Effects of microwave ablation on cysts and cystic neoplasms with tissue-mimicking model: an ex vivo study

Abstract

Background and Purpose Microwave ablation (MWA) is a promising modality that needs to be further investigated for cystic lesions. The present study aimed to determine the effects of MWA on cysts and cystic neoplasms with a tissue-mimicking model. Methods Twenty New Zealand White rabbits were randomly divided into Group A (cyst mimic models, n = 10, φ = 5 cm) and Group B (cystic neoplasm mimicking models, n = 10, φ = 5 cm). For each group, ex vivo rabbit healthy bladder and VX2-implanted tumor bladder were fixed and embedded in agarose gel to mimic cyst and cystic neoplasm. In the MWA experimental subgroups, microwave antennas guided by computed tomography (CT) were introduced into these models. A system thermometer was placed at the outer edge of the bladder wall to monitor temperature changes. Immediately after MWA, ex vivo rabbit healthy bladders and VX2-implanted tumor bladders were harvested for gross anatomy and prepared for pathological evaluation. Results A total of twenty cyst and cystic neoplasm mimicking models were successfully developed. Ninety percent of the MWA procedures were successful, and no peri-procedural complications were encountered. The temperature of the cystic wall increased with duration in both MWA experimental subgroups and an effective ablation temperature (>60 °C) was achieved. Pathological examination of the cyst and cystic neoplasm mimic models revealed degenerative necrosis of the bladder wall mucosal epithelial cells, loss of bladder wall tissue structure and coagulative necrosis of VX2 tumor cells. Conclusion Our data indicate that MWA could cause thermal damage to the tissue structure of cyst and cystic neoplasm, and it is an effective technique for treating cystic diseases. HIGHLIGHTS ex vivo rabbit healthy bladder and VX2-implanted tumor bladder were fixed and embedded in agarose gel to mimic cyst and cystic neoplasm. The temperature of the cystic wall increased with MWA duration and an effective ablation temperature (> 60 °C) was achieved. MWA could cause thermal damage to the tissue structure of the cyst and cystic neoplasm and it is effective in treating cystic diseases, as assessed by histopathology.