ECG-Gated CT Reconstruction Window Adaptation for Irregular Heart Rhythms
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Solution Overview
Problem
Computed tomography (CT) imaging of a beating heart, especially cardiac CT, faces challenges in reconstructing high-quality image data due to irregular heart rhythms, which can result in selecting data from different cardiac phases, leading to degraded images.
Innovation Solution
A system that includes a windowing component to adjust and optimize reconstruction windows based on ECG signals, automatically identifying and addressing premature heart cycles and anomalous signals by repositioning or adding reconstruction windows to ensure data corresponds to the desired cardiac phase, thereby generating high-quality image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If data from multiple heart cycles is used for reconstruction, then temporal resolution is improved, but irregular heart rhythms cause data to correspond to different cardiac phases, degrading image quality
Solution Approach 1:
The system dynamically adjusts the reconstruction window position based on the actual heart cycle timing detected from ECG signals. Instead of using fixed time intervals, the system adapts the window placement to account for variations in heart rate and rhythm, ensuring that data corresponding to the desired cardiac phase is consistently selected across multiple heart cycles.
Solution Approach 2:
The system uses ECG signals as feedback to monitor the actual electrical activity of the heart during scanning. This feedback mechanism allows the system to detect irregular rhythms and adjust the reconstruction window positioning in real-time, ensuring that only data from the correct cardiac phase is selected for reconstruction, thereby maintaining image quality while utilizing multi-cycle data.
2Reliability
If a manual technique is used to delete or add reconstruction windows for premature heart cycles, then some data quality improvement is achieved, but the process is complex and the resulting image data quality remains less than desired
Solution Approach 1:
The system automatically detects premature or irregular heart cycles and autonomously adjusts the reconstruction windows without requiring manual user intervention. The algorithm identifies anomalies in the ECG signal, determines the appropriate window positioning or deletion, and executes the adjustments automatically, simplifying the process while maintaining or improving image data quality.
Solution Approach 2:
The system changes the timing parameters of reconstruction windows based on detected heart rhythm variations. When irregularities are detected, the system modifies the start time, duration, or presence of reconstruction windows to ensure they align with the actual cardiac phase, automatically optimizing the reconstruction process for varying heart conditions.
3Ease of operation
If reconstruction windows are fixed based on average heart cycle timing, then the system is simple to operate, but premature heart cycles cause windows to correspond to different cardiac phases, degrading reconstruction accuracy
Solution Approach 1:
The system transitions from static, fixed reconstruction windows based on average timing to dynamic windows that adapt to actual heart cycle variations. The window positions are continuously adjusted based on real-time ECG signal analysis, allowing the system to maintain operational simplicity while achieving high reconstruction accuracy even during irregular heart rhythms.
Data Source
AI summary
A computed tomography system (100) includes a windowing component (140) that receives an ECG signal that includes a premature heart cycle. The ECG signal is time-synchronized with x-ray projection data of a beating heart. The windowing component (140) either removes or repositions a first reconstruction window within a first heart cycle to correspond to a desired cardiac phase when the premature heart cycle causes the first reconstruction window to correspond to a different cardiac phase, based on available data. A reconstructor (148) that reconstructs projection data corresponding to a plurality of reconstruction windows from different cardiac cycles generates image data indicative of the desired phase of the heart.