RGB Three-Channel SWE-Based Ultrasomics Model: Improving the Efficiency in Differentiating Focal Liver Lesions.

OBJECTIVE: To explore a new method for color image analysis of ultrasomics and investigate the efficiency in differentiating focal liver lesions (FLLs) by Red, Green, and Blue (RGB) three-channel SWE-based ultrasomics model. METHODS: One hundred thirty FLLs were randomly divided into training set (n = 65) and validation set (n = 65). The RGB three-channel and direct conversion methods were applied to the same color SWE images. Ultrasomics features were extracted from the preprocessing images establishing two feature data sets. The least absolute shrinkage and selection operator (LASSO) logistic regression model was applied for feature selection and model construction. Two models, named RGB model (based on RGB three-channel conversion) and direct model (based on direct conversion), were used to differentiate FLLs. The diagnosis performance of the two models was evaluated by area under the curve (AUC), calibration curves, decision curves, and net reclassification index (NRI). RESULTS: In the validation cohort, the AUC of the direct model and RGB model in characterization on FLLs were 0.813 and 0.926, respectively (p = 0.038). Calibration curves and decision curves indicated that the RGB model had better calibration efficiency and provided greater clinical benefits. NRI revealed that the RGB model correctly reclassified 7% of malignant cases and 25% of benign cases compared to the direct model (p = 0.01). CONCLUSION: The RGB model generated by RGB three-channel method yielded better diagnostic efficiency than the direct model established by direct conversion method. The RGB three-channel method may be promising on ultrasomics analysis of color images in clinical application.

Shear wave elastography-based ultrasomics: differentiating malignant from benign focal liver lesions.

PURPOSE: Ultrasomics is a radiomics technique that extracts high-throughput quantitative data from ultrasound imaging. The aim of this study was to differentiate malignant from benign focal liver lesions (FLLs) using two-dimensional shear wave elastography (2D-SWE)-based ultrasomics. METHODS: A total of 175 FLLs in 169 patients were prospectively analyzed. The study population was divided into a training cohort (n = 122) and a validation cohort (n = 53). The maxima, minima, mean, and standard deviation of 2D-SWE measurements were expressed in kilopascals (Emax, Emin, Emean, and ESD). The ultrasonics technique was used to extract the features from the 2D-SWE images. Support vector machine was used to establish two prediction models: the ultrasomics score (ultrasomics features only) and the combined score (SWE measurements and ultrasomics features). The diagnostic performance of the models in differentiating FLLs was analyzed. RESULTS: A total of 1044 features were extracted and 15 features were selected. The AUC for the combined score, ultrasomics score, Emax, Emean, Emin and ESD were 0.94, 0.91, 0.92, 0.89, 0.67, and 0.89, respectively. The combined score had the best diagnostic performance. The sensitivity, specificity, PPV, NPV, +LR, LR of the combined score were 92.59%, 87.50%, 94.59%, 82.50%, 7.35%, and 0.09%, respectively. The decision curve analysis results showed that when the threshold probability was > 29%, the combined score showed improved benefits for patients compared to using the ultrasomics score and 2D-SWE measurements. CONCLUSION: The results of this study demonstrated that the combined score had good diagnostic accuracy in differentiating malignant from benign FLLs.

Transplant renal artery stenosis: Evaluation with contrast-enhanced ultrasound.

OBJECTIVE: To assess the efficacy of contrast-enhanced ultrasound (CEUS) in depicting transplant renal artery stenosis (TRAS). MATERIALS AND METHODS: Seventy-eight patients (56 men and 22 women; aged 36±12.2years) who were suspected of TRAS due to either Doppler ultrasound (DUS) abnormalities or difficult control of blood pressure and/or persistent deterioration of renal function were enrolled to perform CEUS. The reference standard for the TRAS diagnoses was computed tomography angiography (CTA). The diagnostic performance of DUS and CEUS parameters was assessed by the area under the receiver operating characteristic curve (AUC). RESULTS: TRAS was diagnosed in 32 out of 78 cases by CTA. The AUC, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CEUS in predicting TRAS were 0.92, 92.3%, 87.5%, 95.7%, 93.3%, and 91.7%, respectively. CEUS rectified 13 (28.3%) false-positive cases on DUS, which were confirmed by CTA. Compared to DUS parameters, CEUS showed the highest AUC, statistically significant differences of AUC were found (P=0.006-0.039), except for that of the PSV ratio in the main transplant renal artery to that in interlobar artery (PSV-ratio) (AUC: 0.92 versus 0.86, P=0.422). However, CEUS showed a significantly higher specificity (95.7% versus 76.1%, P=0.008) and the same sensitivity compared to PSV-ratio. CONCLUSIONS: CEUS is superior to DUS in depicting TRAS. Moreover, our results suggest that CEUS might potentially be used as a noninvasive tool to spare many patients from unnecessary CTA.

Risk Factors for Bile Duct Injury After Percutaneous Thermal Ablation of Malignant Liver Tumors: A Retrospective Case-Control Study.

BACKGROUND: Bile duct injury after ablation of malignant liver tumors (MLTs) was not unusual and should be avoided. However, few studies have focused on evaluating the risk factors for intrahepatic bile duct injury. AIM: To evaluate the risk factors for intrahepatic bile duct injury after ablation of MLTs and to evaluate the minimum safe distance for ablating tumors abutting bile ducts. METHODS: Sixty-five patients with intrahepatic bile duct injury after ablation of MLTs, and 65 controls were recruited. Risk factors for intrahepatic bile duct injury were analyzed. Tumor location was recorded as ≤5 mm (group A), 5-10 mm (group B), and >10 mm (group C) from the right/left main duct or segmental bile duct. RESULTS: Ascites history (P < 0.001), TACE treatment history (P = 0.025), intrahepatic bile duct dilatation before ablation (P < 0.001), and tumor location (P = 0.000) were identified as significant risk factors for intrahepatic bile duct injury. Significant differences in the risk of intrahepatic bile duct injury were found between groups B and C (P = 0.000), but not between groups A and B (P = 0.751). Ascites history (P = 0.002) and tumor location (P < 0.001) were independent predictors with the OR (95 % confidence interval) of 39.31(3.95-391.69) and 16.56 (5.87-46.71), respectively. CONCLUSIONS: Bile duct injury after ablation of MLTs was the result of local treatment-related factors combined with the patients' general condition. The minimum safe distance for ablation of tumor abutting a bile duct was 10 mm.

Added value of two-dimensional shear wave elastography to ultrasonography for staging common femoral vein thrombi.

prove the performance for staging common femoral vein thrombi (CFVT). MATERIAL AND METHODS: A total of 194 consecutive patients with CFVT who underwent US and 2D-SWE were enrolled. These patients were categorized into three groups according to CFVT duration: Stage A (≤14 days), Stage B (14 days to 6 months), and Stage C (≥6 months). The diagnostic performance was assessed by the area under the receiver operating characteristic curve (AUC). RESULTS: Among all US features, CFV diameter ratio of thrombosed leg to contralateral leg (CFVD_ratio) showed the highest AUC in predicting Stage A and Stage C (0.87 and 0.84, respectively). The diagnostic performance of 2D-SWE value of CFVT (CFVT_E) is comparable with that of CFVD_ratio for Stage A (AUC: 0.85, p=0.630), whereas inferior to that of CFVD_ratio for Stage C (AUC: 0.73, p=0.026). Combining CFVD_ratio with CFVT_E showed lower performance in predicting Stage A (AUC: 0.81, p=0.021) and Stage C (AUC: 0.67, p<0.0001) relative to CFVD_ratio alone. However, this combination increased the specificity from 80.3% to 92.7% (p<0.0001) without a significant reduction of sensitivity (from 77.2% to 70.2%, p=0.371) for predicting Stage A. CONCLUSIONS: Adding 2D-SWE to US did not improve the diagnostic performance for staging CFVT compared with US alone. However, the combination improved the specificity in predicting CFVT less than 14 days without loss of sensitivity.

Ultrasound and Contrast-Enhanced Ultrasound for Evaluation of Irreversible Electroporation Ablation: In Vivo Proof of Concept in Normal Porcine Liver.

The objective of this study was to describe the performance of ultrasound (US) and contrast-enhanced ultrasound (CEUS) within 2 h after irreversible electroporation (IRE) ablation of porcine liver. Six IRE ablations were performed on porcine liver in vivo; ultrasound assessments were performed within 2 h after IRE ablation. On US images, the ablation zone appeared as a hypo-echoic area within 10 min after the ablation, and then the echo of the ablation zone gradually increased. On CEUS images, the ablation zone appeared as a non-enhanced area within 10 min after ablation and then was gradually centripetally filled by microbubbles. A hyper-echoic rim on US images and a hyper-enhanced rim on CEUS images appeared in the periphery of the ablation zone 60 min after the ablation. Characteristic and dynamic ultrasound images of the IRE ablation zone were obtained within 2 h after IRE ablation of in vivo porcine liver.

Maximum Value Measured by 2-D Shear Wave Elastography Helps in Differentiating Malignancy from Benign Focal Liver Lesions.

The goal of the work described here was to evaluate the diagnostic efficacy of 2-D shear wave elastography (2-D SWE) in differentiating malignancy from benign focal liver lesions (FLLs). The maxima, minima, means and the standard deviations of 2-D SWE measurements, expressed in kilopascals (Emax, Emin, Emean, ESD), were obtained for 221 patients with 229 FLLs. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of 2-D SWE. The Mann-Whitney U-test was used to assess inter-group differences. Emax, Emin, Emean and ESD were significantly higher in the 164 malignant lesions than in the 65 benign lesions (p < 0.001). For identification of malignant FLLs, the areas under receiver operating characteristic curves for Emax, Emin, Emean and ESD were 0.920, 0.710, 0.879 and 0.915, respectively. Emax was 96.21 ± 35.40 for 19 intrahepatic cholangiocarcinomas and 90.32 ± 54.71 for 35 liver metastatic lesions, which were significantly higher than 61.83 ± 28.87 for 103 hepatocellular carcinomas (p < 0.0001 and p = 0.0237). Emax was 38.72 ± 18.65 for 15 focal nodular hyperplasias, which was significantly higher than 20.56 ± 10.74 for 37 hemangiomas (p = 0.0009). The Emax values for adjacent liver parenchyma of hepatocellular carcinomas and intrahepatic cholangiocarcinomas were significantly higher than those for the other three lesion types (p < 0.005). In conclusion, Emax values of FLLs and adjacent liver parenchyma could help in differentiating malignant from benign FLLs.

Elastography of shear wave speed imaging for the evaluation of liver fibrosis: A meta-analysis.

AIM: A meta-analysis was carried out to assess the accuracies of shear wave speed imaging (SWSI) in predicting significant fibrosis (stages F2-4) and cirrhosis (stage F4). METHODS: A review was performed of relevant studies published until October 2015. A bivariate binomial model was used to combine the sensitivity, specificity, and the area under the summary receiver operating characteristic (AUC), and 95% confidence intervals were derived to indicate the diagnostic accuracy of imaging modalities. RESULTS: In total, 10 studies with 2182 patients were included in the analysis. The sensitivity, specificity, and AUC (with 95% confidence intervals) of SWSI were: 0.84 (0.81-0.87), 0.83 (0.77-0.88), and 0.88 (0.85-0.90) for significant fibrosis, respectively; and 0.80 (0.66-0.89), 0.93 (0.88-0.96), and 0.95 (0.92-0.96) for cirrhosis, respectively. When SWSI was compared with well-evaluated transient elastography, the AUCs for the prediction of significant fibrosis were 0.93 and 0.86, respectively. The AUCs for the prediction of cirrhosis were both 0.94. CONCLUSION: Shear wave speed imaging is a trustworthy tool for staging hepatic fibrosis, with a high combination of sensitivity and specificity. Compared with transient elastography, SWSI showed better diagnostic performance for the prediction of significant fibrosis.