Usefulness of arrival time parametric imaging in evaluating the degree of liver disease progression in chronic hepatitis C infection

The added value of color parameter imaging for the evaluation of focal liver lesions with "homogenous hyperenhancement and no wash out" on contrast enhanced ultrasound

Objective

The purpose of this study was to investigate the added value of color parameter imaging (CPI) in the differential diagnosis of focal liver lesions (FLLs) with "homogeneous hyperenhancement but not wash out" on contrast-enhanced ultrasound (CEUS).

Methods

A total of 101 patients with 108 FLLs were enrolled in this study. All the FLLs received US and CEUS examinations. The stored CEUS clips of target lesions were postprocessed with CPI analysis by radiologists. The receiver operator characteristic (ROC) curve was used to evaluate the added value of CPI. The McNamara test was used to compare the diagnostic sensitivity, specificity, and accuracy between CEUS and CPI patterns. Univariate and multivariate logistic regression analyses were used to develop a CPI nomogram. The C index and calibration curve were used to evaluate the predictive ability of the nomogram. The intraclass correlation coefficient was used to test the reproducibility and reliability of CPI. Decision curve analysis (DCA) was used to evaluate the added value of applying CPI.

Results

The following CPI features were more frequently observed in malignant FLLs: eccentric perfusion (malignant: 70.0% vs. benign: 29.2%, p < 0.001), feeding artery (51.7% vs. 4.2%, p < 0.001), mosaic (63.3% vs. 6.3%, p < 0.001), red ingredients >1/3 (90.0% vs. 14.6%, p < 0.001). In addition, centripetal (43.8% vs. 18.3%, p = 0.004), peripheral nodular (54.2% vs. 1.7%, p < 0.001), subcapsular vessel (12.5% vs. 0.0%, p = 0.004), spoke-wheel vessels (25.0% vs. 5.0%, p = 0.003), branched vessels (22.9% vs. 5.0%, p = 0.006), blue and pink ingredients >2/3 (85.4% vs. 10.0%, p < 0.001) were more observed in benign FLLs. A nomogram incorporating peripheral nodular, spoke-wheel vessels, and red ingredients >1/3 was constructed. The model had satisfactory discrimination (AUC = 0.937), and the optimal diagnostic threshold value was 0.740 (0.983, 0.850). By the DCA, the model offered a net benefit over the treat-all-patients scheme or the treat-none scheme at a threshold probability 5%-93%.

Conclusion

Using CPI can detect and render subtle information of the main features of FLLs on CEUS; it is conducive to the radiologist for imaging interpretation, and a combining read of the CEUS and CPI of the FLLs with features of "homogenous hyperenhancement and no washout" can improve significantly the diagnostic performance of CEUS for FLLs.

Comparison of strain elastography and shear wave elastography in diagnosis of fibrosis in nonalcoholic fatty liver disease

PURPOSE

To reveal the ability of S-Map strain elastography to diagnose fibrosis in nonalcoholic fatty liver disease (NAFLD) and to compare its diagnostic ability with that of shear wave elastography (SWE).

METHODS

Participants were patients with NAFLD who were scheduled to undergo liver biopsy at our institution between 2015 and 2019. A GE Healthcare LOGIQ E9 ultrasound system was used. For S-Map, the right lobe of the liver was visualized in the section where the heartbeat was detected by right intercostal scanning, a 4 × 2-cm region of interest (ROI) was defined at 5 cm from the liver surface, and ROI strain images were acquired. Measurements were repeated six times, with the average taken as the S-Map value. Correlations of S-Map and SWE values with fibrosis stage determined by liver biopsy were analyzed using multiple comparisons. The diagnostic performance of S-Map for fibrosis staging was assessed using receiver operating characteristic curves.

RESULTS

In total, 107 patients (65 men, 42 women; mean age 51 ± 14 years) were analyzed. The S-Map value by fibrosis stage was 34.4 ± 10.9 for F0, 32.9 ± 9.1 for F1, 29.5 ± 5.6 for F2, 26.7 ± 6.0 for F3, and 22.8 ± 4.19 for F4. By fibrosis stage, the SWE value was 1.27 ± 0.25 for F0, 1.39 ± 0.20 for F1, 1.59 ± 0.20 for F2, 1.64 ± 0.17 for F3, and 1.88 ± 0.19 for F4. The diagnostic performance of S-Map (measured by area under the curve) was 0.75 for F2, 0.80 for F3, and 0.85 for F4. The diagnostic performance of SWE (measured by area under the curve) was 0.88 for F2, 0.87 for F3, and 0.92 for F4.

CONCLUSION

S-Map strain elastography was inferior to SWE in terms of ability to diagnose fibrosis in NAFLD.

Contrast-Enhanced Ultrasonography with Arrival Time Parametric Imaging as a Non-Invasive Diagnostic Tool for Liver Cirrhosis

Liver biopsy is the gold standard method for staging liver fibrosis, but it is an invasive procedure that is associated with some complications. There are also non-invasive techniques for assessing liver fibrosis, such as elastography and biological tests, but these techniques can fail in detection or generate false measurements depending on the subject’s condition. This study aimed to determine whether liver fibrosis can be evaluated using contrast-enhanced ultrasonography with arrival time parametric imaging using the ultrasound machine’s parametric image software, the method being called (CEUS-PAT). CEUS-PAT was performed on each subject using SonoVue as a contrast agent, and images showing liver parenchyma and the right kidney on a single screen were used for analysis in parametric imaging, which was performed using the proprietary software of the ultrasound system. The ratio between the kidney and liver arrival times was calculated. The study included 64 predominantly male (56.3%) subjects, 37 cirrhotic patients, and 27 healthy volunteers, with a mean age of 58.98 ± 8.90 years. Significant differences were found between the liver cirrhosis and healthy groups regarding CEUS-PAT, 0.83 ± 0.09 vs. 0.49 ± 0.11, p < 0.0001. The correlation between CEUS-PAT and VCTE was r = 0.81. The optimal cut-off value for detecting liver cirrhosis was >0.7, with an AUC of 0.98, p < 0.001, Se = 89.19%, Sp = 100%, PPV = 100%, and NPV = 87.1%. We demonstrate that CEUS-PAT achieves excellent performance in diagnosing liver cirrhosis and is a fast method for diagnosing liver cirrhosis that can even be applied in situations where the use of other methods is excluded.

Computer-Aided Color Parameter Imaging of Contrast-Enhanced Ultrasound Evaluates Hepatocellular Carcinoma Hemodynamic Features and Predicts Radiofrequency Ablation Outcome

Computer-aided color parameter imaging (CPI) is a novel technique for contrast-enhanced ultrasound (CEUS) that can highlight hemodynamic features of focal lesions. The purpose of the study was to investigate the role of CPI in evaluation of hepatocellular carcinoma (HCC) hemodynamic features and prognosis after radiofrequency ablation (RFA). One hundred twenty-one patients with HCC underwent CEUS with CPI analysis before RFA. Eighty-nine patients had pathologically proven well- to moderately differentiated HCC (WM-HCC), and 32 patients had poorly differentiated or undifferentiated HCC (PU-HCC). Perfusion features of CEUS and contrast-enhanced computed tomography/magnetic resonance imaging were compared with CPI parameters for WM-HCC and PU-HCC. The results indicated that 67.4% of WM-HCC had a centrifugal perfusion CPI pattern, whereas 84.4% of PU-HCC tumors had a centripetal pattern (p < 0.001, odds ratio = 11.2). The specificity, sensitivity and accuracy of the CPI perfusion pattern regarding HCC pathological grade were higher than those with routine CEUS (84.4% vs. 9.4%, p < 0.001; 67.4% vs. 3.4%, p < 0.001; 71.9% vs. 5.0%, p < 0.001). Moreover, multivariable analysis revealed that the CPI perfusion pattern was an independent risk factor for progression-free survival post-RFA (centripetal group: 28.3 ± 4.1 mo vs. centrifugal group: 45.8 ± 4.4 mo, p = 0.002). A novel CPI technique for CEUS could non-invasively provide valuable hemodynamic information and predict prognosis for HCC patients treated by RFA.

Arrival-Time Parametric Imaging in Contrast-Enhanced Ultrasound for Diagnosing Fibrosis in Primary Biliary Cholangitis

Liver biopsy is usually required for diagnosing fibrosis in primary biliary cholangitis (PBC), but contrast-enhanced ultrasonography (CEUS) is a possible alternative. The aim of this study was to investigate arrival-time parametric imaging (At-PI) in for diagnosing fibrosis in PBC. Forty-eight patients (male/female, 8/40; mean age, 60 ± 13 years) with PBC diagnosed by liver biopsy underwent CEUS during 2009-2019. Of these, 27 who also underwent shear wave elastography (SWE) were further analyzed. Perflubutane was intravenously injected and CEUS performed. Contrast dynamics of hepatic segment V and the right kidney were recorded and At-PI generated. The ratio of red indicating contrast arrival time <5 seconds to the entire liver contrast-enhanced area was calculated and compared with shear wave velocity (Vs) measured by SWE by fibrosis stage (F0-F3), bile duct loss score, cholangitis activity, hepatitis activity (HA0-HA3), and disease stage, as determined by liver biopsy. Ratio of red significantly differed between F0 and F2-F3 and between F1 and F2-F3. Using ratio of red to diagnose ≥F1 (≥F2), area under the receiver operating characteristic curve was 0.77 (0.92) (cutoff, 36.7% [47.1%]; sensitivity, 0.75 [0.92]; specificity, 0.82 [0.81]). At-PI was useful for diagnosing fibrosis, especially F2 or worse, in PBC, suggesting that At-PI can correctly diagnose fibrosis regardless of hepatic inflammation.

Diagnostic value of color parametric imaging and contrast-enhanced ultrasound in the differentiation of hepatocellular adenoma and well-differentiated hepatocellular carcinoma

PURPOSE

To investigate the differential diagnostic value of computer-aided color parametric imaging (CPI) and contrast-enhanced ultrasound (CEUS) in hepatocellular adenoma (HCA) and well-differentiated hepatocellular carcinoma (wHCC).

METHOD

A total of 38 patients who underwent CEUS and were pathologically diagnosed with HCA (10 cases) and wHCC (28 cases) were reviewed retrospectively. The differences between the radiological features of HCA and wHCC were compared by two readers, blinded to the final diagnosis.

RESULTS

(a) Sonographic features: on gray-scale ultrasound, halo sign was more common in wHCC than in HCA (60.7% vs. 10.0%, p = 0.009). On CEUS, hyper- or isoenhancement was more common in HCA in the portal phase (90.0% vs. 50.0%; p = 0.022). On CPI mode, HCA was inclined toward centripetal enhancement (60.0% vs. 14.3% p = 0.010). HCA was characterized by the presence of pseudocapsule enhancement (50.0% vs. 14.3%; p = 0.036). Quantitative analysis showed that the arrival time of HCA was earlier than that of wHCC (12.4 ± 3.7 s vs. 15.9 ± 3.2 s; p = 0.006). (b) Interobserver agreement was improved by using CPI compared with CEUS. The diagnostic sensitivity, specificity, and accuracy of the combination were 80.0%, 85.7%, and 84.2%, respectively.

CONCLUSIONS

CEUS combined with CPI can provide effective information for the differential diagnosis of HCA and wHCC, especially for the non-experienced radiologists.

Adaptation of lenvatinib treatment in patients with hepatocellular carcinoma and portal vein tumor thrombosis

PURPOSE

The aim of this study was to clarify the adaptation of lenvatinib treatment in patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombosis (PVTT).

METHOD

Fifty-three patients with HCC were treated with lenvatinib. Before and after treatment blood sampling, patients were examined by computed tomography and ultrasonography. In patients with portal trunk invasion (Vp4), the analysis focused on the degree of occlusion due to the tumor in the portal trunk. In patients without major PVTT {ie, invasion of the primary branch of the portal vein [Vp3] or Vp4}, portal blood flow volume was measured by Doppler analysis; however, Doppler analysis is difficult to perform in patients with major PVTT, so the time from administration of the contrast agent to when it reached the primary branch of the portal vein (portal vein arrival time) was evaluated with the contrast agent Sonazoid.

RESULTS

Patients with Vp4 had a significantly worse prognosis than patients with Vp3 and a significant increase in Child-Pugh score at 2 months. Patients with major PVTT had a poor prognosis if the degree of occlusion of the portal trunk was 70% or more. In patients without major PVTT, portal blood flow was significantly decreased after administration of lenvatinib; and in patients with major PVTT, the hepatic artery and portal vein arrival times were significantly increased.

CONCLUSION

Lenvatinib treatment should be avoided in patients with Vp4 with a high degree of portal trunk occlusion because of concerns about decreased portal blood flow.

The clinical value of Arrival-time Parametric Imaging using contrast-enhanced ultrasonography in differentiating benign and malignant breast lesions

OBJECTIVES

To evaluate the clinical value of Arrival-time Parametric Imaging (At-PI) in the differentiation of benign and malignant breast lesions.

METHODS

For this ethics committee-approved retrospective study, a total of 184 breast lesions in 176 women were included and gray-scale ultrasound, contrast-enhanced ultrasound (CEUS) and At-PI were performed. In CEUS and At-PI, perfusion patterns, perfusion uniformity and color spatial distribution for lesions were analyzed qualitatively and the maximal diameter ratio of the lesion in accumulated parametric images and that in gray-scale images (MDRAI/GI) and area ratio of the lesion in accumuated parametric images and that in gray-scale images (ARAI/GI) were calculated quantitatively. Kappa and Intraclass Correlation Coefficient were used to evaluate the interobserver reproducibility for CEUS and At-PI and the intraobserver reproducibility for At-PI, respectively. The area under receiver operating characteristic (AUC), sensitivity, specificity, accuracy and positive and negative likelihood ratios (PPV, NPV) were calculated for MDRAI/GI and ARAI/GI.

RESULTS

Good interobserver and intraobserver reproducibility for At-PI were identified. In At-PI, there were statistically significant differences in perfusion patterns, color spatial distribution, MDRAI/GI and ARAI/GI between benign and malignant breast lesions (P < 0.05). The AUCs of MDRAI/GI and ARAI/GI were 0.895 and 0.954, respectively, with no significant difference between them (Z = 1.84, P > 0.05). By using the thresholds of 1.125 for MDRAI/GI and 1.21 for ARAI/GI, the sensitivity, specificity, accuracy, PPV and NPV of At-PI were 84.48%, 88.24%, 85.57%, 92.45% and 76.92%, respectively, for MDRAI/GI and 93.10%, 91.18%, 92.39%, 94.74% and 88.57%, respectively, for ARAI/GI.

CONCLUSIONS

At-PI is helpful to distinguish benign from malignant breast lesions. And MDRAI/GI and ARAI/GI are useful and efficient features for differential diagnosis.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid

The first edition of the guidelines for the use of ultrasound contrast agents was published in 2004, dealing with liver applications. The second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some nonliver applications. The third edition of the contrast-enhanced ultrasound (CEUS) guidelines was the joint World Federation for Ultrasound in Medicine and Biology-European Federation of Societies for Ultrasound in Medicine and Biology (WFUMB-EFSUMB) venture in conjunction with other regional US societies such as Asian Federation of Societies for Ultrasound in Medicine and Biology, resulting in a simultaneous duplicate on liver CEUS in the official journals of both WFUMB and EFSUMB in 2013. However, no guidelines were described mainly for Sonazoid due to limited clinical experience only in Japan and Korea. The new proposed consensus statements and recommendations provide general advice on the use of Sonazoid and are intended to create standard protocols for the use and administration of Sonazoid in hepatic and pancreatobiliary applications in Asian patients and to improve patient management.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid

The first edition of the guidelines for the use of ultrasound contrast agents was published in 2004, dealing with liver applications. The second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some nonliver applications. The third edition of the contrast-enhanced ultrasound (CEUS) guidelines was the joint World Federation for Ultrasound in Medicine and Biology-European Federation of Societies for Ultrasound in Medicine and Biology (WFUMB-EFSUMB) venture in conjunction with other regional US societies such as Asian Federation of Societies for Ultrasound in Medicine and Biology, resulting in a simultaneous duplicate on liver CEUS in the official journals of both WFUMB and EFSUMB in 2013. However, no guidelines were described mainly for Sonazoid due to limited clinical experience only in Japan and Korea. The new proposed consensus statements and recommendations provide general advice on the use of Sonazoid and are intended to create standard protocols for the use and administration of Sonazoid in hepatic and pancreatobiliary applications in Asian patients and to improve patient management.

Automatic Respiratory Gating Hepatic DCEUS-based Dual-phase Multi-parametric Functional Perfusion Imaging using a Derivative Principal Component Analysis

Purpose: Angiogenesis in liver cancers can be characterized by hepatic functional perfusion imaging (FPI) on the basis of dynamic contrast-enhanced ultrasound (DCEUS). However, accuracy is limited by breathing motion which results in out-of-plane image artifacts. Current hepatic FPI studies do not correct for these artifacts and lack the evaluation of correction accuracy. Thus, a hepatic DCEUS-based dual-phase multi-parametric FPI (DM-FPI) scheme using a derivative principal component analysis (PCA) respiratory gating is proposed to overcome these limitations.

Materials and Methods: By considering severe 3D out-of-plane respiratory motions, the proposed scheme's accuracy was verified with in vitro DCEUS experiments in a flow model mimicking a hepatic vein. The feasibility was further demonstrated by considering in vivo DCEUS measurements in normal rabbit livers, and hepatic cavernous hemangioma and hepatocellular carcinoma in patients. After respiratory kinetics was extracted through PCA of DCEUS sequences under free-breathing condition, dual-phase respiratory gating microbubble kinetics was identified by using a derivative PCA zero-crossing dual-phase detection, respectively. Six dual-phase hemodynamic parameters were estimated from the dual-phase microbubble kinetics and DM-FPI was then reconstructed via color-coding to quantify 2.5D angiogenic hemodynamic distribution for live tumors.

Results: Compared with no respiratory gating, the mean square error of respiratory gating DM-FPI decreased by 1893.9 ± 965.4 (p < 0.05), and mean noise coefficients decreased by 17.5 ± 7.1 (p < 0.05), whereas correlation coefficients improved by 0.4 ± 0.2 (p < 0.01). DM-FPI observably removed severe respiratory motion artifacts on PFI and markedly enhanced the accuracy and robustness both in vitro and in vivo.

Conclusions: DM-FPI precisely characterized and distinguished the heterogeneous angiogenic hemodynamics about perfusion volume, blood flow and flow rate within two anatomical sections in the normal liver, and in benign and malignant hepatic tumors. DCEUS-based DM-FPI scheme might be a useful tool to help clinicians diagnose and provide suitable therapies for liver tumors.

A New Method to Quantify Concentration of Microbubbles in Attenuating Media Using Bubble Destruction Curve Analysis of the Contrast-Enhanced Ultrasound

It is known that the microbubbles of Sonazoid are accumulated in the liver parenchyma due to the phagocytosis of Kupffer cells in the sinusoid. Because this phagocytic function decreases due to the progression of fibrosis in chronic liver disease, the deterioration of the liver function may be quantified by measuring the concentration of the accumulated Sonazoid microbubbles. In this article, a new method to quantify the concentration of microbubbles accumulated in attenuating media is proposed. This method utilizes the contrast-enhanced imaging with high mechanical index, measures the depth of the bubble destruction for each frame and analyze the shape of the destruction curve to estimate the concentration of the bubbles. A phantom experiment was performed with various concentrations of the contrast agent Sonazoid solution as well as various attenuation coefficients of the viscous media. Because of the theoretical model proposed, the estimated attenuation indexes, related to the concentration of Sonazoid microbubbles, were independent of the background attenuation of the propagating medium. The result suggest it has a potential to quantify Sonazoid concentration in the liver parenchyma more precisely against different liver attenuation conditions.

Diagnostic Value of Arrival Time Parametric Imaging Using Contrast-Enhanced Ultrasonography in Superficial Enlarged Lymph Nodes

OBJECTIVE

The aim of this study was to evaluate the value of arrival-time parametric imaging for differential diagnosis of superficial enlarged lymph nodes.

METHODS

Patients with lymphadenopathy who received contrast-enhanced ultrasonography (CEUS) and biopsy were included in this study. Following CEUS, a prototype software of the arrival-time parametric imaging system was used to analyze the video footage. Arrival-time patterns during the arterial phase were evaluated. The quantitative parameters including arrival time of periphery, arrival time of center, and the travel time (△T) were calculated.

RESULTS

A total of 145 lymph nodes were analyzed. Arrival-time parametric imaging showed that 80.3% of metastatic lymph nodes and 68.4% of lymphoid tuberculosis presented a centripetal perfusion pattern, 76.5% of lymphoma showed complete homogeneous enhancement, and 81.2% of reactive lymph nodes had centrifugal patterns. The arrival time of periphery (sec) of metastatic lymph nodes was substantially earlier than that of lymphoma (11.0 ± 3.1 versus 12.6 ± 3.6; P < .05). The arrival time of center (sec) of metastatic lymph nodes was obviously later than that of lymphoma and reactive lymph nodes (13.4 ± 3.3 versus 10.5 ± 2.9 and 10.6 ± 1.5; P < .05). The travel time (△T) (sec) in metastatic lymph nodes was substantially longer than in reactive lymph nodes and lymphoma (4.2 ± 2.1 versus 2.3 ± 1.6 and 2.9 ± 2.5; P < .05). At a △T cutoff value of 2.75 seconds (using the receiver operating characteristic curve), the sensitivity and specificity in differentiating metastatic lymph nodes from benign lymph nodes (lymphoid tuberculosis and reactive lymph nodes) were 78.9% and 64.7%, respectively.

CONCLUSIONS

Enhanced patterns and parameters of arrival-time parametric imaging during CEUS could provide more information for the differential diagnosis of enlarged superficial lymph nodes.

Effect of Hepatic Inflammation in Chronic Hepatitis C Infection on Fibrosis Assessment by Arrival Time Parametric Imaging

Arrival time parametric imaging (At-PI) in contrast-enhanced ultrasonography is useful for assessing liver fibrosis in chronic hepatitis C (CHC) infection. The study aimed to elucidate the effect of hepatic inflammation on At-PI efficiency. Subjects were 159 CHC patients who underwent contrast-enhanced ultrasonography immediately before liver biopsy. Ultrasound contrast agent was injected, and contrast dynamics of the S5 to S6 region of the liver and right kidney were recorded for 40 seconds. The At-PI of liver parenchyma blood flow was generated using saved video clips. Hepatic blood flow during the first 5 seconds after starting contrast injection was displayed in red and that after another 5 seconds was displayed in yellow. The ratio of red (ROR) in At-PI images of the entire liver was measured with ImageJ. Ratio of red values of livers with different activity grades (0–3) were compared for each fibrosis (F) stage as determined by biopsy. Correlations of ROR with alanine aminotransferase (ALT) levels were analyzed using a linear regression line from the distribution map. Comparison of ROR for different activity grades in each F stage revealed no significant differences. Correlation coefficient R (P value) for ALT and ROR was R = −0.0094 (P = 0.43) at F0 to F1, R = −0.186 (P = 0.21) at F2, R = −0.233 (P = 0.27) at F3, and R = 0.041 (P = 0.89) at F4, with no significant correlation between ALT and ROR in any F stage. Hepatic inflammation in CHC infection does not affect At-PI diagnostic accuracy.

The Application of Parametric Micro-Flow Imaging in the Evaluation of Liver Fibrosis

This study aims to investigate the application of parametric micro-flow imaging in the evaluation of liver fibrosis. From March 2013 to February 2014, 117 participants were recruited in this research prospectively, which includes 97 patients (who have been infected with hepatitis B virus or/and hepatitis C virus and have undergone liver biopsy) and 20 healthy volunteers. Contrast agent was injected as a bolus via the antecubital vein for the participants. Dynamic images of intercostal liver were collected and then divided into 30-second (30s) group and 10-second (10s) group. Color coding and quantitative analysis were performed, and related parameters were obtained and analyzed with the stage of liver fibrosis. The comparison of parameters between the stages of liver fibrosis was that the value of 30s slope reduced and the value of 10s slope increased with the increasing fibrosis stages. The value of 30s ratio at 5 seconds and 10s ratio at 5 seconds both increased with the increasing fibrosis stages. Receiver operating characteristic curves were obtained to evaluate the cutoff values and diagnosibility of parameters to predict F2 and higher or F3 and higher of fibrosis stages. The results show that parametric micro-flow imaging has potential value of guiding antiviral therapy for patients with viral hepatitis and evaluating the degree of improvement in liver fibrosis.

Hepatic arterialization can predict the development of collateral veins in patients with HCV-related liver disease

Purpose

Arrival time parametric imaging (At-PI) using contrast-enhanced ultrasonography (CEUS) is a procedure for evaluating liver disease progression in chronic hepatitis C infection (CHC). We investigated At-PI diagnostic efficacy in predicting development of collateral veins.

Methods

In total, 171 CHC patients underwent CEUS and upper gastrointestinal (UGI) endoscopy before liver biopsy. Conventional US was performed before CEUS to identify paraumbilical veins (PV) or splenorenal shunts (SRS). After intravenous perflubutane, contrast dynamics of liver segments 5–6 and the right kidney were saved as raw data. At-PI image ratio of red (ROR) pixels to the entire liver was analyzed. Receiver operating characteristic (ROC) curves were generated to investigate the utility of At-PI for collateral vein identification.

Results

Conventional US revealed PV in two patients and SRS in five patients; UGI endoscopy detected esophageal varices (EV) in eight patients. Diagnostic capability of At-PI for detecting PV, SRS, and EV was satisfactory, and high for PV and SRS [PV; area under the ROC curve (AUROC) 0.929, cutoff value 77.9%, SRS; AUROC 0.970, cutoff value 82.0%, EV; AUROC 0.883, cutoff value 66.9%].

Conclusions

Evaluation of hepatic arterialization by At-PI was useful for predicting collateral vein development in CHC patients.

Multiparametric ultrasomics of significant liver fibrosis: A machine learning-based analysis

Objective

To assess significant liver fibrosis by multiparametric ultrasomics data using machine learning.

Materials and Methods

This prospective study consisted of 144 patients with chronic hepatitis B. Ultrasomics—high-throughput quantitative data from ultrasound imaging of liver fibrosis—were generated using conventional radiomics, original radiofrequency (ORF) and contrast-enhanced micro-flow (CEMF) features. Three categories of features were explored using pairwise correlation and hierarchical clustering. Features were selected using diagnostic tests for fibrosis, activity and steatosis stage, with the histopathological results as the reference. The fibrosis staging performance of ultrasomics models with combinations of the selected features was evaluated with machine-learning algorithms by calculating the area under the receiver-operator characteristic curve (AUC).

Results

ORF and CEMF features had better predictive power than conventional radiomics for liver fibrosis stage (both p < 0.01). CEMF features exhibited the highest diagnostic value for activity stage (both p < 0.05), and ORF had the best diagnostic value for steatosis stage (both p < 0.01). The machine-learning classifiers of adaptive boosting, random forest and support vector machine were found to be optimal algorithms with better (all mean AUCs = 0.85) and more stable performance (coefficient of variation = 0.01–0.02) for fibrosis staging than decision tree, logistic regression and neural network (mean AUC = 0.61–0.72, CV = 0.07–0.08). The multiparametric ultrasomics model achieved much better performance (mean AUC values of 0.78–0.85) than the features from a single modality in discriminating significant fibrosis (≥ F2).

Conclusion

Machine-learning-based analysis of multiparametric ultrasomics can help improve the discrimination of significant fibrosis compared with mono or dual modalities.

Key Points

• Multiparametric ultrasomics has achieved much better performance in the discrimination of significant fibrosis (≥ F2) than the single modality of conventional radiomics, original radiofrequency and contrast-enhanced micro-flow.

• Adaptive boosting, random forest and support vector machine are the optimal algorithms for machine learning.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5680-z) contains supplementary material, which is available to authorized users.

Differentiation of Atypical Hepatocellular Carcinoma from Focal Nodular Hyperplasia: Diagnostic Performance of Contrast-enhanced US and Microflow Imaging

PURPOSE

To evaluate diagnostic performance of contrast-enhanced (CE) ultrasonography (US) and microflow (MF) imaging in differentiation of atypical hepatocellular carcinoma (HCC) from focal nodular hyperplasia (FNH).

MATERIALS AND METHODS

Institutional review board approval was obtained, and informed consent was waived. A total of 103 patients (mean age, 43.9 years; age range, 17-75 years) were included; 38 patients with HCC and 65 with FNH underwent CE US, and vascular architecture pattern (VAP) and arrival time parametric (ATP) images were analyzed. Resident and staff radiologists independently and retrospectively reviewed CE US, VAP, and ATP images. χ(2) test and logistic regression analysis were applied to identify specific features of FNH or HCC on CE US and MF images. To compare diagnostic performance of CE US with or without MF imaging, four sets of criteria were assigned: (a) routine CE US alone, (b) VAP and CE US, (c) ATP imaging and CE US, and (d) all three methods in combination. Sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) of resident and staff radiologists were analyzed. Cohen κ statistic was used to assess agreement of CE US and MF imaging features between staff and resident radiologists.

RESULTS

MF imaging offered significant improvements over most detection rates achieved with routine CE US signs in both groups. For staff radiologists, AUCs from criteria sets 3 (AUC = 0.873, P < .05) and 4 (AUC = 0.887, P < .05) were significantly higher than AUC from criteria set 1 (AUC = 0.835). For resident radiologists, specificity (71% and 69% vs 25%, P < .01) and accuracy (78% and 79% vs 50%, P < .01) of criteria sets 3 and 4 were significantly higher than those of criteria set 1. Moreover, AUCs for criteria sets 2 (AUC = 0.728, P < .05), 3 (AUC = 0.823, P < .01), and 4 (AUC = 0.857, P < .01) were significantly higher than those for criteria set 1 (AUC = 0.667).

CONCLUSION

When compared with routine CE US, MF imaging can more effectively depict specific features and offers improved diagnostic performance in the differentiation of atypical HCC from FNH, especially when used by resident radiologists. Online supplemental material is available for this article.

Value of contrast-enhanced ultrasound using perflubutane microbubbles for diagnosing liver fibrosis and cirrhosis in rats

We determined the ability of contrast-enhanced ultrasound (CEUS) using perflubutane microbubbles to diagnose liver fibrosis and cirrhosis in rats using histology as the reference standard. Fibrosis was induced by oral administration of carbon tetrachloride to 32 Wistar rats. Features with baseline ultrasound (US) and enhancement level of liver and spleen with CEUS were obtained. In the post-vascular phase of CEUS, images of normal livers (n = 5) were significantly brighter than images of fibrotic (n = 6) and cirrhotic livers (n = 13) by quantitative analysis (all p < 0.05). The contrast between livers and spleens in rats with cirrhosis was quantitatively greater than that in normal rats and rats with fibrosis (all p < 0.05). Compared with US, CEUS improved sensitivity from 63% to 84% and accuracy from 71% to 88%. Specificity was 100% for both. The increased value of CEUS in diagnosing liver fibrosis and cirrhosis in rats supports its evaluation in clinical trials.

Pretreatment evaluation with contrast-enhanced ultrasonography for percutaneous radiofrequency ablation of hepatocellular carcinomas with poor conspicuity on conventional ultrasonography

Objective

To determine whether pretreatment evaluation with contrast-enhanced ultrasonography (CEUS) is effective for percutaneous radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) with poor conspicuity on conventional ultrasonography (US).

Materials and Methods

This retrospective study was approved by the institutional review board and informed consent was waived. From June 2008 to July 2011, 82 patients having HCCs (1.2 ± 0.4 cm) with poor conspicuity on planning US for RFA were evaluated with CEUS prior to percutaneous RFA. We analyzed our database, radiologic reports, and US images in order to determine whether the location of HCC candidates on planning US coincide with that on CEUS. To avoid incomplete ablation, percutaneous RFA was performed only when HCC nodules were identified on CEUS. The rate of technical success was assessed. The cumulative rate of local tumor progression was estimated with the use of the Kaplan-Meier method (mean follow-up: 24.0 ± 13.0 months).

Results

Among 82 patients, 73 (89%) HCCs were identified on CEUS, whereas 9 (11%) were not. Of 73 identifiable HCCs on CEUS, the location of HCC on planning US corresponded with that on CEUS in 64 (87.7%), whereas the location did not correspond in 9 (12.3%) HCCs. Technical success was achieved for all 73 identifiable HCCs on CEUS in a single (n = 72) or two (n = 1) RFA sessions. Cumulative rates of local tumor progression were estimated as 1.9% and 15.4% at 1 and 3 years, respectively.

Conclusion

Pretreatment evaluation with CEUS is effective for percutaneous RFA of HCCs with poor conspicuity on conventional US.

Arrival time parametric imaging of the hemodynamic balance changes between the hepatic artery and the portal vein during deep inspiration, using Sonazoid-enhanced ultrasonography: A case of Budd-Chiari syndrome

This case report concerns a 40-year-old male who had previously been treated for an esophageal varix rupture, at the age of 30 years. The medical examination at that time revealed occlusion of the inferior vena cava in the proximity of the liver, leading to the diagnosis of the patient with Budd-Chiari syndrome. The progress of the patient was therefore monitored in an outpatient clinic. The patient had no history of drinking or smoking, but had suffered an epileptic seizure in 2004. The patient's family history revealed nothing of note. In February 2012, color Doppler ultrasonography (US) revealed a change in the blood flow in the right portal vein branch, from hepatopetal to hepatofugal, during deep inspiration. Arrival time parametric imaging (At-PI), using Sonazoid-enhanced US, was subsequently performed to examine the deep respiration-induced changes observed in the hepatic parenchymal perfusion. US images captured during deep inspiration demonstrated hepatic parenchymal perfusion predominantly in red, indicating that the major blood supply was the hepatic artery. During deep expiration, the portal venous blood flow remained hepatopetal, and hepatic parenchymal perfusion was displayed predominantly in yellow, indicating that the portal vein was the major source of the blood flow. The original diagnostic imaging results were reproduced one month subsequently by an identical procedure. At-PI enabled an investigation into the changes that were induced in the hepatic parenchymal perfusion by a compensatory mechanism involving the hepatic artery. These changes occurred in response to a reduction in the portal venous blood flow, as is observed in the arterialization of hepatic blood flow that is correlated with the progression of chronic hepatitis C. It has been established that the peribiliary capillary plexus is important in the regulation of hepatic arterial blood flow. However, this case demonstrated that the peribiliary capillary plexus also regulates acute changes in portal venous blood flow, in addition to the chronic reduction in blood flow that is observed in patients with chronic hepatitis C.

Mucinous cystadenocarcinoma of the appendix in which contrast-enhanced ultrasonography was useful for assessing blood flow in a focal nodular lesion in the tumor cavity: A case report

A 63-year-old woman was admitted to hospital with pain in the right lower quadrant. Abdominal computed tomography (CT) revealed a 60-mm cystic mass at a site corresponding to the appendix. The mass wall on the appendicular ostium was thickened and enhanced by contrast, while calcification was observed in the mass wall on the appendicular tip. No projection was observed in the mass cavity. On abdominal ultrasonography (US), the mass wall on the appendicular ostium was thickened and projections were observed at two sites in the mass cavity. On contrast-enhanced US (CEUS), only one of these projections was enhanced. Based on the thickened and contrast-enhanced wall of the mass on the appendicular ostium on CT and US, as well as the contrast enhancement of a projection on US, the mass was diagnosed as mucinous cystadenocarcinoma of the appendix. Ileocecal resection was subsequently performed on day 10. A detailed examination of the surgical specimen revealed carcinoma cells in the mass wall on the appendicular ostium. The contrast-enhanced projection was identified as granulation tissue that had grown to come into contact with the tumor, while the non-contrast-enhanced projection was identified as solidified mucus. US enabled successful visualization of projections in the mass cavity that were not visible on abdominal CT. CEUS also proved useful for assessing blood flow in these projections.

Visualization of segmental arterialization with arrival time parametric imaging using Sonazoid-enhanced ultrasonography in portal vein thrombosis: A case report

A 55-year-old male was admitted in mid-April 2011 with a fever of >39°C and pain in the lower right abdomen. A medical examination revealed sepsis originating from colonic diverticulitis. Abdominal B-mode ultrasonography (US) performed on admission detected thrombi in the superior mesenteric vein and in the right branch of the hepatic portal vein. Arrival time parametric imaging (At-PI) using Sonazoid-enhanced US showed arterialization of the entire right lobe of the liver. The treatment for the sepsis and portal thrombi that had been started upon admission dissolved the thrombi by day 22, with the exception of one thrombus in the P8 branch of the portal vein. At-PI performed on the same day confirmed arterialization in segment 8, but portal vein dominance was restored elsewhere. When the blood inflow from the hepatic portal vein was reduced, the hepatic arterial blood flow was increased to compensate for the reduction in the total blood supply. The At-PI functions used in the Sonazoid-enhanced US were simple yet effective in visualizing the changes in the hepatic hemodynamics caused by the portal thrombus.

Endoscopic nasobiliary drainage improves jaundice attack symptoms in benign recurrent intrahepatic cholestasis: A case report

A 66-year-old male with unbearable pruritus and jaundice was admitted for detailed examination. Blood tests on admission showed increased bilirubin with a dominant direct fraction. Ultrasonography and computed tomography performed subsequent to admission showed no narrowing or distension of the bile ducts. As the jaundice symptoms were not improved by the oral administration of ursodeoxycholic acid (300 mg/day) that had been started immediately after admission, endoscopic retrograde cholangiopancreatography (ERCP) was performed on hospital day 14. This also showed no abnormalities of the bile ducts. After considerating its potential effects for improving jaundice, endoscopic nasobiliary drainage (ENBD) was performed on the same day and was followed by immediate improvements in pruritus and jaundice. Detailed examinations were performed to identify the cause of the jaundice, which was suspected to be viral hepatitis, autoimmune hepatitis or drug-induced liver injury, however, there were no findings suggestive of any of these conditions. Following a further increase in bilirubin levels, confirmed by additional blood tests, a liver biopsy was performed. Histological findings were consistent with the histological features of benign recurrent intrahepatic cholestasis (BRIC). Although ursodeoxycholic acid is used as a first-line treatment in most cases of BRIC, ENBD should also be considered for patients not responding to this treatment.

Evaluation of sorafenib for hepatocellular carcinoma by contrast-enhanced ultrasonography: A pilot study

AIM: To determine the usefulness of arrival time parametric imaging (AtPI) using contrast-enhanced ultrasonography (CEUS) with Sonazoid in evaluating early response to sorafenib for hepatocellular carcinoma (HCC).

METHODS: Fourteen advanced HCC patients who received sorafenib 400/800 mg/d for at least 4 wk and were followed up by CEUS were enrolled in this study. CEUS was performed before treatment and 2 and 4 wk after treatment, and images of the target lesion in the arterial phase were recorded for each patient. The images were analyzed by AtPI. Color mapping (CM) images obtained by AtPI were compared before and after the treatment. In these CM images, the mean arrival time of the contrast agent in the region of interest from the starting point [mean time (MT)] was calculated. In each patient, differences between MT before and MT 2 and 4 wk after the treatment were compared with responses evaluated 4-8 wk after the treatment by dynamic computed tomography (CT), and statistical analysis was performed. Modified response evaluation criteria in solid tumors was used for the response evaluation.

RESULTS: In CM images both 2 and 4 wk after the treatment, delays in the arrival time of the contrast agent were noted in 8 of the 14 patients. In the other 6 patients, no color changes were observed in the tumor, or red and/or yellow increase, suggesting a decrease in blood flow velocity between images 2 and 4 wk after the treatment and those before the treatment. Dynamic CT could be performed 4-8 wk after the treatment in 13 of the 14 patients. Median differences in the MT were 1.13 s and 1.015 s, 2 and 4 wk after the treatment, respectively, in the 8 patients who showed stable disease (SD)/partial response (PR) on dynamic CT. Median differences in the MT were -0.39 s and -0.95 s, 2 and 4 wk after the treatment, respectively, in the 5 patients who showed progressive disease (PD). Differences in the median MT between SD/PR and PD groups were significant 2 and 4 wk after the treatment with P = 0.019 and P = 0.028, respectively.

CONCLUSION: AtPI by CEUS using Sonazoid is suggested to be useful for evaluating early responses to sorafenib.

Hepatic parenchymal hemodynamics of cholangitis with portal trunk thrombus using contrast-enhanced ultrasonography with Sonazoid: delineation of so-called central and peripheral zonal differentiation by arrival-time parametric imaging

We carried out contrast-enhanced ultrasonography using Sonazoid for a patient who had portal thrombosis due to choledocholith and cholangitis, and the video images were analyzed by an offline procedure using arrival-time parametric imaging. Colors were changed with the time course from red to orange, yellow, green, light blue, and blue, with the time the contrast agent reached the right hepatic artery as the starting point. The central part of the liver was primarily colored blue, and the peripheral part primarily yellowish-green. In other words, we confirmed the central and peripheral zonal differentiation observed in the arterial phase of dynamic computed tomography by color mapping image of arrival-time parametric imaging. Particularly, real-time changes in the hemodynamics of the hepatic parenchyma could be captured by color mapping image using arrival-time parametric imaging.