Volume-Selective MRI Using Slab Selection Gradients to Suppress Streak Artifacts
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Solution Overview
Problem
Current three-dimensional radial data acquisition magnetic resonance imaging techniques suffer from streak artifacts due to signals from tissues outside the field of view, which compromise image quality and accuracy in diagnosis and quantitative analysis.
Innovation Solution
The method employs frequency selective excitation pulses and slab selection gradient magnetic fields to selectively excite a predetermined volume region, using a readout gradient magnetic field perpendicular to the slab selection gradient field to minimize artifacts by excluding information outside the field of view during data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-selective spin excitation is applied to the entire object, then complete coverage of the object is achieved, but streak artifacts are generated from tissues outside the field of view
Solution Approach 1:
The excitation space is segmented into a target volume within the field of view and regions outside the field of view. By applying slab selection gradient magnetic fields in multiple directions (e.g., x, y, z axes), the method selectively excites only the target volume while suppressing excitation of surrounding tissues, thereby preventing streak artifacts without compromising complete coverage of the region of interest
Solution Approach 2:
The method applies different excitation characteristics to different spatial regions. Within the field of view, complete spin excitation is achieved for comprehensive coverage, while outside the field of view, excitation is suppressed through orthogonal gradient fields. This local differentiation eliminates artifacts from out-of-view tissues while maintaining image quality in the region of interest
2Area of stationary object
If the field of view is enlarged to cover the entire object, then complete object coverage is achieved, but scanning time increases and resolution decreases
Solution Approach 1:
The method transitions from two-dimensional field of view coverage to three-dimensional volume selection by applying slab selection gradient magnetic fields along multiple spatial dimensions (x, y, z axes). This volumetric approach allows precise definition of the excited region in three-dimensional space, enabling complete coverage of the target volume without unnecessarily enlarging the overall field of view, thus maintaining high resolution and reducing scanning time
3Productivity
If the field of view is reduced to focus on the region of interest, then scanning time decreases and resolution improves, but complete object coverage is lost
Solution Approach 1:
The method dynamically adjusts the excitation volume by applying slab selection gradient magnetic fields in multiple directions. The intersection of slabs selected along different axes creates a flexible, adaptable excitation region that can be precisely tailored to match the three-dimensional boundaries of the region of interest. This dynamic volume definition ensures complete coverage of the target area while excluding unnecessary surrounding tissues, optimizing both scanning efficiency and information completeness
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 from out-of-view tissues, enabling higher resolution images with improved diagnostic accuracy and reduced scanning time, focusing the field of view closely around the region of interest.
Implementation Method 1
a magnetic resonance imaging (MRI) device acquires a tomographic image of a specific part of a patient using a resonance phenomenon occurred by supplying an electromagnetic energy
Implementation Method 2
applying a frequency selective excitation pulse and a slab selection gradient magnetic field together to an object; acquiring a signal generated from the object by the excitation pulse and the slab selection gradient magnetic field
Implementation Method 3
generating a three-dimensional magnetic resonance image through encoding based on a readout gradient magnetic field maintaining vertically to the acquired signal and the slab selection gradient magnetic field
Data Source
AI summary
An apparatus and a method for generating a volume-selective three-dimensional magnetic resonance image are disclosed. The volume-selective three-dimensional magnetic resonance image generating method according to an exemplary embodiment of the present disclosure includes applying a frequency selective excitation pulse and a slab selection gradient magnetic field together to an object; acquiring a signal generated from the object by the excitation pulse and the slab selection gradient magnetic field; and generating a three-dimensional magnetic resonance image through encoding based on a readout gradient magnetic field maintaining vertically to the acquired signal and the slab selection gradient magnetic field.