Eisuke Ueshima

Catheter-based endobronchial electroporation is feasible for the focal treatment of peribronchial tumors

Objective: To evaluate the feasibility of catheter‐based endobronchial electroporation for the treatment of peribronchial tumors and assess the incidence of treatment‐related adverse events. Methods: Cytotoxicity of electroporation with or without cisplatin or gefitinib was assessed in vitro with lung cancer and normal cell lines. A novel catheter was designed for endobronchial electroporation, and computer simulations were used to predict in vivo treatment effects. Electroporation with the test catheter was performed (2000 V, 70 pulses) in the main bronchus of 8 pigs at 11 locations. Computed tomography imaging was performed before they were killed at 4 hours (6 animals) or 4 weeks (2 animals) posttreatment. Treated airway and surrounding parenchyma were compared with sham treatment via gross and histopathology. Results: Significant cell death due to electroporation and increased cytotoxicity in combination with cisplatin or gefitinib were observed in cancer cells only (P < .05). Simulations predicted penetrative electroporation of peribronchial parenchyma without tissue heating. Electric pulse delivery in vivo induced transient venous and bronchial spasms that resolved without intervention. Cross‐sectional measurement of electroporation effects on computed tomography (14.4 ± 1.4 by 10.5 ± 1.3 mm) and gross pathology (17.2 ± 3.0 by 8.8 ± 0.6 mm) were representative of values predicted by simulation (P < .001). Cell death due to irreversible electroporation was observed in bronchial and parenchymal tissue in acute tissue samples. Treated lung rapidly recovered from the effects of electroporation without change in bronchial patency at 4 weeks posttreatment. Conclusions: Catheter‐based endobronchial electroporation is a reproducible technique that can be used to treat peribronchial tumors in combination with cisplatin, without affecting patency of the treated bronchus.

High power microwave ablation of normal swine lung: impact of duration of energy delivery on adverse event and heat sink effects

Abstract Purpose: The purpose of this study is to assess the impact of duration of energy delivery on adverse events (AEs) and heat sink effects during high power microwave ablation (MWA) of normal swine lung. Materials and methods: High power (100 W) MWA was performed with short (2 min, 18 ablations) or long (10 min, nine ablations) duration of energy delivery in unilateral lung of swine (n = 10). CT imaging was done prior to sacrifice at 2 or 28 d post-treatment, with additional imaging at 7 and 14 d for the latter cohort. Ablation zones were assessed with CT imaging and histopathology analysis. Differences in AEs and ablation characteristics between groups were compared with Fisher’s exact test and Student’s t-test, respectively. Results: There were no significant differences in formation of air-filled needle tract, cavitation, and pneumonia (p > 0.5) between the treatment groups. Intra-procedural pneumothorax requiring chest tube placement occurred in three animals. Substantial (>20%, p = 0.01) intra-procedural ablation zone distortion was observed in both groups. The presence of large airways or blood vessels did not result in heat sink effect within the ablation zones and was not indicative of reduced ablation size. Increased energy delivery yielded larger (8.9 ± 3.1 cm3 vs. 3.4 ± 1.7 cm3, p < 0.001) spherical ablations (sphericity: 0.70 ± 0.10 vs. 0.56 ± 0.13, p = 0.01). Conclusions: High power MWA of normal lung with longer duration of energy delivery can create larger spherical ablations, without significant differences in post-procedure AEs when compared with shorter energy delivery time.