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A parametric study delineating irreversible electroporation from thermal damage based on a minimally invasive intracranial procedure.

Garcia PA, Rossmeisl JH, Neal RE, Ellis TL, Davalos RV - Biomed Eng Online (2011)

Bottom Line: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure.We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment.The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, Blacksburg, VA, USA.

ABSTRACT

Background: Irreversible electroporation (IRE) is a new minimally invasive technique to kill undesirable tissue in a non-thermal manner. In order to maximize the benefits from an IRE procedure, the pulse parameters and electrode configuration must be optimized to achieve complete coverage of the targeted tissue while preventing thermal damage due to excessive Joule heating.

Methods: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure. These models were adapted to assess the effects of temperature, electroporation, pulse duration, and repetition rate on the volumes of tissue undergoing IRE alone or in superposition with thermal damage.

Results: Nine different combinations of voltage and pulse frequency were investigated, five of which resulted in IRE alone while four produced IRE in superposition with thermal damage.

Conclusions: The parametric study evaluated the influence of pulse frequency and applied voltage on treatment volumes, and refined a proposed method to delineate IRE from thermal damage. We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment. The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

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Focal and cavitary white matter areas of ablation induced by IRE. The lesion is illustrated with dashed lines using (A) ex vivo 7.0 T MRI in the dorsal plane (insert) and (B) histopathology, hematoxylin and eosin stain.
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Figure 4: Focal and cavitary white matter areas of ablation induced by IRE. The lesion is illustrated with dashed lines using (A) ex vivo 7.0 T MRI in the dorsal plane (insert) and (B) histopathology, hematoxylin and eosin stain.

Mentions: The 0.2 T MRI showed a focal, well circumscribed IRE lesion with calculated volumes of 0.131 cm3 and 0.120 cm3 for the T1-weigthed post-contrast and T2-weighted MRIs, respectively which we reported in Garcia et. al [23]. The lesion appeared hyperintense within the white matter on the T1-weighted post-contrast MRI, where contrast was able to leak into the brain due to breakdown of the blood-brain-barrier. The lesion was also hyperintense on the T2-weighted MRI sequence. Figure 4 demonstrates the focal and cavitary nature of the ablative white matter lesion within 2 hours after pulsing on both the ex vivo 7.0 T MRI (Figure 4A) and with light microscopy (Figure 4B). The most affected region appears to be directly between the electrodes, which is where the highest electric fields were generated. The reconstructed lesion volume from the high-resolution 7.0 T MRI was 0.058 cm3 [23].


A parametric study delineating irreversible electroporation from thermal damage based on a minimally invasive intracranial procedure.

Garcia PA, Rossmeisl JH, Neal RE, Ellis TL, Davalos RV - Biomed Eng Online (2011)

Focal and cavitary white matter areas of ablation induced by IRE. The lesion is illustrated with dashed lines using (A) ex vivo 7.0 T MRI in the dorsal plane (insert) and (B) histopathology, hematoxylin and eosin stain.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108916&req=5

Figure 4: Focal and cavitary white matter areas of ablation induced by IRE. The lesion is illustrated with dashed lines using (A) ex vivo 7.0 T MRI in the dorsal plane (insert) and (B) histopathology, hematoxylin and eosin stain.
Mentions: The 0.2 T MRI showed a focal, well circumscribed IRE lesion with calculated volumes of 0.131 cm3 and 0.120 cm3 for the T1-weigthed post-contrast and T2-weighted MRIs, respectively which we reported in Garcia et. al [23]. The lesion appeared hyperintense within the white matter on the T1-weighted post-contrast MRI, where contrast was able to leak into the brain due to breakdown of the blood-brain-barrier. The lesion was also hyperintense on the T2-weighted MRI sequence. Figure 4 demonstrates the focal and cavitary nature of the ablative white matter lesion within 2 hours after pulsing on both the ex vivo 7.0 T MRI (Figure 4A) and with light microscopy (Figure 4B). The most affected region appears to be directly between the electrodes, which is where the highest electric fields were generated. The reconstructed lesion volume from the high-resolution 7.0 T MRI was 0.058 cm3 [23].

Bottom Line: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure.We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment.The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, Blacksburg, VA, USA.

ABSTRACT

Background: Irreversible electroporation (IRE) is a new minimally invasive technique to kill undesirable tissue in a non-thermal manner. In order to maximize the benefits from an IRE procedure, the pulse parameters and electrode configuration must be optimized to achieve complete coverage of the targeted tissue while preventing thermal damage due to excessive Joule heating.

Methods: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure. These models were adapted to assess the effects of temperature, electroporation, pulse duration, and repetition rate on the volumes of tissue undergoing IRE alone or in superposition with thermal damage.

Results: Nine different combinations of voltage and pulse frequency were investigated, five of which resulted in IRE alone while four produced IRE in superposition with thermal damage.

Conclusions: The parametric study evaluated the influence of pulse frequency and applied voltage on treatment volumes, and refined a proposed method to delineate IRE from thermal damage. We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment. The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

Show MeSH
Related in: MedlinePlus