MRI K-space Segmentation for Time-Resolved Imaging
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Solution Overview
Problem
Current MRI systems face limitations in performing time-resolved imaging with grouped data acquisition, as they struggle to incorporate preparation pulses, are memory and computation intensive, and cannot coordinate k-space sampling with triggering signals, leading to restricted imaging times and resolution, especially in vascular applications.
Innovation Solution
An MRI system and method that samples data points in k-space by dividing it into regions with a central sub-region and multiple peripheral sub-regions, allowing for the use of preparation pulses and coordinated sampling with respiratory or cardiac gating signals, thereby improving imaging efficiency and reducing the need for restrictive signal suppression methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If annular ring segmentation with undersampling is used to reduce imaging time, then imaging time is reduced, but preparation pulses cannot be incorporated
Solution Approach 1:
The patent segments k-space into a central region and multiple peripheral regions, allowing independent sampling strategies for each region. The central region is sampled in every phase, while peripheral regions are selectively sampled based on triggering signals, enabling both time reduction and preparation pulse incorporation.
Solution Approach 2:
The patent implements periodic sampling of the central k-space region at predetermined intervals synchronized with triggering signals (e.g., cardiac or respiratory cycles). This periodic action allows preparation pulses to be applied during specific physiological phases while maintaining consistent central region data for image reconstruction.
2Object-generated harmful factors
If subtraction of pre-contrast phase image is used to suppress unwanted signals, then signal suppression is achieved, but the system is limited to vascular applications and requires multiple echoes
Solution Approach 1:
The patent applies preparation pulses (such as fat suppression pulses, inversion recovery pulses, or saturation bands) before the imaging sequence to pre-suppress unwanted signals like fat signals. This preliminary action eliminates the need for post-acquisition subtraction methods and enables broader application beyond vascular imaging.
3Object-generated harmful factors
If multiple unaliased echoes are used for fat/water separation, then signal suppression is improved, but TE/TR is prolonged and resolution is constrained
Solution Approach 1:
The patent applies fat suppression preparation pulses before the imaging sequence to pre-suppress fat signals, eliminating the need for multiple echoes and Dixon separation. This approach maintains short TE/TR values and preserves imaging resolution while achieving effective fat signal suppression.
4Ease of operation
If k-space sampling is not coordinated with triggering signals, then acquisition is simpler, but gated acquisitions are unreliable
Solution Approach 1:
The patent incorporates triggering signal feedback (such as ECG or respiratory signals) to control the timing of k-space sampling. The central region is sampled periodically based on detected physiological events, ensuring synchronized data acquisition that improves the reliability of gated acquisitions while maintaining operational simplicity through automated trigger-based control.
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 efficient time-resolved MR imaging with improved resolution and reduced motion artifacts, allowing for higher imaging capabilities and more reliable gated acquisitions, while eliminating the need for restrictive signal suppression methods, thus enhancing the overall performance of MRI systems.
Implementation Method 1
Many MRI systems use superconductive magnets to scan a subject/patient via imposing a strong main magnetic field on the nuclei in the subject to be imaged
Implementation Method 2
The nuclei are excited by a radio frequency ('RF') signal at characteristics NMR (Larmor) frequencies
Implementation Method 3
By spatially disturbing localized magnetic fields surrounding the subject and analyzing the resulting RF responses from the nuclei
Data Source
AI summary
An MRI system for performing time resolved MR imaging of an object with grouped data acquisition is provided. The MRI system includes an MRI controller in electronic communication with a magnet assembly and operative to sample a group of data points within a first region of a k-space. The first region includes a central sub-region and a first peripheral sub-region. The MRI controller is further operative to sample a group of data points within a second region of the k-space. The second region includes the central sub-region and a second peripheral sub-region different from the first peripheral sub-region.