The Role of Contrast-Enhanced Ultrasound Plus Color Parametric Imaging in the Differential Diagnosis of Subpleural Pulmonary Lesions.

OBJECTIVES: To distinguish benign and malignant subpleural pulmonary lesions (SPLs) with contrast-enhanced ultrasound (CEUS) and color parametric imaging (CPI), and evaluate the role of CEUS plus CPI in the differential diagnosis of pathological types of SPLs. METHODS: One hundred and thirty-six patients underwent CEUS with a Logiq E9 XD Clear ultrasonic machine equipped with a 3.5- to 5.0-MHz C5-1 transducer in our center were enrolled in our study, including 27 cases of benign lesions and 109 cases of malignant lesions. The ultrasound contrast agent used in this study was SonoVue. CEUS images and CPI of all cases were reviewed and analyzed by the resident and staff radiologist groups separately. RESULTS: With CEUS alone, by both the two groups, the main enhancement pattern of benign SPLs was arborization (P < .001), while centripetal enhancement pattern occurred more frequently in malignant SPLs (P < .001). With CEUS plus CPI, by both the two groups, the main enhancement pattern of benign SPLs was arborization (P < .001), while those of malignant SPLs were centripetal (P < .001) and eccentric (P < .05). The diagnosis performance of CEUS plus CPI was significantly higher than that of CEUS alone in both the resident (area under the curve [AUC] = 0.857 vs 0.677, P < .001) and staff (AUC = 0.866 vs 0.681, P < .001) groups. Moreover, CPI offered remarkable inter-consistency improvements in the enhancement pattern determination between the two groups. CONCLUSION: The CEUS enhancement patterns would provide information of blood perfusion patterns in the differential diagnosis of benign and malignant SPLs. The diagnosis performance could be significantly improved by CEUS plus CPI compared with CEUS alone.

Percutaneous ultrasound-guided radiofrequency ablation for patients with liver metastasis from pancreatic adenocarcinoma.

OBJECTIVE: To analyze the survival outcomes and prognostic factors of radiofrequency ablation (RFA) for pancreatic adenocarcinoma liver metastasis (PALM). METHODS: Between January 2010 and July 2021, 20 patients (13 males) with an average age of 58.9 ± 11.7 years who underwent RFA for PALM were included. The mean maximum diameter of PALMs was 2.6 ± 1.1 cm (1.0-6.0 cm). Survival curves were built using the Kaplan-Meier method and compared by the log-rank test. Multivariable analyses were performed by using the Cox proportional hazards model. RESULTS: Twenty patients with 29 PALMs underwent 23 RFA sessions. Technical efficacy was achieved in 28 PALMs (28/29, 96.6%). The mean overall survival (OS) after RFA was 14.6 months and the 1-, 2-year survival rates were 39.5%, 18.1%, respectively. With multivariate analysis, abnormal serum levels of CA199 (p = 0.023) and extrahepatic metastasis before RFA (p = 0.038) were identified as independent prognostic factors for OS in patients with PALM. Additionally, the mean progression-free survival (PFS) after RFA was 11.5 months and 1-, 2- year survival rates were 26.0%, 17.3%, respectively. With multivariate analysis, abnormal serum levels of CA199 (p = 0.016) and extrahepatic metastasis before RFA (p = 0.043) were also identified as independent prognostic factors for PFS in patients with PALM. CONCLUSION: RFA is a safe and effective treatment for patients with PALM, especially in patients with normal serum level of CA199 or the patients without extrahepatic metastases before RFA.

The 10-year Survival Analysis of Radiofrequency Ablation for Solitary Hepatocellular Carcinoma 5 cm or Smaller: Primary versus Recurrent HCC.

Background Although favorable outcomes have been reported with radiofrequency ablation (RFA) for limited hepatocellular carcinoma (HCC), the efficacy of this treatment for recurrent HCC has not been thoroughly investigated. Purpose To compare the long-term outcomes and analyze the prognostic factors for outcomes after RFA for initial HCC versus as a second-line treatment for recurrent HCC. Materials and Methods This retrospective study included 560 patients with solitary tumors 5 cm or smaller (263 initial HCCs, 297 -recurrent HCCs) who underwent percutaneous US-guided RFA from January 2005 to December 2016. Of 297 patients with -recurrent HCC, 134 had previously undergone hepatectomy, 128 had undergone transarterial chemoembolization (TACE), and 35 had undergone local ablation therapy. Overall survival (OS) between initial HCC and recurrent HCC was compared before and after propensity score matching. Prognostic factors for all patients were analyzed with the log-rank test and Cox proportional hazards model. Results A total of 560 patients (mean age, 60 years ± 12 [standard deviation]; 441 men) were evaluated. Before matching, the OS rates at 1, 3, 5, and 10 years were 92.6%, 73.9%, 59.3%, and 39.6%, respectively, in patients with recurrent HCC and 92.8%, 75.4%, 63.3%, and 44.7% in patients with initial HCC (P = .27). After matching, the OS rates at 1, 3, 5, and 10 years were 94.8%, 75.7%, 61.6%, and 47.3% in the initial HCC group and 91.9%, 71.2%, 58.7%, and 45.2% in the recurrent HCC group (P = .32). Among patients with recurrent HCC, no significant difference in mean OS was noted for local recurrence versus distant recurrence (81.6 months ± 5.1 vs 83.8 months ± 6.6, P = .82) or previous treatment modality (82.0 months ± 7.3 in the resection group, 82.7 months ± 5.3 in the TACE group, and 79.3 months ± 10.8 in the local ablation group; P = .83). Local tumor progression after previous local ablation (10 of 35 [28.6%]) was higher than that after previous hepatectomy (15 of 134 [11.2%], P = .04). Multivariable analysis demonstrated that tumor size (hazard ratio, 1.58; 95% CI: 1.06, 2.36; P = .02), portal hypertension (hazard ratio, 1.52; 95% CI: 1.03, 2.26; P = .04), Child-Pugh class (hazard ratio, 2.01; 95% CI: 1.02, 3.96; P = .045), and serum α-fetoprotein level (hazard ratio, 1.62; 95% CI: 1.10, 2.39; P = .01) were independent predictive factors for recurrent HCC outcomes. Conclusion Radiofrequency ablation provides similar long-term survival for solitary hepatocellular carcinoma of 5 cm or less, regardless of whether treatment is initial or salvage therapy. © RSNA, 2021 Online supplemental material is available for this article.

Long-term outcomes and prognostic analysis of percutaneous radiofrequency ablation in liver metastasis from breast cancer.

OBJECTIVE: To evaluate the long-term efficacy and prognostic factors of ultrasound-guided percutaneous radiofrequency ablation (RFA) for breast cancer liver metastasis (BCLM). METHODS: Between 2000 and 2015, 69 patients who underwent ultrasound-guided percutaneous RFA for BCLM and had regular follow-up examinations were included. All patients had undergone resection of the primary breast cancer and had received chemotherapy, endocrine therapy or both after surgery. The sample included two males and 67 females with an average age of 50.3 ± 10.0 years (31-76 y). The mean maximum diameter of metastatic lesions in the liver was 2.9 ± 1.4 cm (1.0-6 cm). Thirty-five patients had a single metastasis, while 34 patients had multiple liver metastases (2-5 lesions). Survival results were generated using Kaplan-Meier estimates and a multivariate analysis was performed using the Cox regression model. RESULTS: In total, 92 RFA sessions were performed and 135 BCLM lesions were treated. Major complications occurred in one of the 92 sessions (1.1%). Technical efficacy was achieved in 92.6% of lesions (125/135 lesions). Local tumor progression occurred in 11.6% (8/69) of patients and new intrahepatic metastasis occurred in 55.1% (38/69) of patients. From the time of initial RFA, the median overall survival was 26 months, and the one-, two-, three- and five -year survival rates were 81.8, 50.1, 25.3 and 11.0%, respectively. Based on the multivariate analysis, the following three factors were identified as independent prognostic factors for overall survival: tumor size (p = .017), positive estrogen receptor status (p = .009) and extrahepatic metastatic disease (p = .001). The median progression-free survival was 24 months, and the one-, two-, three- and five -year survival rates after RFA were 77.4, 47.0, 23.7 and 8.5%, respectively. Additionally, the independent prognostic factors for progression-free survival included tumor size (p = .011), ER positivity (p = .001), margin size (p = .017) and extrahepatic metastatic disease (p < .001). CONCLUSION: The results of this study showed that RFA is a safe and locally effective method for the treatment of BCLM, especially in patients with lesions measuring less than 3 cm in diameter, a single liver metastasis, positive estrogen receptor status and no extrahepatic metastases. Also, patients with margin size >10 mm had no local tumor progression.

RAD21: A Key Transcriptional Regulator in the Development of Residual Liver Cancer.

Objective: Thermal ablation is a commonly used therapy for hepatocellular carcinoma (HCC). Nevertheless, inadequate ablation can lead to the survival of residual HCC, potentially causing rapid progression. The underlying mechanisms for this remain unclear. This study explores the molecular mechanism responsible for the rapid progression of residual HCC. Methods: We established an animal model of inadequate ablation in BALB/c nude mice and identified a key transcriptional regulator through high-throughput sequencing. Subsequently, we conducted further investigations on RAD21. We evaluated the expression and clinical significance of RAD21 in HCC and studied its impact on HCC cell function through various assays, including CCK-8, wound healing, Transwell migration and invasion. In vitro experiments established an incomplete ablation model verifying RAD21 expression and function. Using ChIP-seq, we determined potential molecules regulated by RAD21 and investigated how RAD21 influences residual tumor development. Results: High RAD21 expression in HCC was confirmed and correlated with low tumor cell differentiation, tumor growth, and portal vein thrombosis. Silencing RAD21 inhibited the migration, invasion, and proliferation significantly in liver cancer cells. Patients with high RAD21 levels showed elevated multiple inhibitory immune checkpoint levels and a lower response rate to immune drugs. Heat treatment intensified the malignant behavior of liver cancer cells, resulting in increased migration, invasion, and proliferation. After subjecting it to heat treatment, the results indicated elevated RAD21 levels in HCC. Differentially expressed molecules regulated by RAD21 following incomplete ablation were primarily associated with the VEGF signaling pathway, focal adhesion, angiogenesis, and hepatocyte growth factor receptor signaling pathway etc. Conclusion: The upregulation of RAD21 expression after incomplete ablation may play a crucial role in the rapid development of residual tumors and could serve as a novel therapeutic target.

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

Objective: The purpose of this study was to investigate the added value of color parameter imaging (CPI) in the differential diagnosis of focal liver lesions (FLLs) with "homogeneous hyperenhancement but not wash out" on contrast-enhanced ultrasound (CEUS). Methods: A total of 101 patients with 108 FLLs were enrolled in this study. All the FLLs received US and CEUS examinations. The stored CEUS clips of target lesions were postprocessed with CPI analysis by radiologists. The receiver operator characteristic (ROC) curve was used to evaluate the added value of CPI. The McNamara test was used to compare the diagnostic sensitivity, specificity, and accuracy between CEUS and CPI patterns. Univariate and multivariate logistic regression analyses were used to develop a CPI nomogram. The C index and calibration curve were used to evaluate the predictive ability of the nomogram. The intraclass correlation coefficient was used to test the reproducibility and reliability of CPI. Decision curve analysis (DCA) was used to evaluate the added value of applying CPI. Results: The following CPI features were more frequently observed in malignant FLLs: eccentric perfusion (malignant: 70.0% vs. benign: 29.2%, p < 0.001), feeding artery (51.7% vs. 4.2%, p < 0.001), mosaic (63.3% vs. 6.3%, p < 0.001), red ingredients >1/3 (90.0% vs. 14.6%, p < 0.001). In addition, centripetal (43.8% vs. 18.3%, p = 0.004), peripheral nodular (54.2% vs. 1.7%, p < 0.001), subcapsular vessel (12.5% vs. 0.0%, p = 0.004), spoke-wheel vessels (25.0% vs. 5.0%, p = 0.003), branched vessels (22.9% vs. 5.0%, p = 0.006), blue and pink ingredients >2/3 (85.4% vs. 10.0%, p < 0.001) were more observed in benign FLLs. A nomogram incorporating peripheral nodular, spoke-wheel vessels, and red ingredients >1/3 was constructed. The model had satisfactory discrimination (AUC = 0.937), and the optimal diagnostic threshold value was 0.740 (0.983, 0.850). By the DCA, the model offered a net benefit over the treat-all-patients scheme or the treat-none scheme at a threshold probability 5%-93%. Conclusion: Using CPI can detect and render subtle information of the main features of FLLs on CEUS; it is conducive to the radiologist for imaging interpretation, and a combining read of the CEUS and CPI of the FLLs with features of "homogenous hyperenhancement and no washout" can improve significantly the diagnostic performance of CEUS for FLLs.

An evaluation of 20-year survival of radiofrequency ablation for hepatocellular carcinoma as first-line treatment.

OBJECTIVES: To evaluate the changes in clinical characteristics, overall survival (OS), and progression-free survival (PFS) by investigating a 20-year cohort of patients with HCC who underwent RFA treatment. METHODS: From 2000 to 2020, 505 consecutive patients with HCC underwent ultrasound-guided percutaneous RFA as first-line therapy at a tertiary cancer hospital. We divided the cohort according to the time when hepatitis-B antiviral therapy was covered by national medical insurance coverage (early 2011), including the first decade (2000-2010) and second decade (2011-2020). The prognostic factors for OS were analyzed by the Cox proportional hazard model. OS and PFS in different groups were compared using the Kaplan-Meier method. To reduce selection bias, matched groups of patients were selected using the propensity score matching (PSM) method. RESULTS: In total, 726 RFA sessions were performed to treat 867 HCC lesions. Patients treated in the second decade were younger (p =.047), had smaller tumors (p <.001), had lower Child-Pugh scores (p <.001), and had a higher proportion of antiviral treatment (p <.001). A total of 96.0% of patients achieved technical efficacy from the initial RFA. After PSM analysis, improved PFS was found for the second decade (median, 68 vs. 49 months, p =.003), but no significant difference in OS was observed between the two groups (median, 71 vs. 65 months, p =.20). CONCLUSIONS: This study demonstrated that improved PFS was achieved in patients with HCC receiving RFA as first-line treatment in the second decade. However, long-term OS was not significantly increased compared to the first decade suggesting that while RFA treatment has improved, it still might not substantially affect OS results.

Enhancement of Copper Uptake of Yeast Through Systematic Optimization of Medium and the Cultivation Process of Saccharomyces cerevisiae.

Copper is an essential trace element for living organisms. Copper enriched by yeast of Saccharomyces cerevisiae is regarded as the biologically available organic copper supplement with great potentiality for application. However, the lower uptake ratio of copper ions makes the production of copper enriched by yeast uneconomically and environmentally unfriendly. In this study, S. cerevisiae Cu-5 with higher copper tolerance and intracellular copper accumulation was obtained by screening of our yeast strains collection. To increase the uptake ratio of copper ions, the medium composition and cultivation conditions for strain Cu-5 were optimized systematically. A medium comprised of glucose, yeast extract, (NH4)2SO4, and inorganic salts was determined, then a novel cultivation strategy including pH control at 5.5 and increasing amounts of yeast extract for a higher concentration of copper ion in the medium was developed. The uptake ratios of copper ions were more than 90% after combining 50 to 100 mg/L copper ions with 3.5 to 5.0 g/L yeast extract, which is the highest until now and is conducive to the cost-effective and environmentally friendly production of bioactive copper in yeast-enriched form.

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

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

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

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

Differentiation of atypical hepatic hemangioma from liver metastases: Diagnostic performance of a novel type of color contrast enhanced ultrasound.

BACKGROUND: In clinical practice, the diagnosis is sometimes difficult with contrast-enhanced ultrasound (CEUS) when the case has an atypical perfusion pattern. Color parametric imaging (CPI) is an analysis software for CEUS with better detection of temporal differences in CEUS imaging using arbitrary colors. It measures the differences in arrival time of the contrast agent in lesions so that the perfusion features of atypical hemangioma and colorectal cancer (CRC) liver metastasis can be distinguished. AIM: To evaluate the role of a novel type of CPI of CEUS in the differential diagnosis of atypical hemangioma from liver metastases in patients with a history of CRC. METHODS: From January 2016 to July 2018, 42 patients including 20 cases of atypical hemangioma and 22 cases of liver metastases from CRC were enrolled. These patients had a mean age of 60.5 ± 9.3 years (range: 39-75 years). All patients received ultrasound, CEUS and CPI examinations. Resident and staff radiologists independently and retrospectively reviewed CEUS and CPI images. Two sets of criteria were assigned: (1) Routine CEUS alone; and (2) CEUS and CPI. The diagnostic sensitivity, specificity, accuracy and receiver operating characteristic (ROC) curve of resident and staff radiologists were analyzed. RESULTS: The following CPI features were significantly different between liver hemangioma and liver metastases analyzed by staff and resident radiologists: Peripheral nodular enhancement (65%-70.0% vs 4.5%-13.6%, P < 0.001, P = 0.001), mosaic/chaotic enhancement (5%-10% vs 68.2%-63.6%, P < 0.001, P < 0.001) and feeding artery (20% vs 59.1%-54.5%, P = 0.010, P = 0.021). CPI imaging offered significant improvements in detection rates compared with routine CEUS in both resident and staff groups. By resident radiologists, the specificity and accuracy of CEUS+CPI were significantly increased compared with that of CEUS (77.3% vs 45.5%, P = 0.030; 78.6% vs 50.0%, P = 0.006). In addition, the area under the curve (AUC) of CEUS+CPI was significantly higher than that of CEUS (0.803 vs 0.757, P = 0.036). By staff radiologists, accuracy was improved in CEUS+CPI (81.0% vs 54.8%, P = 0.010), whereas no significant differences in specificity and sensitivity were found (P = 0.144, P = 0.112). The AUC of CEUS+CPI was significantly higher than that of CEUS (0.890 vs 0.825, P = 0.013) by staff radiologists. CONCLUSION: Compared with routine CEUS, CPI could provide specific information on the hemodynamic features of liver lesions and help to differentiate atypical hemangioma from liver metastases in patients with CRC, even for senior radiologists.

Thermosensitive liposomal doxorubicin plus radiofrequency ablation increased tumor destruction and improved survival in patients with medium and large hepatocellular carcinoma: A randomized, double-blinded, dummy-controlled clinical trial in a single center.

BACKGROUND: Lyso-thermosensitive liposomal doxorubicin (LTLD, ThermoDox) consists of doxorubicin encapsulated contained within a heat-sensitive liposome. AIMS AND OBJECTIVES: We sought to evaluate whether the use of combined radiofrequency ablation (RFA) and LTLD would result in larger coagulation volume and longer overall survival (OS) compared with the use of RFA alone in patients with 3-7 cm unresectable hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Between 2010 and 2012, 22 HCC patients were randomly assigned to one of two treatments in our center: (1) ultrasound-guided percutaneous RFA plus intravenous (IV) infusion of LTLD (combination, n = 11) or (2) RFA plus IV dummy (RFA, n = 11). Four patients withdrew from the study, and the remaining 18 patients entered the final analysis. There were 14 male and 4 female patients with an average age of 61.1 ± 9.3 years (range: 40-73 years). The average tumor size was 4.2 ± 1.0 cm (range: 3.1-6.1 cm). One-month enhanced computed tomography was used to evaluate the ablation efficacy and coagulation volume after RFA. Regular follow-up after RFA was performed to assess toxicity, local response rates, and OS rates. RESULTS: A major complication (empyema) occurred in one case in the combination group. Combination treatment region did not induce any additional toxicity beyond doxorubicin. The primary ablation success rate was 93.3% (14/15 tumors) in the combination group and 77.8% (7/9 tumors) in the RFA group (P = 0.308). The difference in coagulation volume between pre- and post-RFA in the combination group was significantly larger than that of the RFA group (105.7 ± 73.8 cm 3 vs. 37.3 ± 8.5 cm 3, P = 0.013). The follow-up period ranged from 11 to 80 months (average: 49.1 ± 24.8 months). The local progression rate was 6.7% (1/15 tumors) in the combination group and 22.2% (2/9 tumors) in the RFA group. The mean OS for the combination group was 68.5 ± 7.2 months, which was significantly greater compared with the RFA group (46.0 ± 10.6 months, P = 0.045). CONCLUSIONS: RFA with heat target delivery chemotherapy facilitated better tumor coagulation necrosis without additional toxicity. This combined treatment may improve the clinical efficacy of RFA or free doxorubicin and prolong survival in patients with medium to large HCC.

The Role of a Curved Electrode with Controllable Direction in the Radiofrequency Ablation of Liver Tumors Behind Large Vessels.

PURPOSE: To investigate the role of a novel curved radiofrequency ablation (RFA) electrode with controllable direction in the ablation of tumors behind large hepatic vessels in ex vivo bovine and in vivo canine liver experiments. MATERIALS AND METHODS: Approval from the institutional animal care and use committee was obtained. In ex vivo experiments, conventional multi-tines expandable electrodes, conventional monopolar straight electrodes and novel curved electrodes were used in the ablation of the bovine liver (n = 90). The ablated area, parallel axis, vertical axis and shape of different electrodes were compared. Then, 24 beagle dogs (10 months old, female) were used for in vivo experiments. Visual tumor targets deeply located in the portal vein were established, and ultrasound-guided liver ablation was performed with different electrodes. The ablation range, target coverage rate, percentage of normal tissue injury and damage to adjacent vessels were evaluated. The Kruskal-Wallis test and the Chi-squared test were used for statistical analysis. RESULTS: For the ex vivo study with a 3-cm electrode, the ablation area of the multi-tines expandable electrode group (7.14 ± 0.16 cm2) was significantly larger than that of the novel curved electrode group (5.01 ± 0.30 cm2, P < 0.001) and the monopolar straight electrode group (5.43 ± 0.15 cm2, P < 0.001). The results obtained with the 4-cm electrode in the three groups were in accordance with those of the 3-cm electrode. In vivo, the normal tissue damage area of the novel curved electrode group was smaller than that of the multi-tines expandable electrode group (1.10 ± 0.18 cm2 vs. 4.00 ± 0.18 cm2, P < 0.001). The target coverage rate of the novel curved electrode group was better than that of the monopolar straight electrode group (100% vs. 80.86 ± 1.68%, P < 0.001). The hematoxylin and eosin (H&E) and TUNEL staining results showed that the ablation necrosis area was adjacent to large vessels, but the vascular wall was not significantly damaged in the novel curved electrode group. CONCLUSION: Our preliminary results showed that the novel curved RFA electrode with controllable direction could achieve accurate ablation for tumors behind large hepatic vessels, with a better target coverage rate and less damage to normal tissue, than conventional multi-tines expandable electrodes and monopolar straight electrodes.