Er-Jiao Xu

Two-dimensional Shear-Wave Elastography and Conventional US: The Optimal Evaluation of Liver Fibrosis and Cirrhosis

PURPOSE To evaluate the individual and combined performances of two-dimensional (2D) shear-wave elastography (SWE) and conventional ultrasonography (US) in assessing liver fibrosis and cirrhosis to determine when 2D SWE should be added to routine US. MATERIALS AND METHODS This prospective study was approved by the institutional ethics committee, and the patients provided written informed consent. Between April 2012 and March 2013, conventional US and 2D SWE examinations were performed in 198 patients (mean age, 37.7 years; age range, 18-67 years) with chronic liver disease. Liver biopsy was used as a reference standard for 167 patients; the other 31 patients had decompensated liver cirrhosis. Receiver operating characteristic (ROC) curves were obtained to assess the diagnostic performance. Differences between the areas under the ROC curves (AUCs) were compared by using a Delong test. RESULTS Two-dimensional SWE was significantly superior to US in diagnosis of significant fibrosis (score of F2 or greater) (AUC, 0.862 vs 0.725; P = .001) and early cirrhosis (score of F4) (AUC, 0.926 vs 0.789; P = .007). Combining 2D SWE with US did not increase the performance of depicting either significant fibrosis or liver cirrhosis (P = .713 and 0.410, respectively) relative to 2D SWE alone. There was no significant difference between 2D SWE and US in diagnosis of decompensated cirrhosis (AUC, 0.878 vs 0.925; P = .323). In addition, combining 2D SWE with US did not increase the performance relative to that of US alone (P = .372). CONCLUSION Conventional US is sufficient to detect decompensated cirrhosis. Two-dimensional SWE is significantly superior to US in detecting liver fibrosis. Combining 2D SWE and US did not improve the diagnostic performance for either fibrosis or cirrhosis.

Contrast‐enhanced ultrasound for the evaluation of hepatic artery stenosis after liver transplantation: potential role in changing the clinical algorithm

Hepatic artery stenosis (HAS) is a common complication in liver transplant patients. Conventional angiography remains the gold standard for diagnosis. Recently, contrast‐enhanced ultrasound (CEUS) has begun providing real‐time angiographic‐like images of vessels and allowing the accurate diagnosis of arterial diseases such as hepatic artery thrombosis. The purpose of this study was to evaluate the efficacy of CEUS in depicting HAS after liver transplantation. Forty‐seven liver transplant recipients underwent CEUS examinations with the intravenous injection of microbubble contrast agents. The reference standard was conventional angiography for 15 patients and computed tomographic angiography for 32 patients. The presence, degree, location, and type of HAS were evaluated. For the detection of HAS by CEUS, the following was found: an accuracy of 91.5% (43/47), a sensitivity of 92.3% (36/39), a specificity of 87.5% (7/8), a positive predictive value of 97.3% (36/37), and a negative predictive value of 70% (7/10). CEUS corrected false‐positive findings on color Doppler ultrasound in 7 of 47 cases (14.9%). The accuracy of CEUS in identifying the location and type of HAS was 92.3% (36/39) and 84.6% (33/39), respectively. CEUS is a useful noninvasive technique for the detection of HAS in liver transplant patients because it provides comprehensive information, including the presence, location, degree, and type. A positive CEUS finding suggests angiography as the next step rather than a computed tomography scan and may thereby alter the clinical imaging algorithm. Liver Transpl 16:729‐735, 2010.

Intra-biliary contrast-enhanced ultrasound for evaluating biliary obstruction during percutaneous transhepatic biliary drainage: A preliminary study

OBJECTIVES The aimed of this study was to investigate the value of intra-biliary contrast-enhanced ultrasound (IB-CEUS) for evaluating biliary obstruction during percutaneous transhepatic biliary drainage (PTBD). MATERIALS AND METHODS 80 patients with obstructive jaundice who underwent IB-CEUS during PTBD were enrolled. The diluted ultrasound contrast agent was injected via the drainage catheter to perform IB-CEUS. Both conventional ultrasound and IB-CEUS were used to detect the tips of the drainage catheters and to compare the detection rates of the tips. The obstructive level and degree of biliary tract were evaluated by IB-CEUS. Fluoroscopic cholangiography (FC) and computer tomography cholangiography (CTC) were taken as standard reference for comparison. RESULTS Conventional ultrasound displayed only 43 tips (43/80, 53.8%) of the drainage catheters within the bile ducts while IB-CEUS identified all 80 tips (80/80, 100%) of the drainage catheters including 4 of them out of the bile duct (P<0.001). IB-CEUS made correct diagnosis in 44 patients with intrahepatic and 36 patients with extrahepatic biliary obstructions. IB-CEUS accurately demonstrated complete obstruction in 56 patients and incomplete obstruction in 21 patients. There were 3 patients with incomplete obstruction misdiagnosed to be complete obstruction by IB-CEUS. The diagnostic accuracy of biliary obstruction degree was 96.3% (77/80). CONCLUSION IB-CEUS could improve the visualization of the drainage catheters and evaluate the biliary obstructive level and degree during PTBD. IB-CEUS may be the potential substitute to FC in the PTBD procedure.

Usefulness of contrast-enhanced ultrasound in the diagnosis of biliary leakage following T-tube removal

Biliary leakage is a serious complication related to T‐tube removal. Identifying the location of the leak is important for accurate diagnosis and prompt treatment. We report a case of biliary leakage in the common bile duct (CBD) following a T‐tube removal that was successfully diagnosed with contrast‐enhanced ultrasound (CEUS). The micro‐bubble contrast medium was administrated into the bile ducts through the percutaneous transhepatic biliary drainage catheter. The real‐time delineation of contrast agent leaking from the CBD was confirmed by percutaneous transhepatic cholangiography. CEUS can be used to detect biliary leakage after T‐tube removal.

Evaluating Biliary Anatomy and Variations in Living Liver Donors by a New Technique: Three-Dimensional Contrast-Enhanced Ultrasonic Cholangiography

Accurate assessment of the biliary anatomy is important for the safety of liver donors in living donor liver transplantation (LDLT). We evaluated the biliary anatomy and variations of 12 living liver donors with 3-D contrast-enhanced ultrasonic cholangiography (3-D CEUSC) by injecting microbubble contrast agents into the common hepatic ducts intraoperatively. Two radiologists assessed the diagnostically adequate, delineation of biliary branch orders, visibility scores (grades 0 to 3) and anatomical patterns of the intrahepatic biliary tree by consensus. The results were compared with findings on intraoperative cholangiography (IOC) and surgery. 3-D CEUSC successfully demonstrated the spatial structure of the intrahepatic biliary tree in all 12 donors. The maximum branching order of intrahepatic bile ducts displayed on 3-D CEUSC was the fifth order in the right lobe and fourth order in the left lobe of the liver, respectively. The visibility scores of the first-order (3.00 +/- 0.00) and second-order (2.67 +/- 0.69) branches were significantly (p < 0.001) higher than that of the third-order (1.98 +/- 1.13) branches, whereas visibility scores of the second-order (2.88 +/- 0.34) and third-order (2.44 +/- 1.01) branches in the right lobe were significantly (p = 0.040 and p < 0.001, respectively) higher than those in the left lobe (2.46 +/- 0.88 and 1.33 +/- 0.99). The 3-D CEUSC images of the 12 donors were diagnostically adequate for evaluating the biliary anatomy. Normal biliary pattern in nine donors and biliary variations in three donors were confirmed by both IOC and surgical findings. 3-D CEUSC may be a potential alternative to IOC in the evaluation of biliary anatomical variation before graft harvesting in LDLT.

Three-dimensional contrast-enhanced ultrasonic cholangiography: A new technique for delineation of the biliary tract in a liver donor

Currently, intraoperative cholangiography using a radio-opaque contrast medium is widely used for visualizing the biliary tract before donor hepatectomy in living donor liver transplantation (LDLT). However, radiation exposure and adverse reactions to intravenous iodinated contrast have limited its clinical application. Ultrasonography could overcome these limitations if the bile ducts could be visualized adequately. Contrastenhanced ultrasound (CEUS) and 3-dimensional (3D) CEUS have been successfully used for depicting blood flow by the intravenous injection of microbubble contrast media. Recently, the value of intracavitary administration of microbubble contrast media in the diagnosis of vesico-ureteric reflux has been reported. We describe the use of 3D contrast-enhanced ultrasonic cholangiography (CEUSC) to delineate the biliary tree in an adult living liver donor through the injection of microbubble contrast media into the bile ducts intraoperatively.

Immediate evaluation and guidance of liver cancer thermal ablation by three-dimensional ultrasound/contrast-enhanced ultrasound fusion imaging

Abstract Purpose: To investigate the feasibility and value of three-dimensional ultrasound/contrast-enhanced ultrasound (3D US-CEUS) fusion imaging for the immediate evaluation of technical success and the guidance of supplementary ablation during the liver cancer thermal ablation procedure. Materials and methods: Patients diagnosed with malignant liver cancer intending to receive thermal ablation including radiofrequency ablation (RFA) or microwave ablation (MWA) were enrolled. 3D US-CEUS fusion imaging was used to immediately assess the technical success and guide supplementary ablation. Contrast-enhanced computed tomography/magnetic resonance imaging (CECT/CEMRI) was performed one month after ablation to assess the technique effectiveness of the ablation. The registration success rate, duration time of 3D US-CEUS fusion imaging, technique effectiveness rate and major complications were recorded. Results: In total, 76 patients with 95 tumours who underwent RFA or MWA and assessed by 3D US-CEUS fusion imaging were enrolled. The registration success rate of 3D US-CEUS fusion imaging was 93.7% (89/95), and the duration time was 4.0 ± 1.1 min. Thirty lesions received supplementary ablation immediately during the procedure. The technique effectiveness rate of the ablation was 98.8% (81/82). There were no major complications related to ablation. Conclusions: 3D US-CEUS fusion imaging is a feasible and valuable technique for the immediate evaluation and guidance of supplementary ablation during the liver cancer thermal ablation procedure.

Computer-Assisted Hepatocellular Carcinoma Ablation Planning Based on 3-D Ultrasound Imaging

To evaluate computer-assisted hepatocellular carcinoma (HCC) ablation planning based on 3-D ultrasound, 3-D ultrasound images of 60 HCC lesions from 58 patients were obtained and transferred to a research toolkit. Compared with virtual manual ablation planning (MAP), virtual computer-assisted ablation planning (CAP) consumed less time and needle insertion numbers and exhibited a higher rate of complete tumor coverage and lower rate of critical structure injury. In MAP, junior operators used less time, but had more critical structure injury than senior operators. For large lesions, CAP performed better than MAP. For lesions near critical structures, CAP resulted in better outcomes than MAP. Compared with MAP, CAP based on 3-D ultrasound imaging was more effective and achieved a higher rate of complete tumor coverage and a lower rate of critical structure injury; it is especially useful for junior operators and with large lesions, and lesions near critical structures.

Double contrast-enhanced ultrasonography in the detection of periampullary cancer: Comparison with B-mode ultrasonography and MR imaging

PURPOSE To investigate the value of double contrast-enhanced ultrasonography (DCEUS) in the detection of periampullary cancer. MATERIALS AND METHODS Ninety-nine patients with surgery or biopsy-proven periampullary cancer who underwent both DCEUS and magnetic resonance imaging (MRI) examinations before operation were enrolled in our study. DCEUS in which intravenous microbubbles were used in combination with oral contrast agent and MRI were performed preoperatively to make a detection diagnosis of periampullary cancer. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of DCEUS, B-mode ultrasonography (BUS) and MRI were calculated and compared. Receiver operating characteristic (ROC) curves were used to evaluate the accuracy of BUS, DCEUS and MRI in the detection. Stratified analyses were performed for different pathological types and different sizes of periampullary lesions. The inter- and intra-observer reliability of DCEUS for cancer detection was also investigated. RESULT There were no significant differences in sensitivity, specificity, PPV, NPV or accuracy between DCEUS and MRI (all P>0.05). ROC analysis showed that the accuracy of DCEUS or MRI was higher than that of BUS (P<0.001), while no significant differences were noted in the accuracy between DCEUS and MR. In the 76 cases of periampullary cancer, DCEUS appeared to be superior to BUS for ampullary carcinoma, duodenum carcinoma and for lesions with an average diameter of less than 3cm. DCEUS appeared equal to BUS in other groups. No significant differences were noted between DCEUS and MRI in the stratified analysis. A considerably well agreement between DCEUS and MRI was obtained using Kappa analysis (k=0.649, P<0.001). The intra- and inter-observer reproducibility were both good for detection of periampullary cancer by DCEUS, with a Kappa values of 0.783 (P<0.01) and 0.732 (P<0.01), respectively. CONCLUSION DCEUS provides an available and useful imaging modality in the detection of periampullary cancer. This technique can aid in displaying the invisible periampullary region in BUS and may also become an effective supplemental method to MRI.

A clinical validation study for the feasibility and reliability of three-dimensional ultrasound-ultrasound automatic image registration

Abstract Purpose: The purpose of our study was to assess the feasibility and reliability of 3D ultrasound-ultrasound (US-US) automatic registration-based analysis of the hepatic vessel tree (VT) (3D VT-based automatic registration) in clinical applications. Materials and methods: A total of 70 pairs of 3D ultrasound data were acquired from the livers of 10 healthy volunteers enrolled in the study. An automatic registration method was applied to the acquired volumetric data pairs, and anatomic landmarks were picked by an experienced sonographer as ‘ground truth’. The influences of respiration phase, subject posture, and liver lobe on data acquisition and scan volumetric angle on the registration accuracy and robustness were investigated. The registration time, success rate, median registration error distance, and sonographer’s subjective feedback were assessed. Results: The time required for the 3D VT-based automatic registration was approximately 15∼20 s. Overall, the success rate for the hepatic vessel-based registration was 71% (50/70), and the median registration error distance was 1.72 mm (0.57∼4.71 mm). When the influential factors were well controlled, the optimal registration accuracy (median registration error distance = 1.22 mm) could be obtained with an excellent success rate of 100% (10/10). According to the subjective assessment of the sonographer, over 90% (45/50) of the automatic registration results were not inferior to the ground truth. Among them, 42% (21/50) were superior to the fusion results from the ground truth. Conclusions: The results suggest that the 3D VT-based automatic registration is feasible and reliable and has potential for guidance and evaluation of intraoperative ablation of hepatocellular carcinoma.