Irreversible electroporation: a novel image-guided cancer therapy

Abstract

Irreversible electroporation (IRE) is a novel tumor ablation technique using a non-thermal energy to create innumerable permanent nanopores in the cell membrane to disrupt cellular homeostasis. This disruption of cellular homeostasis initiates apoptosis which leads to permanent cell death. In our translational research, we have demonstrated that IRE can be a safe, fast and powerful method of tumor treatment. In this review, we present an overview of IRE ablation including a brief history of IRE, advantages and disadvantages of IRE and clinical and research implications of IRE.

Keywords: Apoptosis; Irreversible electroporation; Tumor treatment.

Fig. 1

Gross pathologic image (A) and hematoxylin and eosin (H&E) staining (B) of irreversible electroporation (IRE) ablation zones show a sharp demarcation between the ablated and non-ablated, normal liver. Within the ablated zone, numerous vessels and bile ducts are observed as small as 1 mm in size with preserved structures.

Fig. 2

Hepatocytes and central vein in the non-ablated zone (A) and irreversible electroporation (IRE)-ablated zone (B). All hepatocytes around the vessel in the IRE-ablated zone have been completely ablated and undergone cell death seen as pyknosis and karyorrhexis (H&E stain, ×40).

Fig. 3

High-magnification image of the irreversible electroporation (IRE)-ablated zone demonstrates normal liver tissue (N) without any TUNEL positive cells and markedly increased TUNEL positive cells seen in the IRE-ablated zone. An involvement of apoptosis has been confirmed by using multiple immunohistochemical assays including TUNEL assay, BCL-2 and Caspase staining.

Fig. 4

Intra-procedure ultrasound image of irreversible electroporation (IRE) (A) demonstrates IRE's capability of real-time monitoring during and immediately after the procedure. A hypoechoic area of IRE ablation is observed with a sharp margin. Contrast-enhanced CT of the liver (B) in the delayed phase demonstrates a hypodense area of IRE ablation with increased contrast enhancement surrounding the ablated area. IRE-ablated area can be also well visualized and assessed using post-contrast fat-saturated T1-weighted MR image (C) demonstrating mildly increased enhancement in the area of ablation.