Capacitance Volume Correction in Fluid Delivery Systems
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Solution Overview
Problem
Current fluid delivery systems in medical procedures, such as contrast-enhanced radiographic imaging, face challenges in accurately delivering fluids due to capacitance volume effects, leading to under-delivery or over-delivery of contrast media, and fail to address these issues comprehensively, resulting in inefficiencies and waste of contrast media.
Innovation Solution
The implementation of algorithm-based techniques to correct for capacitance volume effects in fluid-delivery systems by pressurizing expandable bodies, such as syringes, and controlling the movement of pressurizing elements, like plungers, to compensate for expansion under pressure, ensuring accurate and complete delivery of fluids as a sharp bolus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If powered injectors deliver preset amount of contrast at preset flow rate, then injection automation is improved, but capacitance volume effects cause under-delivery or over-delivery of fluid
Solution Approach 1:
The system continuously monitors actual fluid delivery and compares it to the preset volume, using feedback control to adjust the injection process and compensate for capacitance effects in real-time, ensuring accurate delivery despite system compliance
Solution Approach 2:
The system dynamically adjusts injection parameters such as flow rate and pressure based on real-time measurements of actual fluid delivery, modifying operational parameters to compensate for capacitance volume effects and achieve precise dosage
2Speed
If contrast media is injected rapidly as a sharp bolus, then diagnostic effectiveness is improved, but capacitance effects cause volume delivery errors
Solution Approach 1:
The system pre-characterizes the fluid delivery system to determine capacitance values before injection, using this preliminary information to calculate and apply appropriate compensation factors during the actual injection process
Solution Approach 2:
Real-time monitoring of actual fluid delivery provides feedback that enables dynamic adjustment of injection parameters, allowing the system to maintain both high speed and precise volume delivery by compensating for capacitance effects during the injection process
3Power
If expandable fluid-delivery bodies are pressurized, then fluid delivery capability is improved, but expansion under pressure causes capacitance volume effects
Solution Approach 1:
The system applies a virtual counter-compensation by calculating the expected expansion volume based on pressure and compliance characteristics, then adjusting the injection parameters to offset this expansion and maintain accurate net fluid delivery to the patient
4Measurement precision
If algorithm-based correction is applied, then fluid delivery accuracy is improved, but system complexity increases
Solution Approach 1:
The system performs capacitance characterization and algorithm development during an initial setup phase, storing pre-calculated compensation factors that can be applied during injection without requiring complex real-time calculations, thereby reducing operational complexity while maintaining 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
This approach enables precise delivery of a full required dosage of fluid as a sharp bolus, minimizing residual pressures and improving the accuracy of fluid delivery, thereby reducing waste and ensuring effective medical procedures.
Implementation Method 1
the syringe body is expandable under pressure
Data Source
AI summary
Methods for capacitance volume correction in fluid-containing expandable bodies and associated fluid pathways are disclosed. The methods may be applied in fluid delivery systems used to supply fluids to patients during radiographic imaging procedures, including angiography. The methods control delivery of fluid to a downstream process, including providing a fluid-delivery expandable body and a pressurizing element in fluid communication with the downstream process, pressurizing the expandable body by moving the pressurizing element in the expandable body to reduce volume therein, determining an over-travel distance for the pressurizing element, and ceasing movement of the pressurizing element after allowing the pressurizing element to over-travel the over-travel distance to compensate for expansion of the expandable body under pressure. The expandable body may be a syringe and the pressurizing element may be a plunger disposed within the syringe. Movement of the pressurizing element may be controlled by an algorithm associated with a computer.