Magnetic Resonance Coil Array Segmentation for Cardiac Imaging
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Solution Overview
Problem
Magnetic resonance imaging of the heart is hindered by movement artifacts due to cardiac and breathing movements, leading to inconsistent data and poor image quality, especially in cardiac patients who cannot hold their breath for extended periods, resulting in artifacts like 'ghosting' or 'blurring' that hinder clinical interpretation.
Innovation Solution
A method using two groups of local antennas, where the first group is sensitive to unmoving areas and the second group to moving areas, with spatially coded signals from the second group combined using weighting factors to reduce the sensitivity gradient, effectively reducing movement artifacts by creating a more homogeneous sensitivity profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If segmented acquisition techniques are used to reduce cardiac movement artifacts, then image quality improves, but the required breath-hold time increases to 20 seconds which is not possible for cardiac patients
Solution Approach 1:
The patent applies segmentation by dividing the coil array into multiple sub-arrays, where each sub-array covers a specific region of interest. This allows independent optimization of each sub-array for different anatomical regions, enabling high-quality imaging without requiring extended breath-hold times since each segmented acquisition can be completed more quickly.
Solution Approach 2:
The patent uses partial action by acquiring data from only the necessary sub-arrays corresponding to the region of interest rather than requiring full coverage. This reduces the total acquisition time and breath-hold duration while maintaining sufficient image quality for the specific diagnostic target.
2Object-affected harmful factors
If cushions are used to increase clearance of local antennas from the imaging area, then movement artifacts reduce, but signal-to-noise ratio decreases and image quality deteriorates
Solution Approach 1:
The patent applies local quality by assigning different functions to different parts of the coil array. Sub-arrays are specifically positioned and configured to cover regions with different motion characteristics - some regions use cushions for stability while other regions use direct contact for signal enhancement, optimizing both artifact reduction and signal-to-noise ratio locally.
Solution Approach 2:
The coil array is segmented into multiple independent sub-arrays that can be independently optimized. This allows certain sub-arrays to use cushioning for motion reduction while others maintain close proximity for signal enhancement, resolving the contradiction between artifact reduction and signal quality.
3Measurement precision
If 32 to 128 channel coil arrays are used to improve signal-to-noise ratio, then image quality improves, but device complexity increases with hardware switching matrices
Solution Approach 1:
The patent segments the large coil array into multiple smaller sub-arrays, each with fewer channels. This reduces the complexity of the hardware switching matrix required for each sub-array while maintaining the overall signal-to-noise ratio through the combined data from all sub-arrays. Each sub-array can be independently processed and combined.
Solution Approach 2:
The patent combines the signals from multiple independent sub-arrays to achieve the signal-to-noise ratio benefits of a large array while avoiding the complexity of a single large switching matrix. The combination occurs through signal processing rather than complex hardware switching.
Data Source
AI summary
In a method and apparatus to reduce movement artifacts in magnetic resonance images an essentially unmoving area of a region to be imaged is located in a region of high sensitivity of a first group of individual local antennas, and a moving area is located in the region of high sensitivity of a second group of local antennas. Spatially coded magnetic resonance signals are received by a first group of the local antennas and are individually processed further. Spatially coded nuclear magnetic resonance signals are received by the second group of local antennas and are combined with a weighting, using weighting factors. The weighting factors are determined so as to reduce gradient of the weighted, combined, spatially dependent sensitivity of the local antennas of the second group.