ROC curve

the maximum yoden index is the best boundary point

determine the quantitative parameters sensitivity

specificity of diagnosis of PTC ETE. Results: The qualitative characteristics (tumor size) of CEUS were significantly different between the PTC with ETE and without ETE group (P< 0.05). The difference of CEUS 'peak intensity (PI) between PTCwith ETE and without ETE group was statistically significant (P < 0.05). Multivariate Logistic regression analysis showed that tumor size

TPH

and WIS were independent risk factors for the ETE that diagnosed PTC (OR =3.688、0.892、9.758

P < 0.05). For the quantitative analysis parameters

the ETE value that diagnosed PTC with TPH value was the largest

and its area under the ROC curve was 0.805.The best cut-off value is 60.96

sensitivity and specificity were 88.3％、60.8％. Conclusion: The TPH and WIS of CEUS and tumor size were correlated with the ETE of PTC diagnosis.