Motion Compensated Image Reconstruction for Cardiac CT
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Solution Overview
Problem
Current cardiac x-ray CT imaging techniques face challenges with high radiation doses and insufficient temporal resolution due to neglecting cardiac motion, leading to image blurring and artifacts, and existing methods to reduce radiation often compromise functional information.
Innovation Solution
The development of methods and algorithms for reconstructing images from projection data that compensate for motion, using techniques such as DABPF and DAxBPF algorithms, which estimate motion vector fields and iteratively optimize image reconstruction to improve spatial and temporal resolution while reducing radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrocardiogram-gated cardiac x-ray CT imaging is used to detect cardiac diseases, then diagnostic capability is improved, but radiation dose increases to 10-15 mSv (3-5 times standard chest CT)
Solution Approach 1:
The patent segments the cardiac cycle into multiple time windows and acquires projection data in separate phases. By dividing the imaging process into temporal segments and reconstructing images from each segment independently, the system achieves comprehensive cardiac assessment while enabling radiation dose reduction through selective data acquisition only during necessary time windows.
2Measurement precision
If gating window duration is shortened to improve spatial/temporal resolution, then resolution improves, but image noise increases
Solution Approach 1:
The patent employs dynamic adjustment of the gating window duration based on the specific cardiac phase being imaged. By adaptively modifying the window length according to motion characteristics of different cardiac phases, the system optimizes the balance between temporal resolution and image noise, using shorter windows for high-motion phases and longer windows for stable phases.
3Manufacturing precision
If only projection data within cardiac time window is used for reconstruction, then motion artifacts are reduced, but functional information is lost and radiation dose becomes unnecessary if tube current is not modulated
Solution Approach 1:
The patent utilizes periodic cardiac motion characteristics by acquiring projection data across multiple cardiac cycles at corresponding phases. By synchronizing data acquisition with the periodic nature of heartbeats and combining information from multiple cycles, the system reconstructs comprehensive images that preserve both anatomical detail and functional information while enabling radiation dose reduction through prospective triggering.
Data Source
AI summary
Featured are methods for reconstruction of images acquired from any of a number of scanning devices or apparatuses known to those skilled in the art which methods are established so as to provide a mechanism for compensating for motion of an object being imaged. Such methods of the present invention are such as to allow the clinician to select one or more specific methodologies that is appropriate for the expected motion, severity or complexity of the motion and efficient processing of projection data. Also feature are systems, apparatuses, software code and computer readable media which embody such methodologies.