Helical Cardiac CT ECG-Guided Z-Coverage Rescanning
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Solution Overview
Problem
Current cardiac helical CT scans face challenges in obtaining artifact-free images due to irregular heartbeats, leading to unnecessary radiation exposure and suboptimal image quality, as they conservatively set cardiac pitch to account for potential arrhythmia.
Innovation Solution
A system and method for adaptive data acquisition during helical cardiac CT scans that utilize electrocardiogram (ECG) signals to monitor cardiac cycles, adjust Z-coverage, and perform targeted rescans as needed to ensure artifact-free images, minimizing radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cardiac pitch is set conservatively to account for potential arrhythmia, then artifact-free images can be obtained, but radiation dose increases
Solution Approach 1:
The system dynamically adjusts the cardiac pitch parameter during the scan based on real-time ECG monitoring. When arrhythmia is detected, the system adapts the pitch to maintain image quality; when normal rhythm is confirmed, it increases pitch to reduce radiation dose, making the scanning parameter flexible rather than fixed
Solution Approach 2:
The system implements a feedback loop where ECG signals are continuously monitored during scanning, and the detected cardiac rhythm information is fed back to adjust the scanning parameters. This closed-loop control ensures that pitch settings respond to actual physiological conditions, optimizing both image quality and radiation dose
2Object-affected harmful factors
If cardiac pitch is increased to reduce radiation dose, then radiation exposure decreases, but image quality deteriorates due to insufficient Z-coverage
Solution Approach 1:
The system performs preliminary ECG monitoring and arrhythmia detection before finalizing scan parameters. By anticipating potential arrhythmia events in advance, the system can pre-calculate appropriate pitch values that will maintain sufficient Z-coverage even if arrhythmia occurs, preventing image quality deterioration
Solution Approach 2:
The system changes the pitch parameter adaptively based on detected cardiac conditions. When arrhythmia is detected, pitch is adjusted to maintain adequate Z-coverage for image reconstruction; when normal rhythm persists, pitch is increased to reduce dose, dynamically optimizing the balance between coverage and radiation exposure
3Reliability
If conservative pitch settings are used to ensure sufficient Z-coverage, then image reconstruction reliability improves, but scan time increases
Solution Approach 1:
The system dynamically adjusts pitch during scanning based on real-time ECG feedback. When normal sinus rhythm is confirmed, higher pitch values are used to accelerate scanning; when arrhythmia is detected, pitch is reduced to maintain reconstruction reliability, optimizing scan speed according to actual cardiac conditions
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
Ensures sufficient Z-coverage to minimize artifacts caused by irregular heart rates, providing artifact-free cardiac images while reducing radiation dose by dynamically adjusting scan parameters.
Implementation Method 1
obtain an electrocardiogram (ECG) signal from a subject during a duration of a helical cardiac scan
Implementation Method 2
In computed tomography (CT), X-ray radiation spans an object or a subject of interest being scanned
Implementation Method 3
a photodetector produces signals representative of the amount or intensity of radiation impacting discrete pixel regions of a detector surface
Data Source
AI summary
A method includes obtaining an electrocardiogram (ECG) signal during a scan of a heart of a subject with a CT scanner. The method includes calculating temporal R-R electrocardiogram interval measurements from the ECG signal. The method includes monitoring whether any irregular cardiac cycles are detected in the temporal R-R electrocardiogram interval measurements. The method includes determining whether an initial Z coverage of the scan is sufficient for obtaining an artifact free image of the heart at a target phase when one or more irregular cardiac cycles are detected. The method includes determining a required Z coverage to obtain the artifact free image of the heart at the target phase when the initial Z coverage is not sufficient. The method includes initiating a rescan of the heart to obtain the required Z coverage while continuing both to obtain the ECG signal and to monitor for any irregular cardiac cycles.