MRI Transmit Receive Coil Asymmetry
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Solution Overview
Problem
At high magnetic fields, the sensitivity patterns for magnetic resonance transmit and receive fields become non-uniform and asymmetric, leading to challenges in achieving good spatial resolution and signal strength in magnetic resonance imaging and spectroscopy.
Innovation Solution
A magnetic resonance coil design with separate sets of coil elements for transmit and receive channels, positioned asymmetrically to optimize sensitivity regions, ensuring improved overlap and alignment of transmit and receive sensitivity patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single set of coil elements is used for both transmit and receive channels, then device complexity is reduced, but transmit and receive sensitivity patterns become non-uniform and asymmetric at high magnetic fields
Solution Approach 1:
The coil system is segmented into separate transmit coil elements and receive coil elements. The transmit coil includes first and second coil elements arranged in a first plane, while the receive coil includes third and fourth coil elements arranged in a second plane. This segmentation allows independent optimization of transmit and receive sensitivity patterns, resolving the asymmetry problem at high magnetic fields.
Solution Approach 2:
The invention deliberately introduces asymmetry through different spatial arrangements. The transmit coil elements are positioned at specific asymmetric locations relative to the imaging region, and the receive coil elements are positioned at different asymmetric locations. This controlled asymmetry compensates for the load-induced non-uniformity and asymmetry that occurs at high magnetic fields, achieving uniform sensitivity patterns.
2Reliability
If coil elements are positioned to optimize transmit sensitivity, then transmit performance is improved, but receive sensitivity pattern becomes non-uniform
Solution Approach 1:
Different regions of the coil system are assigned different functional qualities. The transmit coil elements are positioned and configured to optimize transmit sensitivity in specific local regions, while the receive coil elements are positioned and configured to optimize receive sensitivity in potentially different local regions. This allows each coil element to be optimized for its specific function without compromising overall system performance.
Solution Approach 2:
The invention transitions from a single-plane coil configuration to a multi-plane configuration. The transmit coil elements are arranged in a first plane, while the receive coil elements are arranged in a second plane. This dimensional change provides additional spatial degrees of freedom to independently optimize transmit and receive sensitivity patterns, resolving the trade-off between transmit performance and receive uniformity.
3Stability of the object's composition
If a volume coil is used for excitation at low magnetic field, then spatial uniformity is good, but signal strength and spatial resolution are reduced at high magnetic field
Solution Approach 1:
The coil system dynamically adapts its configuration based on operating conditions. At high magnetic fields, the separate transmit and receive coil elements with their different spatial arrangements enable the system to maintain good spatial uniformity while achieving high signal strength and spatial resolution. The dynamic capability lies in the ability to independently optimize transmit and receive functions that are coupled at low fields but can be decoupled at high fields through this configuration.
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 design enhances the correspondence between transmit and receive sensitivity regions, improving magnetic resonance performance at high magnetic fields by ensuring better targeting of excitation and signal reception.
Implementation Method 1
a first set of coil elements operatively connectable with a transmit channel to couple with a transmit region of sensitivity
Implementation Method 2
the first set of coil elements and the second set of coil elements defining substantially similar transmit and receive regions of sensitivity for the selected load at the magnetic field strength
Data Source
AI summary
A magnetic resonance coil comprises a first set of coil elements (54, 56, 80) operatively connectable with a transmit channel (66, 74) to couple with a transmit region of sensitivity for a selected load at a magnetic field strength greater than 3 Tesla, and a second set of coil elements (52, 54, 82) operatively connectable with a receive channel (66, 74) to couple with a receive region of sensitivity for the selected load at the magnetic field strength greater than 3 Tesla. The first set of coil elements is arranged proximate to but not surrounding the transmit region of sensitivity, and the second set of coil elements is arranged proximate to but not surrounding the receive region of sensitivity. The first set of coil elements and the second set of coil elements having at least one coil element (52, 56) not in common. The first and second sets of coil elements define transmit and receive regions of sensitivity for the selected load at the magnetic field strength greater than 3 Tesla that are substantially similar.