Dielectric Element Relaxation Agent B1 Field Homogeneity MRI
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic resonance imaging (MRI) is hindered by inhomogeneous B1 field distributions due to varying RF pulse penetration in conductive and dielectric media, leading to unwanted signal variations and visibility of dielectric elements used to compensate, which prolongs measurement time and distorts image data.
Innovation Solution
A dielectric element with a relaxation agent, such as paramagnetic substances, is used to reduce T1 and T2 relaxation times, making it invisible in MRI images and allowing for interference-free data acquisition without altering typical imaging sequences, while maintaining B1 field homogenization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dielectric elements are positioned on the examination subject to compensate B1 field inhomogeneities, then B1 field homogeneity is improved, but the dielectric elements become visible in the MRI images and measurement time is prolonged
Solution Approach 1:
The patent changes the relaxation time parameter of the dielectric element by incorporating relaxation agents (paramagnetic substances) that reduce T1 and T2 relaxation times. This parameter modification makes the dielectric element invisible in MRI images while preserving its B1 field homogenization function, thereby eliminating the need for prolonged measurement time to correct for visible artifacts
Solution Approach 2:
The patent introduces relaxation agents as intermediary substances within the dielectric element. These paramagnetic substances act as mediators that modify the magnetic resonance properties of the dielectric material, enabling it to fulfill its B1 field compensation role without being detectable in the final image, thus resolving the contradiction between field homogeneity and measurement time
2Stability of the object's composition
If dielectric elements are positioned on the examination subject to compensate B1 field inhomogeneities, then B1 field homogeneity is improved, but fold-over artifacts occur and image data is distorted
Solution Approach 1:
By modifying the relaxation time parameters of the dielectric element through the addition of paramagnetic substances, the patent ensures the element remains invisible in the MRI image. This parameter change prevents fold-over artifacts and maintains image data accuracy while preserving the B1 field homogenization effect
Solution Approach 2:
The patent converts the potentially harmful visibility of dielectric elements into a beneficial invisible state by incorporating relaxation agents. This transformation allows the dielectric element to perform its B1 field compensation function without creating artifacts, thereby converting what would be a harmful visible artifact into a beneficial invisible correction
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
The dielectric element effectively reduces B1 field inhomogeneities, preventing interferences and fold-over artifacts, thus ensuring accurate and efficient MRI data acquisition without additional time for data correction.
Implementation Method 1
The dielectric element (1) comprises a relaxation agent which reduces the relaxation time of the dielectric element (1)
Implementation Method 2
A dielectric element with a relaxation agent, such as paramagnetic substances, is used to reduce T1 and T2 relaxation times
Implementation Method 3
The material of these dielectric elements should exhibit an optimally high dielectric constant, preferably ∈≧50. The dielectric material thus produces a dielectric focusing
Implementation Method 4
The material of the dielectric element, however, should not exhibit a conductivity that is too high because, due to the skin effect, this leads to high eddy currents
Implementation Method 5
With a radio-frequency antenna, RF pulses of a defined field strength are radiated into the examination volume
Implementation Method 6
The nuclear spins then precess in the direction of the basic magnetic field B0
Implementation Method 7
the body or a body part of the patient to be examined must initially be exposed to an optimally homogenous static basic magnetic field (usually designated as B0 field) that is generated by a basic field magnet
Implementation Method 8
rapidly switched gradient fields that are generated by gradient coils are superimposed on this basic magnetic field for spatially coding the magnetic resonance signal
Data Source
AI summary
A dielectric element is formed of a dielectric material exhibiting a magnetic resonance relaxation time, with a relaxation agent incorporated in the dielectric material that reduces the relaxation time of the dielectric material. The dielectric element is adapted for placement on a subject while magnetic resonance data are acquired from the subject, and locally influences the B1 field distribution in the subject during the acquisition of magnetic resonance data.