Multi-Frequency Bio-Impedance Tissue Separation
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Solution Overview
Problem
Traditional bio-impedance and bio-reactance measurements are frequency-dependent and suffer from interference from surrounding tissues, making it difficult to accurately represent cardiovascular states and body fluid characteristics.
Innovation Solution
A non-invasive method using multiple alternating currents of different frequencies to detect changes in resistance and capacitance of internal body tissues, separating information from the cardiovascular system and surrounding tissues through system identification or channel estimation procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional bio-impedance and bio-reactance measurements are used, then non-invasive measurement of blood flow and body fluid levels is achieved, but the measurements are frequency-dependent and suffer from interference from surrounding tissues
Solution Approach 1:
The patent segments the frequency spectrum into multiple discrete frequency components (e.g., 10 kHz, 100 kHz, 1 MHz) and analyzes each frequency separately. This allows the system to distinguish between different tissue types based on their frequency-dependent electrical characteristics, thereby reducing interference from surrounding tissues while maintaining non-invasive measurement capability
Solution Approach 2:
The patent changes the measurement parameter from single-frequency bio-impedance to multi-frequency electrical characteristics. By measuring conductance and capacitance across multiple frequency points, the system obtains a more comprehensive tissue signature that is less susceptible to frequency-dependent interference and surrounding tissue contamination
2Ease of operation
If bio-impedance measurements are used to represent cardiovascular states, then non-invasive monitoring is achieved, but the mixed impedance from targeted and surrounding tissues makes it difficult to determine which impedance dominates
Solution Approach 1:
The patent segments the measurement into separate frequency components and uses system identification techniques to decompose the total impedance into contributions from different tissue regions. This allows the system to maintain non-invasive monitoring while extracting specific tissue information by analyzing frequency-dependent behavior patterns
Solution Approach 2:
The patent introduces system identification and channel estimation procedures as intermediary analysis methods. These computational tools act as mediators that process the mixed impedance signals and separate the contributions from targeted cardiovascular tissues from surrounding tissues, preserving tissue-specific information while maintaining ease of non-invasive operation
3Measurement precision
If multi-frequency alternating currents are used to measure tissue conductance and capacitance, then accurate tissue characterization is achieved, but the device complexity increases
Solution Approach 1:
The patent implements a universal measurement system that can characterize different tissue types (cardiovascular, skeletal muscle, fat) using the same multi-frequency electrical stimulation and system identification framework. This multi-functional approach allows accurate tissue characterization across different body regions while managing device complexity through a unified measurement and processing architecture
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 accurate detection of bodily fluid changes and cardiovascular circulation states by calculating resistance and capacitance values, providing reliable information for monitoring internal body tissues.
Implementation Method 1
AC current is mainly conducted by the extracellular liquid which is mainly resistance at low frequencies
Implementation Method 2
cells have membranes which behave like capacitors, the AC voltage will have phase change
Implementation Method 3
From Ohm's Law, the tissues' conductance and capacitance can be computed from the multiple-frequency alternating electrical currents
Data Source
AI summary
A method and system used to detect characteristic information of internal body tissues applies multiple AC currents of different frequencies simultaneously to a human or animal body. After the modulated voltage signals are received, they are demodulated. Information from both the cardiovascular system and the surrounding tissues is extracted from the carrier waves of specified frequencies. System identification or channel estimation procedures are performed to separate the information from the cardiovascular circulation system and the surrounding tissues. The resistance and capacitance of the cardiovascular system and surrounding tissues are calculated separately. The calculated resistance and capacitance values are used to represent the states of body fluid and cardiovascular circulation. As a result, relevant state information is obtained accurately and reliably to enable accurate measurements of targeted tissues for acquiring health states.