scholarly journals Radiofrequency ablation combined with conductive fluid-based dopants (saline normal and colloidal gold): Computer modeling and ex vivo experiments.

2020 ◽  
Author(s):  
Dora Luz Castro-Lopez ◽  
Enrique Berjano ◽  
Ricardo Romero-mendez
Keyword(s):  
Electrical Conductivity ◽  
Radiofrequency Ablation ◽  
Computer Modeling ◽  
Normal Saline ◽  
Colloidal Gold ◽  
Ex Vivo ◽  
Transverse Diameter ◽  
Cylindrical Domain ◽  
Spherical Domain ◽  
Coagulation Zone

Abstract Background: The volume of the coagulation zones created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g. gold nanoparticles (AuNPs) could enlarge these zones by delaying roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs in a computer modeling study and ex vivo experiments to investigate their effect on coagulation zone volumes. Methods: The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally on agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with 2, 3 and 4 cm diameters. Ex vivo experiments were conducted on bovine liver fragments under three different conditions: 1) non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group). Results: The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modifies the electrical conductivity of the doped substrate with practically no change in the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. There was good agreement between the ex vivo and computational results in terms of transverse diameter of the coagulation zone.Conclusions: Both the computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, especially the transverse diameter and hence enhance sphericity.

scholarly journals Radiofrequency ablation combined with conductive fluid-based dopants (saline normal and colloidal gold): Computer modeling and ex vivo experiments

2020 ◽  
Author(s):  
Dora Luz Castro-Lopez ◽  
Enrique Berjano ◽  
Ricardo Romero-mendez
Keyword(s):  
Electrical Conductivity ◽  
Radiofrequency Ablation ◽  
Computer Modeling ◽  
Normal Saline ◽  
Colloidal Gold ◽  
Ex Vivo ◽  
Transverse Diameter ◽  
Cylindrical Domain ◽  
Spherical Domain ◽  
Coagulation Zone

Abstract Background: The volume of the coagulation zones created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g. gold nanoparticles (AuNPs) could enlarge these zones by delaying roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs in a computer modeling study and ex vivo experiments to investigate their effect on coagulation zone volumes. Methods: The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally on agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with 2, 3 and 4 cm diameters. Ex vivo experiments were conducted on bovine liver fragments under three different conditions: 1) non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group). Results: The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modifies the electrical conductivity of the doped substrate with practically no change in the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. There was good agreement between the ex vivo and computational results in terms of transverse diameter of the coagulation zone.Conclusions: Both the computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, especially the transverse diameter and hence enhance sphericity.

scholarly journals Radiofrequency ablation combined with conductive fluid-based dopants (saline normal and colloidal gold): Computer modeling and ex vivo experiments.

2020 ◽  
Author(s):  
Dora Luz Castro-Lopez ◽  
Enrique Berjano ◽  
Ricardo Romero-mendez
Keyword(s):  
Electrical Conductivity ◽  
Radiofrequency Ablation ◽  
Computer Modeling ◽  
Normal Saline ◽  
Colloidal Gold ◽  
Ex Vivo ◽  
Transverse Diameter ◽  
Cylindrical Domain ◽  
Spherical Domain ◽  
Coagulation Zone

Abstract Background: The coagulation zone volume created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g. gold nanoparticles (AuNPs) could enlarge the coagulation zones by delaying the roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs and to study by computer modeling and ex vivo experiments the effect on coagulation zone volumes.Methods: The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally using agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with diameters of 2, 3 and 4 cm. Ex vivo experiments were conducted on bovine liver fragments and under three different doping conditions: 1) non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group).Results: The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modify the electrical conductivity of the doped substrate with practically no change of the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. We observed a good agreement between ex vivo and computational results in terms of transverse diameter of the coagulation zone.Conclusions: Both computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, specially the transverse diameter, hence achieving more spherical coagulation zones.

scholarly journals Radiofrequency ablation combined with conductive fluid-based dopants (saline normal and colloidal gold): computer modeling and ex vivo experiments

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dora Luz Castro-López ◽  
Enrique Berjano ◽  
Ricardo Romero-Mendez
Keyword(s):  
Electrical Conductivity ◽  
Radiofrequency Ablation ◽  
Computer Modeling ◽  
Normal Saline ◽  
Colloidal Gold ◽  
Ex Vivo ◽  
Transverse Diameter ◽  
Cylindrical Domain ◽  
Spherical Domain ◽  
Coagulation Zone

Abstract Background The volume of the coagulation zones created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g., gold nanoparticles (AuNPs) could enlarge these zones by delaying roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs in a computer modeling study and ex vivo experiments to investigate their effect on coagulation zone volumes. Methods The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally on agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with 2, 3 and 4 cm diameters. Ex vivo experiments were conducted on bovine liver fragments under three different conditions: non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group). Results The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modifies the electrical conductivity of the doped substrate with practically no change in the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. There was good agreement between the ex vivo and computational results in terms of transverse diameter of the coagulation zone. Conclusions Both the computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, especially the transverse diameter and hence enhance sphericity.

scholarly journals Comparisons of Monopolar Lesion Volumes with Hypertonic Saline Solution in Radiofrequency Ablation: A Randomized, Double-Blind, Ex Vivo Study

2020 ◽  
Vol 2;23 (4;2) ◽  
pp. 159-164
Author(s):  
Christopher Paul
Keyword(s):  
Radiofrequency Ablation ◽  
Hypertonic Saline ◽  
Normal Saline ◽  
Saline Solution ◽  
Ex Vivo ◽  
Human Organism ◽  
Lesion Volume ◽  
Rf Ablation ◽  
Hypertonic Saline Solution ◽  
Ex Vivo Study

Background: Chronic degeneration of the zygapophyseal joints in the cervical or lumbar spine are common causes of axial back pain. Radiofrequency (RF) ablation is a treatment modality in the denervation of facet joint–related pain. Although multiple factors have been theorized to contribute to the size of the optimal RF lesion, the addition of hypertonic saline solution has been posited to create larger RF lesion sizes. Objectives: This study compares lesion of 20-gauge RF monopolar probe using 2% lidocaine, 0.9% normal saline solution, and 3% saline solution administered through the RF needle prior to ablation, with subsequent lesion sizes recorded. Study Design: Randomized, double-blinded, ex vivo study using clinically relevant conditions. Setting: Procedural laboratory in an academic institution. Methods: RF ablation lesions were reproduced in room temperature (21°C ± 2°C) chicken breast specimens with 20-gauge monopolar RF probes inserted. RF was applied for 90 seconds at 80°C after injection of 1 mL of either 2% lidocaine, 2% lidocaine and 0.9% normal saline solution in a 1:1 ratio, or 2% lidocaine and 3% saline solution in a 1:1 ratio. Tissues were dissected, measured, and ellipsoid volumes of burn calculated. Homogeneity of variances was assessed via the Bartlett’s test, and heteroskedasticity with the studentized Breusch-Pagan test. One-way analysis of variance (ANOVA) (α of 0.05) was used to evaluate statistical significance between volume means across groups. When the null hypothesis of no difference in burn volume between samples could not be rejected, a predefined equivalence volume of ± 0.05 cm3 was used with Welch’s 2 one-sided t-tests (TOST) with a Bonferroni adjusted α of 0.0167 to evaluate for null acceptance. Results: The mean lesion volume for monopolar RF with 1 mL 2% lidocaine was 0.16 cm3 . Monopolar RF with 1 mL 2% lidocaine + 0.9% normal saline solution had a mean lesion volume of 0.15 cm3 , and treatment with 1 mL 2% lidocaine + 3% saline solution measured 0.17 cm3 . ANOVA failed to reject the null, and TOST accepted as equivalent all 3 comparisons. Limitations: In vivo anatomy and physiology of a human organism was not used for this study. Samples were not warmed to physiologic temperature. Randomization resulted in slightly unequal sample sizes, although all groups were of sufficient size that the central limit theorem should apply. Conclusions: Three commonly used solutions were found to have equivalent lesion sizes from monopolar probe RF ablation. Key words: Radiofrequency, ablation, lesion shape, lesion size, monopolar RF, hypertonic saline solution

Radiofrequency Ablation: Importance of Background Tissue Electrical Conductivity—An Agar Phantom and Computer Modeling Study

Radiology ◽  
2005 ◽  
Vol 236 (2) ◽  
pp. 495-502 ◽  
Author(s):  
Stephanie A. Solazzo ◽  
Zhengjun Liu ◽  
S. Melvyn Lobo ◽  
Muneeb Ahmed ◽  
Andrew U. Hines-Peralta ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Radiofrequency Ablation ◽  
Computer Modeling ◽  
Modeling Study

scholarly journals B-PO04-122 EX-VIVO HISTOPATHOLOGIC EXAMINATION AND IN-VIVO MRI ANALYSIS OF IRRIGATED RADIOFREQUENCY ABLATION UTILIZING HALF-NORMAL SALINE OF HUMAN HEART

Heart Rhythm ◽  
2021 ◽  
Vol 18 (8) ◽  
pp. S328-S329
Author(s):  
Ajay Pillai ◽  
Santosh K. Padala ◽  
John R. Onufer ◽  
Austin Wiles ◽  
Valentina Robila ◽  
...  
Keyword(s):  
Radiofrequency Ablation ◽  
Normal Saline ◽  
Human Heart ◽  
Ex Vivo ◽  
Histopathologic Examination

scholarly journals Optical signatures of radiofrequency ablation in biological tissues

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pranav Lanka ◽  
Kalloor Joseph Francis ◽  
Hindrik Kruit ◽  
Andrea Farina ◽  
Rinaldo Cubeddu ◽  
...  
Keyword(s):  
Radiofrequency Ablation ◽  
Treatment Time ◽  
Ex Vivo ◽  
Biological Tissues ◽  
Tissue Response ◽  
Optical Monitoring ◽  
Diffuse Optical Spectroscopy ◽  
Spectral Changes ◽  
Scattering Spectra ◽  
Optical Behavior

AbstractAccurate monitoring of treatment is crucial in minimally-invasive radiofrequency ablation in oncology and cardiovascular disease. We investigated alterations in optical properties of ex-vivo bovine tissues of the liver, heart, muscle, and brain, undergoing the treatment. Time-domain diffuse optical spectroscopy was used, which enabled us to disentangle and quantify absorption and reduced scattering spectra. In addition to the well-known global (1) decrease in absorption, and (2) increase in reduced scattering, we uncovered new features based on sensitive detection of spectral changes. These absorption spectrum features are: (3) emergence of a peak around 840 nm, (4) redshift of the 760 nm deoxyhemoglobin peak, and (5) blueshift of the 970 nm water peak. Treatment temperatures above 100 °C led to (6) increased absorption at shorter wavelengths, and (7) further decrease in reduced scattering. This optical behavior provides new insights into tissue response to thermal treatment and sets the stage for optical monitoring of radiofrequency ablation.

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