Multi-Frequency RF Excitation for Simultaneous MRI Slice Acquisition
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Solution Overview
Problem
Conventional MRI techniques require extensive time to acquire multi-slice or multi-slab images due to the need for sequential scanning, and existing acceleration methods either require additional coils or computation, or compromise image quality.
Innovation Solution
The method involves applying RF pulses with multiple frequency components and spatial encoding gradients to simultaneously excite and separate multiple slices or slabs, using an apparatus with an RF excitation module, gradient output module, and sequence controller to control the imaging process, allowing for real-time image reconstruction without additional hardware or computation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential scanning is used to acquire multi-slice images, then image quality is maintained, but imaging time increases significantly
Solution Approach 1:
The imaging space is segmented into multiple slices along the Z-axis, each excited by RF pulses with distinct frequency components. This allows simultaneous acquisition of multiple slices instead of sequential scanning, reducing imaging time while maintaining image quality through frequency-based spatial encoding
Solution Approach 2:
The patent introduces frequency as an additional dimension for slice discrimination. By assigning different frequency components to different slices and using frequency-selective RF pulses, the system can simultaneously excite and acquire multiple slices without interfering with each other, thus reducing imaging time while preserving image quality
2Productivity
If existing acceleration methods are used to reduce imaging time, then imaging speed increases, but additional coils or computation is required
Solution Approach 1:
The system uses the existing RF coil to both excite and receive signals from multiple slices simultaneously. The RF coil serves multiple functions (excitation and reception for multiple slices) without requiring additional coils, and the frequency-based encoding allows automatic slice separation without complex post-processing computation
Solution Approach 2:
The patent changes the frequency parameter of RF pulses to encode spatial information for different slices. By varying the frequency of excitation pulses, the system can selectively excite different slices and simultaneously acquire their signals through the same coil, achieving acceleration without additional hardware or complex computation
3Productivity
If existing acceleration methods are used to reduce imaging time, then imaging speed increases, but image quality is compromised
Solution Approach 1:
By utilizing frequency as an additional encoding dimension, the patent enables simultaneous multi-slice acquisition without compromising spatial resolution. Each slice is uniquely identified by its frequency component, allowing clear separation and high-quality reconstruction of individual slice images even when acquired simultaneously
Solution Approach 2:
The imaging volume is segmented into distinct slices with non-overlapping frequency bands. This frequency-based segmentation ensures that signals from different slices do not interfere with each other, maintaining image quality while enabling simultaneous acquisition and thus improving imaging speed
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 time required for imaging by enabling simultaneous acquisition of multiple slices or slabs, maintaining image quality, and eliminating the need for extra coils or computation, thus enhancing the efficiency and compatibility with existing MRI systems.
Implementation Method 1
applying RF pulses, which carries at least two frequency components, and a slice/slab selection gradient so that at least two slices/slabs of the subject respectively corresponding to the at least two frequency components are excited simultaneously
Implementation Method 2
applying a spatial encoding gradient
Implementation Method 3
applying a slice/slab separation gradient for separating at least two slices/slabs
Data Source
AI summary
Provided is a method for simultaneously acquiring magnetic resonance slices/slabs of a subject. The method comprises steps as follows. First, apply one or more than one RF pulse, which carries at least two frequency components, and a slice/slab selection magnetic field gradient so that at least two slices/slabs of the subject respectively corresponding to the at least two frequency components are excited simultaneously. Second, apply a spatial encoding magnetic field gradient. Third, apply a slice/slab separation magnetic field gradient so as to separate the at least two slices/slabs. The method according to the present invention can be used to acquire data for simultaneously reconstructing multiple slices/slabs. The method is compatible with existing MRI systems.