Echo-Specific K-Space Sampling for MRI Artifact Reduction
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Solution Overview
Problem
In magnetic resonance imaging (MRI), multi-echo sequences often result in artifacts due to variations in transverse magnetization during echo trains, particularly when magnetization components are not in a steady state, leading to blurring and edge overshoot in reconstructed images.
Innovation Solution
The method involves acquiring echo signals with different magnetization configurations in a specific order to align and minimize artifacts, using a combination of FID and stimulated echo signals, where the k-space regions are sampled in a manner that optimizes the signal-to-noise ratio and reduces blurring and edge artifacts by employing centric or anticentric reordering strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-echo sequences are used to acquire multiple echo signals from one RF pulse, then acquisition efficiency is improved, but artifacts occur due to different magnetization histories
Solution Approach 1:
The patent segments the k-space sampling process by assigning different sampling orders to different echo signal types. First echo signals (e.g., FID) sample k-space in one order while second echo signals (e.g., stimulated echoes) sample k-space in a different order. This segmentation allows each echo type to be processed independently, preventing artifact contamination while maintaining the efficiency benefits of multi-echo acquisition.
2Loss of time
If echo signals with different magnetization configurations are acquired jointly, then measurement time is reduced, but image quality deteriorates due to artifact alignment issues
Solution Approach 1:
The patent applies different k-space sampling orders tailored to specific echo signal types. First echo signals use one sampling order optimized for their characteristics, while second echo signals use a different sampling order suited to their magnetization history. This localized optimization maintains high image quality for each echo type while still achieving time-efficient joint acquisition.
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 effectively reduces artifacts and maximizes the signal-to-noise ratio in reconstructed images, particularly for B0 and B1 maps, by coordinating the acquisition of echo signals from different magnetization configurations, thereby improving image quality and measurement efficiency.
Implementation Method 1
imaging using magnetic resonance (MR) (e.g., magnetic resonance imaging (MRI)) is characterized by high soft tissue contrasts. Here, radio-frequency (RF) pulses, in order to generate an RF field (e.g., a B1 field) and gradient pulses, in order to generate a magnetic field gradient, are irradiated with the aid of a magnetic resonance device into an examination region
Implementation Method 2
The echo signals may be spatially encoded, so the echo signals may be used for the reconstruction of magnetic resonance mappings
Data Source
AI summary
In a method, an imaging sequence is irradiated into an examination region in which an examination object is located. The imaging sequence includes an acquisition section. The acquisition section includes acquiring a plurality of echo signals, each of which samples a k-space region of a k-space. The plurality of echo signals comprises a plurality of first echo signals and a plurality of second echo signals. The plurality of first echo signals and the plurality of second echo signals are generated from different magnetization configurations. The k-space regions sampled by the plurality of first echo signals sample the k-space in a different order to the k-space regions sampled by the plurality of second echo signals.