Abstract: Objective  To explore the diagnostic value of thyroid imaging reporting and data system(TI-RADS) and tumor invasion into thyroid capsule for papillary thyroid carcinoma(PTC) with central lymph node metastasis (CLNM). 
Methods  A total of 279 patients with single PTC that was surgically removed and pathologically confirmed in our hospital were enrolled in this study. The gender, age, echo of PTC nodules, boundary, aspect ratio, microcalcifications and the relationship between nodules and thyroid capsule were recorded. According to ultrasound characteristics, each nodule was graded based on the TI-RADS grading. Combined with the pathological results of cervical lymph node in each patient, we retrospectively analyzed the value of TI-RADS grading and tumor invasion into thyroid capsule in the diagnosis of PTC with CLNM. 
Results  The univariate analysis showed that male PTC patients with TI-RADS 4c/5, poorly-defined boundary, and the tumor invasion into thyroid capsule are more likely to experience CLNM(P＜0.05). The multivariate analysis showed that male gender, poorly-defined boundary and the tumor invasion into thyroid capsule were independent risk factors for CLNM（OR=0.437, 2.260, 3.603， all P＜0.05）. 
Conclusion  Male gender, poorly-defined boundary and the tumor invasion into thyroid capsule were independent risk factors for CLNM. Meanwhile, the higher the TI-RADS grades, the greater the possibility of CLNM. Therefore, the TI-RADS 4c/5 has predictive values for CLNM.

Key words: thyroid neoplasms, ultrasonography, lymph node