4D Time-Energy Subtraction CT Imaging
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Solution Overview
Problem
Conventional medical imaging technologies, such as X-Ray Computed Tomography (CT), face challenges in achieving high detail and material selectivity due to limitations in implementing time and energy image subtraction techniques, particularly at fixed radiation energy levels, which can result in suboptimal image quality and tissue mis-registration during contrast-based applications.
Innovation Solution
The implementation of multi-energy and multi-time imaging techniques, allowing for the subtraction of images acquired at two or more radiation energy levels and times, enabling access to higher order terms such as dual energy/time derivatives, which enhances image quality by isolating material components like soft tissue, bone, and contrast material, and reduces noise through the inclusion of third-order terms in depth, energy, and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional fixed energy level imaging is used, then device complexity is reduced, but material selectivity and image quality deteriorate
Solution Approach 1:
The patent applies parameter changes by varying the radiation energy level to acquire images at multiple energy levels. This enables differentiation of materials based on their energy-dependent attenuation characteristics, thereby improving material selectivity without requiring complex additional hardware beyond standard CT capabilities
Solution Approach 2:
The patent introduces an energy dimension to traditional spatial imaging by acquiring and processing images at multiple energy levels. This additional dimension enables material decomposition and selective visualization of specific tissues or contrast agents, enhancing material selectivity while using conventional CT system architecture
2Reliability
If time subtraction techniques are used at fixed energy, then motion artifacts are reduced, but image quality and detail deteriorate due to inability to isolate material components
Solution Approach 1:
The patent segments the total attenuation signal into contributions from different materials (e.g., soft tissue, bone, contrast agent) by performing subtractions at multiple energy levels. This material-specific segmentation enables isolated visualization of contrast-enhanced structures while suppressing unrelated tissue, thereby improving both image consistency and detail
Solution Approach 2:
The patent uses energy-level differentiation as an intermediary mechanism to achieve material-specific imaging. By exploiting the different energy attenuation characteristics of various materials, the system can selectively isolate and visualize specific tissue types or contrast agents, enhancing both reliability and image detail
3Measurement precision
If multi-energy and multi-time imaging is implemented, then material selectivity and image quality improve, but device complexity and data processing requirements increase
Solution Approach 1:
The patent utilizes parameter changes by systematically varying the radiation energy level across multiple acquisition phases. This approach enables material decomposition through energy-dependent attenuation differences, achieving high material selectivity using standard CT hardware operated in multiple energy modes, thereby limiting the increase in device complexity
4Object-affected harmful factors
If conventional CT angiography with small detector area is used, then scatter-free signal detection is achieved, but timing problems occur during contrast bolus traversal resulting in suboptimal image quality
Solution Approach 1:
The patent applies continuity of useful action by continuously acquiring images at multiple energy levels throughout the contrast bolus traversal. This continuous multi-energy acquisition ensures that optimal contrast enhancement moments are captured without timing issues, while the small detector area maintains scatter-free signal detection characteristics
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 time-resolved, energy-subtracted 3D image volumes with low sensitivity to tissue motion, improving image quality in applications like digital subtraction angiography by reducing artifacts from tissue motion and enhancing material selectivity, particularly in the heart and abdomen.
Implementation Method 1
X-Ray Computed Tomography (CT) was introduced in the late 1970s as a means for forming three dimensional images of human anatomy
Implementation Method 2
The detector arrays often consist of two dimensional arrays of discrete detectors in conventional CT
Data Source
AI summary
A method is disclosed for generating a time resolved series of time and energy subtracted 3D volume reconstructions, e.g., using a switched dual energy C-Arm type X-ray imaging system or a bi-plane type X-ray imaging system.