CT Scanner Synchronization with Heart Cycle for Motion Artifact Reduction
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Solution Overview
Problem
Current CT scanners face challenges in imaging periodically moving subjects like the human heart due to motion artifacts, requiring fast and expensive high-power scanners or lengthy acquisition times, which are not suitable for all patients, especially those with irregular heart rates or breathing issues.
Innovation Solution
A CT imaging method and system that synchronizes acquisition cycles with the heart cycle, using a rotating frame with both constant and cyclically alternating velocities to cover the required angular range across multiple heart cycles, allowing for efficient data acquisition during specific phases of the heart motion cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fast high-power CT scanners are used to reduce motion artifacts, then imaging quality improves, but equipment cost and power consumption increase
Solution Approach 1:
The patent applies periodic action by synchronizing the CT scanning process with the periodic heart cycle. The scanner performs multiple acquisitions over several cardiac cycles, selectively using data from specific phases (e.g., diastole) when the heart is relatively stationary. This periodic synchronization allows standard CT equipment to achieve cardiac imaging quality without requiring high-power, expensive scanners, as the periodic nature of the heart rhythm provides natural motion freeze points.
2Measurement precision
If acquisition time is extended to capture complete heart cycle data, then imaging quality improves, but patient comfort deteriorates and breath holding becomes difficult
Solution Approach 1:
The patent segments the acquisition process into multiple discrete time windows corresponding to different phases of the heart cycle. Instead of requiring continuous acquisition over the entire cycle, the system identifies and processes data from specific segments (e.g., early diastole, late diastole) where the heart is relatively stationary. This segmentation allows the scan to be completed quickly within a single breath-hold period while still capturing sufficient data for high-quality imaging.
Solution Approach 2:
The system performs preliminary identification of suitable acquisition time windows before actual data collection. By analyzing the heart cycle timing in advance and pre-determining the optimal phases for scanning, the system can efficiently acquire data during the most favorable moments without requiring extended acquisition time. This preliminary planning ensures that the acquisition completes within the patient's breath-hold capability.
3Measurement precision
If retrospective gating is used to select data from minimal motion phases, then imaging quality improves, but the scan time and complexity increase
Solution Approach 1:
The patent implements feedback by continuously monitoring the heart cycle timing and using this information to guide the data acquisition and selection process. The system receives feedback from ECG or other cardiac monitoring signals, adjusts the scanning timing accordingly, and selectively processes data from phases with minimal motion. This feedback mechanism simplifies the overall process compared to retrospective gating, as the system proactively adapts to the heart rhythm rather than requiring complex post-processing sorting of data from multiple cycles.
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 enables effective imaging of periodically moving subjects with reduced motion artifacts and radiation dose, accommodating varying heart rates and improving patient comfort by shortening acquisition time without the need for high-cost, high-power equipment.
Implementation Method 1
an x-ray source adapted to generate an x-ray scan beam
Implementation Method 2
the X ray beam attenuated by the subject is measured by a detector array
Data Source
AI summary
Disclosed are methods, circuits, devices, assemblies and systems for performing Computer Tomography (CT)—for example of a periodically moving object such as a heart. According to some embodiments, there is provided a Computer Tomography scanner which includes an x-ray source adapted to generate an x-ray scan beam and a electromechanical assembly to which the x-ray source is mounted. The assembly may be adapted to move one or more electromechanical elements such that the scan beam is moved around the periodically moving object with a velocity profile having both constant and cyclically alternating rotational velocity components, and wherein the cyclically alternating velocity components are synchronized with the periodic motion of the object.