Planning ultrasound for percutaneous radiofrequency ablation to treat small (≤ 3 cm) hepatocellular carcinomas detected on computed tomography or magnetic resonance imaging: a multicenter prospective study to assess factors affecting ultrasound visibility

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.

Ultrasound and x-ray imageable poloxamer-based hydrogel for loco-regional therapy delivery in the liver

Intratumoral injections have the potential for enhanced cancer treatment efficacy while reducing costs and systemic exposure. However, intratumoral drug injections can result in substantial off-target leakage and are invisible under standard imaging modalities like ultrasound (US) and x-ray. A thermosensitive poloxamer-based gel for drug delivery was developed that is visible using x-ray imaging (computed tomography (CT), cone beam CT, fluoroscopy), as well as using US by means of integrating perfluorobutane-filled microbubbles (MBs). MBs content was optimized using tissue mimicking phantoms and ex vivo bovine livers. Gel formulations less than 1% MBs provided gel depositions that were clearly identifiable on US and distinguishable from tissue background and with minimal acoustic artifacts. The cross-sectional areas of gel depositions obtained with US and CT imaging were similar in studies using ex vivo bovine liver and postmortem in situ swine liver. The gel formulation enhanced multimodal image-guided navigation, enabling fusion of ultrasound and x-ray/CT imaging, which may enhance targeting, definition of spatial delivery, and overlap of tumor and gel. Although speculative, such a paradigm for intratumoral drug delivery might streamline clinical workflows, reduce radiation exposure by reliance on US, and boost the precision and accuracy of drug delivery targeting during procedures. Imageable gels may also provide enhanced temporal and spatial control of intratumoral conformal drug delivery.

Contrast-enhanced ultrasonography-CT/MRI fusion guidance for percutaneous ablation of inconspicuous, small liver tumors: improving feasibility and therapeutic outcome

BACKGROUND

Percutaneous radiofrequency ablation (RFA) is pivotal for treating small malignant liver tumors, but tumors often remain inconspicuous on B-mode ultrasound (US). This study evaluates the potential of CEUS-CT/MRI fusion imaging (FI) to improve tumor visibility and the associated RFA outcomes for small (≤ 3 cm) malignant liver tumors that were inconspicuous on US.

METHODS

Between January 2019 and April 2021, a prospective study enrolled 248 patients with liver malignancies (≤ 3 cm) that were poorly visible on B-mode US. Tumor visibility and ablation feasibility were assessed using B-mode US, US-CT/MRI FI, and CEUS-CT/MRI FI, and graded on a 4-point scale. CEUS was employed post-registration of US and CT/MRI images, utilizing either SonoVue or Sonazoid. Comparisons between US-based and CEUS-based fusion visibility and feasibility scores were undertaken using the Friedman test. Moreover, rates of technical success, technique efficacy, local tumor progression (LTP), and major complications were assessed.

RESULTS

The cohort included 223 hepatocellular carcinomas (HCCs) (89.9%) and 23 metastases (9.3%), with an average tumor size of 1.6 cm. CEUS-CT/MRI FI demonstrated a significant advantage in tumor visibility (3.4 ± 0.7 vs. 1.9 ± 0.6, P < 0.001) and technical feasibility (3.6 ± 0.6 vs. 2.9 ± 0.8, P < 0.001) compared to US-FI. In 85.5% of patients, CEUS addition to US-FI ameliorated tumor visibility. Technical success was achieved in 99.6% of cases. No severe complications were reported. One and two-year post CEUS-CT/MRI FI-guided RFA estimates for LTP were 9.3% and 10.9%, respectively.

CONCLUSIONS

CEUS-CT/MRI FI significantly improves the visualization of tumors not discernible on B-mode US, thus augmenting percutaneous RFA success and delivering improved therapeutic outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05445973. Registered 17 June 2022 - Retrospectively registered, http://clinicaltrials.gov/study/NCT05445973?id=NCT05445973&rank=1 .

Technical and Clinical Outcomes of Laparoscopic-Laparotomic Hepatocellular Carcinoma Thermal Ablation with Microwave Technology: Case Series and Review of Literature

PURPOSE

To evaluate technical and clinical outcomes of intraoperative (laparoscopic/laparotomic) microwave ablation on HCC.

MATERIALS AND METHODS

This is a retrospective single-center study evaluating consecutive patients treated for very early/early-stage HCC with intraoperative microwave ablation from 1 July 2017 to 30 June 2023. In these patients, a percutaneous US-guided approach was excluded due to the nodule's suboptimal visibility or harmful location and liver resection for a deep position or adherences. Data about the clinical stage, surgical approach, liver pathology and nodules characteristics, technical success, complications, and follow-up were collected. Technical success was intended as the absence of locoregional persistence at follow-up CT/MRI controls.

RESULTS

A total of 36 cirrhotic patients (M:F = 30:6, median age 67 years) were enrolled; 18/36 (50%) had a single nodule, 13/36 (36%) had two, 4/36 had three (11%), and 1/36 had four (3%). Among the patients, 24 (67%) were treated with laparoscopy, and 12/36 (33%) with a laparotomic approach. Sixty HCCs of 16.5 mm (6-50 mm) were treated for 7 min (2-30 min) with 100 W of power. A total of 55 nodules (92%) were treated successfully and showed no residual enhancement at the first postoperative follow-up; the other 5/60 (8%) underwent chemo/radioembolization. There was one complication (3%): a biliary fistula treated with percutaneous drainage and glue embolization. The average hospital stay was 3.5 days (1-51 days), and patients were followed up on average for 238 days (13-1792 days). During follow-up, 5/36 patients (14%) underwent liver transplantation, 1/36 (2%) died during hospitalization and 1 after discharge.

CONCLUSIONS

Laparoscopic/laparotomic intraoperative HCC MW ablation is feasible in patients unsuitable for percutaneous approach or hepatic resection, with rare complications and with good technical and clinical outcomes.

3D US-CT/MRI registration for percutaneous focal liver tumor ablations

PURPOSE

US-guided percutaneous focal liver tumor ablations have been considered promising curative treatment techniques. To address cases with invisible or poorly visible tumors, registration of 3D US with CT or MRI is a critical step. By taking advantage of deep learning techniques to efficiently detect representative features in both modalities, we aim to develop a 3D US-CT/MRI registration approach for liver tumor ablations.

METHODS

Facilitated by our nnUNet-based 3D US vessel segmentation approach, we propose a coarse-to-fine 3D US-CT/MRI image registration pipeline based on the liver vessel surface and centerlines. Then, phantom, healthy volunteer and patient studies are performed to demonstrate the effectiveness of our proposed registration approach.

RESULTS

Our nnUNet-based vessel segmentation model achieved a Dice score of 0.69. In healthy volunteer study, 11 out of 12 3D US-MRI image pairs were successfully registered with an overall centerline distance of 4.03±2.68 mm. Two patient cases achieved target registration errors (TRE) of 4.16 mm and 5.22 mm.

CONCLUSION

We proposed a coarse-to-fine 3D US-CT/MRI registration pipeline based on nnUNet vessel segmentation models. Experiments based on healthy volunteers and patient trials demonstrated the effectiveness of our registration workflow. Our code and example data are publicly available in this r epository.

Outcomes of laparoscopic radiofrequency ablation versus percutaneous radiofrequency ablation for hepatocellular carcinoma

BACKGROUND

Few studies have compared the therapeutic outcomes in patients with HCC who underwent laparoscopic radiofrequency ablation (LRFA) versus percutaneous radiofrequency ablation (PRFA) for hepatocellular carcinoma (HCC). Therefore, this study compared the recurrence and survival outcomes of the two RFA methods in patients with HCC.

METHODS

Recurrence and overall survival outcomes were evaluated in 307 patients who underwent LRFA (n = 151) or PRFA (n = 156) as a treatment method for de novo HCC. Inverse probability of treatment weighting (IPTW) analysis was performed to reduce the impact of treatment selection bias.

RESULTS

There were no significant differences in major baseline characteristics between the LRFA and PRFA groups. However, the proportion of cirrhotic patients was higher in the LRFA group, whereas the LRFA group had more tumors and a more advanced tumor-node-metastasis stage. Moreover, the mean tumor size was significantly larger in the LRFA group than in the PRFA group. In a multivariate analysis, serum albumin level, more than three tumors, and the RFA method were identified as significant predictors of recurrence-free survival. Moreover, for the overall survival of HCC patients, serum albumin levels, days of hospital stay during RFA, and the RFA method were independent predictors. In the IPTW-adjusted analysis, the LRFA group showed significantly higher recurrence-free survival and overall survival.

CONCLUSIONS

Our study revealed that compared with PRFA, LRFA was associated with longer recurrence-free survival and favorable overall survival in patients with HCC. Therefore, LRFA should be considered the primary therapy in patients with HCC eligible for RFA.

An alternative second performance of contrast-enhanced ultrasound for large focal liver lesion is necessary for sufficient characterization

Focal liver lesions (FFLs) evaluated using contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) may have the same or similar findings or substantial discrepant findings. Such phenomenon can be found in two performances of CEUS that the second performance of CEUS conducted shortly following the initial performance of CEUS. Discrepancy of two performances of CEUS for FFLs occurring in the same patient at a short internal has not been well addressed, which raises challenge for CEUS for the evaluation of FFLs. In this case study, such phenomenon is illustrated and implication is obtained.

Selecting the Best Approach for the Treatment of Multiple Non-Metastatic Hepatocellular Carcinoma

According to the Barcelona Clinic Liver Cancer (BCLC) staging system, the optimal strategy for patients with multiple HCC within the Milan Criteria is liver transplantation (LT). However, LT cannot be offered to all the patients due to organ shortages and long waiting lists, as well as because of the advanced disease carrying a high risk of poor outcomes. For early stages, liver resection (LR) or thermal ablation (TA) can be proposed, while trans-arterial chemoembolization (TACE) still remains the treatment of choice for intermediate stages (BCLC-B). Asian guidelines and the National Comprehensive Cancer Network suggest LR for resectable multinodular HCCs, even beyond Milan criteria. In this scenario, a growing body of evidence shows better outcomes after surgical resection when compared with TACE. Trans-arterial radioembolization (TARE) and stereotaxic body radiation therapy (SBRT) can also play an important role in this setting. Furthermore, the role of minimally invasive liver surgery (MILS) specifically for patients with multiple HCC is still not clear. This review aims to summarize current knowledge about the best therapeutical strategy for multiple HCC while focusing on the role of minimally invasive surgery and on the most attractive future perspectives.

Combined transarterial chemoembolization and radiofrequency ablation for subphrenic versus nonsubphrenic hepatocellular carcinoma: a propensity score matched study

PURPOSE

To compare therapeutic outcomes of combined transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) treatment for small hepatocellular carcinoma (HCC) in subphrenic versus nonsubphrenic locations by propensity score matching.

METHODS

This retrospective study included 293 patients with single HCC (≤ 3 cm) ineligible for ultrasound-guided RFA who received iodized oil TACE and subsequent RFA between June 2010 and January 2017. The patients were divided into two groups according to the tumor location: subphrenic (n = 99) and nonsubphrenic (n = 194). Subphrenic HCC was defined as a tumor abutting the diaphragm. Local tumor progression (LTP) and overall survival (OS) rates were compared by propensity score matching. Procedure-related complications were also assessed.

RESULTS

Matching yielded 93 matched pairs of patients. In the matched cohorts, cumulative 1-, 3-, and 5-year LTP rates were 5.4%, 12.1%, and 12.1% in the subphrenic group and 1.1%, 7.5%, and 8.6% in the nonsubphrenic group, respectively, with no significant differences (p = 0.278). Corresponding OS rates were 100%, 80.2%, and 71.3% in the subphrenic group and 97.9%, 88.1%, and 75.6% in the nonsubphrenic group, respectively, with no significant differences (p = 0.308). The subphrenic location was not a significant risk factor for LTP and OS in multivariate analysis. There were no significant differences in complication rates between the two groups (p > 0.05).

CONCLUSION

The therapeutic outcomes of combined TACE and RFA for small subphrenic HCC were similar to those for nonsubphrenic HCC. The combination therapy seems to be an effective and safe method in treating small subphrenic HCC.

Assessing the value of volume navigation during ultrasound-guided radiofrequency- and microwave-ablations of liver lesions

Purpose

The goal of our study was to determine the influence of ultrasound (US)-coupled volume navigation on the use of computed tomography (CT) during minimally-invasive radiofrequency and microwave ablation procedures of liver lesions.

Method

Twenty-five patients with 40 liver lesions of different histological origin were retrospectively analysed. Lesions were ablated following standard protocol, using 1) conventional US-guidance, 2) manual registered volume navigation (mVNav), 3) automatic registered (aVNav) or 4) CT-guidance. In case of ultrasonographically inconspicuous lesions, conventional US-guidance was abandoned and mVNav was used. If mVNav was also unsuccessful, the procedure was either continued with aVNav or CT-guidance. The number, size and location of the lesions targeted using the different approaches were documented.

Results

Of the 40 lesions, sixteen (40.0 %) could be targeted with conventional US-guidance only, sixteen (40.0 %) with mVNav, three (7.5 %) with aVNav and five (12.5 %) only through the use of CT-guidance. Of the three alternatives (mVNav, aVNav and CT only) the mean size of the lesions targeted using mVNav (9.1 ± 4.6 mm) was significantly smaller from those targeted using US-guidance only (20.4 ± 9.4 mm; p < 0.001). The location of the lesions did not influence the selection of the modality used to guide the ablation.

Conclusions

In our cohort, mVNav allowed the ablation procedure to become less dependent on the use of CT. mVNav supported the ablation of lesions smaller than those that could be ablated with US only and doubled the application of minimally-invasive US-guided ablations.

Stereotactic Thermal Ablation of Liver Tumors: 3D Planning, Multiple Needle Approach, and Intraprocedural Image Fusion Are the Key to Success-A Narrative Review

Thermal ablation is an emerging, potentially curative approach in treating primary and metastatic liver cancer. Different technologies are available, with radiofrequency ablation (RFA) and microwave ablation (MWA) being the most widely used. Regardless of the technique, destruction of the entire tumor, including an adequate safety margin, is key. In conventional single-probe US- or CT-guided thermal ablation, the creation of such large necrosis zones is often hampered by technical limitations, especially for large tumors (i.e., >2-3 cm). These limitations have been overcome by stereotactic RFA (SRFA): a multiple needle approach with 3D treatment planning and precise stereotactic needle placement combined with intraprocedural image fusion of pre- and post-interventional CT scans for verification of treatment success. With these sophisticated tools and advanced techniques, the spectrum of locally curable liver malignancies can be dramatically increased. Thus, we strongly believe that stereotactic thermal ablation can become a cornerstone in the treatment of liver malignancies, as it offers all the benefits of a minimally invasive method while providing oncological outcomes comparable to surgery. This article provides an overview of current stereotactic techniques for thermal ablation, summarizes the available clinical evidence for this approach, and discusses its advantages.

Percutaneous radiofrequency ablation for hepatic metastasis of colorectal cancer: assessment of tumor visibility and the feasibility of the procedure with planning ultrasonography

Purpose

The aim of this study was to assess the incidence and causes of percutaneous radiofrequency ablation (RFA) infeasibility in cases of metastatic colorectal cancer and to evaluate factors affecting the invisibility of the tumor on planning ultrasonography (US).

Methods

This study screened 386 patients who underwent planning US using fusion imaging and/or contrast-enhanced US for percutaneous RFA for suspected metastatic colorectal cancer between January 2013 and December 2020, from whom 136 patients with a single hepatic metastasis from colorectal cancer measuring <3 cm were included. The factors related to the infeasibility of percutaneous RFA were investigated. Univariate and multivariate analyses were performed to assess the factors associated with tumor invisibility on planning US.

Results

Among the 136 patients, percutaneous RFA was considered infeasible in 24.3% (33/136) due to a high risk of the heat-sink effect caused by the abutment of a large vessel (n=12), an inconspicuous tumor on planning US (n=11), a high risk of collateral thermal damage to an adjacent organ (n=8), and the absence of a safe electrode path (n=2). In univariate and multivariate analyses, tumor size was a statistically significant factor affecting invisibility on planning US (P=0.003 and P=0.018, respectively).

Conclusion

Percutaneous RFA was infeasible in approximately one-fourth of patients with metastatic colorectal cancer. The reason for the infeasibility was mainly an unfavorable tumor location and invisibility on planning US. Small tumor size was the sole significant factor affecting the invisibility of hepatic metastases on planning US.

Additional Diagnostic Value of Fusion Imaging of CEUS and First CEUS of Invisible Hepatic Lesions ≤2 cm

OBJECTIVE

To explore the clinical value of image fusion of contrast-enhanced ultrasonography (CEUS) and contrast-enhanced computed tomography (CECT) in the diagnosis of invisible lesions with a size ≤2 cm on conventional ultrasound imaging, and compare it with the clinical value of "first CEUS" .

METHODS

A total of 132 patients with 147 lesions with abnormal blood supply with a size ≤2 cm on CECT were included in this study. "first CEUS" was performed for these lesions. Then "fusion CEUS," that is, CEUS administered after fusion of US and CECT images, was carried out. The detection rates of the "first CEUS" and "fusion CEUS" were compared. How "fusion CEUS" corrects the misdiagnosis of liver lesions on CECT was analyzed.

RESULTS

One hundred nine lesions considered as HCC and 38 lesions considered as benign lesions on CECT were included. The detection rates for the lesions of "first CEUS" and "fusion CEUS" were 71.4% and 96.6%, respectively (P < 0.001). Among the 147 lesions, 68 were with a diameter ≤ 1 cm. The detection rate of "first CEUS" and "fusion CEUS" were 55.9% and 95.6%, respectively (P < 0.001) for the lesions with a size ≤1 cm. "Fusion CEUS" and "first CEUS" corrected the misdiagnosis in 2 lesions on CECT.

CONCLUSION

The "first CEUS" and "fusion CEUS" can improve the lesion conspicuity. Compared with "first CEUS," "fusion CEUS" has a higher diagnostic ability and hence can detect most of the invisible lesions on the former.

Uni-, Bi- or Trifocal Hepatocellular Carcinoma in Western Patients: Recurrence and Survival after Percutaneous Thermal Ablation

Multifocality is usually reported as a pejorative factor after percutaneous thermal ablation (PTA) of HCC but little is known in Western series. Recurrence and survival were extracted from a prospective database of all patients who underwent PTA for ≤3 cm HCC. From January 2015 to April 2020, we analyzed 281 patients with unifocal (n = 216), bifocal (n = 46) and trifocal (n = 16) HCC. PTA of bi- and trifocal HCC resulted in a high risk of very early (<6 months) distant recurrence (38.8% and 50%, respectively). Median RFS was 23.3 months (95% CI:18.6-30.4), 7.7 months (95% CI:5.1-11.43, p = 0.002) and 5.2 months (95% CI:3-12.3, p = 0.015), respectively, for uni-, bi- and trifocal HCC groups. In a multivariate analysis, both bifocal (HR = 2.46, p < 0.001) and trifocal (HR = 2.70, p = 0.021) vs. unifocal HCC independently predicted shorter RFS. Median OS in trifocal HCC group was 30.3 months (95 CI:19.3-not reached). Trifocal vs. unifocal HCC independently predicted shorter OS (HR = 3.30, p = 0.008), whereas bifocal vs. unifocal HCC did not (p = 0.27). Naïve patient (HR = 0.42, p = 0.007), AFP > 100 ng/mL (HR = 3.03, p = 0.008), MELD > 9 (HR = 2.84, p = 0.001) and steatotic HCC (HR = 0.12, p = 0.038) were also independent predictors of OS. In conclusion, multifocal HCCs in a Western population have a dramatically increased risk of distant recurrence. OS after PTA of trifocal HCC is significantly below what was expected after a curative treatment.

The semi-erect position for better visualization of subphrenic hepatocellular carcinoma during ultrasonography examinations

PURPOSE

This study investigated which body position is more useful for visualizing subphrenic hepatocellular carcinomas (HCCs) during ultrasonography (US) examinations.

METHODS

This prospective study was approved by the institutional review board and written informed consent was obtained from all patients. Twenty consecutive patients with a single subphrenic HCC (treatment-naïve, 1 to 3 cm) underwent a US examination for planning radiofrequency ablation. The examinations were done by one of three radiologists and the patients were examined in four different body positions-supine, right posterior oblique (RPO), left lateral decubitus (LLD), and semi-erect-by being positioned on a tilted table. The visibility of the index tumor was prospectively assessed using a 4-point scale. Needle insertion was considered to be technically feasible if the visibility score was lower than 2. The visibility score and technical feasibility were compared using the Wilcoxon signed rank test and the McNemar test, respectively, for pairwise comparisons between different body positions.

RESULTS

The visibility score was significantly lower in the semi-erect position (median, 2; interquartile range, 1 to 2.75) than in the supine (3, 2 to 4), RPO (3, 2 to 4), and LLD (4, 3.25 to 4) positions (P=0.007, P=0.005, and P=0.001, respectively). The technical feasibility of needle insertion was also significantly higher in the semi-erect position (75%, 15/20) than in the supine (45%, 9/45), RPO (35%, 7/20), and LLD (20%, 4/20) positions (P=0.031, P=0.021, and P=0.001, respectively).

CONCLUSION

The semi-erect position is more useful for the visualization of subphrenic HCCs than the supine, RPO, or LLD positions.

Towards quantitative and intuitive percutaneous tumor puncture via augmented virtual reality

In recent years, the radiofrequency ablation (RFA) therapy has become a widely accepted minimal invasive treatment for liver tumor patients. However, it is challenging for doctors to precisely and efficiently perform the percutaneous tumor punctures under free-breathing conditions. This is because the traditional RFA is based on the 2D CT Image information, the missing spatial and dynamic information is dependent on surgeons' experience. This paper presents a novel quantitative and intuitive surgical navigation modality for percutaneous respiratory tumor puncture via augmented virtual reality, which is to achieve the augmented visualization of the pre-operative virtual planning information precisely being overlaid on intra-operative surgical scenario. In the pre-operation stage, we first combine the signed distance field of feasible structures (like liver and tumor) where the puncture path can go through and unfeasible structures (like large vessels and ribs) where the needle is not allowed to go through to quantitatively generate the 3D feasible region for percutaneous puncture. Then we design three constraints according to the RFA specialists consensus to automatically determine the optimal puncture trajectory. In the intra-operative stage, we first propose a virtual-real alignment method to precisely superimpose the virtual information on surgical scenario. Then, a user-friendly collaborative holographic interface is designed for real-time 3D respiratory tumor puncture navigation, which can effectively assist surgeons fast and accurately locating the target step-by step. The validation of our system is performed on static abdominal phantom and in vivo beagle dogs with artificial lesion. Experimental results demonstrate that the accuracy of the proposed planning strategy is better than the manual planning sketched by experienced doctors. Besides, the proposed holographic navigation modality can effectively reduce the needle adjustment for precise puncture as well. Our system shows its clinical feasibility to provide the quantitative planning of optimal needle path and intuitive in situ holographic navigation for percutaneous tumor ablation without surgeons' experience-dependence and reduce the times of needle adjustment. The proposed augmented virtual reality navigation system can effectively improve the precision and reliability in percutaneous tumor ablation and has the potential to be used for other surgical navigation tasks.

Advanced Techniques in the Percutaneous Ablation of Liver Tumours

Percutaneous ablation is an accepted treatment modality for primary hepatocellular carcinoma (HCC) and liver metastases. The goal of curative ablation is to cause the necrosis of all tumour cells with an adequate margin, akin to surgical resection, while minimising local damage to non-target tissue. Aside from the ablative modality, the proceduralist must decide the most appropriate imaging modality for visualising the tumour and monitoring the ablation zone. The proceduralist may also employ protective measures to minimise injury to non-target organs. This review article discusses the important considerations an interventionalist needs to consider when performing the percutaneous ablation of liver tumours. It covers the different ablative modalities, image guidance, and protective techniques, with an emphasis on new and advanced ablative modalities and adjunctive techniques to optimise results and achieve satisfactory ablation margins.

Accuracy of contrast-enhanced ultrasound liver imaging reporting and data system: a systematic review and meta-analysis

BACKGROUND AND AIM

After the introduction of the contrast-enhanced ultrasound Liver Imaging Reporting and Data System (CEUS LI-RADS), several studies have reported on its performance, but the reported data vary considerably. Therefore, we performed a systematic review and meta-analysis to determine the diagnostic performance of CEUS LI-RADS in patients at risk for hepatocellular carcinoma (HCC) and investigate the causes of study heterogeneity.

METHODS

Original studies published until May 30, 2020, investigating the diagnostic performance of CEUS LI-RADS were identified in the MEDLINE, EMBASE, and Cochrane library databases. Study quality was assessed using the QUADAS-2 tool. Meta-analytic summary sensitivity and specificity for the diagnosis of HCC were calculated using a bivariate random-effects model. Meta-regression analysis was performed to explore the causes of study heterogeneity.

RESULTS

Of the 105 articles screened, eight studies were finally analyzed (5428 hepatic observations). The summary sensitivity and specificity of CEUS LI-RADS category 5 (LR-5) for diagnosing HCC were 73% [95% confidence interval (CI) 65-79%; I² = 93%] and 95% (95% CI 91-97%; I² = 89%), respectively. Substantial study heterogeneity was noted in both sensitivity and specificity. Study heterogeneity was significantly associated with the proportion of cases of HCC and the type of reference standard (p ≤ 0.05).

CONCLUSION

CEUS LI-RADS had high pooled specificity for diagnosing HCC but suboptimal pooled sensitivity. Substantial study heterogeneity was found, which was significantly associated with the proportion of cases of HCC and the type of reference standard.

Manual versus automated image fusion of real-time ultrasonography and MR/CT images for radiofrequency ablation of hepatic tumors: results of a randomized prospective trial (NCT02705118)

PURPOSE

This study compared the technical parameters and clinical outcomes of manual and automatic image fusion techniques of ultrasonography and magnetic resonance imaging/computed tomography for radiofrequency ablation (RFA) of hepatic tumors.

METHODS

Seventy consecutive patients (male:female=47:23, 67.1±10.9 years old) who underwent RFA for hepatic tumors were prospectively enrolled and randomly assigned to the manual or automatic registration group. Two operators performed RFA with one of two imaging fusion techniques. Technical parameters (the registration error, time required for image registration, number of point registrations) and clinical outcomes (technical success, technical effectiveness, local tumor progression [LTP]-free survival, and progression-free survival [PFS]) were compared.

RESULTS

The automatic group contained 35 patients with hepatocellular carcinoma, while the manual group included 34 hepatocellular carcinoma patients and a patient with colon cancer liver metastasis. The registration error, time required for registration, and number of point registrations were 5.7±4.3 mm, 147.8±78.2 seconds, and 3.26±1.20 in the automatic group, and 6.3±5.0 mm, 150.3±89.7 seconds, and 3.20±1.13 in the manual group, respectively. The technical success and effectiveness rates were both 97.1% in the automatic group and both 100.0% in the manual group. The above differences were not significant. The LTP-free survival and PFS (28.3 and 21.2 months in the automatic group, and 29.0 and 24.9 months in the manual group, respectively) showed no significant between-group differences during a median 20.1-month follow-up period.

CONCLUSION

The technical parameters and clinical outcomes of automatic image fusion were not significantly different from those of manual image fusion for RFA of hepatic tumors.

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

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

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

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

Multiple imaging modality-guided radiofrequency ablation combined with transarterial chemoembolization for hepatocellular carcinoma in special locations

PURPOSE

We aimed to evaluate the safety and effectiveness of radiofrequency ablation (RFA) combined with transarterial chemoembolization (TACE) guided by multiple imaging modalities for hepatocellular carcinomas (HCCs) in special (i.e., high-risk or unfavorable) locations compared with those in conventional locations.

METHODS

A total of 122 HCC patients were enrolled, including 85 patients (69.7%) with HCC in conventional locations and 37 (30.3%) with HCC in special locations. The clinical data, overall survival (OS), progression-free survival (PFS), and procedure-related adverse events were analyzed.

RESULTS

RFA combined with TACE was successfully performed in all patients. Three complications (2.5%) occurred, with no significant difference between the conventional (n=1, 1.2%) and special (n=2, 5.4%) locations (P = 0.218). Complete tumor necrosis rate was not significantly different between the conventional (n=73, 85.9%) and special (n=34, 91.9%) locations at one-month imaging (P = 0.353). After a follow-up of 3-48 months, the PFS was 17 months for patients with HCC in conventional locations and 14 months for patients with HCC in special locations; one-year PFS rate was 68.1% in the conventional location group, not significantly (P = 0.741) different from 59.1% in the special location group. The OS was 28 months in the conventional location group while 32 months in the special location group. The cumulative one- and two-year OS rates were 89.9% and 63.3%, respectively, in the conventional location group, not significantly different from 96.3% and 65% in the special location group (P = 0.273). Age (P = 0.043) and tumor size (P < 0.001) were significant prognostic factors for OS, and tumor size (P < 0.001) was the only significant prognostic factor for PFS.

CONCLUSION

RFA guided by multiple imaging modalities combined with TACE may be safe and effective for treating HCCs in special locations.

Multimodal Percutaneous Thermal Ablation of Small Hepatocellular Carcinoma: Predictive Factors of Recurrence and Survival in Western Patients

BACKGROUND

To identify the predictive factors of recurrence and survival in an unselected population of Western patients who underwent multimodal percutaneous thermal ablation (PTA) for small Hepatocellular Carcinomas (HCCs).

METHODS

January 2015-June 2019: data on multimodal PTA for <3 cm HCC were extracted from a prospective database. Local tumor progression (LTP), intrahepatic distant recurrence (IDR), time-to-LTP, time-to-IDR, recurrence-free (RFS) and overall (OS) survival were evaluated.

RESULTS

238 patients underwent 317 PTA sessions to treat 412 HCCs. During follow-up (median: 27.1 months), 47.1% patients had IDR and 18.5% died. LTP occurred after 13.3% of PTA. Tumor size (OR = 1.108, p < 0.001; hazard ratio (HR) = 1.075, p = 0.002) and ultrasound guidance (OR = 0.294, p = 0.017; HR = 0.429, p = 0.009) independently predicted LTP and time-to-LTP, respectively. Alpha fetoprotein (AFP) > 100 ng/mL (OR = 3.027, p = 0.037) and tumor size (OR = 1.06, p = 0.001) independently predicted IDR. Multinodular HCC (HR = 2.67, p < 0.001), treatment-naïve patient (HR = 0.507, p = 0.002) and AFP > 100 ng/mL (HR = 2.767, p = 0.014) independently predicted time-to-IDR. RFS was independently predicted by multinodular HCC (HR = 2.144, p = 0.001), treatment naivety (HR = 0.546, p = 0.004) and AFP > 100 ng/mL (HR = 2.437, p = 0.013). The American Society of Anesthesiologists (ASA) score > 2 (HR = 4.273, p = 0.011), AFP (HR = 1.002, p < 0.001), multinodular HCC (HR = 3.939, p = 0.003) and steatotic HCC (HR = 1.81 × 10-16, p < 0.001) independently predicted OS.

CONCLUSIONS

IDR was associated with tumor aggressiveness, suggesting a metastatic mechanism. Besides AFP association with LTP, IDR, RFS and OS, treatment-naïve patients had longer RFS, and multi-nodularity was associated with shorter RFS and OS. Steatotic HCC, identified on pre-treatment MRI, independently predicted longer OS, and needs to be further explored.

Videolaparoscopic microwave ablation in patients with HCC at a European high-volume center: Results of 815 procedures

BACKGROUND

Videolaparoscopic (VL) microwave ablation (MWA) is not included in most of the international guidelines as a therapeutic option for hepatocellular carcinoma (HCC). Aim of this study was to assess the safety of VL MWA in patients with HCC for whom resection or percutaneous ablation is unsuitable.

METHODS

A retrospective analysis was performed on a prospective database of patients with HCC treated with VL MWA at our institution from 2009 to 2016. Patient demographics, operational characteristics, and complications were recorded. Statistical analysis was performed to identify safety profile, overall survival and recurrence rate.

RESULTS

A total of 815 VL MWA were performed in 674 patients with a mean age of 64 years. Patients had a mean Model for End-stage Liver Disease score of 10 (±3); 32.8% were Child B, 44.1% Barcelona Clinic Liver Cancer B-C. Perioperative mortality was 0.4%. Overall morbidity was 30.8%, with Dindo-Clavien complications ≥3 in 2%. The median length of stay was 2 days. In 43.1% VL MWA was the first-line therapy. Overall 1-, 3-, and 5-year survival rates were 81.9%, 54.9%, and 35.9%.

CONCLUSIONS

The present is the largest series of VL ablation and the bigger number of patients with HCC treated with MW reported nowadays. It confirms the safety of a minimally invasive procedure for patients with HCC when resection or percutaneous ablation is not feasible.

The Optimal Management for Sub-Centimeter Hepatocellular Carcinoma: Curative Treatments or Follow-Up?

Background

The optimal strategy for dealing with sub-centimeter hepatic nodules has not yet been established. This study aimed to assess whether there was a need to provide curative treatments for sub-centimeter hepatocellular carcinomas (HCCs) to patients at risk for high false positives.

Material/Methods

We identified patients with primary pathologically diagnosed HCC ≤2 cm from 2004 to 2015 in the Surveillance, Epidemiology and End Results (SEER) database. They were divided according to the interventions they received: local ablation, surgical resection, or liver transplantation. In each group, overall survival and cancer-specific survival were used as endpoints to compare the prognoses between patients with sub-centimeter HCC and patients with HCC measuring 1 to 2 cm by Kaplan-Meier. Propensity score matching was performed to reduce bias. We also compared the survival of patients with a primary solitary HCC based on interventions, in the different tumor size groups. Bootstrapping was performed to validate the findings.

Results

Overall, 10.4% of patients (197 out of 1894) had HCCs <1 cm, and 89.6% of patients (1697 out of 1894) had HCCs in the 1 to 2 cm range. There was no significant difference in overall and cancer-specific survival between patients with HCCs <1 cm and those with HCCs in the 1 to 2 cm range, in all treatment groups. After adjusting confounding factors, no significant correlation was found between tumor size and survival time. In patients with HCCs measuring ≤2 cm, overall survival and cancer-specific survival were superior in liver transplantation compared with surgical resection and local ablation. Surgical resection provided better survival than local ablation.

Conclusions

Compared to patients with HCCs measuring 1 to 2 cm, the survival rates of patients with sub-centimeter HCCs was not improved through curative treatments, risking high false positives.

Thermal ablation with fusion imaging guidance of hepatocellular carcinoma without conspicuity on conventional or contrast-enhanced US: surrounding anatomical landmarks matter

AIM

Evaluating clinical and technical factors affecting thermal ablation of B-Mode/CEUS inconspicuous HCC nodules, relying only on fusion imaging (FI) performed under conscious sedation and using previously acquired CT or MR.

MATERIALS AND METHODS

Among 367 HCC nodules treated in the study period, data of 37 B-mode/CEUS undetectable HCC nodules treated with FI-guided ablation were extracted from our prospectively collected institutional database. Analyzed variables included patients' sex, age, cirrhosis etiology, Child-Pugh status, size of the lesion, liver segment, subcapsular or central liver site, type of imaging used for fusion (MR/CT), and the presence of surrounding anatomical landmarks (SAL) < 3 cm from the index lesion.

RESULTS

The primary efficacy was 59.4% (22/37 nodules); nine lesions (24.3%) were partially ablated (PA), six lesions (16.7%) were mistargeted (MA). Eight nodules were retreated with a CA obtained in all cases (100% CA, secondary efficacy in 30/37-81.1%). LTP was observed in 2/30 cases (6.7%). Two minor complications were registered (Clavien-Dindo, Grade1, CIRSE Classification Grade 2). SAL were related to a better ablation outcome (37.5% vs 84.6% p = 0.01). No differences were observed between CA group and PA-MA group in terms of lesion size (15.4 mm vs 14.9 mm p = 0.63), liver segment (p = 0.58), subcapsular or central liver site (8/22 36% vs 4/15 26.7% p = 0.84), and imaging (MR vs CT, p = 0.72).

CONCLUSION

Even in the presence of potentially critical conditions (completely B-Mode/CEUS inconspicuous nodules, spontaneous breathing, and previously acquired CT or MRI), FI-only guidance is safe and allows having good primary, secondary efficacy and LTP rates. The outcome of the procedure is heavily affected by the presence of SAL.

Combination therapy of transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) for small hepatocellular carcinoma: comparison with TACE or RFA monotherapy

PURPOSE

To compare the safety and efficacy of combined transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) for small hepatocellular carcinoma (HCC) with those of TACE or RFA monotherapy.

METHODS

This study included 34 combined TACE and RFA (TACE-RFA), 87 TACE, and 136 ultrasound-guided RFA, which were performed to treat HCC (≤ 3 cm, 3 or fewer) between March and August 2009. The safety (Child-Pugh score indicating hepatic functional reserve, patient discomfort requiring medication, duration of hospitalization, and complications) and efficacy (1-month, 6-month, and 1-year tumor responses) profiles of each treatment were evaluated and compared.

RESULTS

TACE-RFA group showed longer hospital stay and more frequent patient discomfort requiring medication than TACE or RFA group (P < 0.001). The frequency of overall complications after TACE-RFA was higher than TACE (P = 0.006) or RFA (P = 0.009). There were no statistical differences in major complication rates between the three groups (P = 0.094). Child-Pugh score at 1-month follow-up showed no significant difference between the three groups (P = 0.162). 1-month, 6-month, and 1-year tumor responses of TACE-RFA were similar to those of RFA and better than those of TACE.

CONCLUSIONS

TACE-RFA appears to result in more frequent patient discomfort requiring medication, longer hospital stay, and more frequent complications than TACE or RFA monotherapy. Tumor response of TACE-RFA seems to be similar to that of RFA and better than TACE monotherapy. Thus, TACE-RFA for treating small HCC may be required for the selected patients, especially patients with small HCC ineligible for RFA monotherapy.

Laparoscopic Microwave Ablation of Hepatocellular Carcinoma at Liver Surface: Technique Effectiveness and Long-Term Outcomes

Background and Aims:

To evaluate long-term outcomes and prognostic factors of laparoscopic microwave ablation as a first-line treatment for hepatocellular carcinoma located at the liver surface not feasible for percutaneous ablation.

Methods:

51 consecutive patients receiving laparoscopic microwave ablation in our center between January 11, 2012, and July 31, 2014, were enrolled. Technique effectiveness (complete ablation or incomplete ablation) was evaluated 1 month postprocedure. Procedure-related complications were recorded. The influences of patients’ baseline characteristics on recurrence-free survival and overall survival were analyzed after a median follow-up of 34.0 (ranging 19.0-49.0) months.

Results:

Complete ablation was gained in 47 (92.2%) of the 51 patients. No patients died within 30 days of microwave ablation procedure. A total of 3 (5.9%) cases of complications were observed. Tumor progression/recurrence were observed in 40 patients (78.4%). The median recurrence-free survival and median overall survival of the total cohort was 11.0 months (95% confidence interval: 7.573-14.427) and 34.0 months (95% confidence interval: 27.244-40.756), respectively. Multivariate analysis identified alanine transaminase level and tumor number as independent significant prognosticators of recurrence-free survival whereas α-fetoprotein level as significant prognosticators of overall survival.

Conclusions:

As a first-line treatment, laparoscopic microwave ablation provides high technique effectiveness rate and is well tolerated in patients with hepatocellular carcinoma located at liver surface. Alanine transaminase and tumor number were significant predictors of recurrence-free survival, whereas α-fetoprotein level was significant predictor of overall survival. Laparoscopic microwave ablation might serve as a rational treatment option for patients with hepatocellular carcinoma with tumors at the liver surface, which merits validation in future perspective studies.

Retrospective analysis of stereotactic body radiation therapy efficacy over radiofrequency ablation for hepatocellular carcinoma

BACKGROUND AND PURPOSE

To evaluate the efficacy of stereotactic body radiotherapy (SBRT) and radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

METHODS AND MATERIALS

Patients treated for HCC between 2012 and 2016 were reviewed. Among these, 668 patients who underwent RFA of 736 tumors and 105 patients who underwent SBRT of 114 tumors were included. Using propensity score matching (PSM) to adjust for clinical factors, 95 tumors were selected from each treatment arm. Freedom from local progression (the primary endpoint, FFLP) was compared before and after adjustment with PSM.

RESULTS

At baseline, SBRT-treated tumors were more advanced, larger (median, 2.4 vs. 1.6 cm), and more frequently located in the subphrenic region than RFA-treated tumors (P < .001). The median follow-up was 21.5 (interquartile range, 11.2-36.7) months. Before PSM, the 2-year FFLP rates were 76.3% for the SBRT group and 70.2% for the RFA groups, respectively. After PSM, the 2-year FFLP rates were 74.9% for the SBRT group and 64.9% for the RFA group, respectively. The local control rates were not significantly different. The Cox proportional hazards model revealed the treatment modality as an independent predictor of local recurrence favoring SBRT in the entire cohort and in the PSM model. Elevated tumor markers, tumor location (subphrenic region), and tumor size (>2.0 cm) were also independent predictors of local progression.

CONCLUSION

SBRT appears to be an effective alternative treatment for HCC when RFA is not feasible due to tumor location or size.

Management of sub-centimeter recurrent hepatocellular carcinoma after curative treatment: Current status and future

Hepatocellular carcinomas (HCCs) frequently recur despite initial successful surgical resection or local ablation therapy. Diagnostic methods for small HCCs have improved with the introduction of gadoxetic acid-enhanced liver magnetic resonance imaging and diffusion-weighted imaging (DWI). Currently, sub-centimeter recurrent nodules showing typical hallmark imaging findings of HCC are frequently detected in patients with a treatment history for HCC. With five typical magnetic resonance findings, including arterial enhancement, washout on portal or transitional phase, high signal intensity on both T2-weighted image and DWI, and low signal intensity on hepatobiliary phase, sub-centimeter recurrent HCC can be diagnosed with high accuracy. Although more information is needed to determine the treatment of choice, local ablation therapy under fusion imaging and/or contrast-enhanced ultrasound guidance or cone-beam computed tomography-guided chemoembolization seem to be promising as they are effective and safe for the management of sub-centimeter recurrent HCCs.

Combined transarterial chemoembolization of the right inferior phrenic artery and radiofrequency ablation for small hepatocellular carcinoma near the diaphragm: its efficacy and safety

PURPOSE

The purpose of the study is to report the efficacy and safety of combined transarterial chemoembolization (TACE) of the right inferior phrenic artery (IPA) and radiofrequency ablation (RFA) for small hepatocellular carcinoma (HCC) near the diaphragm supplied by the right IPA.

METHODS

From July 2009 through April 2015, 11 patients with small (≤ 3 cm) HCC near the diaphragm, which was infeasible for ultrasound-guided RFA and supplied by the right IPA, received TACE of the right IPA and subsequent RFA in one session. The safety and therapeutic efficacy, including technique effectiveness and local tumor progression (LTP), were evaluated.

RESULTS

Technique effectiveness was achieved in all the 11 patients (100%). During average follow-up period of 39.2 months (range 13-89 months), LTP occurred in none of the 11 patients. There were twelve minor complications in eight patients, including right shoulder pain (n = 4), right pleural effusion (n = 2), diaphragmatic thickening (n = 2), transient lung change (n = 2), subsegmental intrahepatic bile duct stricture (n = 1), and subsegmental hepatic infarction (n = 1). No major complications were encountered CONCLUSION: Combined TACE of the right IPA and RFA can be a safe and effective treatment for small HCC near the diaphragm that is supplied by the right IPA.

Combined transarterial chemoembolization and radiofrequency ablation for small treatment-naïve hepatocellular carcinoma infeasible for ultrasound-guided radiofrequency ablation: long-term outcomes

Background Ultrasound (US)-guided radiofrequency ablation (RFA) for small hepatocellular carcinoma (HCC) is often infeasible due to unfavorable location and poor conspicuity. Those small HCCs can be treated with combined transarterial chemoembolization (TACE) and RFA. Purpose To evaluate long-term outcomes of combined TACE and RFA for small treatment-naïve HCC infeasible for US-guided RFA. Material and Methods Between February 2009 and January 2014, 69 patients with small (≤3 cm) HCC infeasible for US-guided RFA received TACE and subsequent RFA in one session as a first-line treatment. Local tumor progression (LTP), overall survival (OS), and event-free survival rates were evaluated. Univariate and multivariate analyses were conducted to identify prognostic factors. Results Cumulative rates of LTP were 4.4%, 6.8%, 8.2%, 9.5%, and 9.5% at one, two, three, five, and seven years, respectively. Cumulative one-, two-, three-, five-, and seven-year OS rates were 100%, 95%, 89%, 80%, and 80%, respectively. Cumulative one-, two-, three-, five-, and seven-year event-free survival rates were 81%, 63%, 54%, 31%, and 20%, respectively. No significant prognostic factors for LTP, OS, and event-free survival were identified in univariate analysis. Conclusion Combined TACE and RFA appears to be an effective treatment for small treatment-naïve HCC infeasible for US-guided RFA in terms of LTP and OS.

Surgical Resection vs. Ablative Therapies Through a Laparoscopic Approach for Hepatocellular Carcinoma: a Comparative Study

BACKGROUND

When compatible with the liver functional reserve, laparoscopic hepatic resection remains the treatment of choice for hepatocellular carcinoma while laparoscopic ablation therapies appear as a promising less invasive alternative. The aim of the study is to compare two homogeneous groups of patients submitted to either hepatic resection or thermoablation for the treatment of single hepatocellular carcinoma (≤ 3 cm).

METHODS

We enrolled 264 cirrhotic patients out of 905 cases consecutively evaluated for hepatocellular carcinoma. We performed 59 hepatic resections and 205 thermoablations through a laparoscopic approach, and they were then followed for similar follow-up (41.7 ± 31.5 months for laparoscopic hepatic resection vs. 38.7±32.3 for laparoscopic ablation therapy). Outcomes included short- and long-term morbidities, tumoral recurrence, and overall survival.

RESULTS

Short-term morbidity was significantly higher in the resection group (but the two groups had similar rates for severe complications) while, during follow-up, recurrence was more frequent in patients treated with thermoablation, with a clear disadvantage in terms of survival. At multivariate analysis, only the type of surgical treatment was an independent predictor of disease recurrence, while plasmatic alpha-fetoprotein and Hb values, model for end-stage liver disease score, time to recurrence, and the type of surgical treatment were independent predictors of overall survival.

CONCLUSION

Our data ultimately support some therapeutic advantages for hepatic resection in patients with a single nodule and preserved liver function. However, thermoablation is an adequate alternative in patients with nodules that would require complex surgical resections or imply a poor prognosis that might therefore better tolerate a less invasive procedure.

3D image guidance assisted identification of colorectal cancer liver metastases not seen on intraoperative ultrasound: results from a prospective trial

BACKGROUND

Neoadjuvant treatment of colorectal liver metastases has become increasingly common, and while effective, often renders small metastases difficult to visualize on intraoperative US. The objective of this study was to determine the utility of a 3D image-guidance system in patients with intraoperative sonographically-occult CRLM.

METHODS

50 patients with at least one CRLM ≤ 1.5 cm were enrolled in this prospective trial of an FDA-approved Explorer image-guidance system. If the tumor(s) seen on preoperative imaging were not identified with intraoperative US, Explorer was used to target the US examination to the involved area for a more focused assessment. The primary endpoint was the proportion of cases with sonographically-occult metastases identified using Explorer.

RESULTS

Forty-eight patients with preoperative scans within eight weeks of surgery were included for analysis. Forty-six patients were treated with preoperative chemotherapy (median 4 months, range 2-24 months). Overall, 22 sonographically-occult tumors in 14 patients were interrogated by Explorer, of which 15 tumors in 10 patients were located with image-guidance assistance. The only difference between patients with tumors not identified on US and those who did was the number of tumors (median 3 vs. 2, p = 0.018).

CONCLUSION

3D image-guidance can assist in identifying small CRLM, particularly after treatment with chemotherapy.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02806037, https://clinicaltrials.gov/ct2/show/NCT02806037.

Does intra-tumoural fat on MRI predict visibility of small (≤3 cm) hepatocellular carcinomas during ultrasound-guided tumour ablation?

AIM

To assess if intra-tumoural fat on magnetic resonance imaging (MRI) affects the ultrasonographic (US) visibility of small (≤3 cm) hepatocellular carcinomas (HCC) during radiofrequency ablation (RFA).

MATERIALS AND METHODS

Institutional review board approval was obtained. A retrospective review of all patients who underwent image-guided ablation between 1 January 2010 and 31 April 2015 was performed. Patients with HCC who underwent US RFA were included. Inclusion criteria included small tumours (≤3 cm), treatment-naive cases or new focus of HCC in a different and untreated segment, and pre-procedural MRI. The presence of intra-tumoural fat was determined retrospectively via in-and-out-of-phase MRI. Other factors that potentially affect ultrasonographic visibility, such as background fatty liver, presence of cirrhosis, tumour size, and distance from diaphragm, were recorded.

RESULTS

Ninety procedures performed on 74 patients (62 men and 12 women; mean age: 67.3 years; range: 39-88 years). Seventy-two tumours were visible on US (hypoechoic n=35, hyperechoic n=28, heterogeneous n=9). Intra-tumoural fat was seen in 23 tumours (25.6%, hyperechoic n=17, hypoechoic n=6). The presence of intra-tumoural fat (p=0.005) and distance from diaphragm (p=0.007) were found to be statistically significant factors affecting tumour visibility on planning US. The presence of background fatty liver (p=0.485), cirrhosis (p=0.48), and tumour size (p=0.15) were not found to be significant.

CONCLUSION

The present study shows that the presence of intra-tumoural fat in small HCCs on pre-procedural MRI can accurately predict their visibility on planning US during percutaneous tumour ablation.

Value of contrast-enhanced sonography of small hepatocellular carcinoma with sonazoid prior to radiofrequency ablation

BACKGROUND

We aimed to determine the value of contrast-enhanced sonography (CEUS) with Sonazoid prior to percutaneous radiofrequency ablation (RFA) of small (<3 cm) hepatocellular carcinoma (HCC).

METHODS

This prospective study was approved by our institutional review board and informed consent was obtained. The following criteria were used for study enrollment: (1) cirrhotic patients with HCCs found by contrast-enhanced CT or Gd-EOB-DTPA-enhanced MRI; (2) a single HCC <3 cm in longest diameter or multinodular HCCs (<3) with each tumor <3 cm in longest diameter; and (3) indeterminate identification of the index tumor from the surrounding cirrhosis-related pseudolesions on conventional US. Percutaneous RFA was performed under the guidance of CEUS with Sonazoid. The value of CEUS in index tumor detection and targeting was compared with that of concurrently performed conventional US.

RESULTS

A total of 38 patients with 43 HCCs (mean size, 1.6 cm; range, 0.5-2.9 cm) were enrolled. The vascular phase of Sonazoid-enhanced ultrasonography showed good tumor enhancement in 30/43 HCCs (70%). The Kupffer phase increased lesion conspicuity and operator's diagnostic confidence in 29 patients with 31 HCCs (31/43, 72%) compared with conventional US.

CONCLUSIONS

CEUS with Sonazoid is useful for detection and targeting of small HCC prior to RFA. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:383-390, 2017.

Pitfalls in surveillance for hepatocellular carcinoma: How successful is it in the real world?

Background/Aims

Surveillance for hepatocellular carcinoma (HCC) with ultrasound in high-risk populations is generally believed to improve opportunities for treatment. However, tumors are still missed due to various factors. This study explores success versus failure of HCC surveillance.

Methods

This is a retrospective study of 1,125 HCC cases. Categories considered for successful detection were largest tumor ≤3.0 cm, single tumors ≤3.0 cm and ≤2.0 cm, and adherence to Milan criteria. Examined factors were age <60 years, gender, rural residence, body-mass index (BMI), hepatitis infection, smoking, diabetes, hyperlipidemia, cirrhosis, ascites, and Model for End-Stage Liver Disease <10.

Results

HCC was found on surveillance in 257 patients with a mean tumor size of 3.17 cm; multiple tumors were seen in 28% of cases, bilateral tumors in 7.4%, and vascular invasion in 3.7%. Surveillance was successful in 61.5% of cases involving a largest tumor ≤3.0 cm, with BMI ≥35 negatively affecting detection (odds ratio [OR] 0.28, P=0.014) and cirrhosis positively affecting detection (OR 2.31, P=0.036). Ultrasound detected 19.1% of single tumors ≤2.0 cm with ascites improving the detection rate (OR 3.89, P=0.001). Finally, adherence to Milan criteria occurred in 75.1% of cases, revealing negative associations with diabetes (OR 0.48, P=0.044 and male gender (OR 0.49, P=0.08).

Conclusions

Although surveillance is recommended for HCC, not all surveillance ultrasound are ideal. Tumor detection can depend on gender, BMI, diabetes, cirrhosis, and ascites and is achieved in 19.1–75% of cases depending on the definition of success. Closer follow-up or additional imaging might be necessary for some patient subgroups.

Utility of T1-weighted MRI as a predictor of liver lesion visibility on ultrasound: A clinical tool to determine feasibility of ultrasound-guided percutaneous interventions

PURPOSE

To determine the utility of fat-suppressed T1-weighted gradient recalled echo (FS-T1W-GRE) MRI to predict visibility of focal liver lesions (FLL) on abdominal ultrasound (US).

MATERIALS AND METHODS

With IRB approval, between 2010 and 2013, 109 patients (28.4% females, age 66.9±10.9years) with 177 FLL (hepatocellular carcinoma=132, metastases=44, other=1) underwent MRI and prospective, radiologist-performed treatment-planning US (to determine eligibility for US-guided ablation). MRI examinations were reviewed by a blinded radiologist who assessed: a) size and location of FLL, b) presence of hepatic steatosis on dual-echo T1W-GRE, and c) quantitative signal intensity of FLL relative to liver on FS-T1W-GRE. Associations between MR imaging findings and visibility on US were assessed using independent t-tests and the chi-squares test.

RESULTS

69.5% (123/177) FLL were identified with US and 30.5% (54/177) were not visible. Size of FLL on MRI was associated with visibility on US (p<0.0001) with no association between FLL visibility on US and segmental or subcapsular location (p=0.29 and p=0.25, respectively). 20.2% (22/109) patients had hepatic steatosis on MRI, which was not associated with non-visibility of FLL on US (p=0.67). 38.4% (68/177) FLL were isointense to liver on FS-T1W-GRE which was associated with non-visibility on US (p=0.036) particularly in non-steatotic livers (p=0.014).

CONCLUSION

FLL size and isointensity of FLL to liver parenchyma on FS-T1W-GRE MRI are associated with non-visibility on US, particularly in non-steatotic livers. These results have implications when planning US-guided percutaneous interventions of FLL detected with MRI.

Clinical impact of cone beam computed tomography on iterative treatment planning during ultrasound-guided percutaneous ablation of liver malignancies

A standardized cone beam computed tomography (CBCT) protocol may impact optimal ablation probe(s) positioning during ultrasound-guided microwave ablation (MWA). To evaluate this hypothesis, 15 patients underwent ultrasound-guided percutaneous MWA of 15 liver lesions (10 hepatocellular carcinomas, 5 metastasis ranging 11-41 mm) with the ultrasound guidance assisted by a dedicated CBCT protocol. Pre-procedural enhanced CBCT (ceCBCT) was performed after intravenous contrast administration to visualize the lesion and determine the optimal approach using CBCT-based ablation planning software. MW antennas were positioned under ultrasound guidance, and non-enhanced CBCT was performed after deployment and fused with pre-procedural ceCBCT to assess tumor targeting and modify subsequent steps of the procedure. CBCT lesion detection accuracy and number of needle repositioning on the basis of CBCT information were recorded. Clinical success was measured on 1-month follow-up contrast-enhanced CT. The target lesion was detected on ceCBCT in 13 out of 15 patients (87%). The undetected lesions were only visible on diagnostic contrast-enhanced magnetic resonance imaging, which was then fused to the CBCT and fluoroscopy to facilitate targeting. MW antennas were repositioned on the basis of CBCT in 11 lesions (73%). Clinical success was achieved in 14/15 ablations (93%) with a mean follow-up of X months. The only case of local recurrence was expected, as the intent was tumor debulking. CBCT imaging during ultrasound-guided liver ablation is feasible and leads to ablation device repositioning in the majority of cases.

Diagnosis of Hepatocellular Carcinoma with Gadoxetic Acid-Enhanced MRI: 2016 Consensus Recommendations of the Korean Society of Abdominal Radiology

Diagnosis of hepatocellular carcinoma (HCC) with gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) poses certain unique challenges beyond the scope of current guidelines. The regional heterogeneity of HCC in demographic characteristics, prevalence, surveillance, and socioeconomic status necessitates different treatment approaches, leading to variations in survival outcomes. Considering the medical practices in Korea, the Korean Society of Abdominal Radiology (KSAR) study group for liver diseases has developed expert consensus recommendations for diagnosis of HCC by gadoxetic acid-enhanced MRI with updated perspectives, using a modified Delphi method. During the 39th Scientific Assembly and Annual Meeting of KSAR (2016), consensus was reached on 12 of 16 statements. These recommendations might serve to ensure a more standardized diagnosis of HCC by gadoxetic acid-enhanced MRI.

Comparison of Laparoscopic Microwave to Radiofrequency Ablation of Small Hepatocellular Carcinoma (≤3 cm)

BACKGROUND

Laparoscopic thermal ablation is a common alternative to surgical resection in treating hepatic tumors, particularly in those located in difficult-to-reach locations.

OBJECTIVE

The aim of this study was to compare the safety and long-term efficacy of laparoscopic radiofrequency ablation (RFA) and microwave ablation (MWA) in treating hepatocellular carcinoma (HCC).

METHOD

From February 2009 to May 2015, data from patients with HCC nodules who had undergone either laparoscopic MWA or laparoscopic RFA were examined. Complications, complete ablation rates, local tumor progression (LTP) rates, and disease-free and cumulative survival rates were compared between the two treatment groups.

RESULTS

A total of 154 patients with HCC (60 MWA and 94 RFA) were treated via the laparoscopic approach. Major complication rates were identified as 1 and 2 % in the RFA and MWA groups, respectively (p = 0.747). Complete ablation rates were 95 % for both treatment groups (p = 0.931), and LTP rates were 21.2 % for RFA and 8.3 % for MWA (p = 0.034). Disease-free survival rates at 5 years were 19 % in the RFA group and 12 % in the MWA group (p = 0.434), while cumulative survival rates at 5 years were 50 % in the RFA group and 37 % in the MWA group (p = 0.185).

CONCLUSION

Laparoscopic RFA and MWA appear to be safe in the treatment of early-stage HCC. The LTP rates were lower in the laparoscopic MWA group compared with the laparoscopic RFA group, but their respective overall and disease-free survival rates remained similar.

Automatic Registration between Real-Time Ultrasonography and Pre-Procedural Magnetic Resonance Images: A Prospective Comparison between Two Registration Methods by Liver Surface and Vessel and by Liver Surface Only

The aim of this study was to compare the accuracy of and the time required for image fusion between real-time ultrasonography (US) and pre-procedural magnetic resonance (MR) images using automatic registration by a liver surface only method and automatic registration by a liver surface and vessel method. This study consisted of 20 patients referred for planning US to assess the feasibility of percutaneous radiofrequency ablation or biopsy for focal hepatic lesions. The first 10 consecutive patients were evaluated by an experienced radiologist using the automatic registration by liver surface and vessel method, whereas the remaining 10 patients were evaluated using the automatic registration by liver surface only method. For all 20 patients, image fusion was automatically executed after following the protocols and fused real-time US and MR images moved synchronously. The accuracy of each method was evaluated by measuring the registration error, and the time required for image fusion was assessed by evaluating the recorded data using in-house software. The results obtained using the two automatic registration methods were compared using the Mann-Whitney U-test. Image fusion was successful in all 20 patients, and the time required for image fusion was significantly shorter with the automatic registration by liver surface only method than with the automatic registration by liver surface and vessel method (median: 43.0 s, range: 29-74 s vs. median: 83.0 s, range: 46-101 s; p = 0.002). The registration error did not significantly differ between the two methods (median: 4.0 mm, range: 2.1-9.9 mm vs. median: 3.7 mm, range: 1.8-5.2 mm; p = 0.496). The automatic registration by liver surface only method offers faster image fusion between real-time US and pre-procedural MR images than does the automatic registration by liver surface and vessel method. However, the degree of accuracy was similar for the two methods.

Application of imaging fusion combining contrast-enhanced ultrasound and magnetic resonance imaging in detection of hepatic cellular carcinomas undetectable by conventional ultrasound

BACKGROUND AND AIM

The aim of this study is to explore the value of volume navigation image fusion-assisted contrast-enhanced ultrasound (CEUS) in detection for radiofrequency ablation guidance of hepatocellular carcinomas (HCCs), which were undetectable on conventional ultrasound.

METHODS

From May 2012 to May 2014, 41 patients with 49 HCCs were included in this study. All lesions were detected by dynamic magnetic resonance imaging (MRI) and planned for radiofrequency ablation but were undetectable on conventional ultrasound. After a bolus injection of 2.4 ml SonoVue® (Bracco, Italy), LOGIQ E9 ultrasound system with volume navigation system (version R1.0.5, GE Healthcare, Milwaukee, WI, USA) was used to fuse CEUS and MRI images. The fusion time, fusion success rate, lesion enhancement pattern, and detection rate were analyzed.

RESULTS

Image fusions were conducted successfully in 49 HCCs, the technical success rate was 100%. The average fusion time was (9.2 ± 2.1) min (6-12 min). The mean diameter of HCCs was 25.2 ± 5.3 mm (mean ± SD), and mean depth was 41.8 ± 17.2 mm. The detection rate of HCCs using CEUS/MRI imaging fusion (95.9%, 47/49) was significantly higher than CEUS (42.9%, 21/49) (P < 0.05). For small HCCs (diameter, 1-2 cm), the detection rate using imaging fusion (96.9%, 32/33) was also significantly higher than CEUS (18.2%, 6/33) (P < 0.01). All HCCs displayed a rapid wash-in pattern in the arterial phase of CEUS.

CONCLUSIONS

Imaging fusion combining CEUS and MRI is a promising technique to improve the detection, precise localization, and accurate diagnosis of undetectable HCCs on conventional ultrasound, especially small and atypical HCCs.

Imaging Diagnosis of Hepatocellular Carcinoma: Recent Advances of Contrast-Enhanced Ultrasonography with SonoVue®

Due to the ability to detect the typical contrast-imaging pattern for hepatocellular carcinoma (HCC), that is hyperenhancement in the arterial phase and hypoenhancement in the late phase on a cirrhotic background, contrast-enhanced ultrasonography (CEUS) was included in the American diagnostic algorithm for HCC in 2005. However, its role has been questioned because of the possibility of misdiagnosis of cholangiocarcinoma. The present review aims to describe the advantages and disadvantages of CEUS applications using Sonovue® for HCC. In particular there is focus on the accuracy of CEUS in detecting the typical HCC pattern, the CEUS patterns of intrahepatic cholangiocarcinoma (ICC), the risk of misdiagnosis with HCC, the diagnostic use of CEUS in cases of locoregional and systemic treatments, and the evaluation of response to antiangiogenic treatment using dedicated software.

Laparoscopic ablation therapies or hepatic resection in cirrhotic patients with small hepatocellular carcinoma

BACKGROUND

The Barcelona Clinic Liver Cancer staging system recommends radiofrequency ablation as treatment of choice for patients with "small" (up to 2 cm in size) hepatocellular carcinoma.

AIMS

Aim of the study was to assess whether laparoscopic ablation therapies or hepatic resection could be proposed as alternative option if percutaneous approach is not feasible.

METHODS

Overall survival and tumour recurrence rate were compared in a retrospective cohort of 176 consecutive patients with small hepatocellular carcinoma on cirrhosis treated by laparoscopic ablation therapies or surgery. To balance the covariates between the two groups, a propensity case-matched analysis was developed to generate a matched sample, which included 76 patients in each arm.

RESULTS

Local tumour progression (p=0.005), intra-segmental recurrence (p=0.0001), and 5-year recurrence rates (80% vs. 60%; p=0.0014) were significantly higher in the ablation therapies group. The 5-year survival rate were 48% after ablation therapies and 69% after hepatic resection (p=0.0006). Multivariate analysis showed that MELD score, alpha-fetoprotein value, procedure category and intraoperative restaging were associated with survival, while the surgery was the only independent predictor of intra-hepatic recurrence.

CONCLUSIONS

The present study suggests that, if percutaneous ablation is not feasible, hepatic resection may be considered as a sound option in the treatment of small hepatocellular carcinoma.