MR Coil Detuning with Uniform Resistive Traces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing MR receiver coil detuning circuits experience hot spots and increased design complexity due to discrete resistive elements, leading to potential equipment failure and patient discomfort.
Innovation Solution
The use of voltage-actuated switches coupled with low-conductivity resistive traces that distribute thermal dissipation uniformly along the transmission lines, eliminating the need for discrete resistors and minimizing interaction with MR coil elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete resistive elements are used in detuning circuits, then the reception coil can be effectively detuned during transmission, but hot spots occur at the locations of discrete resistive elements leading to potential equipment failure or patient discomfort
Solution Approach 1:
The patent extracts the discrete resistive elements from the detuning circuit and replaces them with a continuous resistive trace. This removes the concentrated resistance points that cause hot spots, while maintaining the overall detuning function through the distributed resistive trace that dissipates energy along its entire length rather than at discrete locations.
Solution Approach 2:
The patent applies local quality by transitioning from discrete resistive elements with concentrated resistance to a continuous resistive trace with distributed resistance. Each segment of the trace provides local power dissipation, creating a uniform thermal distribution along the trace rather than concentrated heat generation at specific discrete points.
2Reliability
If discrete resistive elements are used in detuning circuits, then the reception coil can be detuned during transmission, but the cost and design complexity of the detuning circuit increases
Solution Approach 1:
The patent merges multiple discrete resistive elements into a single continuous resistive trace. This consolidation reduces the number of separate components, simplifies the circuit design, and lowers costs by eliminating the need for multiple discrete resistor components and their associated mounting and connection requirements.
Solution Approach 2:
The continuous resistive trace serves multiple functions: it provides the necessary resistance for detuning, distributes power dissipation along its length, and acts as an integrated component that combines the functions previously requiring separate discrete resistive elements. This multi-functionality reduces overall circuit complexity.
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 solution reduces the occurrence of hot spots, decreases design complexity, and lowers costs by evenly distributing heat dissipation, thereby enhancing the reliability and safety of MR receiver coil apparatuses.
Implementation Method 1
the individual magnetic moments of the spins in the tissue attempt to align with this polarizing field, but precess about it in random order at their characteristic Larmor frequency. If the substance, or tissue, is subjected to a magnetic field (excitation field B1) which is in the x-y plane and which is near the Larmor frequency, the net aligned moment, or 'longitudinal magnetization,' MZ, may be rotated, or 'tipped,' into the x-y plane to produce a net transverse magnetic moment Mt.
Implementation Method 2
The plurality of transmission lines are free of discrete resistive elements and have a substantially uniform resistivity such that an interaction between the plurality of transmission lines and the plurality of MR coil elements is minimized and thermal dissipation is distributed over a length of each of the plurality of transmission lines.
Data Source
AI summary
An apparatus includes a plurality of magnetic resonance (MR) coil elements and a plurality of voltage-actuated switches coupled to the plurality of MR coil elements, each voltage-actuated switch configured to selectively activate a respective MR coil element. The apparatus also includes a voltage source configured to supply a voltage to the plurality of voltage-actuated switches, a control unit coupled to the voltage source, and a plurality of transmission lines coupled to the plurality of voltage-actuated switches and to the control unit and configured to provide an actuation signal from the voltage source to the plurality of voltage-actuated switches. The plurality of transmission lines being free of discrete resistive elements and having a substantially uniform resistivity such that an interaction between the plurality of transmission lines and the plurality of MR coil elements is minimized and thermal dissipation is distributed over a length of each of the plurality of transmission lines.