Magnetic Resonance Single Point Imaging for Short T2 Difference Images
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for creating difference images of MR images with short echo times are time-consuming, requiring multiple passes and extended measurement times to isolate substances with very short T2 times, such as bones, which limits the efficiency of magnetic resonance tomography.
Innovation Solution
A method that detects and reads out a single k-space point multiple times using phase coding gradients, where the gradient moment is set to zero between readouts, allowing for the same k-space point to be scanned without additional RF excitation pulses, thereby reducing measurement time and enabling the creation of multiple MR images with varying echo times in a single pass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the RASP method is implemented twice with different echo times to create a difference image, then only substances with very short T2 times are shown in the resulting image, but the total measurement time is extended
Solution Approach 1:
The patent segments the measurement process by acquiring multiple k-space points at different echo times during a single pass through k-space, rather than requiring multiple separate passes. This allows the difference image to be created by combining data from different echo times within one measurement sequence, thereby reducing total measurement time while maintaining the ability to isolate substances with short T2 times.
Solution Approach 2:
The patent performs preliminary actions by acquiring multiple k-space points at different echo times before completing the full k-space scan. This preliminary acquisition of multiple echo time data points allows for the creation of difference images without requiring separate measurement passes, thus reducing the overall measurement time while maintaining measurement precision for isolating substances with short T2 times.
2Adaptability or versatility
If multiple passes are used to acquire MR data at different echo times, then multiple MR images can be created, but the measurement time is doubled or more
Solution Approach 1:
The patent merges the acquisition of multiple k-space points at different echo times into a single pass through k-space. By combining multiple echo time data acquisitions within one measurement sequence rather than using separate passes, the patent creates multiple MR images with different echo times while reducing the total measurement time by a factor of two or more.
Solution Approach 2:
The patent implements multi-functionality by using a single measurement sequence to serve multiple purposes: acquiring data at different echo times, creating multiple MR images, and enabling difference image generation. This universal approach allows one measurement pass to fulfill what previously required multiple separate passes, thereby improving productivity while maintaining adaptability.
3Productivity
If single point imaging is used to reduce measurement time, then measurement time is reduced, but the ability to create difference images with short T2 isolation is compromised
Solution Approach 1:
The patent segments the k-space acquisition into multiple points that can be measured at different echo times within a single pass. This segmentation allows the system to maintain the speed advantage of single point imaging while also acquiring multiple echo time data points necessary for creating difference images and isolating substances with short T2 times.
Solution Approach 2:
The patent performs preliminary actions by acquiring multiple k-space points at different echo times during the single point imaging process. This preliminary acquisition of multiple echo time data points enables the creation of difference images with short T2 isolation while maintaining the reduced measurement time characteristic of single point imaging methods.
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 significantly reduces the total measurement time by allowing multiple MR images to be constructed in a single pass, effectively halving the time required and enabling the creation of difference images that highlight substances with short T2 times, such as bones, while minimizing artifacts from B0 field inhomogeneities and chemical shift variations.
Implementation Method 1
the phase coding gradients are activated in respective spatial directions and the essentially only one k-space point is read out the first time after the radiation of the excitation pulse
Implementation Method 2
the phase coding gradients are subsequently modified such that a gradient moment for each of the phase coding gradients is equal to zero for a time period from the first readout of the essentially only one k-space point until a second readout of the essentially only one k-space point
Implementation Method 3
a raw data point in k-space, whose phase was coded by gradients, is read out at a fixed point in time after the RF excitation relative to the 'echo time' TE
Data Source
AI summary
In a magnetic resonance method and system to create a difference image, essentially only one k-space point in a k-space data set belonging to the difference image is acquired at least twice in the form of k-space measurement values after a radiation of an RF excitation pulse. The difference image is thereby created depending on acquired k-space data set by means of taking the difference of the respective at least two results acquired per k-space point. For each essentially only one k-space point shift multiple phase coding gradients are activated in respective spatial directions, followed by a first readout of the essentially only one k-space point for an acquisition of a first of the k-space measurement values. The phase coding gradients are subsequently modified such that a gradient moment for each of the phase coding gradients is zero for a time period from the first readout of the essentially only one k-space point up to a second readout of the essentially only one k-space point. The essentially only one k-space point is subsequently read out a second time.