[Analyze the factors influencing multi-electrode synchronous radiofrequency ablation via switching controller in ex vivo bovine liver].
0
Citation
0
Reference
10
Related Paper
Abstract:
To investigate the effects of different electrode exposed end and different ablated time on lesion size of Cool-tip multi-electrode synchronous radiofrequency ablation via switching controller in ex vivo bovine liver.Twelve combinations of different electrode exposed end (2 cm, 3 cm and 4 cm) were used, and different ablated time (12, 16, 20 and 24 mins) was as experimental parameter. Ablated lesions in longitudinal diameter, transverse diameter and volume were measured. Analyze the factors influencing the lesion size with ANOVA or t test.The ablated lesions with 3 cm exposed end electrodes were more stable and the spheroidal rate is more close to 1. When ablated 24 mins with 4 cm exposed end electrodes, the longitudinal diameter, transverse diameter and volume were (7.66±0.21), (6.50±0.34) cm and (172±12) cm3, respectively. When the ablated time was constant, the lesions increased with the exposed end length of the electrodes increased. All the data among groups was statistically significant (P<0.01) unless the transverse diameters between 3 and 4 cm exposed end electrode. When the exposed end length of electrodes was constant, the lesions increased with the ablated time increased as a whole. But there was no significant difference in most of the adjacent groups. Only the longitudinal diameters and volumes of 4 cm exposed end electrodes between 20 and 24 min were statistically significant (P<0.05).Within the experimental range, the lesion size ablated by Cool-tip multi-electrode synchronous radiofrequency ablation via switching controller increased with the electrode exposed end and ablated time increased. The spheroidal rate of the ablated lesions with 3 cm exposed end is more close to 1.Keywords:
Ex vivo
Cite
Hintergrund: Radiofrequenzablation (RFA) und Elektrochemische Lyse (ECL) sind konkurrierende intrahepatische Ablationsverfahren. Wir verglichen beide Methoden in einem Perfusionsmodell ex vivo und im Tierversuch (Schwein) in vivo. Methode: Ex vivo wurden 27 frische Schlachthoflebern in ein Perfusionsmodell integriert. Sonografisch unterstützt, platzierten wir perivaskulär in 10 mm Abstand zu Portalvenen RFA- bzw. ECL-Elektroden und erzeugten insgesamt 83 Ablationsherde. In vivo wurden 10 Schweine laparotomiert und je Leber 4 Anwendungen RFA bzw. ECL perivaskulär durchgeführt. Prä- und postoperativ, an den Tagen 1, 3 und 7 wurden Entzündungs- sowie Leberwerte und Zytokine bestimmt. Nach 7 Tagen wurden die Organe entnommen und histologisch unabhängig untersucht. Ergebnisse: Bei 59 RFA-Ablationen (Anwendungszeit 12,4 min) ex vivo wurden in 29 % der Anwendungen die Zieltemperatur nicht erreicht (Abbruch). Bei 70 % der Gefäße innerhalb der Nekrosen ließen sich perivaskulär intakte Hepatozyten nachweisen. Bei 24 ECL-Ablationen war die Anwendungszeit abhängig von der applizierten Ladung in Coulomb (C) und lag zwischen 50 min (150 C) und 200 min (600 C). Die pH-Werte lagen bei 0,9 (Anode) bzw. 12,2 (Kathode). Die Nekrosen waren bei ECL in allen Fällen auch perivaskulär vollständig mit einer Destruktion bis zur Gefäßwand. In vivo betrug das mediane Gewicht der 10 Tiere 39,5 kg. Weder bei RFA noch bei ECL traten Majorkomplikationen wie Blutung, Galleleckage oder Abszess auf. Die Anwendungszeit betrug bei ECL 67 min (200 C), bei RFA 12,4 min. Bei RFA waren die perivaskulären Nekrosen in 73 % unvollständig. Bei ECL waren die Nekrosen bis zur Gefäßwand vollständig. Am 1. postoperativen Tag stiegen Monozyten, CRP und ASAT nach RFA und ECL signifikant, Leukozyten nur nach ECL, Bilirubin nur nach RFA. IL-6, TNF-α, IL-1β differierten nicht signifikant. Schlussfolgerung: RFA und ECL sind intrahepatisch sicher anwendbare Ablationsverfahren. Durch den Kühlungseffekt der Perfusion resultieren bei der thermischen Methode RFA ex vivo und in vivo perivaskulär unvollständige Nekrosen. Ein Nachteil der ECL ist die lange Anwendungszeit, ein Kostenvorteil entsteht durch die wiederverwendbaren Platinelektroden. Eine zentrale RFA bei Tumorlokalisation in Gefäßnähe ohne Limitierung der Leberperfusion muss kritisch beurteilt werden.
Cite
Citations (1)
In Brief Study Design. An experimental study of radiofrequency ablation (RFA) of spine in an ex vivo bovine and in vivo swine animal model. Objective. To study the feasibility of RFA for spine tumors close to the spinal cord, to examine the safety and efficacy of RFA, and to suggest quantitative guidelines for clinical application. Summary of Background Data. RFA has received increased attention as an effective and minimally invasive method for treating soft tissue tumors. However, there is currently only anecdotal evidence to support RFA of spinal tumors and only a few experimental studies have been conducted. Methods. We performed ex vivo experiments by producing 10 RFA zones in extracted bovine spines and an in vivo study by producing 8 RFA zones in a swine spine using internally cooled electrodes. The volume and diameter of ablation zones were evaluated and analyzed by the corresponding energy and ablation times. Results. In the ex vivo study, the average diameters of the ablation zones were 3.05 cm, 1.85 cm, and 1.26 cm, for the D1, D2, and D3 zones, respectively, and the average ablation volume was 4.19 cm3. In the in vivo study, the average diameters were 2.51 cm, 2.05 cm, and 1.28 cm, respectively, and the ablation volume was 6.80 cm3. The ablation zones demonstrated a positive correlation with ablation time, but the coefficients were 0.942 ex vivo and 0.257 in vivo. The temperature in the ex vivo study was inversely proportional to distance, with a maximal temperature of 63.7°C at 10 mm; however, the maximum temperature was 38.2°C in the in vivo study. Conclusion. This study demonstrated that sufficient RFA zone volume could be induced, which suggests that RFA is feasible and safe for application to human spinal tumors with predictability. Level of Evidence: N/A An experimental study of radiofrequency ablation of spine in an ex vivo bovine and in vivo swine animal model was performed. Sufficient volumes of radiofrequency ablation could be induced by using internally cooled radiofrequency electrodes. This study demonstrated the feasibility and safety of radiofrequency ablation for human spinal tumors.
Ex vivo
Ablation zone
Cite
Citations (5)
There are currently limited means by which lesion formation can be confirmed during radiofrequency ablation procedures. The purpose of this study was to evaluate the use of NIRS-integrated RFA catheters for monitoring irrigated lesion progression, ex vivo and in vivo. Open-irrigated NIRS-ablation catheters with optical fibers were fabricated to sample tissue diffuse reflectance. Spectra from 44 irrigated lesions and 44 non-lesion sites from ex vivo swine hearts (n = 15) were used to train and evaluate a predictive model for lesion dimensions based on key spectral features. Additional studies were performed in diluted blood to assess NIRS signatures of catheter-tissue contact status. Finally, the potential of NIRS-RFA catheters for guiding lesion delivery was evaluated in a set of in vivo pilot studies conducted in healthy pigs (n = 4). Model predictions for lesion depth (R = 0.968), width (R = 0.971), and depth percentage (R = 0.924) correlated well with measured lesion dimensions. In vivo deployment in preliminary trials showed robust translational consistency of contact discrimination (P < 0.0001) and lesion depth parameters (< 3% error). NIRS empowered catheters are well suited for monitoring myocardial response to RF ablation and may provide useful intraprocedural feedback for optimizing treatment efficacy alongside current practices.
Ex vivo
Target lesion
Cite
Citations (10)
Ex vivo
Cite
Citations (29)
Ex vivo
Radiofrequency coil
Ablation zone
Cite
Citations (6)
To investigate the effects of different electrode exposed end and different ablated time on lesion size of Cool-tip multi-electrode synchronous radiofrequency ablation via switching controller in ex vivo bovine liver.Twelve combinations of different electrode exposed end (2 cm, 3 cm and 4 cm) were used, and different ablated time (12, 16, 20 and 24 mins) was as experimental parameter. Ablated lesions in longitudinal diameter, transverse diameter and volume were measured. Analyze the factors influencing the lesion size with ANOVA or t test.The ablated lesions with 3 cm exposed end electrodes were more stable and the spheroidal rate is more close to 1. When ablated 24 mins with 4 cm exposed end electrodes, the longitudinal diameter, transverse diameter and volume were (7.66±0.21), (6.50±0.34) cm and (172±12) cm3, respectively. When the ablated time was constant, the lesions increased with the exposed end length of the electrodes increased. All the data among groups was statistically significant (P<0.01) unless the transverse diameters between 3 and 4 cm exposed end electrode. When the exposed end length of electrodes was constant, the lesions increased with the ablated time increased as a whole. But there was no significant difference in most of the adjacent groups. Only the longitudinal diameters and volumes of 4 cm exposed end electrodes between 20 and 24 min were statistically significant (P<0.05).Within the experimental range, the lesion size ablated by Cool-tip multi-electrode synchronous radiofrequency ablation via switching controller increased with the electrode exposed end and ablated time increased. The spheroidal rate of the ablated lesions with 3 cm exposed end is more close to 1.
Ex vivo
Cite
Citations (0)
Cite
Citations (44)
Ablation zone
Rf ablation
Cite
Citations (28)
The objective of this study was to compare the targeting and ablation performance between a newly developed radiofrequency (RF) electrode embedded with an electromagnetic position sensor (EMPS) at the electrode tip and a conventional RF electrode.The institutional animal care and use committee approved this study. The targeting of paint balls within phantoms was performed under ultrasonography guidance by 2 radiologists (beginner vs expert) with an "in-plane" and "out-of-plane" approaches using the new RF electrode and a conventional RF electrode (n = 20 for each method). To evaluate the targeting performance, the electrode placement time and the number of electrode pullbacks for redirection were compared between the 2 electrodes. The ablation performance was also compared by analyzing the ablation volumes in ex vivo bovine and in vivo porcine livers (n = 30 and n = 24, respectively) and the cellular viability of the ablation zone in in vivo specimens.In the phantom study, the RF electrode embedded with an EMPS showed a significantly shorter electrode placement time compared with the conventional RF electrode in both the in-plane and out-of-plane approaches by both radiologists (P < 0.05). The electrode pullback rate for both radiologists was lower in the new RF electrode than in the conventional RF electrode, but it did not reach statistical significance in the in-plane approach by the expert (P = 0.059). The ablation volumes analyzed with and without cellular viability in the ex vivo and in vivo studies were not significantly different between the 2 electrodes (P > 0.05).The RF electrode embedded with an EMPS is faster than the conventional electrode in the electrode placement into the target lesions. The ablation performance is not significantly different between the 2 electrodes.
Electrode array
Ex vivo
Cite
Citations (9)