Intravascular Pressure Sensor Calibration via Resistor Encoding
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Solution Overview
Problem
Miniature pressure sensors used in the human body, such as those mounted on guidewires, exhibit significant variability in signal output due to differing pressure sensitivities, zero pressure offsets, and temperature coefficients, necessitating improved calibration systems for accurate data delivery to processing consoles.
Innovation Solution
The proposed solution involves a system that includes resistors or a microcontroller to encode and translate calibration data into a digital format, with separate calibration memory devices or EEPROMs to ensure accurate calibration coefficients are provided to the processing console, and a signal pre-processing system to output calibrated signals, reducing the need for further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If miniature pressure sensors are used in the human body, then the device size is reduced and versatility is improved, but signal output variability increases due to manufacturing tolerances
Solution Approach 1:
The patent applies preliminary action by encoding calibration coefficients into resistors during the manufacturing process, before the sensor is used in the body. This pre-calibration ensures that each miniaturized sensor's unique characteristics are compensated for in advance, resolving the signal variability issue without requiring larger sensor size
Solution Approach 2:
The patent introduces an intermediary calibration system consisting of resistors and a microcontroller that mediates between the raw sensor output and the final processed signal. This intermediary layer translates and compensates for manufacturing variations, maintaining reliability while preserving the benefits of miniaturization
2Measurement precision
If calibration coefficients are stored in the sensing guidewire, then calibration accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the calibration storage function with the existing guidewire structure by integrating resistors and a microcontroller into the guidewire's connector assembly. This combination provides accurate calibration storage without significantly increasing overall device complexity, as the added components are incorporated into the existing form factor
Solution Approach 2:
The microcontroller serves multiple functions: it reads the calibration coefficients from resistors, processes the raw sensor signals, and communicates with the external processing system. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while maintaining calibration accuracy
3Ease of manufacture
If resistor values are used to encode calibration data, then manufacturing simplicity is maintained, but data reliability is reduced due to resistor tolerance variations
Solution Approach 1:
The patent implements feedback by having the microcontroller read the resistor values and use them to calculate calibration coefficients through a defined algorithm. This feedback process allows the system to compensate for resistor tolerance variations mathematically, maintaining data reliability while preserving the manufacturing simplicity of using resistors
Solution Approach 2:
The patent changes the parameter representation by translating physical resistor values into digital calibration coefficients through the microcontroller's analog-to-digital conversion and mathematical processing. This parameter transformation allows the system to overcome resistor tolerance limitations while maintaining ease of manufacture
Data Source
AI summary
Intravascular devices, systems, and methods are disclosed. In some embodiments, the intravascular devices include at least one pressure sensing component within a distal portion of the device. In that regard, one or more electrical, electronic, optical, and/or electro-optical pressure-sensing components is secured to an elongated member and the system includes components to process the output signals according to various calibration parameters.