Catheter Impedance Sensor for Angiography Reflux Detection
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Solution Overview
Problem
Conventional angiography and embolization procedures rely on X-rays for monitoring, which are hazardous for patients and physicians due to ionizing radiation, and can lead to off-target embolization and diagnostic confusion.
Innovation Solution
An electrical impedance sensor is embedded proximal to the tip of the angiography catheter to detect changes in impedance, allowing for real-time monitoring of fluid injection without X-rays, enabling detection of forward flow, stasis, and reflux, and potentially automating injection control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If X-rays are used for monitoring angiography and embolization procedures, then real-time visualization of contrast and embolic material delivery is achieved, but ionizing radiation exposure to patients and physicians increases
Solution Approach 1:
The patent replaces the X-ray imaging system with an electrical impedance sensing system. The impedance sensor detects changes in electrical impedance caused by contrast material and embolic material, providing real-time monitoring without ionizing radiation. This substitution eliminates the harmful radiation effect while maintaining the monitoring function.
Solution Approach 2:
The patent introduces electrical impedance as an intermediary parameter to monitor fluid delivery. Instead of directly visualizing contrast and embolic material with X-rays, the system measures electrical impedance changes in the blood, which are affected by the presence of these materials. This intermediary measurement approach achieves monitoring without radiation exposure.
2Productivity
If contrast or embolic material are injected at high rate, then delivery efficiency is improved, but reflux backward around the catheter occurs
Solution Approach 1:
The patent implements a feedback control system using real-time electrical impedance measurements. When the sensor detects impedance changes indicating reflux, the system provides feedback to reduce the injection rate. This closed-loop feedback ensures high delivery efficiency while preventing reflux and off-target embolization, maintaining both productivity and reliability.
3Measurement precision
If X-ray monitoring is used to detect reflux, then off-target embolization can be detected, but radiation exposure increases and procedure complexity increases
Solution Approach 1:
The patent extracts the monitoring function from the external X-ray imaging system and integrates it directly into the catheter tip through an embedded electrical impedance sensor. This extraction eliminates the need for complex X-ray equipment while providing continuous real-time reflux detection, simplifying the overall system while maintaining detection 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
This approach reduces radiation exposure, minimizes off-target embolization, and enhances safety by providing real-time monitoring, potentially allowing more effective targeting of lesions in a single session and reducing contrast agent overload.
Implementation Method 1
the sensor detects electrical impedance changes in injected contrast or embolic material
Data Source
AI summary
A method of monitoring a fluid injection procedure is provided. The method includes: disposing a sensor on a catheter, where the sensor is in proximity to a tip of the catheter; inserting at least the tip of the catheter into a patient; delivering a fluid to a location within the patient via the tip of the catheter; and automatically monitoring a sensor signal from the sensor while the fluid is being delivered. Reflux end-point detection using an electrical impedance sensor has been demonstrated in a phantom. Applications include embolotherapy and angiography.