Title: Early stiffness increase detected by elastography hints local thermal damage during irreversible electroporation ablation
Abstract: Introduction: Irreversible electroporation (IRE) is a nonthermal ablation technique that induces permanent cell membrane damage and death. Elastography used to be introduced to monitor ablation effect in the liver, and the stiffness change of ablation zone will develop one hour later. Methods: 6 Lanyu pigs underwent IRE ablation of the liver and were imaged with ultrasound and elastography. Central and peripheral temperature of ablation zone were monitored, too. Histologic evaluation of cell death by triphenyltetrazolium chloride staining was performed. Within these animals, a total of 270 electric pulses were given on 18 areas of livers in 3 animals, and 90 pulses were given on 18 areas in other 3 animals. Results: Elastography showed that liver ablated by IRE did not exhibited significantly increased tissue stiffness till one hour after ablation in 90 pulses group. The local temperature is 38–40 °C. The local temperature increased to 52–57 °C in 270 electric pulsed group, and the stiffness increasing was also noted 10-20 minutes after IRE ablation. Conclusion: IRE ablation does not led to increased tissue stiffness immediately, however, when repeated IRE ablation over an area results in local hyperthermia, the thermal effect will increase tissue stiffness detectable by elastography within 20 minutes and indicative of malpractice. Elastography may be used to monitor IRE ablation of the liver in the future.