Contrast-enhanced Ultrasound for Evaluation of Active Needle Tract Bleeding during Thermal Ablation of Liver Cancer

Objective: To investigate the accuracy of contrast-enhanced ultrasound (CEUS) in the diagnosis and localization of active needle-tract bleeding (ANTB) during thermal ablation for liver cancer. Methods:Between June 2013 and December 2018, liver cancer patients with poor coagulation function or suspected needle-tract bleeding during ablation were enrolled in the study.Conventional US and CEUS were applied to detect ANTB and the bleeding sites, and sequentially abdominal paracentesis drainage (APD) was used as the gold standard for the diagnosis of ANTB.Thermal ablation guided by conventional US or CEUS was used to stop the bleeding.Results: Among the 77 enrolled patients, 21 patients (27.3%, 21/77) had ANTB.In total, four (19.0%) and 21 (100%) cases of ANTB were diagnosed by colour Doppler US and CEUS, respectively.The sensitivity, specificity and accuracy of colour Doppler US for diagnosing ANTB were 19.0%, 100% and 77.6%, respectively.The sensitivity, specificity, and accuracy of CEUS for diagnosing ANTB were 100%, 100% and 100%, respectively.The sensitivity of CEUS to diagnose ANTB was significantly higher than that of colour Doppler US (P < 0.001).All cases of ANTB were arterial bleeding and were stopped by thermal ablation under the guidance of colour Doppler US or CEUS. Conclusion:Compared to colour Doppler US, CEUS could detect ANTB with significantly higher sensitivity and accurately guide needle-tract ablation during thermal ablation of liver cancer.