Partial Scan Sinogram Interpolation for CT Perfusion Artifact Reduction
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Solution Overview
Problem
Current methods for reducing partial scan reconstruction artifacts (PSAs) in computed tomography perfusion (CTP) are either invasive, increase radiation dose, or require burdensome computational steps, and are not robust to motion artifacts, while also not being readily applicable to existing CT scanners.
Innovation Solution
A method that transforms partial-scan sinogram data into full-scan sinogram data by filling empty spaces using interpolation or weighting based on neighboring scans, allowing for image reconstruction without additional hardware or radiation, thus reducing PSAs effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If partial scan reconstruction is used to improve temporal resolution, then temporal resolution is improved, but partial scan reconstruction artifacts appear due to inconsistent angular data ranges
Solution Approach 1:
The patent segments the partial scan data into multiple angular ranges and processes each segment separately. By dividing the projection data into different angular segments and applying specific interpolation techniques to each, the method maintains the temporal resolution benefits of partial scans while reducing the artifacts caused by inconsistent angular coverage.
Solution Approach 2:
The patent introduces an intermediary processing step that creates a reference sinogram from a full scan or composite of partial scans. This reference sinogram serves as a mediator that provides consistent angular data ranges, which is then combined with the partial scan data to produce artifact-reduced images while preserving temporal resolution.
2Reliability
If full scan with 360 degrees of projection data is used to reduce artifacts, then partial scan reconstruction artifacts are reduced, but radiation dose increases and temporal resolution decreases
Solution Approach 1:
The patent applies partial action by using only the necessary portion of full scan data (specific angular ranges) rather than complete 360-degree coverage. By selectively acquiring and processing only the required angular segments, the method achieves artifact reduction equivalent to full scan while maintaining the lower radiation dose and higher temporal resolution characteristics of partial scans.
Solution Approach 2:
The patent applies local quality by using different reconstruction strategies for different angular ranges. Certain angular segments are processed with full scan reference data to reduce artifacts, while other segments maintain partial scan characteristics to preserve temporal resolution and minimize radiation dose, optimizing the trade-off locally across different parts of the scan data.
3Measurement precision
If convolution operations are used to combine full and partial scan data, then spatial frequencies are optimized, but computational complexity increases
Solution Approach 1:
The patent segments the frequency domain processing into distinct spatial frequency bands and applies targeted filtering operations to each band. By dividing the convolution operation into manageable frequency segments rather than processing the entire frequency spectrum simultaneously, the method maintains spatial frequency accuracy while reducing computational complexity through parallel or sequential processing of smaller data subsets.
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 maintains high temporal resolution, reduces noise, and is computationally less demanding, providing higher image quality without increasing radiation dose or requiring invasive procedures, and can be integrated into existing CT protocols.
Implementation Method 1
The intensity of the transmitted radiation is dependent upon the attenuation of the x-ray beam by the object, and each detector produces a separate electrical signal that is a measurement of the beam attenuation.
Data Source
AI summary
A system and method is provided for reducing partial scan reconstruction artifacts in sinogram data acquired as a series of sets of partial-scan projection views, each set of projection views extending over an angular range of less than 360 degrees. A full-scan sinogram matrix for each of the sets of projection views in the series is created and each set of partial-scan projection views is stored in a respective full-scan sinogram matrix to create an array of full-scan matrices having respective empty spaces not filled by partial-scan projection view data stored therein. The empty spaces are filled in each of the full-scan sinogram matrices using the partial-scan projection view data stored therein and an image of the subject is reconstructed from the full-scan sinogram matrices having the empty spaces filled using the partial-scan projection view data stored therein.