Real-time ultrasound imaging of irreversible electroporation in a porcine liver model adequately characterizes the zone of cellular necrosis.
BACKGROUND
Irreversible electroporation (IRE) is a largely non-thermal method for the ablation of solid tumours. The ability of ultrasound (US) to measure the size of the IRE ablation zone was studied in a porcine liver model.


METHODS
Three normal pig livers were treated in vivo with a total of 22 ablations using IRE. Ultrasound was used within minutes after ablation and just prior to liver harvest at either 6 h or 24 h after the procedure. The area of cellular necrosis was measured after staining with nitroblue tetrazolium and the percentage of cell death determined by histomorphometry.


RESULTS
Visible changes in the hepatic parenchyma were apparent by US after all 22 ablations using IRE. The mean maximum diameter of the ablation zone measured by US during the procedure was 20.1 ± 2.7 mm. This compared with a mean cellular necrosis zone maximum diameter of 20.3 ± 2.9 mm as measured histologically. The mean percentage of dead cells within the ablation zone was 77% at 6 h and 98% at 24 h after ablation.


CONCLUSIONS
Ultrasound is a useful modality for measuring the ablation zone within minutes of applying IRE to normal liver tissue. The area of parenchymal change measured by US correlates with the area of cellular necrosis.
Department of Surgery, Ohio State University, Columbus, OH, USA. carl.schmidt@osumc.edu
Carl R
CR
Schmidt
Peter
P
Shires
Mary
M
Mootoo
D000818:Animals; D018274:Electroporation; D005260:Female; D008099:Liver / Q000000981:diagnostic imaging* / Q000473:pathology; D023421:Models, Animal; D009336:Necrosis; D013552:Swine; D013997:Time Factors; D014463:Ultrasonography