Role of contrast-enhanced ultrasound in follow-up assessment after ablation for hepatocellular carcinoma

Dynamic Contrast-Enhanced Ultrasound in the Prediction of Advanced Hepatocellular Carcinoma Response to Systemic and Locoregional Therapies

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and the sixth most common malignant tumor in the world, with an incidence of 2-8% per year in patients with hepatic cirrhosis or chronic hepatitis. Despite surveillance schedules, it is sometimes diagnosed at an advanced stage, requiring complex therapeutic efforts with both locoregional and systemic treatments. Traditional radiological tools (computed tomography and magnetic resonance) are used for the post-treatment follow-up of HCC. The first follow-up imaging is performed at 4 weeks after resection or locoregional treatments, or after 3 months from the beginning of systemic therapies, and subsequently every 3 months for the first 2 years. For this reason, these radiological methods do not grant the possibility of an early distinction between good and poor therapeutic response. Contrast-enhanced ultrasound (CEUS) and dynamic contrast-enhanced ultrasound (DCE-US) have gained the interest of several researchers for their potential role in the early assessment of response to locoregional treatments (chemoembolization) or antiangiogenic therapies in patients with advanced HCC. In fact, DCE-US, through a quantitative analysis performed by specific software, allows the construction of time-intensity curves, providing an evaluation of the parameters related to neoplastic tissue perfusion and its potential changes following therapies. It has the invaluable advantage of being easily repeatable, minimally invasive, and able to grant important evaluations regarding patients' survival, essential for well-timed therapeutic changes in case of unsatisfying response, and eventual further treatment planning.

Achievement of Complete Response and Drug-Free Status by Atezolizumab plus Bevacizumab Combined with or without Curative Conversion in Patients with Transarterial Chemoembolization-Unsuitable, Intermediate-Stage Hepatocellular Carcinoma: A Multicenter Proof-Of-Concept Study

Introduction

Atezolizumab plus bevacizumab therapy is extremely effective in the treatment of intermediate-stage hepatocellular carcinoma (HCC), with a response rate of 44%, as reported in the IMbrave150 trial. When tumor shrinkage is obtained, achieving complete response (CR) is possible in many cases using curative conversion with resection, ablation, or superselective transarterial chemoembolization (TACE) with curative intent. This concept, i.e., curative conversion by combining systemic therapy and locoregional therapy, has not been reported before. This multicenter proof-of-concept study was conducted to show the value of curative conversion in immunotherapy-treated intermediate-stage HCC meeting TACE-unsuitable criteria.

Methods

This study included 110 consecutive Child-Pugh A patients who received atezolizumab plus bevacizumab as first-line treatment for unresectable and TACE-unsuitable intermediate-stage HCC at seven centers in Japan. CR rate, drug-free rate, time to CR, change in liver function, efficacy in positron emission tomography (PET)-positive HCC, progression-free survival (PFS), and overall survival (OS) were assessed in patients who achieved CR using resection, ablation, superselective TACE with curative intent following atezolizumab plus bevacizumab or atezolizumab plus bevacizumab alone.

Results

Clinical or pathological CR was achieved in 38 patients (35%) (median observation period: 21.2 months). The modalities of curative conversion in 35 patients were as follows: resection, 7; ablation, 13; and superselective TACE, 15. Three patients achieved clinical CR with atezolizumab plus bevacizumab therapy alone. Among the 38 CR patients, 25 achieved drug-free status. PFS was not reached, and 3 patients experienced recurrence after reaching CR. Regarding OS, there were no deaths in any of the CR patients. The albumin-bilirubin score did not deteriorate after locoregional therapy or resection. Of seven PET-positive patients who achieved CR with atezolizumab plus bevacizumab followed by curative conversion, five achieved drug-free status.

Conclusion

The achievement of CR rate by curative conversion in patients treated with atezolizumab plus bevacizumab as the preceding therapy for unresectable and TACE-unsuitable intermediate-stage HCC was 35%. Overall, 23% of patients achieved drug-free status and no recurrence was observed from this patient subgroup with CR and drug-free status. Thus, achieving CR and/or drug-free status should be a therapeutic goal for patients with intermediate-stage HCC without vascular invasion or extrahepatic spread.

Indian College of Radiology and Imaging Guidelines on Interventions in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies and a significant cause of cancer-related death. Treatment of HCC depends on the stage of the tumor. As many patients with HCC are not deemed fit for surgical resection or liver transplantation, locoregional therapies play an essential role in the management. Image-guided locoregional treatments include percutaneous ablative therapies and endovascular therapies. The choice of an individual or a combination of therapies is guided by the tumor and patient characteristics. As the outcomes of image-guided locoregional treatments depend on the ability to achieve necrosis of the entire tumor along with a safety margin around it, it is mandatory to follow standard guidelines. In this manuscript, we discuss in detail the various aspects of image-guided locoregional therapies to guide interventional radiologists involved in the care of patients with HCC.

Application of the CT/MRI LI-RADS Treatment Response Algorithm to Contrast-Enhanced Ultrasound: A Feasibility Study

Purpose

The contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) treatment response algorithm (TRA) is still in development. The aim of this study was to explore whether the CT/MRI LI-RADS TRA features were applicable to CEUS in evaluating the liver locoregional therapy (LRT) response.

Patients and Methods

This study was a retrospective review of a prospectively maintained database of patients with hepatocellular carcinoma undergoing ablation between July 2017 and December 2018. The standard criteria for a viable lesion were a histopathologically confirmed or typical viable appearance in the follow-up CT/MRI. Performance of the LI-RADS TRA assessing tumor viability was then compared between CEUS and CT/MRI. Inter-reader association was calculated.

Results

A total of 244 patients with 389 treated observations (118 viable) were evaluated. The sensitivity and specificity of the CEUS TRA and CT/MRI LI-RADS TRA viable categories for predicting viable lesions were 55.0% (65/118) versus 56.8% (67/118) (P = 0.480) and 99.3% (269/271) versus 96.3% (261/271) (P = 0.013), respectively. The PPV of CEUS was higher than that of CT/MRI (97.0% vs 87.0%). Subgroup analysis showed that the sensitivity was low in the 1-month assessment for both CEUS (38.1%, 16/42) and CT/MR (47.6%, 20/42) and higher in the 2–6-month assessment for both CEUS (65.7%, 23/35) and CT/MR (62.9%, 22/35). Interobserver agreements were substantial for both CEUS TRA and CT/MRI LI-RADS TRA (κ, 0.74 for both).

Conclusion

The CT/MRI LI-RADS TRA features were applicable to CEUS TRA for liver locoregional therapy. The CEUS TRA for liver locoregional therapy has sufficiently high specificity and PPV to diagnose the viability of lesions after ablation.

Contrast-Enhanced Ultrasound for Monitoring Treatment Response in Different Stages of Hepatocellular Carcinoma

Simple Summary

The evaluation of tumor response to anti-cancer therapy is critical in oncology for the prompt determination of subsequent treatment and follow-up strategies. Historically, response criteria have been based on tumor size changes; however, since the development of locoregional and molecular-targeted therapies in HCC (which act by disrupting tumor vascularization rather than tumor cells), changes in tumor vascularity and enhancement patterns have been considered to be more reliable. Contrast-enhanced ultrasound (CEUS) and dynamic CEUS, which allow microvessel perfusion studies, are emerging as promising tools for early tumor response evaluation. This article provides a general review of the current literature regarding the usefulness of CEUS in monitoring HCC response to therapy, highlighting the role of the procedure at different stages of the disease.

Abstract

The capacity of contrast-enhanced ultrasound (CEUS) to detect microvessel perfusion has received much attention in cancer imaging since it can be used to evaluate the enhancement patterns of the lesions during all vascular phases in real time, with higher temporal resolution as compared other imaging modalities. A rich body of literature has demonstrated the potential usefulness of CEUS in the assessment of HCC in response to both locoregional and systemic therapies. It is useful to evaluate the efficacy of ablation immediately after treatment to provide guidance for the retreatment of residual unablated tumors. In patients treated with transarterial chemoembolization (TACE), CEUS showed a high degree of concordance with computed tomography and magnetic resonance for the differentiation of responders from non-responders. Dynamic CEUS (D-CEUS) has emerged as a promising tool for the depicting changes in tumor perfusion during anti-angiogenetic treatment that can be associated with tumor response and clinical outcome. This article provides a general review of the current literature regarding the usefulness of CEUS in monitoring HCC response to therapy, highlighting the role of the procedure in different stages of the disease.

Meta-analysis and systematic review of contrast-enhanced ultrasound in evaluating the treatment response after locoregional therapy of hepatocellular carcinoma

PURPOSE

Contrast-enhanced ultrasound (CEUS) is a useful tool to assess treatment response after percutaneous ablation or transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). Here, we performed a systematic review and meta-analysis to evaluate the usefulness of CEUS in identifying residual tumor after locoregional therapy.

METHODS

PubMed, Scopus, and Cochrane library databases were searched from their inception until March 8, 2021, for diagnostic test accuracy studies comparing CEUS to a reference standard for identifying residual tumors after locoregional therapy of HCC. The pooled sensitivity, specificity, accuracy, and diagnostic odds ratio (DOR) were obtained using a bivariate random effects model. Subgroup analyses were performed by stratifying the studies based on study design, type of locoregional therapy, CEUS criteria for residual tumor, timing of CEUS follow up, and type of standard reference.

RESULTS

Two reviewers independently evaluated 1479 publications. After full-text review, 142 studies were found to be relevant, and 43 publications (50 cohorts) were finally included. The overall sensitivity of CEUS in detection of residual disease estimated from the bivariate random effects model was 0.85 (95% CI 0.80-0.89). Similarly, the overall specificity was 0.94 (95% CI 0.91-0.96). The diagnostic accuracy was 93.5%. The DOR was 70.1 (95% CI 62.2-148), and the AUROC was 0.95. Importantly, subgroup analysis showed no apparent differences in the diagnostic performance between locoregional therapy (TACE vs. ablation) and criteria used to define residual enhancement, timing of performing CEUS, study design, or type of reference standard.

CONCLUSION

CEUS is a highly accurate method to identify HCC residual tumor after TACE or percutaneous ablation.

A Systematic Review about Imaging and Histopathological Findings for Detecting and Evaluating Electroporation Based Treatments Response

BACKGROUND

Imaging methods and the most appropriate criteria to be used for detecting and evaluating response to oncological treatments depend on the pathology and anatomical site to be treated and on the treatment to be performed. This document provides a general overview of the main imaging and histopathological findings of electroporation-based treatments (Electrochemotherapy-ECT and Irreversible electroporation-IRE) compared to thermal approach, such as radiofrequency ablation (RFA), in deep-seated cancers with a particular attention to pancreatic and liver cancer.

METHODS

Numerous electronic datasets were examined: PubMed, Scopus, Web of Science and Google Scholar. The research covered the years from January 1990 to April 2021. All titles and abstracts were analyzed. The inclusion criteria were the following: studies that report imaging or histopathological findings after ablative thermal and not thermal loco-regional treatments (ECT, IRE, RFA) in deep-seated cancers including pancreatic and liver cancer and articles published in the English language. Exclusion criteria were unavailability of full text and congress abstracts or posters and different topic respect to inclusion criteria.

RESULTS

558 potentially relevant references through electronic searches were identified. A total of 38 articles met the inclusion criteria: 20 studies report imaging findings after RFA or ECT or IRE in pancreatic and liver cancer; 17 studies report histopathological findings after RFA or ECT or IRE; 1 study reports both imaging and histopathological findings after RFA or ECT or IRE.

CONCLUSIONS

Imaging features are related to the type of therapy administrated, to the timing of re-assessment post therapy and to the imaging technique being used to observe the effects. Histological findings after both ECT and IRE show that the treated area becomes necrotic and encapsulated in fibrous tissue, suggesting that the size of the treated lesion cannot be measured as an endpoint to detect response. Moreover, histology frequently reported signs of apoptosis and reduced vital tissue, implying that imaging criteria, which take into account the viability and not the size of the lesion, are more appropriate to evaluate response to treatment.

Ultrasound-Guided Percutaneous Ethanol-Paclitaxel Combined Therapy for Rabbit VX2 Liver Tumors

Background

It is difficult to achieve whole tumor ablation using percutaneous ethanol ablation therapy (PEAT) due to the limited diffusion of ethanol.

Purpose

To determine whether chemotherapy can be an adjuvant therapy to benefit PEAT, we investigated ultrasound-guided percutaneous ethanol-paclitaxel combined therapy (PEPCT) of VX2 carcinoma, a rabbit liver cancer model.

Materials and Methods

A six-arm study was designed to quantify the correlation between paclitaxel (PTX) dose and tumor necrosis or cell proliferation, including sham group (2 mL saline, n=6), incremented dose of PTX (0, 12.5, 25, 37.5 mg) in 2.0 mL ethanol (n=6) and a conventional PEAT group (n=6) as comparison. The test was followed by contrast-enhanced ultrasonic (CEUS) before 7-day sacrifice, tumor harvest, and sectioning. Tumor necrosis ratio was radiologically and histologically quantified; modified proliferation index (m-PI) was proposed to quantify the PTX's pharmacological effects. A linear regression model was set to correlate the PTX dose with tumor necrosis ratio or cell proliferation index. The difference of radiological, histological necrosis ratio (HNR) and modified PI in six groups was analyzed via Kruskal-Wallis H-test, Welch analysis of variance and one-way ANOVA.

Results

Incremental increases of PTX (0, 12.5, 25, 37.5 mg) correlated with greater fraction of tumor necrosis (R² = 0.946, P<0.001 for radiological necrosis ratio [RNR], R² = 0.843, P<0.001 forHNR), indicating that one week after procedure PTX's anti-proliferation and ethanol's dehydration co-induced severe tumor necrosis. Correlation analysis further testified a significant association between PTX dose and m-PI (R² = 0.860, P<0.001).

Conclusion

These results suggest a clear role for PTX-induced cytotoxicity and support the use of chemotherapeutic drugs in ablation therapy.

Contrast-enhanced ultrasound imaging of the liver: a review of the clinical evidence for SonoVue and Sonazoid

Contrast-enhanced ultrasound (CEUS) has become an established modality in various clinical indications for liver diseases. SonoVue^®, a pure blood pure agent, and Sonazoid^®, which exhibits an additional Kupffer phase, are contrast agents approved for liver imaging. This review discusses and compares the current clinical evidence for these two ultrasound contrast agents in the characterization and detection of focal liver lesions in the non-cirrhotic and cirrhotic liver, as well as for the use in interventional procedures such as liver biopsy guidance, and local ablation treatment monitoring. Reference is made to clinical studies which evaluated the accuracy of CEUS using a standard of reference, its safety, or to comparative studies of these two agents.

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

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS), first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications.The 2012 guideline requires updating as previously the differences of the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including the United States Food and Drug Administration (FDA) approval as well as the extensive Asian experience, to produce a truly international perspective.These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCA) and are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis to improve the management of patients.

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

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast-enhanced ultrasound, first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology. The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications. The 2012 guideline requires updating as, previously, the differences in the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including U.S. Food and Drug Administration approval and the extensive Asian experience, to produce a truly international perspective. These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCAs) and are intended to create standard protocols for the use and administration of UCAs in liver applications on an international basis to improve the management of patients.

The Perfusion Features of Recurrent Hepatocellular Carcinoma After Radiofrequency Ablation Using Contrast-Enhanced Ultrasound and Pathological Stemness Evaluation: Compared to Initial Tumors

Objective: To investigate the perfusion features of local recurrence in hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA) with contrast-enhanced ultrasound (CEUS) and pathological correlation, as well as to compare with those of initial HCC. Methods: From 2010 to 2018, 42 patients with recurrent HCC after RFA were enrolled in this study. The initial HCC patients included 32 males and 10 females with an average age of 58.2 ± 8.1 years. The CEUS images for initial HCC lesions and local recurrence after RFA were compared. The perfusion features were analyzed, including enhancement time, process, boundary, morphology, washout time, washout degree, feeding vessels, and internal necrosis. H&E staining and CD133/EpCAM staining were performed with biopsy samples for the stemness study. Results: According to CEUS, 59.5% of initial HCC lesions had centripetal enhancement, and 61.9% of recurrent HCC lesions had homogeneous enhancement in the arterial phase (p < 0.001). A total of 73.8% of initial HCC lesions had well-defined margins at the peak, and 81.0% of recurrent HCC lesions had poorly defined margins (p < 0.001). A total of 78.6% of initial HCC lesions had regular morphology at the peak, and 83.3% of recurrent HCC lesions were irregular (p < 0.001). Feeding vessels were more frequently found in initial HCC lesion (71.4%) than in recurrent HCCs (38.1%, p = 0.002). In the late phase, 60% of initial HCCs had marked washout while 83.3% of recurrent HCC lesion had marked washout (p = 0.019). A total of 31.3% of the initial HCC lesions had internal necrosis areas while only 7.1% of recurrent HCC lesions had internal necrosis areas (p = 0.035). In tumors 3-5 cm in size, the washout time of recurrent HCCs was shorter than that of initial HCCs (50.3 ± 13.5 s vs. 75.6 ± 45.8 s, p = 0.013). Pathological staining showed that the tumor stem cell markers (CD133 and EpCAM) were both highly expressed in recurrent samples compared with initial tumor samples (CD133+: 19 vs. 5%, p = 0.002; EpCAM+:15 vs. 6%, p = 0.005). Conclusions: Recurrent HCC after RFA had more homogeneous enhancement with a poorly defined border, marked washout, and fewer less feeding vessels and inner necrosis areas compared to initial HCC. The stemness study also found upregulated stemness in recurrent HCC. These specific features might be related to the aggressive biological behavior of recurrent HCC.

Response Assessment Following Image-Guided Therapy of Hepatocellular Carcinoma

Image-guided locoregional therapies have an important role in the management of patients with hepatocellular carcinoma (HCC). Recent advances in the ablative as well as endovascular therapies have expanded the role of interventional radiologists in the treatment of HCC. Following image-guided therapy, an accurate response assessment is vital. Knowledge regarding normal postprocedure changes and subtle signs of residual or recurrent disease is important. In this review, we discuss various response evaluation criteria currently employed for HCC. We also discuss the postprocedure imaging features suggestive of residual disease or recurrence and imaging biomarkers for response assessment.

The Application Comparison of Contrast-Enhanced Ultrasound and Contrast-Enhanced Computed Tomography in Radiofrequency Ablation Treatment for Hepatocellular Carcinoma

Objective: To compare the application value of contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) in radiofrequency ablation (RFA) for treatment of hepatocellular carcinoma (HCC). Methods: A total of 112 patients with primary HCC were enrolled for the treatment of RFA and they were randomly equally divided into the CEUS group and CECT group. The gender, age, and number and maximum diameter of tumors between the two groups were compared. The median duration of follow-up was 27.0 months and the clinical outcomes were compared. Results: The average examination time period before ablation, of guiding needle insertion and of ablation in the CEUS group were significantly shorter than those in the CECT group (p < 0.05). The complete ablation rate of the CEUS group was significantly higher than that of the CECT group (86.36% vs. 73.17%, χ² = 4.618, p = 0.032). There was no comparative difference in the incidence of complications (including fever, infection, pain, and liver injury) between the two groups (p > 0.05). The relapse rate of the CEUS group was lower and the survival rate was higher than that in the CECT group (p < 0.05). Conclusions: Compared with the CECT, the RFA for treatment of HCC guided by the CEUS shorten the time of examination and treatment. The immediate postoperative assessment can improve the overall complete ablation rate, reduce the relapse rate, and increase the survival rate, which provides insights for the clinical application.

Negative Predictive Value of Contrast-Enhanced Ultrasound of Liver and Kidney Thermal Ablation Sites for Local Tumour Progression During Long-term Follow-up: A Retrospective Consecutive Study

PURPOSE

To determine negative predictive value (NPV) of contrast-enhanced ultrasound (CEUS) to demonstrate local tumour progression (LTP) at thermal ablation (TA) sites.

METHODS

Our institutional review board approved this retrospective study; acquisition of consent was waived. Consecutive CEUS examinations performed between 2004-2014 for TA site evaluation on patients who could not undergo enhanced computed tomography (CT) or magnetic resonance imaging (MRI), or had inconclusive CT or MRI, were retrospectively reviewed. Those reported as no abnormal enhancement in or surrounding TA site were included. CEUS examination was considered true-negative based on stability or lack of enhancement/washout on follow-up imaging for at least 1 year, and false-negative (FN), if there was an arterially enhancing focus with wash-out at or surrounding TA site on subsequent follow-up imaging.

RESULTS

Study population included 56 tumours in 54 patients, 11 women, 43 men; mean age 71 years. Two patients had TA of two different hepatocellular carcinomas. Thirty-six examinations were for hepatic TA and twenty for renal TA. Lesion sizes ranged from 1 cm to 7 cm (mean 3.1 ± 1.2). Mean diameter of 7 recurrences was 13.8 mm. Overall FN rate was 12.5% (7/56). Corresponding numbers were 0% (0/20) for renal TA and 19.4% (7/36) for hepatic TA. Overall NPV of CEUS was 87.5% (49/56) (confidence interval [CI]: 78.8%-96.2%). NPV for renal TA was 100% (20/20) (CI: 100%-100%) and for hepatic TA 81.5% (29/36) (CI: 67.6 %-93.5%).

CONCLUSION

In this cohort, CEUS showed high NPV for exclusion of LTP at renal TA sites. NPV for hepatic TA sites was high but lower than renal TA.

3-D Contrast-Enhanced Ultrasound Fusion Imaging: A New Technique to Evaluate the Ablative Margin of Radiofrequency Ablation for Hepatocellular Carcinoma

To investigate the feasibility of assessing the ablative margin (AM) of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) with 3-D contrast-enhanced ultrasound fusion imaging (3-DCEUS-FI), pre- and post-RFA 3-DCEUS images of 84 patients with HCC were fused for two radiologists to independently assess the AMs. The success rate, duration and influencing factors for registration; inter-observer agreement for AM classification; and local tumor progression (LTP) rate were evaluated. The success rate of the automatic registration (AR), which was completed within 4-12 s, was 57.1% (48/84). The duration and success rate of the interactive registration (IR) were 4.2 ± 1.8 min and 91.7% (77/84) for radiologist A and 4.8 ± 2.1 min and 91.7% (77/84) for radiologist B, respectively. The multivariate analysis demonstrated that the pre-RFA image quality, number of vessels (≥3 mm) and presence of acoustic shadow were independent factors for AR (p < 0.05), while the number of vessels was an independent factor for IR (p = 0.001). The agreement between observers was excellent (kappa = 0.914). LTP rate was significantly higher for AMs <5 mm than for AMs ≥5 mm (p = 0.024). Quantitatively evaluating the AM immediately after RFA for HCC with 3-DCEUS-FI was feasible.

Contrast-enhanced ultrasonography used for post-treatment responses evaluation of radiofrequency ablations for hepatocellular carcinoma: a meta-analysis

OBJECTIVE

This meta-analysis aims to analyze the usefulness of contrast-enhanced ultrasonography (CEUS) for post-treatment responses evaluation of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) management.

METHODS

Literature retrieval in three databases PubMed, Embase and Cochrane Library was conducted up to September 2015, with pre-defined criteria. The technical success rate, local tumour recurrence and local tumour progression were the measurement indexes. Cochran's Q test and I(2) were used for heterogeneity detection. Subgroup analyses were performed for complete ablation rate stratified by study designs, contrast agents and post-operative testing time points. Statistical analyses were conducted using Stata(®) 12.0 software (Stata Corporation, College Station, TX).

RESULTS

12 studies consisting of 772 patients were included in this study. The CEUS-evaluated success rate of RFA for HCCs was 91%. The proportion of ablative margin <5 mm was 53%. The local tumour recurrence rate and local tumour progression rate were 4% and 8%, respectively. Subgroup analysis indicated that the CEUS-assessed technical success rate with Sonazoid™ (Daiichi-Sankyo, Tokyo, Japan) as the contrast agent was higher (95%) than those with other agents [SH U 508A (Schering AG, Berlin, Germany) 86%; SonoVue (Bracco SpA, Milan, Italy) 87%]. The success rate assessed within 24 h (94%) after treatment was higher than longer time (1-3 days 86%; 1 month 91%).

CONCLUSION

The meta-analysis showed that the CEUS-evaluated success rate of RFA for HCCs was 91%. The local tumour recurrence rate and local tumour progression rate were 4% and 8%, respectively.

ADVANCES IN KNOWLEDGE

Using meta-analysis, the study provided more reliable assessment of usefulness of CEUS, which could provide guidelines for HCC treatment.

Imaging evaluation of residual cancer after radiofrequency ablation of hepatocellular carcinoma

Primary liver cancer is one of the most common malignant tumors in the world, and only a few patients have the chance of surgical resection. Radiofrequency ablation (RFA) is a good treatment for patients with unresectable liver cancer. The existence of residual cancer after radiofrequency ablation has a direct impact on the prognosis of patients, so it is important to accurately determine whether there is residual cancer after RFA treatment in order to reduce the local recurrence and prolong the survival time of patients. In this paper, we discuss the evaluation of residual cancer after radiofrequency ablation of hepatocellular carcinoma by ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), digital subtraction angiography (DSA) and nuclear medicine modalities.

Usefulness of contrast enhanced ultrasound in monitoring therapeutic response after hepatocellular carcinoma treatment

In the last years, the development in the oncology field has been huge and rapid. In particular, the evaluation of response to anti-tumour treatments has been being object of intense research, producing significant changes. Response assessment after therapy in solid neoplasias has always used radiological imaging techniques, with tumour size reduction representing a presumed therapeutic efficacy. However, with the introduction of anti-angiogenetic drugs the evaluation of tumour size has become unsuitable because some tumours, under treatment, show only tumour perfusion changes rather than lesion shrinkage. Between different imaging techniques with contrast-enhancement, contrast-enhanced ultrasound (CEUS) and, in particular, dynamic CEUS have arisen as a promising and non-invasive device for monitoring cancer treatments. Moreover, the introduction of perfusion software has even more refined the technique since it is able to provide quantitative parameters related to blood flow and blood volume that can be associated with tumour response and clinical outcome such as the progression free survival and the overall survival. Here, we give an overview of the current status of CEUS in monitoring hepatocellular carcinoma response to different kind of treatments.

Integrating contrast-enhanced sonography in the follow-up algorithm of hepatocellular carcinoma treated with radiofrequency ablation: single cancer center experience

BACKGROUND

Hepatocellular carcinoma (HCC) patients treated with percutaneous ablation require close follow-up for early detecting and treating tumor recurrence.

PURPOSE

To illustrate our single-center prospective experience on using contrast-enhanced ultrasound (CEUS) as a follow-up tool alternated with computed tomography (CT).

MATERIAL AND METHODS

In a 7-year period 588 patients with one to three HCCs were treated with radiofrequency ablation (alone or combined with ethanol injection). Patients with completely ablated tumors at 1-month CT scan were followed up serially, using alternated CEUS (one microbubbles injection per lobe) and CT every 3 months for 2 years. In few cases magnetic resonance imaging (MRI) was employed instead of or in addition to CT. The following patterns of recurrence were considered: A, enhancing tissue within the lesion; B, enhancing tissue adherent to the lesion; C, enhancing tissue within the same liver segment of the treated nodule; and D, enhancing tissue within a different segment. Patients with positive CEUS underwent confirmatory CT/MRI (standard reference).

RESULTS

Median follow-up was 19 months. There were 221 recurrences. Three pattern A recurrences (2 detected by CEUS and 1 by CT), 86 pattern B recurrences (44 detected by CEUS and 42 by CT), 70 pattern C recurrences (32 detected by CEUS and 38 by CT), and 62 pattern D recurrences (23 detected by CEUS and 39 by CT). CT detected additional nodules in 16/101 patients with positive CEUS.

CONCLUSION

CEUS follow-up of HCC patients after ablation is feasible. Since 72% recurrences develop in the same segment of the necrotic nodule, CEUS proves to be effective despite the minor visualization of the entire liver during the arterial phase when compared to CT and MRI. Including CEUS in patient follow-up may reduce the number of CT and MRI examinations.

Acoustic radiation force impulse elastography for efficacy evaluation after hepatocellular carcinoma radiofrequency ablation: a comparative study with contrast-enhanced ultrasound

Aim. To explore acoustic radiation force impulse (ARFI) elastography in assessing residual tumors of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA). Materials and Methods. There were 83 HCC lesions among 72 patients. All patients were examined with ARFI, contrast enhanced ultrasound (CEUS), and CT or MRI. Tumor brightness on virtual touch tissue imaging (VTI) and shear wave velocity (SWV) were assessed before and approximately one month after RFA. Results. There were 14 residual tumors after RFA. VTI showed that all the tumors were darker after RFA. VTI was not able to distinguish the ablated lesions and the residual tumors. 13 residual tumor lesions were detected by CEUS. All completely ablated nodules had SWV demonstration of x.xx., while with those residual nodules, 6 tumors had x.xx measurement and 8 tumors had measurable SWV. nine lesions with residual tumors occurred in cirrhosis subjects and 5 lesions with residual tumors occurred in fibrosis subjects; there was no residual tumor in the normal liver subjects. Conclusion. VTI technique cannot demonstrate residual tumor post RFA. While SWV measurement of less than x.xx is likely associated with residual tumors, measurement of less than x.xx cannot exclude residual tumors. Liver cirrhosis is associated with decreased chance of a complete ablation.

Management of hepatocellular carcinoma: The role of contrast-enhanced ultrasound

Hepatocellular carcinoma (HCC) is the sixth most common neoplasm and the third cause of cancer death worldwide. Contrast enhanced ultrasound (CEUS) has been applied for more than ten years and plays increasingly important roles in the management of HCC. On the basis of the Guideline and Good Clinical Practice Recommendations for CEUS in the liver-update 2012 and related literature about the management of HCC, we summarize the main roles and applications of CEUS in the management of HCC, including HCC surveillance, diagnosis, CEUS-guided treatment, treatment response evaluation and follow-up. The diagnostic algorithm for HCC is also suggested. Meanwhile, the comparisons between CEUS and contrast enhanced computed tomography/magnetic resonance imaging (CECT/CEMRI) in these areas are made. Although CEUS is subject to the same limitation as ordinary US and is inferior to CECT/CEMRI in some aspects, CEUS has proved to be of great value in the management of HCC with inherent advantages, such as sufficient high safety profile making it suitable for patients with renal failure or allergic to iodine, absence of radiation, easy reproducibility and high temporal resolution. The tremendous application of CEUS to the diagnosis and treatment of HCC provides more opportunities for patients with HCC diagnosed at different stages.

Hepatocellular carcinoma after ablation: The imaging follow-up scheme

Percutaneous ablation using thermal or chemical methods has been widely used in the treatment of hepatocellular carcinoma (HCC). Nowadays, contrast-enhanced imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), and contrast-enhanced ultrasound (CEUS) are widely used to evaluate local treatment response after ablation therapies. CEUS is gaining increasing attention due to its characteristics including real-time scanning, easy performance, lack of radiation, wide availability, and lack of allergy reactions. Several studies have documented that CEUS is comparable to CT or MRI in evaluating local treatment efficacy within 1 mo of treatment. However, little information is available regarding the role of CEUS in the follow-up assessment after first successful ablation treatment. Zheng et al found that in comparison with contrast-enhanced computed tomography (CECT), the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of CEUS in detecting local tumor progression (LTP) were 67.5%, 97.4%, 81.8%, 94.4% and 92.3%, respectively, and were 77.7%, 92.0%, 92.4%, 76.7% and 84.0%, respectively for the detection of new intrahepatic recurrence. They concluded that the sensitivity of CEUS in detecting LTP and new intrahepatic recurrence after ablation is relatively low in comparison with CECT, and CEUS cannot replace CECT in the follow-up assessment after percutaneous ablation for HCC. These results are meaningful and instructive, and indicated that in the follow-up period, the use of CEUS alone is not sufficient. In this commentary, we discuss the discordance between CT and CEUS, as well as the underlying mechanisms involved. We propose the combined use of CT and CEUS which will reduce false positive and negative results in both modalities. We also discuss future issues, such as an evidence-based ideal imaging follow-up scheme, and a cost-effectiveness analysis of this imaging follow-up scheme.