Radiologic-Pathologic Analysis of Increased Ethanol Localization and Ablative Extent Achieved by Ethyl Cellulose

Purpose
Ethanol provides a rapid, low-cost ablative solution for liver tumors with a small technological footprint but suffers from uncontrolled diffusion in target tissue, limiting treatment precision and accuracy. The authors demonstrate that incorporating the gel-forming polymer ethyl cellulose to ethanol localizes the distribution. This therapy may have a low barrier of entry for cancer care in low- and middle- income countries.

Materials and Methods
The relationship of radiodensity to ethanol concentration was characterized with water-ethanol surrogates. Ex vivo EC-ethanol ablations were performed to optimize the formulation (n=6). In vivo ablations were performed to compare the optimal EC-ethanol formulation to pure ethanol (n=6). Ablations were monitored with CT and ethanol distribution volume was quantified. Livers were explanted, sectioned and stained with NADH-diaphorase to determine the ablative extent.

Results
CT imaging of ethanol-water surrogates demonstrated the ethanol concentration-radiodensity relationship is approximately linear. A concentration of 12% EC in ethanol created the largest distribution volume, more than 8-fold that of pure ethanol, ex vivo. In vivo, 12% EC-ethanol was superior to pure ethanol, yielding a distribution volume 3 times greater and an ablation zone 6 times greater than pure ethanol.

Conclusions
EC-ethanol, a novel gel formulation injectable ablative injectate, safely increases distribution and necrosis compared to pure ethanol.