Determination of the electrical conductivity of human liver metastases: impact on therapy planning in the radiofrequency ablation of liver tumors

2016 ◽  
Vol 58 (2) ◽  
pp. 164-169 ◽  
Author(s):  
Urte Zurbuchen ◽  
Franz Poch ◽  
Ole Gemeinhardt ◽  
Martin E Kreis ◽  
Stefan M Niehues ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Radiofrequency Ablation ◽  
Liver Metastasis ◽  
Liver Metastases ◽  
Liver Tissue ◽  
Colorectal Liver Metastases ◽  
Liver Tumors ◽  
Tissue Temperature ◽  
Specific Electrical Conductivity

Background Radiofrequency ablation is used to induce thermal necrosis in the treatment of liver metastases. The specific electrical conductivity of a liver metastasis has a distinct influence on the heat formation and resulting tumor ablation within the tissue. Purpose To examine the electrical conductivity σ of human colorectal liver metastases and of tumor-free liver tissue in surgical specimens. Material and Methods Surgical specimens from patients with resectable colorectal liver metastases were used for measurements (size of metastases <30 mm). A four-needle measuring probe was used to determine the electrical conductivity σ of human colorectal liver metastasis (n = 8) and tumor-free liver tissue (n = 5) in a total of five patients. All measurements were performed at 470 kHz, which is the relevant frequency for radiofrequency ablation. The tissue temperature was also measured. Hepatic resections were performed in accordance with common surgical standards. Measurements were performed in the operating theater immediately after resection. Results The median electrical conductivity σ was 0.57 S/m in human colorectal liver metastases at a median temperature of 35.1℃ and 0.35 S/m in tumor-free liver tissue at a median temperature of 34.9℃. The electrical conductivity was significantly higher in tumor tissue than in tumor-free liver tissue ( P = 0.005). There were no differences in tissue temperature between the two groups ( P = 0.883). Conclusion The electrical conductivity is significantly higher in human colorectal liver metastases than in tumor-free liver tissue at a frequency of 470 kHz.

scholarly journals Resection or radiofrequency ablation of colorectal liver metastasis

2014 ◽  
Vol 71 (6) ◽  
pp. 542-546 ◽  
Author(s):  
Damir Jasarovic ◽  
Dragos Stojanovic ◽  
Nebojsa Mitrovic ◽  
Dejan Stevanovic
Keyword(s):  
Overall Survival ◽  
Radiofrequency Ablation ◽  
Liver Metastasis ◽  
Liver Metastases ◽  
Colorectal Liver Metastasis ◽  
Colorectal Liver Metastases ◽  
Disease Free Survival ◽  
University Hospital ◽  
Term Survival ◽  
Cancer Metastases

Background/Aim. Liver resection is the treatment of choice for solitary colorectal liver metastases in suitable candidates. Recently, radiofrequency ablation (RFA) has become a very popular procedure in the treatment of liver metastases. The aim of this study was to compare outcomes in patients with solitary colorectal liver metastasis who had been subjected to resection or ablation. Methods. In this retrospective study we analyzed and compared patients with solitary colorectal liver metastases treated by resection or ablation in the University Hospital Centre ?Dr Dragisa Misovic? in Belgrade from January 2002 until December 2009. Results. In this study 94 (67.1%) patients underwent resection whereas 46 (32.9%) patients underwent RFA. Most of the resected patients (59.6%) required major hepatectomy. The median follow-up time was 28.4 months. Tumor ablation was a significant predictor of the overall survival (p = 0.002; OR 3.75; 95% CI 1.696-8.284). Our study demonstrated longer disease free-survival in the group of resected patients compared to the RFA group (37.6 vs 22.3 months, p = 0.073). The median overall survival was 56.3 months for patients who underwent resection vs 25.1 months for those in the RFA group (p = 0.005). Conclusion. This study shows that the patients with solitary hepatic colorectal cancer metastases should be considered for hepatic resection whenever it is feasible, because this procedure provides superior long-term survival as compared to radiofrequency ablation.

Radiofrequency ablation of colorectal liver metastases

2019 ◽  
Vol 98 (10) ◽  
Keyword(s):  
Radiofrequency Ablation ◽  
Liver Resection ◽  
Liver Metastases ◽  
Colorectal Liver Metastases ◽  
Survival Rates ◽  
Postoperative Mortality ◽  
Disease Free Survival ◽  
Female Ratio ◽  
Liver Resections ◽  
Multi Stage

Introduction: Radical liver resection is the only method for the treatment of patients with colorectal liver metastases (CLM); however, only 20–30% of patients with CLMs can be radically treated. Radiofrequency ablation (RFA) is one of the possible methods of palliative treatment in such patients. Methods: RFA was performed in 381 patients with CLMs between 01 Jan 2001 and 31 Dec 2018. The mean age of the patients was 65.2±8.7 years. The male to female ratio was 2:1. Open laparotomy was done in 238 (62.5%) patients and the CT-navigated transcutaneous approach was used in 143 (37.5%) patients. CLMs <5 cm (usually <3 cm) in diameter were the indication for RFA. We used RFA as the only method in 334 (87.6%) patients; RFA in combination with resection was used in 36 (9.4%), and with multi-stage resection in 11 (3%) patients. We performed RFA in a solitary CLM in 170 (44.6%) patients, and in 2−5 CLMs in 211 (55.6%) patients. We performed computed tomography in each patient 48 hours after procedure. Results: The 30-day postoperative mortality was zero. Complications were present in 4.8% of transcutaneous and in 14.2% of open procedures, respectively, in the 30-day postoperative period. One-, 3-, 5- and 10-year overall survival rates were 94.8, 66.8, 43.9 and 16.6%, respectively, in patients undergoing RFA, and 90.6, 69.1, 52.8 and 39.2%, respectively, in patients with liver resections. Disease free survival was 63.2, 30.1, 18.4 and 13.1%, respectively, in the same patients after RFA, and 71.1, 33.3, 22.8 and 15.5%, respectively, after liver resections. Conclusion: RFA is a palliative thermal ablation method, which is one of therapeutic options in patients with radically non-resectable CLMs. RFA is useful especially in a non-resectable, or resectable (but for the price of large liver resection) solitary CLM <3 cm in diameter and in CLM relapses. RFA is also part of multi-stage liver procedures.

Percutaneous stereotactic radiofrequency ablation of colorectal liver metastases

2011 ◽  
Vol 22 (4) ◽  
pp. 930-937 ◽  
Author(s):  
Reto Bale ◽  
Gerlig Widmann ◽  
Peter Schullian ◽  
Marion Haidu ◽  
Georg Pall ◽  
...  
Keyword(s):  
Radiofrequency Ablation ◽  
Liver Metastases ◽  
Colorectal Liver Metastases

scholarly journals A Method For Determination Of Specific Electrical Resistance Of Steel And Nano-Coating Sputtered On It

2015 ◽  
Vol 2 ◽  
pp. 118 ◽  
Author(s):  
Andris Martinovs ◽  
Josef Timmerberg ◽  
Konstantins Savkovs ◽  
Aleksandrs Urbahs ◽  
Paul Beckmann
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Permeability ◽  
Electrical Resistance ◽  
Skin Effect ◽  
Specific Electrical Resistance ◽  
Specific Electrical Conductivity ◽  
Relative Magnetic Permeability ◽  
Nano Coating ◽  
Cylindrical Steel

The paper describes methods developed to determine specific electrical conductivity and relative magnetic permeability of cylindrical steel items and nano-coatings deposited on them by sputtering. Research enables development of a new method for determination of thickness of vacuum deposited nano- coating that is based on application of skin effect.

scholarly journals 3D Quantitative Ablation Margins for Prediction of Ablation Site Recurrence After Stereotactic Image-Guided Microwave Ablation of Colorectal Liver Metastases: A Multicenter Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Simeon J. S. Ruiter ◽  
Pascale Tinguely ◽  
Iwan Paolucci ◽  
Jennie Engstrand ◽  
Daniel Candinas ◽  
...  
Keyword(s):  
Liver Metastases ◽  
Multicenter Study ◽  
Microwave Ablation ◽  
Colorectal Liver Metastases ◽  
Liver Tumors ◽  
Three Dimensional ◽  
Multivariable Logistic Regression Analysis ◽  
Tumor Diameter ◽  
Ablation Margin ◽  
The Impact

BackgroundThree-dimensional (3D) volumetric ablation margin assessment after thermal ablation of liver tumors using software has been described, but its predictive value on treatment efficacy when accounting for other factors known to correlate ablation site recurrence (ASR) remains unknown.PurposeTo investigate 3D quantitative ablation margins (3D-QAMs) as an algorithm to predict ASR within 1 year after stereotactic microwave ablation (SMWA) for colorectal liver metastases (CRLM).Materials and MethodsSixty-five tumors in 47 patients from a prospective multicenter study of patients undergoing SMWA for CRLM were included in this retrospective 3D-QAM analysis. Using a previously developed algorithm, 3D-QAM defined as the distribution of tumor to ablation surface distances was assessed in co-registered pre- and post-ablation CT scans. The discriminatory power and optimal cutoff values for 3D-QAM were assessed using receiver operating characteristic (ROC) curves. Multivariable logistic regression analysis using generalized estimating equations was applied to investigate the impact of various 3D-QAM outputs on 1-year ASR while accounting for other known influencing factors.ResultsTen of the 65 (15.4%) tumors included for 3D-QAM analysis developed ASR. ROC analyses identified i) 3D-QAM &lt;1 mm for &gt;23% of the tumor surface, ii) 3D-QAM &lt;5 mm for &gt;45%, and iii) the minimal ablation margin (MAM) as the 3D-QAM outputs with optimal discriminatory qualities. The multivariable regression model without 3D-QAM yielded tumor diameter and KRAS mutation as 1-year ASR predictors. When adding 3D-QAM, this factor became the main predictor of 1-year ASR [odds ratio (OR) 21.67 (CI 2.48, 165.21) if defined as &gt;23% &lt;1 mm; OR 0.52 (CI 0.29, 0.95) if defined as MAM].Conclusions3D-QAM allows objectifiable and standardized assessment of tumor coverage by the ablation zone after SMWA. Our data shows that 3D-QAM represents the most important factor predicting ASR within 1 year after SMWA of CRLM.

scholarly journals Predicting local regrowth after radiofrequency ablation of colorectal liver metastases by 3D merging of pre- and post-ablation imaging

HPB ◽  
2018 ◽  
Vol 20 ◽  
pp. S355-S356
Author(s):  
B.G. Sibinga Mulder ◽  
P. Hendriks ◽  
T.R. Baetens ◽  
A. van Erkel ◽  
C.J.H. van de Velde ◽  
...  
Keyword(s):  
Radiofrequency Ablation ◽  
Liver Metastases ◽  
Colorectal Liver Metastases
Sign in / Sign up

Export Citation Format

Share Document