MRI Apparatus Adaptive Rotation Angle for Motion Artifacts
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Solution Overview
Problem
Magnetic resonance imaging (MRI) using radial-type acquisition sequences can be affected by cyclic movements such as respiration and heartbeats, leading to degraded image quality when these movements synchronize with imaging cycles.
Innovation Solution
A magnetic resonance imaging apparatus and method that dynamically adjusts the acquisition pattern by selecting a rotation angle based on the platinum angle, which generalizes the golden angle, to optimize k-space data distribution and improve image quality despite cyclic movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed rotation angle (golden angle) is used for radial acquisition, then k-space data dispersiveness is improved, but image quality deteriorates when cyclic movements synchronize with imaging cycles
Solution Approach 1:
The patent applies dynamics by making the rotation angle adaptive rather than fixed. The system dynamically adjusts the rotation angle based on the detected cyclic movement characteristics (respiratory cycle period). Specifically, when a respiratory cycle is detected, the system modifies the rotation angle for acquisitions triggered at specific phases (e.g., expiration phase) to avoid synchronization artifacts, thereby maintaining both k-space dispersiveness and image quality under varying physiological conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the rotation angle parameter according to detected biological cycle information. The system calculates an adjusted rotation angle that accounts for the respiratory cycle period, transforming the fixed golden angle into a variable parameter that adapts to the patient's physiological state, thus preventing synchronization between imaging cycles and respiratory movements.
2Device complexity
If acquisition window and trigger delay are fixed, then imaging process is simple, but adaptability to different coronary branch regions and motion states is reduced
Solution Approach 1:
The system applies dynamics by making the acquisition window and trigger delay adaptive parameters. Instead of fixed values, these parameters are dynamically adjusted based on detected motion states (e.g., respiratory phase, cardiac cycle phase). The system can modify the trigger delay and acquisition window duration to optimize imaging for different coronary branch regions and motion conditions, enhancing versatility without significantly complicating the overall imaging workflow.
Solution Approach 2:
The patent applies preliminary action by performing motion detection and cycle analysis before the actual image acquisition. The system detects respiratory and cardiac cycles in advance, determines optimal trigger delays and acquisition windows based on these detected cycles, and then executes the imaging protocol with pre-optimized parameters. This preliminary preparation enables adaptive imaging without adding significant complexity during the acquisition phase.
Data Source
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AI summary
A magnetic resonance imaging apparatus according to an embodiment includes processing circuitry (150). The processing circuitry (150) is configured to set a rotation angle of a non-Cartesian trajectory in a k-space on the basis of information related to cyclic movements of a subject to be imaged, to obtain k-space data by rotating the non-Cartesian trajectory at the set rotation angle, and to generate an image by reconstructing the k-space data.