Outer Volume Suppression for MRI Scan Time Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MRI techniques face challenges in reducing scan time while maintaining diagnostic image quality, particularly in cardiac imaging, due to large field-of-view coverage and residual signal artifacts, which compromise spatiotemporal resolution and patient comfort.
Innovation Solution
The integration of an outer volume suppression (OVS) module with an accelerated imaging module in MRI systems, using multiband RF pulses or spatially selective adiabatic pulses, allows for simultaneous excitation and suppression of multiple slices, reducing inter-slice leakage and enabling faster data acquisition without introducing fold-over artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If outer volume suppression is used to reduce field-of-view, then scan time can be reduced, but residual signal outside the ROI creates fold-over artifacts that compromise image quality
Solution Approach 1:
The patent divides the suppression task into multiple segments by applying OVS separately to different slices simultaneously excited by multiband RF pulses. Each slice receives tailored outer volume suppression, preventing signal leakage from adjacent slices while maintaining the ability to reduce FOV and scan time.
Solution Approach 2:
The patent applies spatially selective adiabatic pulses that create different magnetic resonance properties in different spatial locations. The OVS is applied locally to each slice's outer volumes rather than uniformly across the entire FOV, allowing suppression of unwanted signals while preserving diagnostic signal quality in the ROI.
2Productivity
If simultaneous multislice imaging is used to accelerate data acquisition, then scan time is reduced, but inter-slice leakage and signal contamination occur
Solution Approach 1:
The patent segments the excitation into multiple frequency bands, each targeting a specific slice. By using multiband RF pulses with distinct frequencies for different slices, the system can simultaneously excite multiple slices while preventing signal contamination between them through frequency separation.
Solution Approach 2:
The patent uses adiabatic pulses as an intermediary mechanism to achieve slice-selective excitation. These pulses create a frequency-dependent spatial encoding that acts as a mediator between the RF excitation and the slice selection, enabling simultaneous multi-slice imaging with reduced inter-slice leakage.
3Area of stationary object
If conventional MRI techniques are used with large field-of-view, then complete anatomical coverage is achieved, but scan time increases and patient discomfort increases
Solution Approach 1:
The patent dynamically adjusts the field-of-view for each slice based on the anatomical region of interest. By using spatially selective excitation and OVS, the system can reduce the FOV dynamically for slices outside the ROI while maintaining full coverage where needed, optimizing both scan time and anatomical coverage.
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 scan time by allowing for higher acceleration factors and improved image quality, as demonstrated by 10-fold acceleration in myocardial perfusion imaging with reduced artifacts and minimal patient discomfort.
Implementation Method 1
The OVS module contains at least one radio frequency ("RF") pulse that suppresses magnetic resonance signals in one or more outer volume regions in the plurality of different slices
Implementation Method 2
an accelerated imaging module that is performed after the OVS module... provides an accelerated data acquisition along at least one direction
Data Source
AI summary
Methods for fast magnetic resonance imaging (“MRI”) using a combination of outer volume suppression (“OVS”) and accelerated imaging, which may include simultaneous multislice (“SMS”) imaging, data acquisitions amenable to compressed sensing reconstructions, or combinations thereof. The methods described here do not introduce fold-over artifacts that are otherwise common to reduced field-of-view (“FOV”) techniques.