Perfusion Wave Delay Detection for Partial Occlusion

Solution Overview

Problem

Current clinical diagnosis methods for peripheral artery disease (PAD) are sporadic, require professional skills, and have low sensitivity and high false negative rates, often leading to late-stage detection of severe disease.

Innovation Solution

A method using wavelet coherence analysis to measure wave propagation associated with blood perfusion, differentiating between arterial and venous occlusions by analyzing cardiac and respiratory modulations of perfusion waves, and correlating delays in wave propagation to the extent of occlusion, employing a system with sensors and a processor for continuous monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sporadic clinical diagnosis methods (Doppler, ABI) are used, then professional skills and equipment are required, but the diagnosis is done infrequently leading to late-stage detection

Engineering Contradiction:

Improvedetection accuracyVSAvoiddiagnosis frequency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The system enables patients to perform self-monitoring of blood flow waveforms at home without requiring professional technicians or physicians. The automated waveform acquisition and analysis allows patients to continuously monitor their own peripheral blood flow, transforming a professional service into a self-service capability that can be performed frequently at home.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces the mechanical/manual Doppler ultrasound method with an automated optical detection system using photoplethysmography (PPG). This substitution eliminates the need for manual probe placement and interpretation by professionals, enabling automated, frequent monitoring by patients themselves.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If Doppler measurements are performed, then blood flow velocity can be measured, but it depends on availability of professional technicians and physicians

Engineering Contradiction:

Improveblood flow measurement accuracyVSAvoidoperation simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The system enables patients to perform self-monitoring of blood flow waveforms at home without requiring professional technicians or physicians. The automated waveform acquisition and analysis allows patients to continuously monitor their own peripheral blood flow, transforming a professional service into a self-service capability that can be performed frequently at home.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces the mechanical/manual Doppler ultrasound method with an automated optical detection system using photoplethysmography (PPG). This substitution eliminates the need for manual probe placement and interpretation by professionals, enabling automated, frequent monitoring by patients themselves.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If ABI tests are used, then blood pressure differences can be assessed, but sensitivity is low resulting in high false negative rates

Engineering Contradiction:

Improvediagnosis efficiencyVSAvoiddiagnosis reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention shifts from measuring blood pressure (ABI) to directly measuring blood flow waveform characteristics. By analyzing flow velocity, waveform shape, and temporal patterns of blood flow rather than pressure differences, the system achieves higher sensitivity for detecting peripheral artery disease while maintaining diagnostic efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical/manual Doppler ultrasound method with an automated optical detection system using photoplethysmography (PPG). This substitution eliminates the need for manual probe placement and interpretation by professionals, enabling automated, frequent monitoring by patients themselves.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 continuous, non-invasive, and precise detection of partial obstructions before they become symptomatic, improving early diagnosis and preventing irreversible damage, with increased sensitivity and specificity compared to existing methods.

Implementation Method 1

utilizing photo-plethysmography (PPG) on fingers and toes

Methodology Applied

Scientific EffectPhotoplethysmography: Absorption (EM radiation)

Implementation Method 2

measurement of the wave propagation associated with blood perfusion (arterial or venous delivery of blood) is used to measure occlusions in blood lumens

Methodology Applied

Scientific EffectWave propagation: Pressure Gradient

Data Source

PatentUS11638534B2Continuous monitoring of the perfusion of an organ or extremity

Publication Date: 2023.05.02 THE MEDICAL RES INFRASTRUCTURE & HEALTH SERVICES FUND OF THE TEL AVIV MEDICAL CENT

AI summary

A method and system are provided for continuous monitoring perfusion of an organ or extremity, and for early detection of progressive partial occlusion of arterial blood supply or venous drainage of tissue. The method and system measure a delay in wave propagation of a blood perfusion wave, which is associated with flow of blood through a blood vessel. The delay is correlated to an amount of obstruction in the blood vessel.