Perfusion Wave Analysis for Arterial Stenosis Detection
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Solution Overview
Problem
Current methods for detecting and quantifying arterial stenosis, such as the ankle-brachial index (ABI), are limited by low sensitivity and inaccuracy, particularly in asymptomatic patients and those with diabetes or elderly individuals, and often require invasive or expensive procedures like Doppler ultrasonography, CT angiography, or MRI, which are cumbersome and pose health risks.
Innovation Solution
The development of novel perfusion dynamics indices, including the slow phase duration and maximum acceleration time of the perfusion wave upstroke, measured through impedance plethysmography or ultrasound, which differentiate between general arteriosclerosis and focal stenosis, providing sensitive detection and quantification of arterial stenosis severity without significant changes in ABI or pulse transit time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ABI is used for detecting arterial stenosis, then the method is simple and noninvasive, but the sensitivity is low and inaccuracy is high
Solution Approach 1:
The patent segments the perfusion wave upstroke into two distinct phases: an initial slow phase and a fast phase. By analyzing the duration and characteristics of the slow phase specifically, the method achieves high sensitivity in detecting arterial stenosis while maintaining the simplicity of noninvasive measurement. This segmentation allows differentiation between general arteriosclerosis and focal stenosis.
Solution Approach 2:
The patent employs dynamic analysis of the perfusion wave morphology, specifically measuring the slow phase duration and maximum acceleration time. These dynamic parameters capture the temporal evolution of blood flow following arterial occlusion, providing sensitive indicators of stenosis severity while using simple noninvasive techniques.
2Measurement precision
If Doppler ultrasonography or CT angiography is used for detecting arterial stenosis, then the measurement precision is improved, but the device complexity and health risks increase
Solution Approach 1:
The patent replaces complex mechanical imaging systems (Doppler ultrasonography, CT angiography, MRI) with a simple noninvasive technique that measures peripheral perfusion dynamics. By substituting sophisticated imaging equipment with a straightforward perfusion measurement approach, the method achieves comparable diagnostic accuracy without the associated complexity and health risks.
Solution Approach 2:
The patent uses simple, inexpensive noninvasive measurement techniques instead of expensive, complex imaging equipment. The approach relies on basic perfusion dynamics measurement that can be performed with minimal equipment, making it accessible and eliminating the need for costly imaging procedures while maintaining diagnostic precision.
3Measurement precision
If CTA is used for detecting arterial stenosis, then the measurement precision is improved, but the harmful factors increase due to X-ray radiation and iodine dye
Solution Approach 1:
The patent converts the physiological response to arterial occlusion (which would normally be a harmful event) into a beneficial diagnostic opportunity. By inducing temporary arterial occlusion and measuring the resulting perfusion dynamics, the method transforms a potentially harmful vascular event into a safe, informative test that reveals stenosis characteristics without exposing patients to radiation or contrast dye.
Solution Approach 2:
The patent replaces ionizing radiation-based imaging (CTA) with a mechanical/physiological measurement approach. Instead of using X-rays and iodine contrast, the method measures blood flow dynamics and perfusion changes in response to arterial occlusion, eliminating all radiation exposure and contrast dye-related risks while maintaining diagnostic accuracy.
4Measurement precision
If MRI is used for detecting arterial stenosis, then the measurement precision is improved, but the duration of action and device complexity increase
Solution Approach 1:
The patent applies partial action by focusing measurement on specific critical phases of the perfusion wave (the slow phase and maximum acceleration time) rather than attempting to capture the entire perfusion process. This selective measurement approach achieves high diagnostic precision with significantly reduced measurement time compared to comprehensive MRI imaging.
Solution Approach 2:
The patent replaces complex, time-consuming MRI imaging with a rapid physiological measurement technique. By measuring perfusion dynamics in response to arterial occlusion, the method achieves comparable diagnostic accuracy in a fraction of the time, eliminating the need for lengthy MRI procedures while maintaining measurement precision.
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
These indices significantly improve the sensitivity and accuracy of arterial stenosis detection, enabling early detection and monitoring of stenosis severity, even in the presence of arteriosclerosis, and can be used as an alternative or complementary tool for diagnosis and follow-up, reducing the need for invasive procedures and health risks.
Implementation Method 1
impedance plethysmography (IPG)...measured through impedance plethysmography or ultrasound
Implementation Method 2
measured through impedance plethysmography or ultrasound
Data Source
AI summary
A method measures a perfusion wave upstroke associated with leg perfusion dynamics, the perfusion wave upstroke including two phases, an initial slow phase and a fast-rising phase, and using prolongation of the slow phase to detect a presence of arterial stenosis and to assess stenosis severity.