In Vivo Temperature Mapping during CT-Guided Thermal Ablations: Proof of Feasibility Using Spectral CT

Area of Science:

• Medical Imaging
• Biophysics
• Interventional Radiology

Background:

• Accurate temperature monitoring is crucial for effective clinical ablations.
• Computed tomography (CT) signal properties are known to correlate with temperature.
• Developing non-invasive temperature mapping techniques is an ongoing challenge.

Purpose of the Study:

• To develop and validate a method for temperature mapping during clinical ablations using spectral computed tomography (CT).
• To correlate CT signal changes with temperature variations in different tissue types.
• To generate in vivo temperature maps for microwave and cryoablations.

Main Methods:

• Characterized spectral CT signal dependence on temperature for soft tissue and fat mimics.
• Acquired spectral CT images alongside fiber optic thermal sensor data.
• Correlated electron density changes with local temperatures.
• Utilized effective atomic number images for tissue segmentation (soft tissue, fat, bone).
• Applied derived electron density-temperature relationships to generate temperature maps.

Main Results:

• Material-specific thermal properties and temperature dependencies were measured and validated.
• Effective atomic number imaging enabled accurate tissue segmentation.
• Generated in vivo temperature maps during microwave and cryoablations.
• The generated temperature maps aligned with interventional radiologist expectations.
• Observed smooth temperature transitions at fat/soft tissue interfaces.

Conclusions:

• Spectral CT-based temperature mapping is a feasible technique for clinical ablations.
• The method provides accurate, non-invasive temperature visualization.
• This approach can enhance the precision and safety of ablation procedures.