MRI Multi-Segment Excitation for Full-FOV High-Resolution Imaging
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Solution Overview
Problem
Existing magnetic resonance imaging (MRI) techniques face challenges in achieving high spatial resolution and reducing image distortion, particularly when using reduced field-of-view (rFOV) methods, especially in 3D imaging applications.
Innovation Solution
The implementation of in-plane simultaneous multi-segment (IP-SMS) and 3D reduced field-of-view (3D-rFOVI) techniques, which utilize integrated multi-band excitation 2D RF pulses and magnetic field gradients to simultaneously excite multiple segments within an imaging slice or slab, allowing for full FOV coverage without lengthening imaging times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reduced field-of-view (rFOV) methods are used to achieve high spatial resolution and reduce image distortion, then image quality improves, but field-of-view coverage is limited
Solution Approach 1:
The patent divides the full field-of-view into multiple segments and simultaneously excites multiple segments within the same imaging plane using multi-band RF pulses. Each segment is acquired with reduced FOV for high spatial resolution, then all segments are combined to form a complete full-FOV image, thus resolving the contradiction between limited FOV coverage and high spatial resolution.
Solution Approach 2:
The patent transitions from conventional 2D multi-slice imaging to 3D volumetric imaging by adding through-slab phase encoding. This enables isotropic high spatial resolution in three dimensions while maintaining reduced FOV benefits, effectively extending the solution from two-dimensional slice imaging to three-dimensional volume imaging.
2Measurement precision
If 2D multi-slice imaging with rFOV is used, then spatial resolution improves, but slice thickness is limited to a few millimeters
Solution Approach 1:
The patent extends 2D multi-slice imaging to 3D volumetric imaging by introducing through-slab phase encoding in the third dimension. This enables isotropic high spatial resolution with thin slices throughout the entire volume, overcoming the slice thickness limitation of conventional 2D imaging while maintaining rFOV benefits.
3Area of stationary object
If full FOV imaging is used to achieve complete coverage, then field-of-view coverage improves, but image distortion increases and spatial resolution decreases
Solution Approach 1:
The patent segments the full FOV into multiple reduced-FOV segments that are simultaneously excited and acquired. Each segment maintains high spatial resolution with reduced distortion characteristic of rFOV imaging, while the combination of all segments provides complete full-FOV coverage, thus resolving the contradiction between full coverage and high resolution.
4Productivity
If multiple segments are acquired simultaneously using multi-band RF pulses, then imaging efficiency improves, but RF pulse complexity increases
Solution Approach 1:
The patent combines multiple band-selective RF pulses into a single integrated multi-band RF pulse that simultaneously excites multiple segments. This merging approach maintains imaging efficiency by acquiring all segments in one shot while managing RF pulse complexity through unified pulse design and coordinated gradient application.
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
These techniques achieve high spatial resolution and reduced image distortion across full FOV without increasing scan time, benefiting various MRI applications by leveraging the benefits of rFOV imaging.
Implementation Method 1
A two-dimensional (2D) RF pulse is designed to have a spatial excitation profile that periodically replicates along the phase-encoded direction
Implementation Method 2
A 3D reduced FOV (rFOV) imaging method uses a 2D RF pulse to generate a spatial excitation profile... followed by phase-encoding along the slab direction
Data Source
AI summary
The present disclosure provides technologies that allow reduced field of view or fast imaging with reduced image distortion. The first technique capitalizes on the benefit of reduced field of view imaging for full field of view coverage. The second technique allows achieves high resolution 3D images in a focused region. These techniques are expected to have applications for cancer imaging, neuro imaging, and other biomedical imaging areas.