Active Position Marker Wireless Signal Transmission in MRI
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Solution Overview
Problem
Active position markers in MR imaging systems require an RF cable connection for signal transmission, which limits flexibility, increases safety risks, and complicates MR imaging procedures due to induced resonant common mode currents.
Innovation Solution
An active position marker system using a parametric amplifier to amplify and frequency-upconvert MR signals, allowing wireless transmission via a small-diameter microwave cable with reduced common mode currents, and a remote transceiver unit for downconversion and image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an RF cable connection is used for signal transmission from the active position marker, then the MR signal can be transmitted to the receiver, but the flexibility is limited and safety risks increase due to induced resonant common mode currents
Solution Approach 1:
The patent extracts the problematic RF cable connection from the system by implementing wireless communication between the active position marker and the receiver. The marker transmits position data and identification signals wirelessly, eliminating the physical cable that caused safety risks and reduced flexibility while maintaining reliable signal transmission.
Solution Approach 2:
The patent introduces wireless communication as an intermediary medium to transfer signals between the active position marker and the receiver. This intermediary approach replaces the direct cable connection, allowing signal transmission without the harmful effects of resonant common mode currents while preserving handling flexibility.
2Reliability
If an RF cable connection is used for signal transmission, then the MR signal can be conveyed, but safety risks increase due to induced resonant common mode currents
Solution Approach 1:
The patent removes the RF cable connection that generated resonant common mode currents by implementing wireless communication. The active position marker transmits signals wirelessly to the receiver, eliminating the source of harmful currents while maintaining signal transmission capability.
Solution Approach 2:
The patent replaces the mechanical/electrical cable connection system with a wireless electromagnetic communication system. This substitution eliminates the physical conductor that supported resonant common mode currents while achieving the same signal transmission function without the harmful effects.
3Ease of operation
If wireless transmission is used instead of cable connection, then flexibility and safety are improved, but signal attenuation and noise may increase
Solution Approach 1:
The patent optimizes wireless signal transmission parameters including frequency selection, modulation scheme, and transmission power to minimize signal attenuation. By carefully selecting the operating frequency and communication protocol, the system achieves reliable wireless transmission without excessive signal loss.
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
Enables easy and flexible handling of active position markers with reduced safety risks, maintaining MR-based position determination accuracy and compatibility with existing MR imaging systems, while minimizing signal attenuation and noise.
Implementation Method 1
an active position marker (10) for receiving, amplifying, frequency-upconverting and transmitting local MR signals
Implementation Method 2
a remote transceiver unit (20) for receiving and frequency-downconverting the transmitted local MR signals
Implementation Method 3
an examination object, usually a patient, is exposed to a uniform main magnetic field (B0 field) so that the magnetic moments of the nuclei within the examination object form a certain net magnetization
Implementation Method 4
the magnetic moments of the nuclei within the examination object form a certain net magnetization of all nuclei parallel to the B0 field, which can be tilted leading to a rotation around the axis of the applied B0 field (Larmor precession)
Implementation Method 5
MR signals which are generated by the precessing magnetization, are detected by means of an RF receive antenna or coil
Implementation Method 6
gradient magnetic fields are superimposed on the B0 field, having the same direction as the B0 field, but having gradients in the orthogonal x-, y- and z-directions
Data Source
AI summary
An active position marker system comprising at least one active position marker (10) and a remote transceiver unit (20) for communicating with the position marker is disclosed. Basically, the position marker (10) comprises a local RF receive coil (11) for receiving MR signals which are excited in a local volume, and a parametric amplifier (14) for amplifying and upconverting the frequency of the received MR signal into at least one microwave sideband frequency signal. This microwave signal is transmitted wirelessly or wire-bound to the transceiver unit for downconverting the same and supplying it to an image processing unit of an MR imaging apparatus.