CT Elastography via Phase-Synchronized Projection Acquisition
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Solution Overview
Problem
Current elastography methods using X-ray computed tomography (CT) require multiple full scans, increasing ionizing radiation exposure and limiting diagnostic power due to repeated radiation exposure, while ultrasound and MRI methods have limitations in accuracy and field of view.
Innovation Solution
A method for CT elastography that uses a single conventional CT scan, synchronizing CT projection acquisition with periodic tissue deformation caused by a mechanical exciter, reducing radiation exposure and improving accuracy by leveraging tissue density information from standard CT images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple full CT scans are performed to acquire elastographic images, then tissue elasticity measurement capability is improved, but ionizing radiation exposure increases
Solution Approach 1:
The patent segments the elastography measurement process into multiple phases within a single CT scan acquisition. Instead of performing multiple full scans, the system acquires CT projection data at different phases of tissue deformation (caused by external mechanical excitation) during one continuous scan, then reconstructs elastographic images from these phase-separated datasets.
Solution Approach 2:
The patent employs periodic mechanical excitation of the tissue and synchronizes CT projection acquisition with specific phases of this periodic deformation. By acquiring projections at predetermined phases of the excitation cycle, the system captures tissue deformation information needed for elastography while maintaining a single scan acquisition.
2Measurement precision
If multiple full CT scans are performed to acquire elastographic images, then tissue elasticity measurement capability is improved, but scan time increases
Solution Approach 1:
The patent segments the elastography measurement process into multiple phases within a single CT scan acquisition. Instead of performing multiple full scans, the system acquires CT projection data at different phases of tissue deformation (caused by external mechanical excitation) during one continuous scan, then reconstructs elastographic images from these phase-separated datasets.
Solution Approach 2:
The patent maintains continuous CT scan operation throughout the tissue excitation cycle, continuously acquiring projection data at all phases of the periodic deformation. This continuous acquisition approach eliminates the time losses associated with stopping and restarting multiple separate scans, capturing all necessary elastographic information in one uninterrupted scan.
3Speed
If ultrasound is used for elastography, then acquisition speed is improved, but measurement accuracy in non-axial directions deteriorates
Solution Approach 1:
The patent employs CT imaging technology to perform multiple functions: it provides both standard anatomical imaging and elastographic measurement capability within a single system. CT's inherently three-dimensional imaging geometry allows accurate measurement of tissue deformation in all spatial directions (x, y, and z axes), unlike ultrasound which is primarily optimized for axial direction measurements.
4Measurement precision
If MRI is used for elastography, then image quality and quantitative accuracy are improved, but acquisition time increases
Solution Approach 1:
The patent replaces the MRI imaging mechanism with CT technology for elastography acquisition. While MRI provides excellent soft tissue contrast and quantitative accuracy, it requires prolonged acquisition times. CT scanning completes the same elastographic measurement much faster, leveraging its rapid acquisition capability to obtain phase-resolved projection data throughout the tissue excitation cycle in a fraction of the time required by MRI.
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
This approach generates effective elastographic images with reduced radiation exposure, providing 3D strain and quantitative elasticity measurements, and enhances diagnostic imaging by reducing patient motion errors, thus improving the quality of elasticity imaging.
Implementation Method 1
applying, by a vibration source, periodic excitation waves to the volume of tissue
Implementation Method 2
acquiring by the CT scanner a first plurality of CT projections at a first phase corresponding to a first deformation state of the volume of tissue
Data Source
AI summary
A system and method includes applying, by a vibration source, periodic excitation waves to the volume of tissue, the periodic excitation wave having a plurality of phases, acquiring by the CT scanner a first plurality of CT projections at a first phase, the first plurality of CT projections comprising a first CT projection set, acquiring by the CT scanner a second plurality of CT projections at a second phase, wherein the second phase is different than the first phase a second set of CT projections, the second plurality of CT projections comprising a second CT projection set, and determining, based on the first set of CT projections and the second set of CT projections, at least one of a tissue deformation field and a tissue mechanical property of the volume of tissue.