Detection of electroporation-induced membrane permeabilization states in the brain using diffusion-weighted MRI

TY - JOUR

T1 - Detection of electroporation-induced membrane permeabilization states in the brain using diffusion-weighted MRI

AU - Mahmood, Faisal

AU - Hansen, Rasmus H

AU - Agerholm-Larsen, Birgit

AU - Gissel, Hanne

AU - Ibsen, Per

AU - Gehl, Julie

PY - 2015/3/1

Y1 - 2015/3/1

N2 - BACKGROUND: Tissue permeabilization by electroporation (EP) is a promising technique to treat certain cancers. Non-invasive methods for verification of induced permeabilization are important, especially in deep-seated cancers. In this study we evaluated diffusion-weighted magnetic resonance imaging (DW-MRI) as a quantitative method for detecting EP-induced membrane permeabilization of brain tissue using a rat brain model.MATERIAL AND METHODS: Fifty-four anesthetized Sprague-Dawley male rats were electroporated in the right hemisphere, using different voltage levels to induce no permeabilization (NP), transient membrane permeabilization (TMP), and permanent membrane permeabilization (PMP), respectively. DW-MRI was acquired 5 minutes, 2 hours, 24 hours and 48 hours after EP. Histology was performed for validation of the permeabilization states. Tissue content of water, Na+, K+, Ca2+, and extracellular volume were determined. The Kruskal-Wallis test was used to compare the DW-MRI parameters, apparent diffusion coefficient (ADC) and kurtosis, at different voltage levels. The two-sample Mann- Whitney test with Holm's Bonferroni correction was used to identify pairs of significantly different groups. The study was approved by the Danish Animal Experiments Inspectorate.RESULTS AND CONCLUSION: Results showed significant difference in the ADC between TMP and PMP at 2 hours (p<0.001) and 24 hours (p<0.05) after EP. Kurtosis was significantly increased both at TMP (p<0.05) and PMP (p<0.001) 5 minutes after EP, compared to NP. Kurtosis was also significantly higher at 24 hours (p<0.05) and 48 hours (p<0.05) at PMP compared to NP. Physiological parameters indicated correlation with the permeabilization states, supporting the DW-MRI findings. We conclude that DW-MRI is capable of detecting EP-induced permeabilization of brain tissue and to some extent of differentiating NP, TMP and PMP using appropriate scan timing.

AB - BACKGROUND: Tissue permeabilization by electroporation (EP) is a promising technique to treat certain cancers. Non-invasive methods for verification of induced permeabilization are important, especially in deep-seated cancers. In this study we evaluated diffusion-weighted magnetic resonance imaging (DW-MRI) as a quantitative method for detecting EP-induced membrane permeabilization of brain tissue using a rat brain model.MATERIAL AND METHODS: Fifty-four anesthetized Sprague-Dawley male rats were electroporated in the right hemisphere, using different voltage levels to induce no permeabilization (NP), transient membrane permeabilization (TMP), and permanent membrane permeabilization (PMP), respectively. DW-MRI was acquired 5 minutes, 2 hours, 24 hours and 48 hours after EP. Histology was performed for validation of the permeabilization states. Tissue content of water, Na+, K+, Ca2+, and extracellular volume were determined. The Kruskal-Wallis test was used to compare the DW-MRI parameters, apparent diffusion coefficient (ADC) and kurtosis, at different voltage levels. The two-sample Mann- Whitney test with Holm's Bonferroni correction was used to identify pairs of significantly different groups. The study was approved by the Danish Animal Experiments Inspectorate.RESULTS AND CONCLUSION: Results showed significant difference in the ADC between TMP and PMP at 2 hours (p<0.001) and 24 hours (p<0.05) after EP. Kurtosis was significantly increased both at TMP (p<0.05) and PMP (p<0.001) 5 minutes after EP, compared to NP. Kurtosis was also significantly higher at 24 hours (p<0.05) and 48 hours (p<0.05) at PMP compared to NP. Physiological parameters indicated correlation with the permeabilization states, supporting the DW-MRI findings. We conclude that DW-MRI is capable of detecting EP-induced permeabilization of brain tissue and to some extent of differentiating NP, TMP and PMP using appropriate scan timing.

KW - Animals

KW - Body Water

KW - Brain

KW - Brain Chemistry

KW - Calcium

KW - Cell Membrane Permeability

KW - Diffusion

KW - Diffusion Magnetic Resonance Imaging

KW - Electroporation

KW - Extracellular Fluid

KW - Male

KW - Normal Distribution

KW - Potassium

KW - Rats, Sprague-Dawley

KW - Sodium

KW - Statistics, Nonparametric

KW - Time Factors

U2 - 10.3109/0284186x.2014.991045

DO - 10.3109/0284186x.2014.991045

M3 - Journal article

C2 - 25591820

SN - 0284-186X

VL - 54

SP - 289

EP - 297

JO - Acta Oncologica

JF - Acta Oncologica

IS - 3

ER -