[Liver regeneration after radiofrequency ablation versus irreversible electroporation]

To compare liver regeneration after radiofrequency ablation versus irreversible electroporation (IRE).

A total of 10 pigs were divided into IRE and radiofrequency ablation groups. And two ablation foci were established in the liver of each pig. Computed tomography (CT)-guided IRE and radiofrequency ablation were performed. Cell death, liver regeneration and recovery speed were compared. Before ablation, immediately, 1 and 3 weeks after ablation, contrast enhanced ultrasound, CT and magnetic resonance imaging (MRI) were regularly performed. Immediately after ablation, 24 hours, 3 days, 3 weeks and 6 weeks, biopsy and pathologic examination were performed.

At 1-3 days after IRE ablation, apoptotic cells were detected in the ablation zone and numerous red blood cells were present in hepatic cords. Three days after IRE, fibroblasts were found. Three weeks after, most ablation lesions disappeared or significantly reduced. There was no formation of fibrous capsule. And indistinct boundary existed between the surrounding liver tissue and lesion. Immediately after ablation, coagulative necrosis of ablation zone in liver was confirmed. After 3 weeks, all lesions persisted in the radiofrequency ablation group. There was formation of fibrous capsule. Immediately after ablation, the ablation volume was similar between two groups on CT scan. Three weeks later, 6 ablation foci in IRE group disappeared while another 4 lesions shrank more than 50%. There was no significant volume reduction in the radiofrequency ablation group.

Compared with radiofrequency ablation, IRE resulted in faster liver regeneration and intact extracellular structure.