Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver - Update 2020 - WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

Review of Clinical Applications of Sonazoid Ultrasound Contrast for Liver Evaluation

ABSTRACT

Sonazoid is a new ultrasound contrast agent with unique Kupffer phase imaging advantages and high mechanical index stability. This paper introduces the basic theories and advantages of Sonazoid ultrasound. Then, the application and latest advances of Sonazoid in the diagnosis and treatment of liver diseases are reviewed in detail. In addition, the advantages and disadvantages of Sonazoid ultrasound and its future directions are discussed. Sonazoid is expected to become an important tool for clinical ultrasound diagnosis and treatment.

A Comparative Study of SonoVue and Sonazoid for Contrast-Enhanced Ultrasound CT/MRI Fusion Guidance During Radiofrequency Ablation of Poorly Visualized Hepatic Malignancies: A Prospective Intra-Individual Analysis

PURPOSE

This study aimed to evaluate the effectiveness of two contrast agents, SonoVue (SV) and Sonazoid (SZ), by comparing them intra-individually in contrast-enhanced ultrasound (CEUS)-CT/MRI fusion imaging (FI) to improve the visibility of inconspicuous liver malignancies on B-mode sonography for guiding percutaneous radiofrequency ablation (RFA). Additionally, the radiologists' preference between SonoVue- CT/MRI FI (SV-FI) and Sonazoid-CT/MRI FI (SZ-FI) was determined.

METHODS

This prospective study enrolled 23 patients with inconspicuous hepatic malignancies (≤ 3 cm) on B-mode US who underwent both SV-FI and SZ-FI for RFA guidance. The patients underwent real-time CEUS FI with CT/MRI on the same day, utilizing both SV and SZ with at least 15-min intervals. Tumor visibility and radiologists' preferences were assessed and graded using a 4-point scale during the dynamic phases of both SV-FI and SZ-FI and the Kupffer phase of SZ-FI.

RESULTS

The tumor visibility scores obtained from CEUS-CT/MRI FI were significantly better than those obtained from US-FI. Indeed, SV-FI and SZ-FI demonstrated comparable visibility scores when corresponding phases were compared (p > 0.05). However, the Kupffer phase images of SZ-FI displayed superior visibility scores (3.70 ± 0.56 vs. 2.96 ± 0.88; p = 0.002) than the late vascular phase images of SV-FI. The radiologists favored SZ-FI in many cases, exhibiting moderate inter-observer agreement (Kappa value = 0.587; 95% CI, 0.403-0.772).

CONCLUSION

Although CEUS-CT/MRI FI with either SV or SZ substantially improved the visibility of inconspicuous tumors on US-CT/MRI FI, radiologists preferred SZ to SV to guide the RFA procedure.

Diagnostic Test Accuracy of Contrast-Enhanced Ultrasound With Sonazoid for Assessment of Focal Liver Lesions: A Systematic Review and Meta-Analysis

This meta-analysis examined the diagnostic accuracy of Sonazoid-enhanced ultrasonography (SZ-CEUS) in discriminating malignant from benign focal liver lesions (FLLs) and HCC from non-HCC FLLs. Finding relevant studies required a rigorous PubMed, EMBASE, and other database search. To distinguish malignant from benign FLLs, SZ-CEUS had a pooled sensitivity of 94% (95% CI: 0.91-0.95) and specificity of 84% (95%: 0.78-0.89). HCC distinction had 83% sensitivity and 96% specificity (95% CI: 0.80-0.85 and 0.95-0.97). SZ-CEUS accurately distinguishes malignant from benign FLLs and HCC from non-HCC lesions, especially smaller HCC lesions.

Diagnostic insights into splenic pathologies: the role of multiparametric ultrasound

Ultrasound (US) evaluation of the spleen is mandatory in the assessment of patients with chronic liver disease, and splenomegaly can be a sign of systemic diseases. However, due to the lack of distinctive ultrasound findings in specific splenic pathologies, clinical diagnosis can be very challenging. Splenomegaly, defined by increased splenic dimensions, can indicate underlying systemic conditions and is a common manifestation of portal hypertension (PH). Ultrasound and Doppler techniques help assessing splenic involvement in PH. Splenic stiffness measurement, using elastography, offers additional diagnostic accuracy, especially when liver stiffness measurements are inconclusive. CEUS enhances the diagnostic capability for focal splenic lesions, differentiating between benign and malignant lesions by their distinct enhancement patterns, and plays also a critical role in the context of splenic traumatic pathology. Overall, CEUS significantly improves the characterization of splenic pathology, reducing the need for invasive procedures and ensuring appropriate patient management. This review article describes the normal US findings of the spleen and examines the role of multiparametric US in the evaluation of the most common splenic pathologies encountered in the daily clinical practice.

Prospects of perfusion contrast-enhanced ultrasound (CE-US) in diagnosing axillary lymph node metastases in breast cancer: a comparison with lymphatic CE-US

Accurate diagnosis of lymph node (LN) metastasis is vital for prognosis and treatment in patients with breast cancer. Imaging 1modalities such as ultrasound (US), MRI, CT, and 18F-FDG PET/CT are used for preoperative assessment. While conventional US is commonly recommended due to its resolution and sensitivity, it has limitations such as operator subjectivity and difficulty detecting small metastases. This review shows the microanatomy of axillary LNs to enhance accurate diagnosis and the characteristics of contrast-enhanced US (CE-US), which utilizes intravascular microbubble contrast agents, making it ideal for vascular imaging. A significant focus of this review is on distinguishing between two types of CE-US techniques for axillary LN evaluation: perfusion CE-US and lymphatic CE-US. Perfusion CE-US is used to assess LN metastasis via transvenous contrast agent administration, while lymphatic CE-US is used to identify sentinel LNs and diagnose LN metastasis through percutaneous contrast agent administration. This review also highlights the need for future research to clarify the distinction between studies involving "apparently enlarged LNs" and "clinical node-negative" cases in perfusion CE-US research. Such research standardization is essential to ensure accurate diagnostic performance in various clinical studies. Future studies should aim to standardize CE-US methods for improved LN metastasis diagnosis, not only in breast cancer but also across various malignancies.

A combined model based on radiomics features of Sonazoid contrast-enhanced ultrasound in the Kupffer phase for the diagnosis of well-differentiated hepatocellular carcinoma and atypical focal liver lesions: a prospective, multicenter study

OBJECTIVE

The objective of this study was to develop a combined model based on radiomics features of Sonazoid contrast-enhanced ultrasound (CEUS) during the Kupffer phase and to evaluate its value in differentiating well-differentiated hepatocellular carcinoma (w-HCC) from atypical benign focal liver lesions (FLLs).

METHODS

A total of 116 patients with preoperatively Sonazoid-CEUS confirmed w-HCC or benign FLL were selected from a prospective multiple study on the clinical application of Sonazoid in FLLs conducted from August 2020 to March 2021. According to the randomization principle, the patients were divided into a training cohort and a test cohort in a 7:3 ratio. Seventy-nine patients were used for establishing and training the radiomics model and combined model. In comparison, 37 patients were used for validating and comparing the performance of the models. The diagnostic efficacy of the models for w-HCC and atypical benign FLLs was evaluated using ROCs curves and decision curves. A combined model nomogram was created to assess its value in reducing unnecessary biopsies.

RESULTS

Among the patients, there were 55 cases of w-HCC and 61 cases of atypical benign FLLs, including 28 cases of early liver abscess, 16 cases of atypical hepatic hemangioma, 8 cases of hepatocellular dysplastic nodules (DN), and 9 cases of focal nodular hyperplasia (FNH). The radiomics model and combined model we established had AUCs of 0.905 and 0.951, respectively, in the training cohort, and the AUCs of the two models in the test cohort were 0.826 and 0.912, respectively. The combined model outperformed the radiomics feature model significantly. Decision curve analysis demonstrated that the combined model achieved a higher net benefit within a specific threshold probability range (0.25 to 1.00). A nomogram of the combined model was developed.

CONCLUSION

The combined model based on the radiomics features of Sonazoid-CEUS in the Kupffer phase showed satisfactory performance in diagnosing w-HCC and atypical benign FLLs. It can assist clinicians in timely detecting malignant FLLs and reducing unnecessary biopsies for benign diseases.

Artificial Intelligence for Contrast-Enhanced Ultrasound of the Liver: A Systematic Review

INTRODUCTION

The research field of artificial intelligence (AI) in medicine and especially in gastroenterology is rapidly progressing with the first AI tools entering routine clinical practice, for example, in colorectal cancer screening. Contrast-enhanced ultrasound (CEUS) is a highly reliable, low-risk, and low-cost diagnostic modality for the examination of the liver. However, doctors need many years of training and experience to master this technique and, despite all efforts to standardize CEUS, it is often believed to contain significant interrater variability. As has been shown for endoscopy, AI holds promise to support examiners at all training levels in their decision-making and efficiency.

METHODS

In this systematic review, we analyzed and compared original research studies applying AI methods to CEUS examinations of the liver published between January 2010 and February 2024. We performed a structured literature search on PubMed, Web of Science, and IEEE. Two independent reviewers screened the articles and subsequently extracted relevant methodological features, e.g., cohort size, validation process, machine learning algorithm used, and indicative performance measures from the included articles.

RESULTS

We included 41 studies with most applying AI methods for classification tasks related to focal liver lesions. These included distinguishing benign versus malignant or classifying the entity itself, while a few studies tried to classify tumor grading, microvascular invasion status, or response to transcatheter arterial chemoembolization directly from CEUS. Some articles tried to segment or detect focal liver lesions, while others aimed to predict survival and recurrence after ablation. The majority (25/41) of studies used hand-picked and/or annotated images as data input to their models. We observed mostly good to high reported model performances with accuracies ranging between 58.6% and 98.9%, while noticing a general lack of external validation.

CONCLUSION

Even though multiple proof-of-concept studies for the application of AI methods to CEUS examinations of the liver exist and report high performance, more prospective, externally validated, and multicenter research is needed to bring such algorithms from desk to bedside.

Ultrasonographic features of female urethral caruncle: a retrospective study of 20 patients

Female urethral caruncle is the most common urethral mass in postmenopausal women, yet there is a lack of studies on its imaging. The aim of this study was to provide a summary of the clinical and ultrasound features as well as the precise location of female urethral caruncle. This study reviewed the clinical and ultrasonographic records of 20 consecutive women with pathologically confirmed urethral caruncle. Data on patient demographics, symptoms, and transperineal and transrectal ultrasound imaging features, including location, shape, margin, size, blood flow, and inner echo of the caruncle, were extracted. Each patient presented with only one mass at the urethral meatus. Most caruncles were located on the posterior lip (75%) of the urethra, presenting as oval (80%), mixed-echoic (50%), or hypo-echoic (40%) nodules with abundant linear (40%) or dendritic (60%) blood flow. The average distance between the bladder neck and the cranial end of the masses was 28 mm. Hyper-echogenic spots, cystic echo areas, and macrocalcifications were detected in thirteen caruncles (70%). This study shows that transperineal combined with transrectal ultrasound can be used to assess female urethral caruncle, and its relative location to the urethra can be accurately described, which is helpful for surgeons making preoperative localization and conversations.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine contrast-enhanced ultrasound guidelines: Multiparametric imaging and EUS-guided sampling in rare pancreatic tumors. Benign mesenchymal pancreatic tumors

The focus of the review is on primary benign mesenchymal pancreatic tumors and their imaging appearance. These tumors are extremely rare. Usually, they are not diagnosed until postoperative histology is available, and so even benign tumors have undergone extensive pancreatic resection. The very limited data on abdominal and EUS findings including contrast-enhanced techniques of these pancreatic lesions are summarized here. Case reports will be presented for some of these rare tumors with application of modern ultrasound and endosonographic techniques.

Assessment of arterial-phase hyperenhancement and late-phase washout of hepatocellular carcinoma-a meta-analysis of contrast-enhanced ultrasound (CEUS) with SonoVue® and Sonazoid®

OBJECTIVES

The recognition of arterial phase hyperenhancement (APHE) and washout during the late phase is key for correct diagnosis of hepatocellular carcinoma (HCC) with contrast-enhanced ultrasound (CEUS). This meta-analysis was conducted to compare SonoVue®-enhanced and Sonazoid®-enhanced ultrasound in the assessment of HCC enhancement and diagnosis.

METHODS

Studies were included in the analysis if they reported data for HCC enhancement in the arterial phase and late phase for SonoVue® or in the arterial phase and Kupffer phase (KP) for Sonazoid®. Forty-two studies (7502 patients) with use of SonoVue® and 30 studies (2391 patients) with use of Sonazoid® were identified. In a pooled analysis, the comparison between SonoVue® and Sonazoid® CEUS was performed using chi-square test. An inverse variance weighted random-effect model was used to estimate proportion, sensitivity, and specificity along with 95% confidence interval (CI).

RESULTS

In the meta-analysis, the proportion of HCC showing APHE with SonoVue®, 93% (95% CI 91-95%), was significantly higher than the proportion of HCC showing APHE with Sonazoid®, 77% (71-83%) (p < 0.0001); similarly, the proportion of HCC showing washout at late phase/KP was significantly higher with SonoVue®, 86% (83-89%), than with Sonazoid®, 76% (70-82%) (p < 0.0001). The sensitivity and specificity for the detection of APHE plus late-phase/KP washout detection in HCC were also higher with SonoVue® than with Sonazoid® (sensitivity 80% vs 52%; specificity 80% vs 73% in studies within unselected patient populations).

CONCLUSION

APHE and late washout in HCC are more frequently observed with SonoVue® than with Sonazoid®. This may affect the diagnostic performance of CEUS in the diagnosis of HCCs.

CLINICAL RELEVANCE STATEMENT

Meta-analysis data show the presence of key enhancement features for diagnosis of hepatocellular carcinoma is different between ultrasound contrast agents, and arterial hyperenhancement and late washout are more frequently observed at contrast-enhanced ultrasound with SonoVue® than with Sonazoid®.

KEY POINTS

• Dynamic enhancement features are key for imaging-based diagnosis of HCC. • Arterial hyperenhancement and late washout are more often observed in HCCs using SonoVue®-enhanced US than with Sonazoid®. • The existing evidence for contrast-enhanced US may need to be considered being specific to the individual contrast agent.

Value of Sonazoid-enhanced ultrasonography in characterizing indeterminate focal liver lesions on gadoxetic acid-enhanced liver MRI in patients without risk factors for hepatocellular carcinoma

PURPOSE

To evaluate the added value of contrast-enhanced ultrasonography (CEUS) using Sonazoid in characterizing focal liver lesions (FLLs) with indeterminate findings on gadoxetic acid-enhanced liver MRI in patients without risk factors for hepatocellular carcinoma (HCC).

METHODS

Patients who underwent CEUS using Sonazoid for characterizing indeterminate FLLs on gadoxetic acid-enhanced liver MRI were. The indeterminate FLLs were classified according to the degree of malignancy on a 5-point scale on MRI and combined MRI and CEUS. The final diagnosis was made either pathologically or based on more than one-year follow-up. The diagnostic performance was assessed using a receiver operating characteristic (ROC) curve analysis, and the net reclassification improvement (NRI) was calculated.

RESULTS

A total of 97 patients (mean age, 49 years ± 16, 41 men, 80 benign and 17 malignant lesions) were included. When CEUS was added to MRI, the area under the ROC curve increased, but the difference was not statistically significant (0.87 [95% confidence interval {CI}, 0.77-0.98] for MRI vs 0.93 [95% CI, 0.87-0.99] for CEUS added to MRI, P = 0.296). The overall NRI was 0.473 (95% CI, 0.100-0.845; P = 0.013): 33.8% (27/80) of benign lesions and 41.2% (7/17) of malignant lesions were appropriately reclassified, whereas 10.0% (8/80) of benign lesions and 17.6% (3/17) of malignant lesions were incorrectly reclassified.

CONCLUSIONS

Although performing CEUS with Sonazoid did not significantly improve the overall diagnostic performance in characterizing indeterminate FLLs on gadoxetic acid-enhanced liver MRI in patients without risk factors for HCC, it may increase radiologist's confidence in classifying FLLs.

[State of the art: Simulation in US]

Technical simulation of diagnostic and therapeutic procedures is of growing relevance for student education and advanced medical training and has already been introduced in the field of ultrasound. This review gives a broad overview on different levels of simulation for ultrasound diagnostics and highlights the technical background of the methodology. A critical review of the literature reveals recommendations for implementing simulation techniques in medical studies and professional ultrasound training. An analysis of strengths and weaknesses shows the advantages of simulation especially in the context of individual learning situations and COVID-19-related restrictions for personal interaction. However, simulation techniques cannot replace the experiences of complex clinical examinations with direct interaction to real patients. Therefore, future applications may focus on repetition and assessment of achieved competencies by using standardized feedback mechanisms in order to preserve the limited resources for practical medical training.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine contrast-enhanced ultrasonography guidelines: multiparametric imaging and EUS-guided sampling in rare pancreatic tumors. Mesenchymal pancreatic tumors of intermediate biological behaviour

The focus of the review is on mesenchymal pancreatic tumors with intermediate biological behavior and their imaging appearance. Similar to benign and malignant mesenchymal pancreatic tumors, these tumors are extremely rare. The diagnosis is often confirmed only by postoperative histology. The very limited data on abdominal ultrasound and EUS findings including contrast-enhanced techniques of these pancreatic lesions are summarized here.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine contrast-enhanced ultrasound guidelines. Rare pancreatic tumors, imaging features on transabdominal ultrasound and EUS with contrast enhancement: Rare epithelial pancreatic tumors: solid pseudopapillary neoplasm, acinar cell carcinoma, mixed neuroendocrine-non-neuroendocrine neoplasms, some rare subtypes of pancreatic adenocarcinoma and pancreatoblastoma

Rare malignant pancreatic lesions are systematically reported in this review. The focus is on the imaging appearance of the rare epithelial pancreatic tumors such as the solid pseudopapillary neoplasm, acinar cell carcinoma, rare subtypes of adenocarcinoma, and pancreatoblastoma as seen on ultrasound, EUS, and contrast-enhanced ultrasound or EUS. The present overview summarizes the data and shows that not every pancreatic tumor is likely to be the most common entities of ductal adenocarcinoma or neuroendocrine tumor.

Contrast-enhanced ultrasound of the liver: Vascular pathologies and interventions

Over the past two decades, contrast-enhanced ultrasound (CEUS) has been established as a method complementary to B-mode ultrasound and color Doppler sonography for diagnosing vascular liver pathologies and interventions.The objective of this review is to elucidate the application of CEUS in diagnosing vascular pathologies and interventional procedures.Considering the limitations of ultrasound, CEUS presents a similar alternative to other imaging modalities, such as computed tomography and magnetic resonance imaging, for evaluating vascular pathologies, guiding interventions, identifying complications, and assessing outcomes post intervention. Due to its widespread availability and the absence of radiation exposure, CEUS should be employed as a primary modality. · CEUS plays an important role in the detection of vascular liver pathologies.. · CEUS is helpful in characterizing vascular pathologies.. · CEUS is helpful in guiding interventions and identifying complications..

Tips and tricks for a correct interpretation of contrast-enhanced ultrasound

Although contrast-enhanced ultrasound (CEUS) is a widespread and easily manageable technique, image interpretation errors can occur due to the operator's inexperience and/or lack of knowledge of the frequent pitfalls, which may cause uncertain diagnosis and misdiagnosis. Indeed, knowledge of the basic physical and technical principles of ultrasound is needed both to understand sonographic image findings and to evaluate the potential and limits of the method. Like the B-mode ultrasound, the quality of the CEUS examination is also subject not only to the adequate manual skill of the operator but also to his/her deep knowledge of the technique which improves the quality of the image helping avoid misleading artifacts. In this review, the main parameters influencing a CEUS examination will be described by taking into account the most common errors and pitfalls and their possible solutions.

Malignancy diagnosis of liver lesion in contrast enhanced ultrasound using an end-to-end method based on deep learning

BACKGROUND

Contrast-enhanced ultrasound (CEUS) is considered as an efficient tool for focal liver lesion characterization, given it allows real-time scanning and provides dynamic tissue perfusion information. An accurate diagnosis of liver lesions with CEUS requires a precise interpretation of CEUS images. However,it is a highly experience dependent task which requires amount of training and practice. To help improve the constrains, this study aims to develop an end-to-end method based on deep learning to make malignancy diagnosis of liver lesions using CEUS.

METHODS

A total of 420 focal liver lesions with 136 benign cases and 284 malignant cases were included. A deep learning model based on a two-dimensional convolution neural network, a long short-term memory (LSTM), and a linear classifier (with sigmoid) was developed to analyze the CEUS loops from different contrast imaging phases. For comparison, a 3D-CNN based method and a machine-learning (ML)-based time-intensity curve (TIC) method were also implemented for performance evaluation.

RESULTS

Results of the 4-fold validation demonstrate that the mean AUC is 0.91, 0.88, and 0.78 for the proposed method, the 3D-CNN based method, and the ML-based TIC method, respectively.

CONCLUSIONS

The proposed CNN-LSTM method is promising in making malignancy diagnosis of liver lesions in CEUS without any additional manual features selection.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine guidelines: Rare pancreatic tumors, ultrasound and contrast-enhanced ultrasound features-Malignant mesenchymal tumors

Rare malignant mesenchymal pancreatic tumors are systematized and reported in this review. The focus is on the appearance on imaging. The present overview summarizes the data and shows that not every pancreatic tumor corresponds to the most common entities of ductal adenocarcinoma or neuroendocrine tumor.

A retrospective study on adverse events of intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications in 83,778 patients

OBJECTIVES

To investigate the rate of adverse events (AEs) caused by intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications retrospectively and to explore practical measures for prevention and treatment of them.

MATERIALS AND METHODS

This study enrolled 83,778 contrast-enhanced ultrasound (CEUS) examinations using sulfur hexafluoride microbubbles intravenously performed during 11 years. Age, gender, and target organs of all CEUS patients were recorded. For cases of AEs, their medical history and laboratory results were also collected. The process of AEs was assessed and categorized. Besides, the management of AEs were recorded.

RESULTS

Twenty patients had sulfur hexafluoride microbubbles-related AEs. The AE rate was 0.024%. No significant difference was observed between patients with AEs and the whole group for age and sex distribution. All AEs happened in liver examinations. Among them, 7 (35%) were mild, 8 (40%) were moderate, and 5 (25%) were severe. They were categorized into 15 allergic-like reactions and 5 physiologic reactions. The manifestations of mild and moderate AEs mainly include urticaria, chills, and mild hypoxia, which could be eased by simple management. Severe cases had anaphylactic shock, generalized convulsions, and diffuse erythema with hypotension respectively. They need close monitoring and oxygen inhalation with anti-shock and anti-anaphylactic treatment. Most cases started within 30 min and recovered within 1 day.

CONCLUSIONS

Intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications was safe with rare AEs. AEs were more likely to happen in abdominal applications than superficial ones. A well-designed emergency plan should be available for clinical use of sulfur hexafluoride microbubbles to reduce AEs and to deal with AEs properly.

CRITICAL RELEVANCE STATEMENT

Intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications reported few AEs and could be considered safe but severe AEs are life-threatening. We analyzed the influence factors of AEs and propose some methods for prevention and treatment of them, which can further improve the safety of sulfur hexafluoride microbubbles in clinical practice.

KEY POINTS

• The AE rate of sulfur hexafluoride microbubbles in abdominal and superficial applications was 0.024%. • Patients were more likely to have AEs in abdominal applications than superficial ones. • Severe AEs are life-threatening and need prompt identification and treatment. • We summarized some detailed suggestions for clinical prevention and treatment of AEs.

EFSUMB Technical Review - Update 2023: Dynamic Contrast-Enhanced Ultrasound (DCE-CEUS) for the Quantification of Tumor Perfusion

Dynamic contrast-enhanced ultrasound (DCE-US) is a technique to quantify tissue perfusion based on phase-specific enhancement after the injection of microbubble contrast agents for diagnostic ultrasound. The guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) published in 2004 and updated in 2008, 2011, and 2020 focused on the use of contrast-enhanced ultrasound (CEUS), including essential technical requirements, training, investigational procedures and steps, guidance regarding image interpretation, established and recommended clinical indications, and safety considerations. However, the quantification of phase-specific enhancement patterns acquired with ultrasound contrast agents (UCAs) is not discussed here. The purpose of this EFSUMB Technical Review is to further establish a basis for the standardization of DCE-US focusing on treatment monitoring in oncology. It provides some recommendations and descriptions as to how to quantify dynamic ultrasound contrast enhancement, and technical explanations for the analysis of time-intensity curves (TICs). This update of the 2012 EFSUMB introduction to DCE-US includes clinical aspects for data collection, analysis, and interpretation that have emerged from recent studies. The current study not only aims to support future work in this research field but also to facilitate a transition to clinical routine use of DCE-US.

Contrast-Enhanced Ultrasound With Perfluorobutane for Hepatocellular Carcinoma Diagnosis: Comparison of Imaging Phases and Diagnostic Criteria

BACKGROUND. Contrast-enhanced ultrasound (CEUS) with perfluorobutane has used varying protocols and diagnostic criteria for hepatocellular carcinoma (HCC). OBJECTIVE. The purpose of this article was to assess diagnostic performance for HCC of CEUS with perfluorobutane in high-risk patients using various criteria. METHODS. This retrospective post hoc study evaluating individual patient data from three earlier prospective studies from one hospital included 204 patients (136 men, 68 women; mean age, 63 ± 11 [SD] years) at high risk of HCC with 213 liver observations. Patients underwent CEUS using perfluorobutane from March 2019 to June 2022. Three radiologists (the examination's operator and two subsequent reviewers) independently interpreted examinations, assessing arterial, portal venous (arterial phase completion through 2 minutes), transitional (2-5 minutes after injection), and Kupffer (≥ 10 minutes after injection) phase findings. Six criteria for HCC were tested: 1, any arterial phase hyperenhancement (APHE) with Kupffer phase hypoenhancement; 2, nonrim APHE with Kupffer phase hypoenhancement; 3, nonrim APHE with portal venous washout; 4, nonrim APHE with portal venous washout and/or Kupffer phase hypoenhancement; 5, nonrim APHE with portal venous and/or transitional washout; 6, nonrim APHE with any of portal venous washout, transitional washout, or Kupffer phase hypoenhancement. Depending on the criteria, observations were instead deemed to be a non-HCC malignancy if showing rim APHE, early washout (at < 1 minute), or marked washout (at 2 minutes). Reference was pathology for malignant observations and pathology or imaging follow-up for benign observations. Diagnostic performance was assessed, pooling readers' data. RESULTS. Criterion 1 (no recognized features of non-HCC malignancy) had highest sensitivity (86.9%) but lowest specificity (43.2%) for HCC. Compared with nonrim APHE and portal venous washout (criterion 3), the addition of Kupffer phase hypoenhancement (criterion 4), transitional washout (criterion 5), or either feature (criterion 6) significantly increased sensitivity (34.4% vs 62.6-64.2%) and accuracy (61.8% vs 75.1-76.5%), but significantly decreased specificity (98.5% vs 91.9-94.1%). Criteria 2, 4, 5, and 6 (all incorporating transitional washout and/or Kupffer phase hypoenhancement) showed no significant differences in sensitivity (62.6-64.2%), specificity (91.9-94.1%), or accuracy (75.1-76.5%). CONCLUSION. Recognition of features of non-HCC malignancy improved specificity for HCC. Incorporation of the findings of transitional washout and/or Kupffer phase hypoenhancement improved sensitivity and accuracy, albeit lowered specificity, versus arterial and portal venous findings alone, without further performance variation among criteria incorporating those two findings. CLINICAL IMPACT. Kupffer phase acquisition may be optional for observations classified as HCC or non-HCC malignancy by arterial, portal venous, and transitional phases.

Diagnostic Performance of Modified Contrast-Enhanced Ultrasound Liver Imaging Reporting and Data System in Patients Without Risk Factors for Hepatocellular Carcinoma: Comparison With World Federation for Ultrasound in Medicine and Biology Guideline

OBJECTIVE

The aim of this study was to assess the ability of the modified contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) to distinguish malignancy in patients without known hepatocellular carcinoma (HCC) risk factors and compare diagnostic accuracy with that of the World Federation for Ultrasound in Medicine and Biology (WFUMB) guideline across radiologists with different levels of CEUS experience.

METHODS

A total of 848 individuals with no hepatitis infection presenting with 870 lesions in non-cirrhotic livers were included and divided into the Testing and Validation groups. The modified CEUS LI-RADS was proposed, including downgrading of focal nodular hyperplasia with typical features. Diagnostic performance of the modified CEUS LI-RADS was assessed in the Testing group. In the Validation group, two radiologists with more than 9 y of CEUS experience (Experts) and two radiologists with less than 6 mo of CEUS experience (Novices) used both the modified CEUS LI-RADS and the WFUMB guideline to evaluate performance in diagnosis of the lesions.

RESULTS

LR-5 + M (combination of modified LR-5 and modified LR-M) revealed optimal performance with a sensitivity, specificity and area under the curve (AUC) of 99.3%, 81.6% and 0.904, respectively. Novices using the modified CEUS LI-RADS outperformed those using the WFUMB guideline (AUC: 0.858 vs. 0.767, p = 0.005). Additionally, the sensitivity, specificity and AUC of Novices were comparable to those of Experts using the modified CEUS LI-RADS (94.1%, 77.6% and 0.858 vs. 96.1%, 77.6% and 0.868 for experts, respectively).

CONCLUSION

The modified CEUS LI-RADS is a valuable method for distinguishing hepatic malignancy in patients without HCC risk factors. This is particularly beneficial for radiologists with limited CEUS expertise.

Liver Lesions at Risk of Transformation into Hepatocellular Carcinoma in Cirrhotic Patients: Hepatobiliary Phase Hypointense Nodules without Arterial Phase Hyperenhancement

Recent technical advances in liver imaging and surveillance for patients at high risk for developing hepatocellular carcinoma (HCC) have led to an increase in the detection of borderline hepatic nodules in the gray area of multistep carcinogenesis, particularly in those that are hypointense at the hepatobiliary phase (HBP) and do not show arterial phase hyperenhancement. Given their potential to transform and advance into hypervascular HCC, these nodules have progressively attracted the interest of the scientific community. To date, however, no shared guidelines have been established for the decision management of these borderline hepatic nodules. It is therefore extremely important to identify features that indicate the malignant potential of these nodules and the likelihood of vascularization. In fact, a more complete knowledge of their history and evolution would allow outlining shared guidelines for their clinical-surgical management, to implement early treatment programs and decide between a preventive curative treatment or a watchful follow-up. This review aims to summarize the current knowledge on hepatic borderline nodules, particularly focusing on those imaging features which are hypothetically correlated with their malignant evolution, and to discuss current guidelines and ongoing management in clinical practice.

Clinical Practice Report of Contrast-Enhanced Ultrasound in Renal Artery Disease

OBJECTIVES

To evaluate the diagnostic performance of renal artery contrast-enhanced ultrasound (CEUS) with modified inspection section and summarize subsequent changes in imaging assessment of renal artery disease.

METHODS

A total of 1015 patients underwent renal artery CEUS were included in the study. Among them, 79 patients (156 renal arteries) suspected with renal artery stenosis (RAS) underwent digital subtraction angiography (DSA) subsequently. DSA was used as the gold standard to evaluate the diagnostic performance of CEUS in detecting RAS (≥30%) and severe stenosis (≥70%), as well as the diagnostic accuracy of classification of stenosis degree. Besides, 127 of the 1015 patients underwent other imaging examinations such as computed tomography angiography (CTA) or magnetic resonance angiography (MRA) after CEUS and annual proportion of these imaging examinations was assessed.

RESULTS

The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of CEUS for detecting RAS (≥30%) was 96.4%, 88.6%, 94.2%, 95.6% and 90.7%, respectively and the kappa value was .857 (P < .01). CEUS had a good performance in distinguishing severe stenosis (≥70%) with a sensitivity of 91.1%, specificity of 95.5%, accuracy of 92.9%, PPV of 96.5%, NPV of 88.7% and the kappa value was 0.857(P < .01). There was no significant difference between CEUS and DSA in detecting stenosis (P = 1.0) and severe stenosis (P = .227). The diagnostic accuracy of CEUS in grading RAS was 85.3% and the kappa value was 0.753 (P < .01). Besides, the annual proportion of other imaging examinations decreased for 4 consecutive years.

CONCLUSIONS

CEUS is a non-invasive, safe and valuable technique for the assessment of renal artery disease and worthy of promotion.

Diagnostic performance of magnetic resonance imaging and contrast-enhanced ultrasound in differentiating intrahepatic cholangiocarcinoma from hepatocellular carcinoma: a meta-analysis

PURPOSE

To compare the diagnostic ability between magnetic resonance imaging (MRI) and contrast-enhanced ultrasound (CEUS) in distinguishing intrahepatic cholangiocarcinoma (ICC) from hepatocellular carcinoma (HCC).

METHODS

Original studies reporting the diagnostic accuracy of MRI and CEUS in differentiating ICC from HCC were identified in PubMed and EMBASE databases. Histopathological examination was used as the reference standard for tumor diagnosis. Study quality was assessed using QUADAS-2 scale. Data were extracted to calculate the pooled diagnostic sensitivity, specificity, and diagnostic odds ratio (DOR) using a bivariate random-effects model, as well as the area under the curve (AUC). Sensitivity analysis, subgroup analysis, meta-regression, and investigation of publication bias were also performed.

RESULTS

A total of 26 studies with 28 data subsets (18 on MRI, 10 on CEUS) were included, consisting of 4169 patients with 1422 ICC lesions and 2747 HCC lesions. Most MRI studies were performed at 3T with hepatobiliary agents, and most CEUS studies used SonoVue as the contrast agent. In MRI, the pooled sensitivity, specificity, DOR, and AUC in distinguishing ICC from HCC were 0.81 (0.79, 0.84), 0.90 (0.88, 0.91), 41.47 (24.07, 71.44), and 0.93 (0.90, 0.96), respectively. The pooled sensitivity, specificity, DOR, and AUC of CEUS were 0.88 (0.84, 0.90), 0.80 (0.78, 0.83), 42.06 (12.38, 133.23), and 0.93 (0.87, 0.99), respectively. Subgroup analysis and meta-regression analysis demonstrated significant heterogeneity among the studies associated with the type of contrast agent in MRI studies. No publication bias was found.

CONCLUSION

Both MRI and CEUS showed excellent diagnostic performance in differentiating ICC from HCC. CEUS showed higher pooled sensitivity and MRI showed higher pooled specificity.

US LI-RADS in surveillance for recurrent hepatocellular carcinoma after curative treatment

OBJECTIVES

To investigate the performance of US LI-RADS in surveillance for recurrent hepatocellular carcinoma (RHCC) after curative treatment.

MATERIALS AND METHODS

This study enrolled 644 patients between January 2018 and August 2018 as a derivation cohort, and 397 patients from September 2018 to December 2018 as a validation cohort. The US surveillance after HCC curative treatment was performed. The US LI-RADS observation categories and visualization scores were analyzed. Four criteria using US LI-RADS or Alpha-fetoprotein (AFP) as the surveillance algorithm were evaluated. The sensitivity, specificity, and negative predictive value (NPV) were calculated.

RESULTS

A total of 212 (32.9%) patients in derivation cohort and 158 (39.8%) patients in validation cohort were detected to have RHCCs. The criterion of US-2/3 or AFP ≥ 20 µg/L had higher sensitivity (derivation, 96.7% vs 92.9% vs 81.1% vs 90.6%; validation, 96.2% vs 90.5% vs 80.4% vs 89.9%) and NPV (derivation, 95.7% vs 93.3% vs 88.0% vs 91.8%; validation, 94.6% vs 89.4% vs 83.6% vs 89.0%), but lower specificity (derivation, 35.9% vs 48.2% vs 67.6% vs 51.9%; validation, 43.5% vs 52.7% vs 66.1% vs 54.0%) than criterion of US-2/3, US-3, and US-3 or AFP ≥ 20 µg/L. Analysis of the visualization score subgroups confirmed that the sensitivity (89.2-97.6% vs 81.0-83.3%) and NPV(88.4-98.0% vs 80.0-83.3%) of score A and score B groups were higher than score C group in criterion of US-2/3 in both two cohorts.

CONCLUSIONS

In the surveillance for RHCC, US LI-RADS with AFP had a high sensitivity and NPV when US-2/3 or AFP ≥ 20 µg/L was considered a criterion.

CLINICAL RELEVANCE STATEMENT

The criterion of US-2/3 or AFP ≥ 20 µg/L improves sensitivity and NPV for RHCC surveillance, which provides a valuable reference for patients in RHCC surveillance after curative treatment.

KEY POINTS

• US LI-RADS with AFP had high sensitivity and NPV in surveillance for RHCC when considering US-2/3 or AFP ≥ 20 µg/L as a criterion. • After US with AFP surveillance, patients with US-2/3 or AFP ≥ 20 µg/L should perform enhanced imaging for confirmative diagnosis. Patients with US-1 or AFP < 20 µg/L continue to repeat US with AFP surveillance. • Patients with risk factors for poor visualization scores limited the sensitivity of US surveillance in RHCC.

Evaluation and Classification of Incidentally Detected Splenic Lesions Based on B-Mode and Contrast-Enhanced Ultrasound

PURPOSE

To evaluate B-mode ultrasound (B-US) and contrast-enhanced ultrasound (CEUS) patterns of focal splenic incidentalomas (FSIs), and to correlate ultrasound patterns with benignity and malignancy via histologic examination and/or the clinical course.

MATERIALS AND METHODS

Between 2004 and 2021, 139 consecutive patients with an FSI detected by B-US were investigated additionally with CEUS. On CEUS, the arterial enhancement (AE) of the FSI (hyperenhancement, isoenhancement, hypoenhancement, and absent enhancement) was analyzed. Subsequently, the malignancy rate according to different B-US echo patterns and CEUS perfusion patterns was determined.

RESULTS

The final diagnosis of FSI was malignant in 9/139 (6.5%) and benign in 130/139 (93.5%) cases. The hypoechoic and hyperechoic lesions on B-US with arterial hyperenhancement on CEUS and the echogenic cystic or complex lesions on B-US with predominantly absent enhancement on CEUS were benign in 54/54 (100%) cases. 6/37 (16.2%) hypoechoic lesions on B-US with arterial hypo-/isoenhancement on CEUS and 3/48 (6.3%) of hyperechoic lesions on B-US with an arterial hypo-/isoenhancement on CEUS were malignant.

CONCLUSION

Based on these results, FSIs reveal different malignancy rates depending on the B-US und CEUS patterns, and classification according to these B-US and CEUS patterns may be helpful in further evaluation of an FSI.

[Contrast-Enhanced Ultrasound of Fibrolamellar Hepatocellular Carcinoma]

We present the case of a 24-year-old male patient, who was admitted for endoscopy due to sustained pain in the upper abdomen with nausea and postprandial fullness without vomiting for more than 5 months. In the physical examination, an epigastric induration was found. Endoscopy revealed an external impression of the proximal duodenum. Beyond that, normal findings could be ascertained in gastroscopy and ileo-colonoscopy. Abdominal ultrasound identified a large hypoechoic lesion in the left liver lobe with a sharp delineation. Along the upper mesenteric vessels, enlarged lymphnodes were visible with contact to the proximal duodenum. Contrast-enhanced ultrasound (CE-US) was conducted and revealed the typical perfusion pattern of hepatocellular carcinoma. For further assessment, an ultrasound-guided core-biopsy of the lesion was performed. The histopathological evaluations resulted in the diagnosis of a hepatocellular carcinoma of fibrolamellar subtype.With the present case, we want to illustrate the perfusion pattern of a fibrolamellar hepatocellular carcinoma in contrast-enhanced ultrasound. Even though the tumor tissue is surrounded by lamellar bands of fibrosis with collagen-rich fibers, the perfusion pattern is consistent with the previously known appearance of HCC in CE-US.

Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part I

Malignant focal liver lesions (FLLs) are commonly reported in adults but rarely seen in the pediatric population. Due to the rarity, the understanding of these diseases is still very limited. In children, most malignant FLLs are congenital. It is very important to choose appropriate imaging examination concerning various factors. This paper will outline common pediatric malignant FLLs, including hepatoblastoma, hepatocellular carcinoma, and cholangiocarcinoma and discuss them against the background of the latest knowledge on comparable/similar tumors in adults. Medical imaging features are of vital importance for the non-invasive diagnosis and follow-up of treatment of FLLs in pediatric patients. The use of CEUS in pediatric patients for characterizing those FLLs that remain indeterminate on conventional B mode ultrasounds may be an effective option in the future and has great potential to be integrated into imaging algorithms without the risk of exposure to ionizing radiation.

Value of contrast-enhanced ultrasound for vascular diseases of the liver - current indications and open questions

Contrast-enhanced ultrasonography (CEUS) is a widely available and well-tolerated technique that can expand the diagnosis of a variety of vascular liver diseases. This paper presents an overview of the current possibilities of the use of CEUS in vascular liver diseases. Particularly where Doppler sonography has technical limitations, CEUS provides additional opportunities to visualize vascular thrombosis and other obstructions restricting blood flow. When CT or MRI contrast agents cannot be used because of severe allergy or renal insufficiency, CEUS can be a valuable diagnostic alternative and has demonstrated comparable diagnostic performance in at least some vascular liver diseases, such as portal vein thrombosis. In addition, CEUS works without radiation and, therefore, might be particularly suitable for young patients and children. This may be useful, for example, in congenital disorders such as persistent umbilical vein or preduodenal portal vein. Vascular liver disease is rare and comprehensive data are still lacking, but the available literature provides promising insights into potential new ways to study vascular liver disease. Although most studies are based on small sample sizes or even case reports, the high diagnostic utility is undisputed.

Inflammatory Hepatocellular Adenoma Mimicking Focal Nodular Hyperplasia That Grew during Pregnancy and Changed Its Appearance on Magnetic Resonance Imaging after Delivery

We reported a notable case of inflammatory hepatocellular adenoma that grew during pregnancy, consequently changing its appearance on magnetic resonance imaging remarkably. A 5-months-pregnant 35-year-old woman presented with a 37-mm liver nodule that had been diagnosed as focal nodular hyperplasia 3 years earlier. She had never used oral contraceptives. After 2 months, the nodule grew to 57 mm. The patient delivered a full-term infant without complications. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging performed after delivery revealed markedly different findings compared with the first images. A liver biopsy was performed, and the tumor was diagnosed as inflammatory hepatocellular adenoma.

Intraductal papillary neoplasms of the bile ducts-what can be seen with ultrasound?

Intraductal papillary neoplasm of the bile ducts is a rare tumor. Characteristic features include bile duct dilatation, cystic lesions with communication to the bile ducts, and intraluminal solid nodules arising from the bile duct wall. As in pancreatic intraductal papillary mucinous neoplasia, intestinal, pancreaticobiliary, gastric, and oncocytic types are described. Intraductal papillary neoplasm of the bile ducts has a high potential for malignancy, and patients should be surgically resected when possible. In this review, the complex imaging diagnosis is presented. The main focus is on contrast-enhanced ultrasound, an established method for many other indications whose potential on the biliary system should be better exploited. In the present article, typical contrast-enhanced ultrasound findings in intraductal papillary neoplasm of the bile ducts are demonstrated.

Contrast-Enhanced Ultrasonography for Transabdominal and Transrectal Ultrasound in Staging Cervical Cancer: A Reliability Study

OBJECTIVE

This retrospective study aimed to evaluate the consistency of transrectal contrast-enhanced ultrasonography (TR-CEUS) with post-operative pathology and the value of contrast-enhanced ultrasonography (CEUS) in staging surgically treated cervical cancer when combined with conventional ultrasonography (US).

METHODS

From October 2020 to March 2023, hospitalized patients with stage IB and II cervical cancer confirmed by total hysterectomy were consecutively enrolled. The standard images of US and CEUS by transabdominal (TA-US/CEUS) and transrectal (TR-US/CEUS) approaches and magnetic resonance imaging (MRI) were acquired, on which the size and stage of the tumors were evaluated, and the consistency of results with the pathological specimen was analyzed.

RESULTS

Thirty-nine patients with cervical cancer were finally enrolled in this study. The results showed that CEUS significantly improved the reliability of TA-US in evaluating tumor diameter; the intraclass correlation coefficient (ICC) was from 0.672 to 0.735. TR-US indicated good reliability with or without the addition of CEUS (ICC = 0.796 and 0.780). In terms of tumor staging, CEUS improved the consistency of transabdominal (weighted κ values from 0.689 to 0.731) and transrectal staging of tumors (κ from 0.758 to 0.785), and the staging of TR-US combined with TR-CEUS had the highest consistency with post-operative results, similar to MRI (κ, respectively 0.785 and 0.789). CEUS can reflect the heterogeneity of the tumor. Heterogeneous enhancement and perfusion defects were more common in >2 cm cervical cancer (50%, 20/40 and 52.5%, 21/40), respectively, and perfusion defects were more common in moderately to poorly differentiated tumors (66.67%, 20/30).

CONCLUSION

For stage IB and IIA cervical cancer, CEUS can aid in assessing the International Federation for Gynecology and Obstetrics staging of tumors alongside TA-US and TR-US. The combination of TR-US and TR-CEUS has shown good consistency with pathology in the staging of cervical cancer, comparable to that of MRI.

Sonazoid-enhanced ultrasonography for noninvasive imaging diagnosis of hepatocellular carcinoma: special emphasis on the 2022 KLCA-NCC guideline

Contrast-enhanced ultrasonography (CEUS) is a noninvasive imaging modality used to diagnose hepatocellular carcinoma (HCC) based on specific imaging features, without the need for pathologic confirmation. Two types of ultrasound contrast agents are commercially available: pure intravascular agents (such as SonoVue) and Kupffer agents (such as Sonazoid). Major guidelines recognize CEUS as a reliable imaging method for HCC diagnosis, although they differ depending on the contrast agents used. The Korean Liver Cancer Association-National Cancer Center guideline includes CEUS with either SonoVue or Sonazoid as a second-line diagnostic technique. However, Sonazoid-enhanced ultrasound is associated with several unresolved issues. This review provides a comparative overview of these contrast agents regarding pharmacokinetic features, examination protocols, diagnostic criteria for HCC, and potential applications in the HCC diagnostic algorithm.

Perfluorobutane-Enhanced Ultrasound for Characterization of Hepatocellular Carcinoma From Non-hepatocellular Malignancies or Benignancy: Comparison of Imaging Acquisition Methods

OBJECTIVE

The aim of the work described here was to evaluate the diagnostic performance of perfluorobutane (PFB)-enhanced ultrasound in differentiating hepatocellular carcinoma (HCC) from non-HCC malignancies and other benign lesions using different acquisition methods.

METHODS

This prospective study included 69 patients with solid liver lesions larger than 1 cm who were scheduled for biopsy or radiofrequency ablation between September 2020 and March 2021. Lesion diagnosis was designated by three blinded radiologists after reviewing three different sets of acquired images selected according to the following presumed acquisition methods: (i) method A, acquisition up to 5 min after contrast injection; (ii) method B, acquisition up to 1 min after contrast injection with additional Kupffer phase; and (iii) method C, acquisition up to 5 min after contrast injection with additional Kupffer phase.

RESULTS

After excluding 7 technical failures, 62 patients with liver lesions (mean size: 24.2 ± 14.8 mm), which consisted of 7 benign lesions, 37 non-HCC malignancies and 18 HCCs. For the HCC diagnosis, method C had the highest sensitivity (75.9%), followed by method B (72.2%) and method A (68.5%), but failed to exhibit statistical significance (p = 0.12). There was no significant difference with respect to the pooled specificity between the three methods (p = 0.28). Diagnostic accuracy was the highest with method C (87.1%) but failed to exhibit statistical significance (p = 0.24).

CONCLUSION

Image acquisition up to 5 min after contrast injection with additional Kupffer phase could potentially result in high accuracy and sensitivity without loss of specificity in diagnosing HCC with PFB-enhanced ultrasound.

Analysis of Sonazoid contrast-enhanced ultrasound for predicting the risk of microvascular invasion in hepatocellular carcinoma: a prospective multicenter study

OBJECTIVES

The aim of this study was to evaluate the potential of Sonazoid contrast-enhanced ultrasound (SNZ-CEUS) as an imaging biomarker for preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC).

METHODS

From August 2020 to March 2021, we conducted a prospective multicenter study on the clinical application of Sonazoid in liver tumor; a MVI prediction model was developed and validated by integrating clinical and imaging variables. Multivariate logistic regression analysis was used to establish the MVI prediction model; three models were developed: a clinical model, a SNZ-CEUS model, and a combined model and conduct external validation. We conducted subgroup analysis to investigate the performance of the SNZ-CEUS model in non-invasive prediction of MVI.

RESULTS

Overall, 211 patients were evaluated. All patients were split into derivation (n = 170) and external validation (n = 41) cohorts. Patients who had MVI accounted for 89 of 211 (42.2%) patients. Multivariate analysis revealed that tumor size (> 49.2 mm), pathology differentiation, arterial phase heterogeneous enhancement pattern, non-single nodular gross morphology, washout time (< 90 s), and gray value ratio (≤ 0.50) were significantly associated with MVI. Combining these factors, the area under the receiver operating characteristic (AUROC) of the combined model in the derivation and external validation cohorts was 0.859 (95% confidence interval (CI): 0.803-0.914) and 0.812 (95% CI: 0.691-0.915), respectively. In subgroup analysis, the AUROC of the SNZ-CEUS model in diameter  ≤ 30 mm and ˃ 30 mm cohorts were 0.819 (95% CI: 0.698-0.941) and 0.747 (95% CI: 0.670-0.824).

CONCLUSIONS

Our model predicted the risk of MVI in HCC patients with high accuracy preoperatively.

CLINICAL RELEVANCE STATEMENT

Sonazoid, a novel second-generation ultrasound contrast agent, can accumulate in the endothelial network and form a unique Kupffer phase in liver imaging. The preoperative non-invasive prediction model based on Sonazoid for MVI is helpful for clinicians to make individualized treatment decisions.

KEY POINTS

• This is the first prospective multicenter study to analyze the possibility of SNZ-CEUS preoperatively predicting MVI. • The model established by combining SNZ-CEUS image features and clinical features has high predictive performance in both derivation cohort and external validation cohort. • The findings can help clinicians predict MVI in HCC patients before surgery and provide a basis for optimizing surgical management and monitoring strategies for HCC patients.

Comparison of non-radiomics imaging features and radiomics models based on contrast-enhanced ultrasound and Gd-EOB-DTPA-enhanced MRI for predicting microvascular invasion in hepatocellular carcinoma within 5 cm

OBJECTIVES

The purpose of this study is to establish microvascular invasion (MVI) prediction models based on preoperative contrast-enhanced ultrasound (CEUS) and ethoxybenzyl-enhanced magnetic resonance imaging (EOB-MRI) in patients with a single hepatocellular carcinoma (HCC) ≤ 5 cm.

METHODS

Patients with a single HCC ≤ 5 cm and accepting CEUS and EOB-MRI before surgery were enrolled in this study. Totally, 85 patients were randomly divided into the training and validation cohorts in a ratio of 7:3. Non-radiomics imaging features, the CEUS and EOB-MRI radiomics scores were extracted from the arterial phase, portal phase and delayed phase images of CEUS and the hepatobiliary phase images of EOB-MRI. Different MVI predicting models based on CEUS and EOB-MRI were constructed and their predictive values were evaluated.

RESULTS

Since univariate analysis revealed that arterial peritumoral enhancement on the CEUS image, CEUS radiomics score, and EOB-MRI radiomics score were significantly associated with MVI, three prediction models, namely the CEUS model, the EOB-MRI model, and the CEUS-EOB model, were developed. In the validation cohort, the areas under the receiver operating characteristic curve of the CEUS model, the EOB-MRI model, and the CEUS-EOB model were 0.73, 0.79, and 0.86, respectively.

CONCLUSIONS

Radiomics scores based on CEUS and EOB-MRI, combined with arterial peritumoral enhancement on CEUS, show a satisfying performance of MVI predicting. There was no significant difference in the efficacy of MVI risk evaluation between radiomics models based on CEUS and EOB-MRI in patients with a single HCC ≤ 5 cm.

CLINICAL RELEVANCE STATEMENT

Radiomics models based on CEUS and EOB-MRI are effective for MVI predicting and conducive to pretreatment decision-making in patients with a single HCC within 5 cm.

KEY POINTS

• Radiomics scores based on CEUS and EOB-MRI, combined with arterial peritumoral enhancement on CEUS, show a satisfying performance of MVI predicting. • There was no significant difference in the efficacy of MVI risk evaluation between radiomics models based on CEUS and EOB-MRI in patients with a single HCC ≤ 5 cm.

Contrast-Enhanced Ultrasound for Image-Guided Procedures

Contrast-enhanced ultrasound (CEUS) uses intravenously injected gas microbubbles as a pure blood pool contrast agent to demonstrate blood flow and tissue perfusion at a much higher sensitivity than color Doppler and power Doppler ultrasound. CEUS has gained traction in abdominal diagnostic imaging for improved lesion detection and characterization and a complementary problem-solving tool to CT and MRI. In addition to its diagnostic applications, CEUS has also proven useful for pre-procedure planning, procedure guidance, and post-procedure evaluation. This review provides a practical overview and guides to the application of CEUS in percutaneous, ultrasound-guided, needle-driven procedures, focusing on 2 common procedures, which illustrate the many benefits of CEUS- core needle biopsy (CNB) and percutaneous hepatic lesion ablation.

[Ultrasound systems for abdominal diagnostics - current methods, clinical applications and new technologies]

Abdominal ultrasound is the method of first choice in many clinical situations. Gray scale imaging (B-mode) and conventional Doppler techniques are nowadays complemented by contrast-enhanced ultrasound (CEUS), elastography, fat quantification and further technologies which allow multimodal characterization of organs and tissue structure using panoramic imaging, 3D-techniques and image fusion. The development of small portable devices augments the spectrum for sonographic diagnostics. In this review, we describe the current status of ultrasound technology based on published evidence. In addition, we provide guidance for quality assurance.

Hepatic epithelioid hemangioendothelioma-a single-institution experience with 51 cases

Objectives

The aim of the present study was to describe the experience at a single institution in the management of hepatic epithelioid hemangioendothelioma (HEHE).

Methods

We included 51 patients with histologically confirmed HEHE. We performed log-rank (Cox-Mantel) survival analyses using Kaplan-Meier methods to test differences in survival between patients in different groups. Univariate Cox regression analyses and multivariate proportional hazards regression model were carried out to identify independent prognostic factors.

Results

Different imaging modalities were used to diagnose HEHE with various presentations. Liver resection (LR), liver transplantation (LT), systemic treatment (ST), and surveillance had been used in our study. A significant difference was noted between the LR group and the surveillance group with respect to mean survival (p = 0.006), as was in the LR group and the ST group (p = 0.036), and in surgical approach (LR and LT) and nonsurgical approach (ST and surveillance) (p = 0.008). The mean survival between the ST group and the surveillance group was not significantly different (p = 0.851). LR (p = 0.010) and surgical approach (p = 0.014) were favorable predictors of outcome, while macrovascular invasion (MaVI) (p = 0.037), lung metastasis (p = 0.040), and surveillance (p = 0.033) were poor prognostic factors in univariate analysis. Multivariate analysis showed that LR (p = 0.010) and surgical approach (p = 0.014) were independently associated with good OS, while surveillance (p = 0.033) was independently associated with poor OS. After adjusting for confounding factors, patients in the LR group have much better OS than those in the surveillance group (p = 0.013). However, there was no significant difference in OS between the LR group and ST group (p = 0.254), as was in the ST group and the surveillance group (p = 0.857).

Conclusions

The definitive diagnosis of HEHE was dependent on histopathology, and it was not possible to make a specific diagnosis without biopsy because the radiological findings were similar to those in some hepatic malignancies. ST was not recommended for patients who were not candidates for surgical approaches, and surgical approaches should be warranted regardless of disease stage. The retrospective nature and the small size of the data limited the generalizability of the study, designing a worldwide database that contains all data about patients with HEHE independent of their therapy, which was highly recommended.

Value of Multimodal Data From Clinical and Sonographic Parameters in Predicting Recurrence of Hepatocellular Carcinoma After Curative Treatment

OBJECTIVE

The objective of the work described here was to assess the value of the combination of pre-operative multimodal data-including clinical data, contrast-enhanced ultrasound (CEUS) information and liver stiffness measurement (LSM) based on 2-D shear wave elastography (SWE)-in predicting early (within 1 y) and late (after 1 y) recurrence of hepatocellular carcinoma (HCC) after curative treatment.

METHODS

We retrospectively included 101 patients with HCC who met the Milan criteria and received curative treatment. The multimodel data from clinical parameters, LSM by 2-D SWE and CEUS enhancement patterns were collected. The association between different variables in HCC recurrence was accessed using a Cox proportional hazard model. On the basis of the independent factors of early recurrence, models with different source variables were established (Clinical Model, CEUS-Clinical Model, SWE-Clinical Model, CEUS-SWE-Clinical Model). The goodness-of-fit of models was evaluated and the performance trends of different models were calculated by time-dependent area under the curve (AUC).

RESULTS

Two-dimensional SWE, CEUS enhancement patterns and clinical parameters (spleen length, multiple tumors, α-fetoprotein, albumin and prothrombin time) were independently associated with early recurrence (all p values <0.05). Multiple tumors and a decrease in albumin independently contributed to the late recurrence. The model fit of CEUS-SWE-Clinical Model was superior to other models in predicting early recurrence (all p values <0.05). The AUCs of the CEUS-Clinical Model were higher from 2 mo to 7 mo, while the SWE-Clinical Model had higher AUCs from 9 mo to 12 mo.

CONCLUSION

CEUS enhancement patterns and 2-D SWE were independent predictors of HCC early recurrence as the two factors contributed to the predictive performance at different times. The multimodal model, which included diverse data in predicting early HCC recurrence, had the best goodness-of-fit.

Prognostic and pathological implications of contrast-enhanced ultrasound features in hepatocellular carcinoma

Background

Contrast-enhanced ultrasound (CEUS) plays a vital role in diagnosing hepatocellular carcinoma (HCC) and, to some extent, reflects tumor prognosis. This suggests that some pathological features of HCC may be associated with CEUS features.

Aim

This study aimed to verify the prognostic significance of four CEUS features and further explore their pathological significance.

Materials and Methods

This study included 243 HCC patients who underwent a preoperative CEUS examination. All pathological diagnoses and immunohistochemical information were obtained from the pathological report. The prognostic significance of four CEUS features, including nodule-in-nodule architecture, mosaic architecture, intratumoral feeding arteries, and peritumoral arterial phase (AP) hyperenhancement, was analyzed. The correlation between prognostic-related features and immunohistochemical information was further analyzed.

Results

The disease-free survival (DFS) of HCC was significantly affected by mosaic architecture or intratumoral feeding arteries (HR = 1.79; 95% confidence interval (95% CI), 1.09-2.95; P = 0.004; HR = 1.70; 95% CI, 1.07-2.71; P = 0.025, respectively). Intratumoral feeding arteries were positively correlated with the expression of serum alpha-fetoprotein (AFP), microvascular invasion (MVI), differentiation, size, and Ki-67, among which the correlation with size was the strongest, followed by Ki-67 and MVI. The mosaic architecture was positively correlated with serum AFP, MVI, differentiation, and size, among which the correlation with size was strongest, followed by MVI.

Conclusion

The mosaic architecture and intratumoral feeding arteries of CEUS were closely related to the postoperative progression of HCC. Mosaic architecture had a good correlation with tumor size and MVI, whereas intratumoral feeding arteries were closely associated with tumor size and Ki-67 expression.

A deep learning model with data integration of ultrasound contrast-enhanced micro-flow cines, B-mode images, and clinical parameters for diagnosing significant liver fibrosis in patients with chronic hepatitis B

OBJECTIVE

To develop and investigate a deep learning model with data integration of ultrasound contrast-enhanced micro-flow (CEMF) cines, B-mode images, and patients' clinical parameters to improve the diagnosis of significant liver fibrosis (≥ F2) in patients with chronic hepatitis B (CHB).

METHODS

Of 682 CHB patients who underwent ultrasound and histopathological examinations between October 2016 and May 2020, 218 subjects were included in this retrospective study. We devised a data integration-based deep learning (DIDL) model for assessing ≥ F2 in CHB patients. The model contained three convolutional neural network branches to automatically extract features from ultrasound CEMF cines, B-mode images, and clinical data. The extracted features were fused at the backend of the model for decision-making. The diagnostic performance was evaluated across fivefold cross-validation and compared against the other methods in terms of the area under the receiver operating characteristic curve (AUC), with histopathological results as the reference standard.

RESULTS

The mean AUC achieved by the DIDL model was 0.901 [95% CI, 0.857-0.939], which was significantly higher than those of the comparative methods, including the models trained by using only CEMF cines (0.850 [0.794-0.893]), B-mode images (0.813 [0.754-0.862]), or clinical data (0.757 [0.694-0.812]), as well as the conventional TIC method (0.752 [0.689-0.808]), APRI (0.792 [0.734-0.845]), FIB-4 (0.776 [0.714-0.829]), and visual assessments of two radiologists (0.812 [0.754-0.862], and 0.800 [0.739-0.849]), all ps < 0.01, DeLong test.

CONCLUSION

The DIDL model with data integration of ultrasound CEMF cines, B-mode images, and clinical parameters showed promising performance in diagnosing significant liver fibrosis for CHB patients.

KEY POINTS

• The combined use of ultrasound contrast-enhanced micro-flow cines, B-mode images, and clinical data in a deep learning model has potential to improve the diagnosis of significant liver fibrosis. • The deep learning model with the fusion of features extracted from multimodality data outperformed the conventional methods including mono-modality data-based models, the time-intensity curve-based recognizer, fibrosis biomarkers, and visual assessments by experienced radiologists. • The interpretation of the feature attention maps in the deep learning model may help radiologists get better understanding of liver fibrosis-related features and hence potentially enhancing their diagnostic capacities.

Intraoperative Contrast-Enhanced Ultrasonography (Io-CEUS) in Minimally Invasive Thoracic Surgery for Characterization of Pulmonary Tumours: A Clinical Feasibility Study

BACKGROUND

The intraoperative detection of solitary pulmonary nodules (SPNs) continues to be a major challenge, especially in minimally invasive video-assisted thoracic surgery (VATS). The location, size, and intraoperative frozen section result of SPNs are decisive regarding the extent of lung resection. This feasibility study investigates the technical applicability of intraoperative contrast-enhanced ultrasonography (Io-CEUS) in minimally invasive thoracic surgery.

METHODS

In this prospective, monocentric clinical feasibility study, n = 30 patients who underwent Io-CEUS during elective minimally invasive lung resection for SPNs between October 2021 and February 2023. The primary endpoint was the technical feasibility of Io-CEUS during VATS. Secondary endpoints were defined as the detection and characterization of SPNs.

RESULTS

In all patients (female, n = 13; mean age, 63 ± 8.6 years) Io-CEUS could be performed without problems during VATS. All SPNs were detected by Io-CEUS (100%). SPNs had a mean size of 2.2 cm (0.5-4.5 cm) and a mean distance to the lung surface of 2.0 cm (0-6.4 cm). B-mode, colour-coded Doppler sonography, and contrast-enhanced ultrasound were used to characterize all tumours intraoperatively. Significant differences were found, especially in vascularization as well as in contrast agent behaviour, depending on the tumour entity. After successful lung resection, a pathologic examination confirmed the presence of lung carcinomas (n = 17), lung metastases (n = 10), and benign lung tumours (n = 3).

CONCLUSIONS

The technical feasibility of Io-CEUS was confirmed in VATS before resection regarding the detection of suspicious SPNs. In particular, the use of Doppler sonography and contrast agent kinetics revealed intraoperative specific aspects depending on the tumour entity. Further studies on Io-CEUS and the application of an endoscopic probe for VATS will follow.

Non-invasive preoperative prediction of Edmondson-Steiner grade of hepatocellular carcinoma based on contrast-enhanced ultrasound using ensemble learning

Purpose

This study aimed to explore the clinical value of non-invasive preoperative Edmondson-Steiner grade of hepatocellular carcinoma (HCC) using contrast-enhanced ultrasound (CEUS).

Methods

212 cases of HCCs were retrospectively included, including 83 cases of high-grade HCCs and 129 cases of low-grade HCCs. Three representative CEUS images were selected from the arterial phase, portal vein phase, and delayed phase and stored in a 3-dimensional array. ITK-SNAP was used to segment the tumor lesions manually. The Radiomics method was conducted to extract high-dimensional features on these contrast-enhanced ultrasound images. Then the independent sample T-test and the Least Absolute Shrinkage and Selection Operator (LASSO) were employed to reduce the feature dimensions. The optimized features were modeled by a classifier based on ensemble learning, and the Edmondson Steiner grading was predicted in an independent testing set using this model.

Results

A total of 1338 features were extracted from the 3D images. After the dimension reduction, 10 features were finally selected to establish the model. In the independent testing set, the integrated model performed best, with an AUC of 0.931.

Conclusion

This study proposed an Edmondson-Steiner grading method for HCC with CEUS. The method has good classification performance on independent testing sets, which can provide quantitative analysis support for clinical decision-making.

Long-term liver lesion tracking in contrast-enhanced ultrasound videos via a siamese network with temporal motion attention

Propose: Contrast-enhanced ultrasound has shown great promises for diagnosis and monitoring in a wide range of clinical conditions. Meanwhile, to obtain accurate and effective location of lesion in contrast-enhanced ultrasound videos is the basis for subsequent diagnosis and qualitative treatment, which is a challenging task nowadays. Methods: We propose to upgrade a siamese architecture-based neural network for robust and accurate landmark tracking in contrast-enhanced ultrasound videos. Due to few researches on it, the general inherent assumptions of the constant position model and the missing motion model remain unaddressed limitations. In our proposed model, we overcome these limitations by introducing two modules into the original architecture. We use a temporal motion attention based on Lucas Kanade optic flow and Karman filter to model the regular movement and better instruct location prediction. Moreover, we design a pipeline of template update to ensure timely adaptation to feature changes. Results: Eventually, the whole framework was performed on our collected datasets. It has achieved the average mean IoU values of 86.43% on 33 labeled videos with a total of 37,549 frames. In terms of tracking stability, our model has smaller TE of 19.2 pixels and RMSE of 27.6 with the FPS of 8.36 ± 3.23 compared to other classical tracking models. Conclusion: We designed and implemented a pipeline for tracking focal areas in contrast-enhanced ultrasound videos, which takes the siamese network as the backbone and uses optical flow and Kalman filter algorithm to provide position prior information. It turns out that these two additional modules are helpful for the analysis of CEUS videos. We hope that our work can provide an idea for the analysis of CEUS videos.

Usefulness of Contrast-Enhanced Ultrasound in the Differentiation between Hepatocellular Carcinoma and Benign Liver Lesions

A differentiation between hepatocellular carcinoma (HCC) and benign liver lesions is required. The aim of the study was to perform an analysis of the time of enhancement of focal liver lesions in a contrast-enhanced ultrasound (CEUS) examination. The curves of enhancement and the homogeneity of the tumor enhancement were assessed. The study included 52 patients with diagnoses of hepatocellular adenoma (18), focal nodular hyperplasia (11) and HCC (28). The study included magnetic resonance imaging or computed tomography and a comparison of the obtained information with CEUS. In the benign lesions groups after 20-30 s, the enhancement was similar to the liver parenchyma. In the HCC group, the enhancement was slightly less intense compared to the liver parenchyma and the benign lesions. The difference of the enhancement in the arterial phase (benign lesions vs. HCC) was p = 0.0452, and the difference of enhancement in the late venous phase (benign lesions vs. HCC) was p = 0.000003. The homogeneity of the enhancement (benign lesions vs. HCC), respectively, was p = 0.001 in the arterial phase, p = 0.0003 in the portal venous phase and p = 0.00000007 in the late venous phase. Liver tumors can be classified as benign when they are homogenous in the arterial phase and don't present washout. HCC in the arterial phase is inhomogeneous and washout is observed in the venous phases. When radiological symptoms suggest malignant lesion, CEUS can be used to select the best biopsy access.

Preoperative Value of Contrast-Enhanced Ultrasound in Totally Laparoscopic Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy for Liver Tumors: A Preliminary Study

ABSTRACT

The clinical data of 15 cases that planned to receive totally laparoscopic associating liver partition and portal vein ligation for staged hepatectomy were retrospectively collected. Before the stage 1 operation, the size and number of the tumors in future liver remnant (FLR) and the presence of cancer embolus in the portal vein were assessed using contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT). Before the stage 2 operation, CEUS was performed to assess the presence of traffic blood flow between the diseased liver and FLR after round-the-liver ligation. Before the stage 1 operation, 5 cases with tumors in FLR were found by CEUS and 6 cases were found by CECT ( P > 0.05). Similarly, CEUS found 5 cases with cancer thrombus in portal vein, and CECT found 7 cases ( P = 0.500). The consistency between the 2 modalities was good (κ = 0.857, P < 0.05, κ = 0.727, P < 0.05, respectively). Before the stage 2 operation, CEUS confirmed that there were 7 cases without traffic blood flow between the diseased liver and FLR, and 3 cases with residual traffic blood flow. The daily growth rate of FLR in the group without traffic blood flow (mean rank = 7.00) was higher than that in the group with traffic blood flow (2.00) significantly ( P < 0.05). Contrast-enhanced ultrasound is a promising application in the preoperative evaluation of totally laparoscopic associating liver partition and portal vein ligation for staged hepatectomy.