X-Ray CT Motion Estimation for Body-Axis Image Continuity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing X-ray CT systems face challenges in maintaining image continuity, particularly in the body axis direction, due to asynchronous imaging and varying image reconstruction conditions, leading to reduced motion correction accuracy and computational inefficiencies.
Innovation Solution
A motion estimation model with independently adjustable regularization terms for spatial and temporal continuity is introduced, allowing dynamic adjustment to image reconstruction conditions, using a free-form deformation model based on a 3D B-spline function for motion correction reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple PAR image pairs are used for motion correction reconstruction, then motion correction accuracy is improved, but computational cost increases significantly
Solution Approach 1:
The patent extracts only the essential motion information from a single PAR image pair by applying a motion estimation model, rather than using multiple PAR image pairs. This extraction approach obtains sufficient motion correction data while avoiding the computational burden of processing multiple image pairs.
Solution Approach 2:
The patent changes the parameter of motion information acquisition from using multiple PAR image pairs to using a single PAR image pair combined with a motion estimation model. This parameter change maintains motion correction accuracy while significantly reducing computational cost.
2Productivity
If asynchronous imaging is performed with faster table speed, then imaging efficiency is improved, but motion correction accuracy deteriorates due to reduced data for PAR image creation
Solution Approach 1:
The patent replaces the mechanical approach of acquiring extensive projection data through slower scanning with a computational approach using a motion estimation model. This model can accurately estimate motion from limited data, enabling fast table speeds while maintaining motion correction accuracy.
Solution Approach 2:
The patent changes the data acquisition parameter to work effectively with sparse data from faster scanning by introducing a motion estimation model that can derive accurate motion information from reduced datasets, thus maintaining precision while improving speed.
3Adaptability or versatility
If image reconstruction conditions such as slice thickness and FOV are changed, then adaptability to different imaging needs is improved, but motion correction accuracy becomes difficult to maintain
Solution Approach 1:
The patent introduces a motion estimation model that dynamically adapts to different reconstruction conditions. The model can adjust its parameters and calculations based on the specific slice thickness, FOV, and other reconstruction settings, maintaining motion correction accuracy across varying conditions.
Solution Approach 2:
The patent enables the motion estimation model to change its operational parameters according to the reconstruction conditions. When slice thickness or FOV changes, the model adjusts its estimation parameters accordingly, preserving motion correction accuracy despite varying reconstruction settings.
4Reliability
If electrocardiographic synchronization is performed, then cardiac motion artifacts are reduced, but image continuity in body axis direction deteriorates due to different reconstruction center phases
Solution Approach 1:
The patent segments the motion correction approach into two independent components: a motion estimation model for handling cardiac motion and a separate continuity maintenance mechanism for ensuring image consistency in the body axis direction. This segmentation allows both objectives to be achieved simultaneously.
Solution Approach 2:
The patent introduces an intermediary continuity maintenance mechanism that mediates between the cardiac-synchronized images with different reconstruction center phases. This intermediary ensures smooth transitions and continuity in the body axis direction while preserving the benefits of electrocardiographic synchronization.
Data Source
AI summary
Provided is an X-ray CT apparatus capable of preventing excessive motion correction or deformation, particularly maintaining continuity of images in a body axis direction, and performing motion correction reconstruction under an optimal condition according to an image reconstruction condition, in motion correction reconstruction.A processor for image processing of an X-ray CT apparatus according to the present invention includes a motion estimation model including regularization terms that are independently adjustable for continuity of a spatial domain and continuity of a time domain, as a motion estimation model for acquiring motion information. The motion estimation model is configured to adjust a weight of the regularization term and a control point position. A motion information acquisition unit automatically adjusts the motion estimation model or a calculation method of a control point parameter using the motion estimation model according to a FOV or an image reconstruction interval which is an image reconstruction condition. As a result, it is possible to satisfactorily maintain image continuity in one cross section and inter-slice image continuity in a body axis direction.