Morphometric characterization and temporal temperature measurements during hepatic microwave ablation in swine
Fig 1
Procedural workflow, imaging, and post-processing steps towards validation of a patient-specific thermal model.
(A) Procedural workflow. A pre-ablation contrast-enhanced CT was taken to plan for the ablation probe positioning. A general pattern for microwave ablation probe and thermocouple placement was planned and placed with assistance from a 3D printed grid. During ablation, temperatures were monitored. Immediately following ablation, a CT scan was taken both with and without the ablation probe in place, which could be used to co-localize thermocouples in relation to the ablation zone. After removal of the thermocouples, a post-ablation contrast-enhanced CT was taken to visualize both vessels and the ablation zone (non-perfusion zone). The liver was excised, and the ablation zone was identified and measured on cross-sectional slices that were cut perpendicularly to the axis of the probe. (B) During post-processing, the liver, vasculature, probe, and thermocouple locations can be identified. After image-registration, vasculature can be registered to identify vascular stasis. The segmented ablation zone and the probe location can then be used for comparison of expected and actual temperatures and ablation zones. A thermal simulation model can be run, based on the surrounding segmented tissue, and isotherms can be calculated and compared.