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.

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.

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.

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.

To evaluate the technical success rate and reproducibility of sound touch elastography (STE) and sound touch quantification (STQ) in liver and spleen stiffness measurement and the reference ranges of normal liver and spleen stiffness. We also compared with a previous validated acoustic radiation force impulse (ARFI) technique.

Two hundred and fifty-three healthy adults and 40 chronic hepatitis B patients were recruited. All patients underwent liver and spleen stiffness measurements using STE, STQ, and ARFI. A hundred and five patients (36 patients with chronic hepatitis and 69 healthy adults) were examined twice, by two trained sonographers who are familiar with STE and STQ techniques independently. Another 36 healthy adults were examined twice by ARFI imaging. The technical success rates and reproducibility were evaluated.

The success rates of STE, STQ, and ARFI were 96.5%, 95.1%, and 94.8% in liver, and 87.5%, 84.0%, and 78.0% in spleen, respectively. The inter-observer reproducibility of STE, STQ and ARFI were 0.914, 0.896, and 0.845 in liver, and 0.629, 0.601, and 0.543 in spleen, respectively. When the thickness of spleen was greater than 30mm, the reproducibility was 0.704 in STE and 0.668 in STQ. The normal ranges of liver stiffness were 5.80-6.04 kPa measured by STE and 5.87-6.13 kPa measured by STQ, and normal spleen stiffness ranged from 14.83-15.54 kPa measured by STE and 15.85-16.62 kPa measured by STQ.

Our study showed STE and STQ in liver and spleen stiffness measurement had a high success rate with good reproducibility, which were comparable to ARFI. The inter-observer reproducibility of spleen was barely satisfactory, but was good when the thickness of spleen was greater than 30mm.