Optically Coupled Catheter Eliminates Noise Interference
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Solution Overview
Problem
Conventional diagnostic catheters suffer from noise interference, far-field signal recording, and inability to differentiate low amplitude, high-frequency signals from background noise, leading to inaccurate interpretation of biopotential signals in medical applications.
Innovation Solution
An optically coupled catheter system with local amplifiers and optical data transmission, eliminating electromagnetic interference by using InGaN/GaN LEDs and photodiodes for signal detection and amplification directly at the catheter tip, enabling precise biopotential recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If long cables connect electrodes to distant amplifiers, then device complexity is reduced, but noise interference from power mains and operating room equipment increases
Solution Approach 1:
The patent introduces an optical fiber as an intermediary medium to transmit electrical signals from electrodes to amplifiers. The optical converter at the amplifier end converts optical signals back to electrical signals. This intermediary optical transmission system replaces direct electrical cable connections, thereby eliminating electromagnetic noise pickup while maintaining signal transmission capability.
Solution Approach 2:
The patent substitutes the traditional electrical cable transmission system with an optical transmission system. Instead of using electrical conductors that are susceptible to electromagnetic interference, the system uses optical fibers that are immune to such interference, replacing the mechanical/electrical transmission mechanism with an optical one.
2Measurement precision
If amplifier gain is increased to record low amplitude signals, then measurement precision improves, but background noise also increases
Solution Approach 1:
The patent applies preliminary filtering and signal conditioning at the electrode level before signals are transmitted through optical fibers. By preprocessing signals close to the source and converting them to optical domain early in the transmission path, the system enhances weak signals while suppressing noise before amplification occurs, avoiding the need to amplify noise along with signals.
3Ease of manufacture
If conventional electrodes are used, then ease of manufacture is maintained, but ability to differentiate local from far-field signals deteriorates
Solution Approach 1:
The patent employs MOSFET sensors with very small sensing areas (e.g., 0.05 mm²) that are locally coupled to tissue. This local quality approach ensures that each sensor records primarily local electrical activity with minimal far-field contamination. The small sensing area creates a localized measurement zone that distinguishes local signals from distant far-field signals, improving signal localization accuracy.
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 system provides noise-immune, high-resolution biopotential recording, allowing for accurate identification of complex arrhythmias, renal nerve locations, and precise ablation sites, enhancing diagnostic and therapeutic efficacy.
Implementation Method 1
using InGaN/GaN LEDs and photodiodes for signal detection and amplification directly at the catheter tip
Implementation Method 2
using InGaN/GaN LEDs and photodiodes for signal detection and amplification directly at the catheter tip
Data Source
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AI summary
The embodiments include an apparatus used in combination with a computer for sensing biopotentials. The apparatus includes a catheter in which there is a plurality of sensing electrodes, a corresponding plurality of local amplifiers, each coupled to one of the plurality of sensing electrodes, a data, control and power circuit coupled to the plurality of local amplifiers, and a photonic device bidirectionally communicating an electrical signal with the data, control mid power circuit. An optical fiber optically communicated with the photonic device. The photonic device bidirectionally communicates an optical signal with the optical fiber. An optical interface device provides optical power to the optical fiber and thence to the photonic device and receives optical signals through the optical fiber from the photonic device. Tire optical interface device bidirectionally communicates an electrical data, control and power signal to the computer.