Thermal ablation in the treatment of intrahepatic cholangiocarcinoma: a systematic review and meta-analysis.

OBJECTIVE: To summarize the efficacy and safety of thermal ablation for the treatment of intrahepatic cholangiocarcinoma (ICC). METHODS: MEDLINE, EMBASE, Cochran Library, and Web of Science databases were searched for studies reporting outcomes in patients with ICC treated with thermal ablation. Meta-analyses of cumulative overall survival (OS) and recurrence-free survival (RFS), Kaplan-Meier survival rates according to time to local tumor progression (TTLTP), technical efficacy, and incidence of complications were analyzed. Pooled hazard ratios of common variables were calculated to explore factors associated with OS. RESULTS: Twenty observational studies comprising 917 patients were reviewed (primary ICC [n = 502]; post-surgical recurrent ICC [n = 355]; information not available [n = 60]). The pooled proportion of technical efficacy was 91.9% (95% CI, 87.3-94.9%). The pooled 1-, 3-, and 5-year OS rates were 82.4% (95% CI, 75.1-88.9%), 42.1% (95% CI, 36.0-48.4%), and 28.5% (95% CI, 21.2-36.2%). Primary tumors showed higher 3-year OS rates than recurrent ones, with borderline significance (p = 0.072). The pooled 1- and 3-year RFS rates were 40.0% (95% CI, 33.6-46.4%) and 19.2% (95% CI, 8.4-32.7%). The pooled 1-, 3-, and 5-year TTLTP rates were 79.3% (95% CI, 65.1-90.9%), 59.5% (95% CI, 49.1-69.4%), and 58.2% (95% CI, 44.9-70.9%). The pooled incidence of major complications was 5.7% (95% CI, 4.1-7.8%). Tumor size (> 3 cm), multiple tumors, and age (> 65 years) were factors associated with shorter OS. CONCLUSION: Thermal ablation is a successful alternative with a good safety profile, especially for a single ICC smaller than 3 cm. KEY POINTS: • The pooled 1-, 3-, and 5-year OS rates following thermal ablation for the treatment of intrahepatic cholangiocarcinoma were 82.4%, 42.1%, and 28.5%. • The pooled incidence of major complications was 5.7%. • A tumor size > 3 cm (HR: 2.12, p = 0.006), multiple tumors (HR: 1.67, p = 0.004), and age > 65 years (HR: 1.67, p = 0.006) were factors associated with shorter OS.

Outcome of No-Touch Radiofrequency Ablation for Small Hepatocellular Carcinoma: A Multicenter Clinical Trial.

Background Recently introduced no-touch radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) has the potential to improve local tumor control. Purpose To evaluate midterm clinical outcomes of monopolar no-touch RFA in single HCCs 2.5 cm or smaller. Materials and Methods In this multicenter clinical trial (ClinicalTrials.gov: NCT03375281), participants were evaluated for eligibility from November 2017 to January 2019. Patients with single HCCs 2.5 cm or smaller planning to be treated with no-touch RFA were enrolled. The rate of successful no-touch RFA, defined as performing RFA without violation of the tumor itself, was recorded. Multivariable logistic regression analysis was used to determine associated factors for failure of no-touch RFA. Development of major complication after no-touch RFA was also recorded. Cumulative incidence of local tumor progression (LTP) and recurrence-free survival were estimated by using the Kaplan-Meier method. Results A total of 140 participants (mean age, 62 years ± 9 [standard deviation]; 106 men) were evaluated. No-touch RFA was successfully performed in 128 participants (128 of 140; 91.4%), and conversion to tumor puncture RFA was undertaken in 12 participants because of the lack of a safe access route. By using either no-touch RFA or conversion to tumor puncture RFA, all participants achieved technical success of RFA, which was defined as complete coverage of target tumor by ablation zone. Insufficient peritumoral parenchyma (<5 mm width around more than half portion of tumor; odds ratio, 74; 95% CI: 18, 309; P < .001) was the only significant predictive factor for failure of the no-touch technique. Among the 140 participants, LTP developed in two participants, and the estimated 1- and 2-year cumulative incidence of LTP was 0.7% and 1.6%, respectively. The estimated 1- and 2-year recurrence-free survival was 82.8% and 74.1%, respectively. Conclusion No-touch radiofrequency ablation was an effective and safe treatment method for small hepatocellular carcinomas (≤2.5 cm), with 1.6% of cumulative incidence of local tumor progression at 2 years. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Soulen and García-Mónaco in this issue.

A Single-Center Retrospective Analysis of Periprocedural Variables Affecting Local Tumor Progression after Radiofrequency Ablation of Colorectal Cancer Liver Metastases.

Background Local tumor progression (LTP) is associated with poorer survival in patients undergoing radiofrequency ablation (RFA) for colorectal liver metastasis (CLM). An algorithmic strategy to predict LTP may help in selection of patients who would benefit most from RFA for CLM. Purpose To estimate local tumor progression-free survival (LTPFS) following RFA of CLM and develop an algorithmic strategy based on clinical variables. Materials and Methods In this retrospective study, between March 2000 and December 2014, patients who underwent percutaneous RFA for CLM were randomly split into development (60%) and internal validation (40%) data sets. Kaplan-Meier method was used to estimate LTPFS and overall survival (OS) rates. Independent factors affecting LTPFS in the development data set were investigated by using multivariable Cox proportional hazard regression analysis. Risk scores were assigned to the risk factors and applied to the validation data set. Results A total of 365 patients (mean age, 60 years ± 11 [standard deviation]; 259 men) with 512 CLMs were evaluated. LTPFS and OS rates were 85% and 92% at 1 year, 73% and 41% at 5 years, 72% and 30% at 10 years, and 72% and 28% at 15 years, respectively. Independent risk factors for LTP included tumor size of 2 cm or greater (hazard ratio [HR], 3.8; 95% CI: 2.3, 6.2; P < .001), subcapsular tumor location (HR, 1.9; 95% CI: 1.1, 3.1; P = .02), and minimal ablative margin of 5 mm or less (HR, 11.7; 95% CI: 4.7, 29.2; P < .001). A prediction model that used the risk factors had areas under the curve of 0.89, 0.92, and 0.90 at 1, 5, and 10 years, respectively, and it showed significantly better areas under the curve when compared with the model using the minimal ablative margin of 5 mm or less alone. Conclusion Radiofrequency ablation provided long-term control of colorectal liver metastases. Although minimal ablative margin of 5 mm or less was the most dominant factor, the multifactorial approach including tumor size and subcapsular location better predicted local tumor progression-free survival. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Soulen and Sofocleous in this issue.

Percutaneous Radiofrequency Ablation for Recurrent Intrahepatic Cholangiocarcinoma After Curative Resection: Multivariable Analysis of Factors Predicting Survival Outcomes.

OBJECTIVE. The purpose of this study was to evaluate the factors associated with local tumor progression (LTP) and overall survival (OS) in patients who have undergone percutaneous radiofrequency ablation (RFA) for recurrent intrahepatic cholangiocarcinoma (iCCA) after curative resection. MATERIALS AND METHODS. Data from 40 patients (mean age, 56.3 years) with 64 recurrent iCCAs (median diameter, 1.5 cm) who underwent percutaneous RFA between 1999 and 2019 were retrospectively analyzed. Patients were included if they had three or fewer metastases, a maximum tumor diameter of 5 cm or less, and disease confined to the liver. RESULTS. Technical success was achieved in all patients, with no procedure-related mortality. During follow-up, local progression of treated lesions was observed in 31.3% of tumors. The median OS and 5-year survival rate from initial RFA were 26.6 months and 18.3%, respectively. Multivariable analysis showed that a larger tumor diameter (> 2 cm, p = .004) was significantly associated with reduced LTP-free survival and that both a larger tumor diameter and less than 1 year from surgery to recurrence (p = .005 and .006, respectively) were statistically significant predictors of reduced OS after RFA. CONCLUSION. Percutaneous RFA may offer a well-tolerated and successful approach to local tumor control in patients with recurrent iCCA after curative surgery. Patients with a small-diameter tumor (≤ 2 cm) and late hepatic recurrence (≥ 1 year after curative resection) benefited most from RFA treatment.

Liver imaging reporting and data system category M: A systematic review and meta-analysis.

BACKGROUND AND AIMS: The Liver Imaging Reporting and Data System (LI-RADS) category M (LR-M) was introduced to preserve the high specificity of LI-RADS algorithm for diagnosing hepatocellular carcinoma (HCC). We aimed to systematically determine the probability of the LR-M for HCC and non-HCC malignancy, and to determine the sources of heterogeneity between reported results. METHODS: Original studies reporting the probability of LR-M for HCC and non-HCC malignancy on magnetic resonance imaging (MRI) were identified in MEDLINE and EMBASE. The meta-analytic pooled percentages of HCC and non-HCC in LR-M were calculated. Meta-regression analysis was performed to explore study heterogeneity. The meta-analytic frequency of each LR-M imaging feature was determined. RESULTS: We found 10 studies reporting the diagnostic performance of LR-M (1819 lesions in 1631 patients), and six reporting the frequency of LR-M imaging features. The pooled percentages of HCC and non-HCC malignancy for LR-M were 28.2% (95% confidence interval [CI], 23.8%-33.1%; I2  = 83%) and 69.6% (95% CI, 64.6%-74.1%; I2  = 83%) respectively. The study type and MRI scanner field strength were significantly associated with study heterogeneity (P ≤ .04). Of the seven imaging features, rim arterial phase hyperenhancement showed the highest frequency in both non-HCC (48.9%; 95% CI, 43.0%-54.8%) and HCC groups (9.8%; 95% CI, 6.9%-13.6%). CONCLUSIONS: The LR-M category most commonly included non-HCC malignancy but also included 28.2% of HCC. Substantial study heterogeneity was noted, and it was significantly associated with study type and MRI scanner field strength. In addition, the frequency of LR-M imaging features was variable.

Ancillary features in the Liver Imaging Reporting and Data System: how to improve diagnosis of hepatocellular carcinoma ≤ 3 cm on magnetic resonance imaging.

OBJECTIVES: To determine the strength of association with hepatocellular carcinoma (HCC) of each ancillary feature (AF) in LI-RADS version 2018, and to develop an appropriate strategy for applying AFs to improve the diagnosis of HCC ≤ 3 cm on gadoxetate-enhanced MRI. METHODS: A total of 385 nodules (283 HCCs, 18 non-HCC malignancies, 84 benign nodules) of ≤ 3 cm in 266 patients at risk for HCC who underwent gadoxetate-enhanced MRI in 2016 were retrospectively evaluated. Two radiologists independently evaluated the presence/absence of AFs, and assigned a LI-RADS category to each nodule. Diagnostic odds ratio (DOR) of each AF was assessed. To improve the diagnostic performance for HCC, various criteria were developed based on the number of AFs favoring malignancy in general or HCC in particular. Generalized estimating equation models were used to compare the diagnostic performance of each criterion with that of the major features (MFs) only. RESULT: All AFs favoring HCC in particular and malignancy in general were more common in the HCC group than in the non-HCC group. Of these AFs, hepatobiliary-phase hypointensity had the strongest association with HCC (DOR, 21.82; 95% confidence interval, 5.59-85.20). When we applied AFs in addition to MFs, the new criterion (with a number of AFs ≥ 4) had significantly higher sensitivity (80.6% vs. 70.0%; p < 0.001) than MFs only, without significant lower specificity (85.3% vs. 90.2%; p = 0.060). CONCLUSIONS: The AFs varied in the strengths of association with HCC. More strict application of AFs (AFs ≥ 4) in LR-3 may improve the diagnostic performance for probable HCC ≤ 3 cm. KEY POINTS: • The ancillary features (AFs) in the Liver Imaging Reporting and Data System version 2018 showed variable frequencies of occurrence and strengths of association with hepatocellular carcinoma (HCC). • Of the various AFs, hepatobiliary-phase hypointensity had the highest frequency and strongest association with HCC on gadoxetate disodium-enhanced MRI. • When applying AFs in addition to major features, a criterion of four or more AFs significantly increased the sensitivity for diagnosing HCC, without a significantly decreased specificity, especially in LR-3 observations.

Tract ablation after radiofrequency ablation to prevent viable tumor cell adhesion to the needle electrode.

PURPOSE: To evaluate whether the additive needle tract ablation (TA) can reduce adherent cells on the needle tract after radiofrequency ablation (RFA) in a preclinical HCC mouse model. METHODS: Hep3B-Luc cells were engrafted in the Balb/c-nude mice. Nineteen mice were randomly assigned into three groups: the needle only group (needle placement only without performing RFA), the RFA only group (needle placement with active RFA treatment), and the RFA-TA group (needle placement with active RFA treatment and additive tract ablation). The 17-gauge needle with a 10-mm active tip was used. After RFA and TA, the viability of adherent tumor cells on the RFA needle was evaluated with bioluminescence imaging (BLI) and live-cell counting. RESULTS: We observed that RFA-TA group had the lowest BLI values compared with other groups (needle only group, 11.2 ± 6.4 million; RFA only group, 13.6 ± 9.1 million; RFA-TA group, 1.11 ± 0.8 million, p = 0.001). Live cell counting with acridine orange/propidium iodide staining also confirmed that the counted viable cell numbers in RFA-TA group were lowest compared to the other groups (needle only group, 14.8 ± 4.5; RFA only group, 643.8 ± 131.9; RFA-TA group, 1.5 ± 0.9, p < 0.001). CONCLUSIONS: The additive tract ablation can significantly reduce the number of viable tumor cells adherent to the RFA needle, which can prevent needle tract seeding after RFA procedure.

Arterial subtraction images of gadoxetate-enhanced MRI improve diagnosis of early-stage hepatocellular carcinoma.

BACKGROUND & AIMS: Although gadoxetate disodium-enhanced magnetic resonance imaging (MRI) shows higher sensitivity for diagnosing hepatocellular carcinoma (HCC), its arterial-phase images may be unsatisfactory because of weak arterial enhancement. We investigated the clinical effectiveness of arterial subtraction images from gadoxetate disodium-enhanced MRI for diagnosing early-stage HCC using the Liver Imaging Reporting and Data System (LI-RADS) v2018. METHODS: In 258 patients at risk of HCC who underwent gadoxetate disodium-enhanced MRI in 2016, a total of 372 hepatic nodules (273 HCCs, 18 other malignancies, and 81 benign nodules) of 3.0 cm or smaller were retrospectively analyzed. Final diagnosis was assessed histopathologically or clinically (marginal recurrence after treatment or change in lesion size on follow-up imaging). The detection rate for arterial hyperenhancement was compared between ordinary arterial-phase and arterial subtraction images, and the benefit of arterial subtraction images in diagnosing HCC using LI-RADS was assessed. RESULTS: Arterial subtraction images had a significantly higher detection rate for arterial hyperenhancement than ordinary arterial-phase images, both for all hepatic nodules (72.3% vs. 62.4%, p <0.001) and HCCs (91.9% vs. 80.6%, p <0.001). Compared with ordinary arterial-phase images, arterial subtraction images significantly increased the sensitivity of LI-RADS category 5 for diagnosis of HCC (64.1% [173/270] vs. 55.9% [151/270], p <0.001), without significantly decreasing specificity (92.9% [91/98] vs. 94.9% [93/98], p = 0.155). For histopathologically confirmed lesions, arterial subtraction images significantly increased sensitivity to 68.8% (128/186) from the 61.3% (114/186) of ordinary arterial-phase images (p <0.001), with a minimal decrease in specificity to 84.8% (39/46) from 89.1% (41/46) (p = 0.151). CONCLUSIONS: Arterial subtraction images of gadoxetate disodium-enhanced MRI can significantly improve the sensitivity of early-stage HCC diagnosis using LI-RADS, without a significant decrease in specificity. LAY SUMMARY: Gadoxetate disodium-enhanced magnetic resonance imaging is an imaging technique with a high sensitivity for the diagnosis of hepatocellular carcinoma. However, arterial-phase images may be unsatisfactory because of weak arterial enhancement. We found that using arterial subtraction images led to clinically meaningful improvements in the diagnosis of early-stage hepatocellular carcinoma.

Surgical resection versus radiofrequency ablation very early-stage HCC (≤2 cm Single HCC): A propensity score analysis.

BACKGROUND & AIM: Hepatocellular carcinoma (HCC) is increasingly being detected at a very early-stage due to the wide implementation of the surveillance of at-risk patient populations combined with improved imaging technologies. Whether patients with HCC at a very early stage can be offered local ablation as a first-line treatment option still remains controversial. We retrospectively compared the effectiveness of surgical resection (SR) and radiofrequency ablation (RFA) for Barcelona Clinic Liver Cancer (BCLC) very early-stage HCC in patients with long-term follow-up. METHODS: Propensity score analysis using inverse probability weighting (IPW) from a large-volume liver centre. We included adult patients who between 2000 and 2013 received a diagnosis of very early-stage HCC (BCLC stage 0; a single tumour ≤2 cm, Child-Pugh A class, eastern cooperative oncology group [ECOG] 0) and who were treated with SR or RFA as the first-line treatment. RESULTS: We identified 1208 patients, 631 in the SR group and 577 in the RFA group. The median follow-up time was 86.2 months. After propensity score analysis using IPW, the 15-year overall survival rates were 60.4% and 51.6% in the SR and RFA group respectively. RFA group showed poorer overall survival than SR group (adjusted hazard ratio, 1.29; P = .0378). The 15-year recurrence-free survival rates were 37% and 23.6% in the SR and RFA group respectively (P < .001). CONCLUSION: For patients with very early-stage HCC, the SR group was associated with better overall and recurrence-free patient survival compared to the RFA group. Therefore, SR should be considered as the first-line treatment for these patients.

Whole tumor ablation of locally recurred hepatocellular carcinoma including retained iodized oil after transarterial chemoembolization improves progression-free survival.

OBJECTIVES: To evaluate and compare clinical outcomes of two different radiofrequency ablation (RFA) methods for locally recurred hepatocellular carcinoma (LrHCC) after locoregional treatment. METHODS: Our institutional review board approved this study with a waiver of informed consent. A total of 313 patients previously treated with transarterial chemoembolization (TACE) (n = 167) and RFA (n = 146) with a single LrHCC ≤ 3 cm was included from five tertiary referral hospitals. RFA was done for LrHCCs using either viable tumor alone ablation (VTA) method (VTA: n = 61 in the TACE group and n = 127 in the RFA group) or whole tumor ablation (WTA) method which includes both viable tumor and retained iodized oil or previously ablated zone (WTA: n = 106 in the TACE group and n = 19 in the RFA group). Local tumor progression (LTP)-free survival as well as progression-free survival (PFS) were estimated using the Kaplan-Meier method, and prognostic factors were evaluated using the Cox proportional hazards regression model. RESULTS: In 167 patients with LrHCC who underwent TACE, the 5-year LTP-free survival after RFA was significantly higher with the VTA method than with the WTA method (26.9% vs. 87.8%; p < 0.001; hazard ratio (HR) = 8.53 [4.16-17.5]). The estimated 5-year PFS after RFA for LrHCC after TACE using the VTA method was 5.7%, which was significantly lower than that with the WTA method (26.4%) (p = 0.014; HR = 1.62 [1.10-2.38]). However, in 146 patients with LrHCC after initial RFA, there were no significant differences in cumulative incidence of LTP (p = 0.514) or PFS (p = 0.905) after RFA between the two ablation methods. CONCLUSIONS: For RFA of LrHCC after TACE, the WTA method including both viable tumor and retained iodized oil could significantly lower LTP and improve PFS than VTA. KEY POINTS: • Whole tumor ablation (WTA) could provide significantly better local tumor control for locally recurred HCC (LrHCC) after TACE than viable tumor alone ablation (VTA). • WTA for LrHCC after TACE could also provide significantly better progression-free survival than VTA. • Regarding LrHCC after RFA, VTA would provide a comparable clinical outcome to WTA.

Chemoembolization Combined with Radiofrequency Ablation for Medium-Sized Hepatocellular Carcinoma: A Propensity-Score Analysis.

PURPOSE: To compare survival outcomes of patients with single medium-sized hepatocellular carcinomas (HCCs) who underwent treatment with transarterial chemoembolization, radiofrequency (RF) ablation, or a combination of the 2 therapies. MATERIALS AND METHODS: Between 2000 and 2016, 538 patients underwent combined chemoembolization and RF ablation (n = 109), chemoembolization alone (n = 314), or RF ablation alone (n = 115) as first-line treatment for a single medium-sized (3.1-5.0 cm) HCC. Baseline demographic data (age, sex, etiology, Eastern Cooperative Oncology Group performance status, presence of liver cirrhosis, and serum bilirubin, albumin, and α-fetoprotein levels) were similar among groups except for Child-Pugh class, albumin level, and tumor size. Propensity-score analysis with inverse probability weighting (IPW) was used to reduce any bias in treatment selection and other potential confounding factors. RESULTS: Median follow-up time was 46.2 months. Before IPW, overall survival (OS) durations were significantly different among the 3 groups (median, 85 months for combined therapy, 56.5 months for chemoembolization alone, and 52.1 months for RF ablation alone; P = .01). The 10-year OS rates were 40.1%, 25.5%, and 19.5% for the combined, chemoembolization-only, and RF ablation-only groups, respectively. After IPW, OS remained superior in the combined chemoembolization/RF ablation group compared with the monotherapy groups (10-y OS, 41.8% with combined therapy, 28.4% with chemoembolization alone, and 11.9% with RF ablation alone; P = .022). CONCLUSIONS: Chemoembolization plus RF ablation may provide better survival outcomes than chemoembolization or RF ablation monotherapy, and can be considered a viable alternative treatment for unresectable single medium-sized HCCs.

Liver Imaging Reporting and Data System: Patient Outcomes for Category 4 and 5 Nodules.

Purpose To determine the outcomes after initial therapy in patients with chronic liver disease and retrospectively assigned Liver Imaging Reporting and Data System (LI-RADS; version 2014) category 4 (LR-4) and 5 (LR-5) nodules at gadoxetate disodium-enhanced MR imaging. Materials and Methods In this retrospective study, 260 patients with a single LR-4 (n = 132) or LR-5 (n = 128) nodule who were assigned a LI-RADS category were included. Patients were identified between January 2012 and December 2012, and were initially treated by resection, liver transplant, radiofrequency ablation (RFA), or transcatheter arterial chemoembolization (TACE) according to the Barcelona Clinic Liver Cancer staging system. Follow-up continued until August 31, 2016. The incidences of local tumor recurrence (ILRs) and distant tumor recurrence (IDRs) and recurrence-free survival (RFS) were compared between the LR-4 and LR-5 patients. For each category, ILRs, IDRs, and RFS were compared across the four treatments. Results LR-5 patients were more frequently treated by surgical resection than LR-4 patients (72.7% [93 of 128] vs 41.7% [55 of 132], respectively; P < .001), but less frequently treated by RFA (19.5% [25 of 128] vs 30.3% [40 of 132], respectively; P = .047) and TACE (6.3% [eight of 128] vs 22.0% [29 of 132], respectively; P < .001). ILRs and IDRs were not significantly different between LR-4 and LR-5 patients according to the type of treatment (0%-48.3% [14 of 29] vs 0%-25.0% [two of eight], P $ .423; 0%-55.2% [16 of 29] vs 0%-37.5% [three of eight], P $ .447, respectively). There was no difference in RFS between the two categories (36.3 months vs 41.7 months, respectively; P = .084). Liver transplant showed no local or distant tumor recurrence in either category. Resection showed higher RFS and lower ILR and IDR than RFA and TACE in both LR-4 and LR-5 patients. Conclusion Patients with LR-4 nodules had ILRs and IDRs similar to patients with LR-5 nodules when stratified by treatment type. RFS was also similar between patients with LR-4 and LR-5 nodules. Among the four initial treatments, liver transplant and resection showed better local tumor control, with longer RFS than RFA or TACE. © RSNA, 2018 Online supplemental material is available for this article.

Utility and Safety of Repeated Ultrasound-Guided Core Needle Biopsy of Focal Liver Masses.

OBJECTIVES: To evaluate the accuracy and safety of repeated ultrasound-guided core needle biopsy (CNB) for hepatic focal lesions and to assess the predictive factors for success of repeated CNB. METHODS: For 5 years, 3085 CNBs were performed for focal hepatic lesions using an automated biopsy gun with an 18-gauge needle. Seventy-eight patients underwent repeated CNB because of pathologically inconclusive or unexpected results. Twelve patients were excluded because of unavailable additional tissue or follow-up imaging by radiofrequency ablation (n = 5), repeated CNB greater than than 3 months after the first CNB (n = 5), and insufficient follow-up time (n = 2). Sixty-six patients were finally enrolled after the exclusion criteria were applied. We retrospectively evaluated tumor necrosis, tumor size, number of passes, lesion site, depth, tumor conspicuity, and complications. Continuous data and the total scores of the grading system were analyzed by the Student t test, and categorical data and each category were analyzed by the Fisher exact test. RESULTS: The repeated CNB rate was 2.5% (78 of 3085). The diagnostic accuracy of the repeated biopsies was 83.3% (55 of 66). Comparing the diagnostic group with the nondiagnostic group, no variable (ie, size, depth, necrosis, lesion site [segment], and number of passes) had a statistically significant difference. Tumor conspicuity was a significant factor for predicting successful repeated biopsy (P < .001). The cumulative complication rate was 10.6% (7 of 66), with only minor complications. CONCLUSIONS: Repeated CNB is an accurate and safe procedure for obtaining a histologic diagnosis of hepatic focal lesions if the initial biopsy fails. High tumor conspicuity showed a significant correlation with successful repeated CNB.

Efficacy and Safety of Radiofrequency Ablation for Focal Hepatic Lesions Adjacent to Gallbladder: Reconfiguration of the Ablation Zone through Probe Relocation and Ablation Time Reduction.

PURPOSE: To evaluate the safety and efficacy of radiofrequency (RF) ablation for treatment of focal hepatic lesions adjacent to the gallbladder with electrode relocation and ablation time reduction. MATERIALS AND METHODS: Thirty-nine patients who underwent RF ablation for focal hepatic lesions adjacent to the gallbladder (≤ 10 mm) were evaluated retrospectively from January 2011 to December 2014 (30 men and 9 women; age range, 51-85 y; mean age, 65 y). Of 36 patients with hepatocellular carcinoma, 3 had a second treatment for recurrence (mean tumor size, 15 mm ± 6). Patients were divided into 2 subgroups based on lesion distance from the gallbladder: nonabutting (> 5 mm; n = 19) and abutting (≤ 5 mm; n = 20). Electrodes were inserted parallel to the gallbladder through the center of a tumor in the nonabutting group and through the center of the expected ablation zone between a 5-mm safety zone on the liver side and the gallbladder in the abutting group. Ablation time was decreased in proportion to the transverse diameter of the expected ablation zone. RESULTS: Technical success and technical effectiveness rates were 89.7% and 97.4%, respectively, with no significant differences between groups (P = 1.00). Local tumor progression was observed in 3 patients (1 in the nonabutting group and 2 in the abutting group; P = 1.00). There were no major complications. The gallbladder was thickened in 10 patients, with no significant difference between groups (P = .72). Biloma occurred in 1 patient in the nonabutting group. CONCLUSIONS: RF ablation with electrode relocation and reduction of ablation time can be a safe and effective treatment for focal hepatic lesions adjacent to the gallbladder.

Embolization for Bleeding after Hepatic Radiofrequency Ablation.

PURPOSE: To evaluate safety and clinical efficacy of embolization for management of bleeding after hepatic radiofrequency (RF) ablation. MATERIALS AND METHODS: From January 2000 to December 2014, 5,196 patients with 9,743 tumors underwent 8,303 RF ablation sessions. Of these patients, 62 experienced bleeding after hepatic RF ablation; 15 patients (12 men and 3 women; mean age 62 y; range, 49-76 y) underwent embolization and composed the final study cohort. Tumors were hepatocellular carcinomas in 13 (87%) patients and metastatic adenocarcinomas from colorectal cancer in 2 (13%) patients. Mean number of tumors was 1.5 (22 nodules; range, 1-3). Tumor locations were segment I (n = 1), segment II (n = 2), segment III (n = 1), segment IV (n = 1), segment V (n = 3), segment VI (n = 5), segment VII (n = 1), and segment VIII (n = 9). Mean tumor size was 2.3 cm (range, 0.9-5 cm). RESULTS: Median time interval between presentation and angiography was 22 hours (mean 38.4 h; range, 3-168 h). On angiography, contrast extravasation with or without pseudoaneurysm was seen in all 15 patients; 14 patients underwent transarterial embolization, and 1 patient underwent percutaneous transhepatic portal vein embolization. Successful hemostasis was achieved in all patients. There was no rebleeding within 30 days after embolization. No embolization-related major complications were observed. CONCLUSIONS: Embolization is safe and effective for controlling bleeding related to hepatic RF ablation without the need for surgery.

Changes in echogenicity of hepatic hemangiomas during the valsalva maneuver.

BACKGROUND: We aimed to evaluate changes in echogenicity of hepatic hemangiomas during the Valsalva maneuver. METHODS: We examined 16 liver hemangiomas in 12 patients with a mean diameter of 1.5 cm (range, 0.7-2.2 cm), which showed variations in echogenicity during the Valsalva maneuver. Two radiologists reviewed the sonographic (US) images of the hemangiomas at three different times: prior to the Valsalva maneuver, during the Valsalva maneuver, and on follow-up US examinations. RESULTS: Prior to Valsalva maneuver, the 16 hemangiomas appeared as hypoechoic nodules with an echogenic rim (n = 7), homogeneously echogenic nodules (n = 5), one hypoechoic nodule with sound-through enhancement, one heterogeneous nodule with a hyperechoic rim, one heterogeneous nodule, and one echogenic nodule with a hyperechoic rim. During the Valsalva maneuver, increased echogenicity was observed in 11 cases, as a diffuse increase in 5 cases, and as a partial increase in 6. Prior to the Valsalva maneuver, 9 of 16 hemangiomas exhibited an echogenic rim. During the maneuver, all the rims were accentuated, and an additional five hemangiomas exhibited an echogenic rim. Throughout follow-up, 12 of 15 hemangiomas underwent some echogenicity change. CONCLUSIONS: Use of the Valsalva maneuver during US examination of the liver can increase the echogenicity of hepatic hemangiomas and accentuate the echogenic rim, which could enhance the operator's confidence in the diagnosis of hemangioma. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:328-331, 2017.

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.

Diagnostic criteria for hepatocellular carcinoma ⩽3 cm with hepatocyte-specific contrast-enhanced magnetic resonance imaging.

BACKGROUND & AIMS: Current diagnostic imaging criteria for hepatocellular carcinoma (HCC) are dedicated to imaging with nonspecific extracellular contrast agents. This study aimed to evaluate diagnostic criteria for HCC ⩽3 cm on magnetic resonance imaging (MRI) with a hepatocyte-specific contrast agent through an inception cohort study. METHODS: Of 291 patients with chronic liver disease and new nodules of 1-3 cm in diameter at surveillance ultrasonography, 295 solid nodules (194 HCCs, 98 benign nodules, and three other malignancies) in 198 patients with a confirmed final diagnosis or ⩾24 months follow-up were evaluated on gadoxetic acid-enhanced MRI. Through univariate and multivariate logistic regression analyses, various diagnostic criteria were developed by combining significant MRI findings for diagnosing HCC. The diagnostic performance of each criterion was compared with that of the European Association for the Study of the Liver (EASL) criteria. RESULTS: Four MRI findings (arterial-phase hyperintensity, transitional-phase hypointensity, hepatobiliary-phase hypointensity, and rim enhancement) were independently significant for diagnosis of HCC ⩽3 cm. For whole nodules, EASL criteria showed the best performance for diagnosing HCC (sensitivity, 83.5%; specificity, 81.2%). For nodules ⩽2 cm in diameter, a new criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) showed a significantly higher sensitivity than that of the EASL criteria (83.0% vs. 74.5%, p=0.008), without a significantly different specificity (76.7% vs. 81.1%, p=0.125). CONCLUSIONS: EASL criteria exhibit the best diagnostic performance for HCC ⩽3 cm on hepatocyte-specific contrast-enhanced MRI. A newly identified criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) may increase the diagnostic sensitivity of small (⩽2 cm) HCC.

Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI.

OBJECTIVES: To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). METHODS: On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤ 50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. RESULTS: Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. CONCLUSIONS: Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. KEY POINTS: On gadoxetate disodium-enhanced MRI, some hepatic haemangiomas show pseudo-washout in transitional phase. Regardless of chronic liver disease, pseudo-washout is significantly more common in rapidly enhancing haemangiomas. Rapidly enhancing haemangiomas show complete or progressive incomplete enhancement or pseudo-washout in TP. Slowly enhancing haemangiomas show progressive incomplete enhancement in portal venous phase and TP.

Feasibility of a Low-Power Radiofrequency Ablation Protocol to Delay Steam Popping.

PURPOSE: Steam popping frequently occurs during conventional high-power radiofrequency (RF) ablation, increasing the risk of tumor spread. The aim of this study was to evaluate the effect of a low-power RF ablation protocol on the intensity and timing of steam popping in ex vivo bovine liver. MATERIALS AND METHODS: High-power (maximum 200 W; group 1) and low-power (maximum 70 W; group 2) RF ablation protocols were established. In the first phase, RF ablation was conducted for 12 min. Ablation volume, intensity, and timing of maximal popping sounds and total energy generated for RF ablation were compared between groups 1 and 2. In the second phase, RF ablation was conducted until maximal popping occurred, and ablation zones on histologic specimens were compared. RESULTS: Relative to group 1, maximal popping occurred at significantly delayed timing in group 2 (50 s ± 11 vs 397 s ± 117; P < .001), but without a difference in intensity (ratios vs reference sound of 0.70 ± 0.18 vs 0.83 ± 0.26; P = .138). The ablation volume after 12 min of RF ablation did not differ between groups 1 and 2 (18.46 cm(3) ± 1.35 vs 15.78 cm(3) ± 0.64; P = .086). However, in the histologic specimens obtained when maximal popping occurred, the area of complete coagulative necrosis was significantly larger in group 2 (P < .05). CONCLUSIONS: Low-power RF ablation delays steam popping while providing comparable therapeutic effects to high-power RF ablation. Delaying maximal popping may prevent tumor cell dispersion because maximal popping occurs after an adequate ablation zone has been achieved.