Adaptive Keyhole Compression for MRI Resolution Trade-offs
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Solution Overview
Problem
Dynamic contrast enhanced MRI faces a trade-off between spatial and temporal resolution, where high spatial resolution is difficult to maintain with high temporal resolution, and vice versa, due to the fixed sampling rate of MR scanners, limiting the repeatability and effectiveness of imaging procedures.
Innovation Solution
Adaptive keyhole compression dynamically adjusts the size of the central and peripheral portions of k-space based on the rate of change of the contrast agent, allowing for improved temporal resolution when the agent is moving quickly and increased spatial resolution when there is little change, using existing hardware and software protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If many lines of k-space are generated for reconstruction into each image, then the spatial resolution of each image is high, but the temporal resolution is low
Solution Approach 1:
The patent divides k-space into central and peripheral portions, applying different sampling strategies to each segment. The central portion is sampled at every time point to capture temporal changes, while the peripheral portion is sampled less frequently to reduce data volume. This segmentation allows the system to maintain high spatial resolution from the central k-space while improving temporal resolution by reducing the sampling burden on peripheral k-space.
Solution Approach 2:
The patent implements dynamic adjustment of the keyhole compression parameter based on the rate of change of the contrast agent. When the contrast agent changes rapidly, the system increases temporal resolution by reducing peripheral k-space sampling. When changes are slow, the system can afford to sample more peripheral lines to maintain spatial resolution. This dynamic adaptation resolves the contradiction by making the sampling strategy responsive to actual imaging needs.
2Loss of time
If few lines of k-space are reconstructed into each image, then the temporal resolution is high, but the spatial resolution is low
Solution Approach 1:
By segmenting k-space into central and peripheral regions with different sampling densities, the patent ensures that the central portion (which contains most of the image contrast and structural information) is always adequately sampled, even when peripheral sampling is reduced to improve temporal resolution. This prevents spatial resolution degradation while achieving high temporal resolution.
Solution Approach 2:
The patent applies different sampling qualities to different regions of k-space. The central region receives high-quality sampling at every time point to preserve spatial resolution, while the peripheral region receives lower-quality or intermittent sampling. This local differentiation allows the system to achieve high temporal resolution without sacrificing the spatial resolution that depends on central k-space data.
3Ease of operation
If the compression percentage is fixed, then the imaging protocol is simple to operate, but the balance between spatial and temporal resolution cannot be optimized for different imaging conditions
Solution Approach 1:
The patent incorporates feedback mechanisms that automatically adjust the keyhole compression parameter based on the observed rate of change of the contrast agent in the imaging region. The system monitors contrast agent dynamics and adaptively modifies the sampling strategy without requiring manual intervention. This maintains ease of operation while achieving optimal resolution balance through automated adaptation to imaging conditions.
Solution Approach 2:
The imaging system performs self-adjustment of the compression parameter based on real-time analysis of contrast agent behavior. The system serves itself by automatically determining the appropriate sampling strategy without external input, combining operational simplicity with adaptive optimization for different imaging scenarios.
Data Source
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AI summary
A magnetic resonance imaging system (3) includes a sequence control unit (18), a sampling unit (26), and a control unit (24). The sequence control unit (18) controls a magnetic resonance scanner (4) to acquire compressed magnetic resonance data from an imaged region of a subject. The sampling unit (26) determines a change in a concentration of a contrast agent present in the image region of the subject based on magnetic resonance signals received by a radio frequency receiver. The control unit (24) adjusts a degree of compression of the acquired magnetic resonance data based on the determination made by the sampling unit (26).