To assess the value of intra-operative contrast-enhanced ultrasound(CEUS) in detecting wall invasion during robot-assisted inferior vena cava thrombectomy.

The intraoperative CEUS findings of 60 patients who were treated in first medical center, PLA General Hospital with renal tumors accompanied by IVC tumor thrombus were retrospectively analyzed between Oct. 2017 and Mar. 2019. The CEUS features were compared with the intra- and post-operative pathological findings. The IVC wall invasion was detected based on the typical CEUS findings. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CEUS were statistically analyzed.

CEUS in patients with wall invasion showed that the tumor thrombus was enhanced synchronously with the IVC wall, and the continuity of the IVC wall was poor. In contrast, in patients without wall invasion, CEUS showed that the contrast agent could pass between the tumor thrombus and the IVC wall and the continuity of IVC wall was good. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the typical enhancement mode of CEUS were 93.1%, 93.5%, 93.3%, 93.1%, and 93.5% in identifying wall invasion.

Intraoperative CEUS in robot-assisted IVC thrombectomy is highly valuable in clinical application. It can provide important information about wall invasion, thus offering real-time information to the operator during surgery.