ObjectiveTo investigate the correlation between contrast-enhanced ultrasound（CEUS） quantitativeparameters and papillary thyroid carcinoma（PTC）with extrathyroidal extension（ETE）.MethodsRetrospective analysis of thepathological diagnosis in 112 patients with PTC（157 nodules）were performed

including 60 lesions with extrathyroidal extension（ETE group）and 97 lesions without extrathyroidal extension（no ETE group）. The size

internal echo

size of the edge

blood flowsignal

ration of anteroposterior diameter to transverse diameter

CEUS enhancement pattern and intensity of the nodules betweentwo groups were compared. Then Logistic regression analysis was used to analyze risk factors for screening of PTC with ETE.ROCwas drawn to analyze the time from peak to one half（TPH）

the wash in slope（WIS）and tumor maximum size in the diagnosis ofPTC with ETE. Taken maximum Youden index as cutoff value

the sensitivity

specificity of diagnosis of PTC with ETE weremeasured.ResultsTumor maximum size and the quantitative parameters of CEUS（WIS

RT

TTP

TPH）were significantlydifferent between the ETE group and no ETE group（all P<0.05）. Multivariate Logistic regression analysis showed that tumormaximum size

TPH and WIS were independent risk factors in diagnosing PTC with ETE（OR=4.135

0.907

16.721

all P<0.05）.Among the quantitative analysis parameters

TPH had the greatest value in diagnosing PTC with ETE. When cutoff value was60.96

the sensitivity and specificity were 88.3% and 60.8%

and area under the ROC curve was 0.805.ConclusionTumormaximum size

TPH and WIS are correlated with the PTC with ETE.