Thermochemical ablation in an ex-vivo porcine liver model using acetic acid and sodium hydroxide: proof of concept.
OBJECTIVE
To establish proof of concept in tissue, using the exothermic neutralization reaction of acetic acid and sodium hydroxide in ex vivo porcine liver and to conduct an initial probe into the relationships of volume and concentration of reagents to temperatures and the areas affected.


METHODS
A total of 0.5 mL or 2 mL of either 5 mole/L or 10 mole/L acid and base solutions was injected simultaneously into the periphery of ex vivo porcine liver using a prototype injection device. Tissue temperature was recorded at the injection site for 5 minutes using a type T thermocouple temperature probe inserted parallel to and near the tip of the injection device. The injections were repeated for infrared thermography, and ablated tissues were sectioned quickly and imaged. A gross photograph was captured in each case to provide correlation.


RESULTS
Maximum temperatures (17°C baseline) ranged from 42.1° ± α3.34°C to 61.7° ± α10°C (P<.05) when injecting 0.5 mL of 5 mole/L reactants and 2 mL of 10 mole/L reactants, respectively. The maximum temperature measured by infrared imaging ranged from 31°-47°C. Using an infrared viewing scale from 19°-40°C, the cross-sectional area of tissue heating above baseline measured from 1.07 cm(2)± 0.45 to 4.95 cm(2)± 0.28 (P <05).


CONCLUSIONS
The reaction of acetic acid and sodium hydroxide releases significant heat energy at the site of injection, and histologic changes are consistent with coagulation necrosis. Increased reagent concentration and volume were associated with larger temperature changes and larger areas of hyperthermia at gross pathology and infrared imaging.
Farnam
Joseph L
JL
Department of Radiology, University of Minnesota Medical Center MMC 292, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
Smith
Benjamin C
BC
Johnson
Brandon R
BR
Estrada
Rodolfo
R
Edelman
Theresa L
TL
Farah
Rina
R
Cressman
Erik N K
EN
D019342:Acetic Acid / Q000008:administration & dosage*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D008099:Liver / Q000187:drug effects* / Q000473:pathology* / Q000601:surgery; D010865:Pilot Projects; D012597:Sclerosing Solutions / Q000008:administration & dosage*; D012972:Sodium Hydroxide / Q000008:administration & dosage*; D013552:Swine
D012597:Sclerosing Solutions; D012972:Sodium Hydroxide; D019342:Acetic Acid