MRI Slab Distortion Compensation via Selective Thickness Expansion
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Solution Overview
Problem
Magnetic resonance imaging (MRI) techniques face challenges in acquiring and restoring images distorted by metal implants due to inhomogeneities in the external magnetic field, leading to geometric distortions and incomplete data acquisition when using a uniform expansion factor for all sub-slabs.
Innovation Solution
The method involves dividing the imaging region into sub-slabs, detecting deformation using a first fast spin echo sequence, determining specific expansion factors for each sub-slab based on deformation detection results, and expanding the encoded thickness of each sub-slab accordingly to perform a targeted imaging scan with a second fast spin echo sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a uniform expansion factor is used for all sub-slabs, then the imaging process is simple and fast, but geometric distortion occurs and image quality deteriorates due to varying deformations caused by metal implants
Solution Approach 1:
The patent applies different expansion factors to different sub-slabs based on their specific deformation characteristics. Each sub-slab is analyzed individually and assigned a customized expansion factor that matches its local deformation pattern, thereby resolving the geometric distortion while maintaining imaging efficiency.
Solution Approach 2:
The imaging region is divided into multiple sub-slabs, and each sub-slab is processed independently with its own expansion factor. This segmentation allows the system to handle varying deformations in different regions without compromising overall imaging speed, as each segment can be optimized separately.
2Device complexity
If the encoded thickness is expanded uniformly for all sub-slabs, then data acquisition is simplified, but incomplete data acquisition occurs for sub-slabs with varying deformation patterns
Solution Approach 1:
The patent determines the expansion factor for each sub-slab based on its specific deformation characteristics detected during the imaging process. This localized approach ensures that each sub-slab's encoded thickness is expanded appropriately to capture complete data, preventing data loss while avoiding unnecessary complexity in the overall system.
3Manufacturing precision
If deformation detection is performed for each sub-slab, then image quality improves through targeted expansion, but the imaging process time increases
Solution Approach 1:
The patent performs deformation detection and determines expansion factors for all sub-slabs before the actual imaging process begins. This preliminary action allows the imaging process to proceed efficiently with pre-determined parameters, avoiding time-consuming adjustments during imaging while still achieving high-quality results.
Solution Approach 2:
The patent divides the imaging region into multiple sub-slabs and processes each independently with its own predetermined expansion factor. This segmentation allows parallel processing of deformation detection and expansion factor determination, reducing overall processing time while maintaining high image quality through targeted expansion for each sub-slab.
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 allows for full acquisition and restoration of distorted images, improving image quality by adapting expansion factors to each sub-slab's deformation, enabling asymmetrical expansion to compensate for varying distortions caused by metal implants.
Implementation Method 1
Magnetic resonance imaging is a technique for performing imaging using the phenomenon of magnetic resonance. The principles of magnetic resonance imaging mainly include: in an atomic nucleus containing a single proton, such as the hydrogen nuclei which are present throughout the human body, the proton thereof has spin motion and so resembles a small magnet.
Implementation Method 2
Once emission of the RF pulse has stopped, the excited nuclei emit an echo signal, gradually releasing the absorbed energy in the form of an electromagnetic wave
Data Source
AI summary
A magnetic resonance imaging method and imaging device are disclosed. The magnetic resonance imaging method includes dividing the current slab of an imaging region into an initial number of detection sub-slabs, and expanding the encoded thickness of each detection sub-slab according to a predetermined initial expansion factor, subjecting each expanded detection sub-slab to deformation detection using the first fast spin echo sequence, and determining the position of each imaging sub-slab of the current slab and an expansion factor corresponding to each imaging sub-slab, wherein the readout gradient of the first fast spin echo sequence is applied in the direction of the slice selection gradient, expanding the encoded thickness of each imaging sub-slab of the current slab of the imaging region on the basis of the determined position of each imaging sub-slab and the corresponding expansion factor, and performing an imaging scan of each expanded imaging sub-slab using a second fast spin echo sequence.