MRI Relaxation Mapping Fluid Signal Nulling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MRI relaxation parameter mapping techniques face challenges due to the partial volume effect, which leads to bright spots and cluttered images, making it difficult to achieve practical utility with high spatial resolution and broad volume coverage.
Innovation Solution
The method involves using an inversion module to null fluid signal and minimize the partial volume effect, applied to T1, T2, or diffusion pulse sequences, and utilizing a model-based reconstruction method with spatial sparsity regularization for improved image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI relaxation parameter mapping is performed with high spatial resolution and broad volume coverage, then image quality and diagnostic utility are improved, but scan time becomes excessively long
Solution Approach 1:
The patent applies preliminary magnetization preparation (inversion recovery or saturation) before the actual imaging acquisition. This pre-conditioning of the magnetization state allows for more efficient encoding of relaxation parameters during the subsequent rapid 3D stack-of-spiral acquisition, reducing the need for repeated scans while maintaining measurement precision.
Solution Approach 2:
The patent transitions from conventional 2D slice-by-slice acquisition to 3D stack-of-spiral acquisition. This dimensional change enables volumetric coverage to be achieved in a single continuous acquisition rather than through multiple sequential 2D slices, dramatically reducing scan time while maintaining or improving spatial resolution through isotropic voxels.
2Loss of time
If conventional MRI mapping is performed with high undersampling to reduce scan time, then scan time is reduced, but image quality deteriorates and artifacts increase
Solution Approach 1:
The patent employs 3D stack-of-spiral acquisition which provides more robust undersampling performance compared to conventional 2D Cartesian methods. The spiral trajectory in 3D k-space allows for incoherent sampling patterns that are more amenable to compressed sensing reconstruction, maintaining image quality at higher acceleration factors.
Solution Approach 2:
The patent utilizes T1 or T2 magnetization preparation parameters to encode additional information into the signal. By preparing the magnetization in specific states before acquisition, the method extracts more information per unit time, allowing aggressive undersampling while preserving reliable parameter estimation through the additional contrast encoding.
3Device complexity
If conventional MRI mapping is performed without fluid signal suppression, then acquisition is simpler, but partial volume effect creates bright spots and clutter that reduce image readability
Solution Approach 1:
The patent applies preliminary inversion recovery or saturation pulses specifically tuned to null or suppress fluid signal (CSF) before the imaging acquisition. This pre-suppression prevents fluid-related partial volume effects from contaminating the tissue measurements, eliminating bright spots and clutter without requiring complex post-processing.
Solution Approach 2:
The patent converts the potentially harmful fluid signal that causes partial volume artifacts into a beneficial contrast mechanism. By using the fluid's known T1/T2 characteristics to design targeted suppression pulses, the method transforms what would be a source of error into a controlled contrast element that improves tissue visualization by suppressing the interfering fluid signal.
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 the partial volume effect, resulting in improved image resolution and accuracy of T2 estimation, with a significant reduction in noise and artifacts, thereby enhancing the clinical utility of MRI relaxation parameter mapping.
Implementation Method 1
an inversion module to null fluid signal and minimize the partial volume effect
Data Source
AI summary
Magnetic resonance imaging according to the present invention includes T1, T2, or diffusion mapping with improved image resolution. The improved image resolution is achieved by leveraging the delay in the image acquisition to remove the partial volume effect of fluid in and around the tissue being imaged.