Tomographic Image Reconstruction Using Temporal Subsets for Motion Artifact Reduction
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Solution Overview
Problem
Current tomographic imaging systems face challenges in achieving high temporal resolution due to motion artifacts, particularly in cardiac imaging, where the existing methods either require costly hardware upgrades or compromise reliability and efficiency.
Innovation Solution
A method and apparatus that acquire and reconstruct tomographic images by identifying regions of motion and using a temporal subset of projection datasets to correct motion artifacts, thereby improving temporal resolution without the need for additional hardware, applicable to CT, SPECT, and PET systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-source MDCT scanners use standard gantry rotational speeds (270-350 ms), then system reliability and operational stability are maintained, but temporal resolution is insufficient (135-175 ms) to adequately capture cardiac motion
Solution Approach 1:
The patent segments the projection data acquisition into multiple temporal subsets by dividing the cardiac cycle into distinct phases (e.g., early diastole, mid-diastole, early systole, mid-systole). This allows selective use of data from specific cardiac phases to reconstruct images with improved temporal resolution while maintaining system stability during each segment's acquisition.
Solution Approach 2:
The patent implements dynamic temporal resolution adjustment by varying the gantry rotation speed and projection data acquisition parameters based on the specific cardiac phase being imaged. The system dynamically adapts acquisition parameters to optimize temporal resolution for different cardiac phases without compromising overall system reliability.
2Measurement precision
If dual-source MDCT systems are deployed to improve temporal resolution, then temporal resolution increases by approximately a factor of two, but system cost and complexity increase significantly
Solution Approach 1:
Instead of using dual-source hardware, the patent segments the projection data from a single source into multiple temporal subsets corresponding to different cardiac phases. This software-based segmentation achieves improved temporal resolution without requiring additional hardware sources, thereby avoiding the associated cost and complexity increases.
Solution Approach 2:
The patent creates virtual copies of projection data by reconstructing multiple images from the same physical projection data set, each representing a different cardiac phase. This allows the system to simulate multiple simultaneous acquisitions using a single physical source, achieving dual-source-like temporal resolution without the hardware duplication costs.
3Measurement precision
If faster gantry rotational speeds are used to reduce acquisition time, then temporal resolution improves, but the gantry weight and forces acting on the gantry increase, limiting further speed improvements
Solution Approach 1:
The patent implements dynamic adjustment of gantry rotation speed based on the specific imaging requirements and cardiac phase being captured. The system optimizes rotation speed for each temporal subset, using higher speeds when acceptable to improve temporal resolution while maintaining lower speeds when necessary to manage gantry forces, thereby achieving optimal temporal resolution without excessive force requirements.
Solution Approach 2:
The patent changes multiple acquisition parameters simultaneously including gantry rotation speed, projection data sampling rate, and reconstruction algorithms to achieve improved temporal resolution. By coordinating these parameter changes rather than relying solely on increasing gantry speed, the system improves temporal resolution while keeping gantry forces within acceptable limits.
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 effectively enhances temporal resolution by approximately a factor of two in cardiac imaging, reducing motion artifacts and improving image quality without the costs and reliability issues associated with dual-source systems, and is applicable to various tomographic imaging modalities.
Implementation Method 1
a scintillator adjacent to the collimator for converting x-rays to light energy
Implementation Method 2
photodiodes for receiving the light energy from the scintillator and producing electrical signals therefrom
Data Source
AI summary
A tomographic system includes a gantry having an opening for receiving an object to be scanned, a radiation source, a detector positioned to receive radiation from the source that passes through the object, and a computer. The computer is programmed to acquire a plurality of projection datasets of the object, define a temporal subset of projection datasets from the plurality of projection datasets, reconstruct a working image of the object using the plurality of projection datasets, identify a region of motion in the working image, and minimize motion artifacts in the region of motion in the working image using the temporal subset of projection datasets.