Quantitative analysis of lung microwave ablation zone volume and shape

Area of Science:

• Medical Imaging
• Interventional Radiology
• Oncology

Background:

• Lung microwave ablation (LMWA) is a minimally invasive treatment for lung tumors.
• Accurate prediction of ablation zone volume and shape is crucial for treatment efficacy and safety.
• Existing vendor models may not fully capture the variability in ablation outcomes.

Purpose of the Study:

• To quantify the volume and shape variability of LMWA zones.
• To compare actual ablation zones with predicted zones from vendor models.
• To investigate the correlation between tissue contraction and ablation zone characteristics.

Main Methods:

• Retrospective analysis of 111 LMWA procedures in 72 patients.
• Utilized Pyradiomics for volume generation and Euler characteristic transform for 3D shape analysis.
• Quantified tissue contraction using CT scans and anatomical landmarks.

Main Results:

• Ablation volumes were comparable to vendor predictions, but length and maximum width were significantly greater.
• Ablation shapes exhibited significant variability, being more elongated, less spherical, and asymmetric than predicted ellipsoids.
• No correlation was found between tissue contraction and ablation zone volume, power, or time.

Conclusions:

• Vendor models provide a reasonable estimate of mean ablation volume but lack precision for individual cases due to high shape variability.
• Development of bespoke ablation zone prediction models is necessary to account for observed variations in LMWA.
• Tissue contraction is not a significant factor influencing the variability of LMWA zone dimensions.