Objective To investigate the correlation between the characteristics of contrast-enhanced ultrasound（CEUS）and microvascular density（MVD）in papillary thyroid carcinoma（PTC）.Methods Sixty-one patients with thyroid nodules（61 nodules）who underwent thyroid CEUS examination in the ultrasound department of our hospital were retrospective analyzed. The enhanced features of CEUS were analyzed and the surgical pathological results were compared. MVD of PTC nodule was counted by CD31 immunohistochemistry. Pearson method was used to analyze the correlation between CEUS quantitative parameters and MVD.Results CEUS indicated that 55 nodules were heterogeneous and low enhancement pattern.The accuracy of CEUS in diagnosing PTC was 90.1%. The peak intensity and area under the curve of time intensity curve

in 55 nodules were（14.47±6.42）dB and（603.1±222.80）dB·s

respectively

which were lower than those of（21.06±5.65）dB and（1025.43±260.37）dB·s in the surrounding normal thyroid tissues

and differences were statistically significant（both P<0.05）.The mean MVD of CD31 immunohistochemical staining PTC nodules was（64.99±17.51）twigs/HP

which was lower than that of（91.71±7.54）twigs/HP in surrounding normal thyroid tissue

and the differences was statistically significant（P<0.05）. The significantly positive correlation were observed between PI

AUC and MVD in PTC（r=0.811

0.734

both P<0.001）.Conclusion CEUS quantitative parameters can reflect the microvessels of PTC. This study provides a non-invasive preoperative detection method for clinical evaluation of MVD of PTC.