Interleaved STEAM MRI Acquisition for B1 Artifact Reduction
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Solution Overview
Problem
Magnetic Resonance Imaging (MRI) techniques face challenges with long measurement times and image artifacts, particularly at higher field strengths, which limit their diagnostic efficiency and market share in soft tissue clinical diagnostics.
Innovation Solution
A method and apparatus that utilize a stimulated echo acquisition mode (STEAM) with interleaved and temporally multiplexed acquisitions, applying spatially selective RF pulses in sequence blocks to reduce scanning time and minimize B1 artifacts, enabling faster acquisition of T1-, T2-, and diffusion-weighted images without specific absorption rate (SAR) limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher field strength (3T, 7T) is used to improve image quality and reduce scan time, then measurement efficiency is improved, but B1 field inhomogeneity increases causing more artifacts
Solution Approach 1:
The patent segments the imaging process into multiple interleaved acquisitions with different RF pulse sequences (e.g., SPGR, FSE, STEAM) that are sensitive to different B1 field characteristics. By acquiring multiple datasets with different B1 sensitivities and combining them, the method reduces the impact of B1 inhomogeneity artifacts while maintaining high field strength advantages
Solution Approach 2:
The patent changes multiple parameters including RF pulse flip angles, echo times, inversion times, and timing parameters across different acquisition sequences. These parameter variations allow the system to acquire complementary information that can be combined to reduce B1 artifacts while maintaining measurement efficiency at high field strengths
2Loss of information
If conventional MRI sequences are used to ensure comprehensive tissue characterization, then diagnostic information is improved, but measurement time increases
Solution Approach 1:
The patent merges multiple conventional MRI sequences (SPGR, FSE, STEAM) into a single interleaved acquisition protocol. Different tissue contrast mechanisms are captured simultaneously or in rapid succession within the same measurement block, providing comprehensive diagnostic information while reducing total scan time compared to sequential acquisition of separate sequences
Solution Approach 2:
The patent implements continuous interleaved acquisition where different sequence types are executed in alternating blocks without full repetition between them. This continuous acquisition approach maintains measurement efficiency while gathering diverse tissue characterization data, avoiding the time loss associated with stopping and restarting separate sequence protocols
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 speeds up MRI scanning, allowing multiple imaging volumes to be acquired quickly while reducing B1 artifacts, making it suitable for high and ultra-high field scanners and enhancing diagnostic efficiency.
Implementation Method 1
at least one main magnet unit and at least one gradient magnet unit for applying - during use - one or more magnetic field gradients along three independent orthogonal spatial axes in said target area
Implementation Method 2
at least one radiofrequency (RF) pulse generation unit for applying one or more sets of RF pulses towards said target area
Implementation Method 3
a RF receiving unit for acquiring MRI signals possibly having multi-channel spatially sensitive characteristics
Data Source
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AI summary
The invention also relates to a MRI apparatus for obtaining images of a target volume of a human and/or animal subject using magnetic resonance imaging (MRI), said MRI apparatus at least comprising: a housing defining a target area for accommodating said human and/or animal subject; at least one main magnet unit and at least one magnetic gradient unit for applying - during use - one or more magnetic field gradients along three independent orthogonal spatial axes in said target area, as well as at least one radiofrequency (RF) pulse generation unit for applying one or more sets of RF pulses towards said target area; a RF receiving unit for acquiring MRI signals possibly having multi-channel spatially sensitive characteristics; and a computer processing unit for processing said acquired MRI signals and for producing said magnetic resonance image data.