MRI Fluid Labeling Segment Optimization
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Solution Overview
Problem
In MRI imaging, the use of a two-dimensional selective excitation pulse as a pre-pulse for labeling a specific region can result in insufficient labeling due to inappropriate settings of the number of segments, the size of the excitation region, and fluid flow velocity, leading to contrast reduction and artifacts, especially when the flow velocity is high or the number of segments is too large, which complicates achieving high-quality images in a short time.
Innovation Solution
Determine the optimal number of segments and k-space ordering based on the flow velocity and size of the excitation region, and adjust the flip angle of the pre-pulse to ensure accurate labeling, allowing for efficient data acquisition and image reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of segments N is increased to reduce imaging time, then productivity is improved, but labeling becomes insufficient when flow velocity V is high, causing contrast reduction and artifacts
Solution Approach 1:
The patent dynamically adjusts the number of segments N based on the measured flow velocity V. The system calculates an optimal N value using the formula N ≤ φ/(V×TReff), where φ is the excitation region size and TReff is the measurement time per segment. This dynamic adjustment ensures that the two-dimensional selective excitation pulse is applied the appropriate number of times while the fluid passes through the excitation region, maintaining labeling accuracy across different flow conditions while optimizing imaging speed.
2Manufacturing precision
If the number of segments N is decreased to improve labeling accuracy, then manufacturing precision is improved, but imaging time increases
Solution Approach 1:
The patent changes the parameter N (number of segments) based on measured flow velocity V and excitation region size φ. By calculating the optimal N value using the relationship N ≤ φ/(V×TReff), the system adapts the segmentation parameter to match actual physiological conditions, achieving both accurate labeling and efficient imaging time utilization.
3Manufacturing precision
If the excitation region size φ is reduced to improve labeling specificity, then manufacturing precision is improved, but the number of times the pulse is applied decreases, worsening labeling sufficiency
Solution Approach 1:
The patent dynamically adjusts the number of segments N in response to changes in excitation region size φ and flow velocity V. When φ is reduced to improve specificity, the system compensates by adjusting N to ensure that the total number of pulse applications (N×V×TReff) remains sufficient for reliable labeling, thus maintaining both specificity and sufficiency.
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 the acquisition of high-quality images in a short time by optimizing the number of segments and k-space ordering, preventing artifacts and contrast reduction, while ensuring the pre-pulse effectively labels the desired fluid region with high accuracy.
Implementation Method 1
In MRI imaging, a pre-pulse may be applied to selectively excite a proton signal of a specific region
Implementation Method 2
an RF pulse for two-dimensional selective excitation and a gradient magnetic field for two-dimensional selective excitation are applied in combination
Implementation Method 3
a gradient magnetic field for two-dimensional selective excitation are applied in combination
Implementation Method 4
measuring echo signals of one or more segments each time the two-dimensional selective excitation pulse is applied
Data Source
AI summary
In imaging for labeling only the fluid of a specific region, a high-quality image is acquired in a short time. In order to achieve this, the optimal number of segments N is determined from the flow velocity V and the size φ of a specific region to be labeled when performing imaging by labeling only the fluid of the specific region using a two-dimensional selective excitation pulse as a pre-pulse. In addition, the k-space ordering is determined according to the arrival timing of the fluid to the imaging region. In addition, the optimal flip angle (FA) is determined depending on the type of pre-pulse.