CT Thermography Image Correction via Temperature Field Estimation
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Solution Overview
Problem
CT thermography images for thermal ablation procedures are often degraded by imaging artefacts and noise, particularly due to imperfect registration of pre-ablation and post-ablation images, which hinders their clinical use.
Innovation Solution
A medical image processing apparatus and method that estimates a temperature field based on heating parameters and uses this field to intelligently smooth CT thermography images, removing noise and artefacts by preferentially averaging voxels with similar temperatures, thereby generating a corrected image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-ablation and post-ablation images are registered and subtracted to obtain thermography images, then temperature information can be obtained, but imaging artefacts and noise are introduced that degrade image quality
Solution Approach 1:
The patent applies preliminary registration correction to the pre-ablation and post-ablation images before performing subtraction. By pre-aligning the images using registration transforms and correcting for patient motion and anatomical changes, the method eliminates registration misalignment artefacts that would otherwise appear as noise in the thermography image, thereby improving both measurement precision and reliability
Solution Approach 2:
The patent introduces an intermediary processing step that models and corrects for tissue deformation and patient motion between pre-ablation and post-ablation scans. This intermediary correction layer acts as a mediator that reconciles the two images before subtraction, removing artefacts while preserving the true temperature-dependent HU value differences
2Productivity
If simple subtraction of registered images is performed, then processing speed is maintained, but image artefacts and noise prevent clinical use
Solution Approach 1:
The patent performs preliminary image registration and correction operations before the subtraction step. By pre-processing the images to correct for motion and deformation, the actual subtraction operation remains computationally efficient while the preliminary actions ensure clinical usability by eliminating artefacts that would otherwise require complex post-processing
Solution Approach 2:
The patent employs iterative optimization that uses feedback from the temperature field estimation to refine the image correction. The system continuously adjusts registration parameters and correction factors based on the estimated temperature distribution, improving image quality while maintaining reasonable processing speeds through intelligent iteration
3Loss of information
If registration is performed to align pre-ablation and post-ablation images, then temperature mapping is enabled, but registration imperfections create artefacts
Solution Approach 1:
The patent applies preliminary registration with iterative optimization to align pre-ablation and post-ablation images before subtraction. By using feedback from temperature field estimation to refine registration parameters, the system recovers temperature information while minimizing registration-induced artefacts through continuous improvement of alignment accuracy
Solution Approach 2:
The patent introduces an intermediary deformation model that accounts for tissue changes between pre-ablation and post-ablation scans. This intermediary model acts as a mediator that compensates for registration imperfections by modeling expected tissue deformation, thereby reducing artefacts while preserving true temperature-related HU value changes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method improves the clarity and accuracy of CT thermography images, making them more suitable for clinical use by reducing noise and artefacts, allowing for better assessment of heating during thermal ablation procedures.
Implementation Method 1
estimate a temperature field corresponding to the thermography image or pair of medical images
Implementation Method 2
uses this field to intelligently smooth CT thermography images, removing noise and artefacts by preferentially averaging voxels with similar temperatures
Data Source
AI summary
Certain embodiments provide a medical image processing apparatus comprising processing circuitry configured to: receive a thermography image, or a pair of medical images from which a thermography image is obtainable; estimate a temperature field corresponding to the thermography image or pair of medical images; and generate a corrected thermography image based on the thermography image or pair of medical images and on the estimated temperature field.