Intravascular Doppler Flow Measurement With EMI Spectrum Suppression
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Solution Overview
Problem
Electromagnetic interference (EMI) from disposable guidewires and cabling in intravascular Doppler flow measurements leads to erroneous blood flow velocity estimations, particularly affecting instantaneous peak velocity (IPV) and average peak velocity (APV), which can impact clinical decision-making.
Innovation Solution
A system and method to differentiate and suppress interference components in Doppler flow spectra by analyzing spectral statistics, using similarity metrics such as statistical coefficients of variation, and employing a fixed pattern operation mode for switch-mode electronics to prevent harmonic distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If disposable guidewires and cabling are used for intravascular Doppler flow measurements, then the device complexity is reduced and ease of operation is improved, but electromagnetic interference increases causing measurement precision to deteriorate
Solution Approach 1:
The patent introduces an intermediary processing system that separates and identifies different signal components (blood flow signal, noise, and electromagnetic interference) through spectral analysis. This mediator system processes the contaminated signal to extract the useful blood flow information while eliminating interference, thus preserving measurement precision while allowing the use of disposable guidewires.
Solution Approach 2:
The patent replaces physical shielding and filtering mechanisms with a digital signal processing approach. Instead of using complex electromagnetic shielding hardware to prevent interference, the system uses computational methods (spectral analysis, similarity metrics) to identify and remove interference components from the signal, achieving the same protective function through information processing rather than physical barriers.
2Measurement precision
If electromagnetic shielding and filtering are implemented to reduce interference, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces physical shielding and filtering mechanisms with a digital signal processing approach. Instead of using complex electromagnetic shielding hardware to prevent interference, the system uses computational methods (spectral analysis, similarity metrics) to identify and remove interference components from the signal, achieving the same protective function through information processing rather than physical barriers.
Solution Approach 2:
The system performs self-diagnosis and self-correction by automatically identifying interference components through spectral analysis and similarity metrics. The processing system autonomously distinguishes between blood flow signals and electromagnetic interference without requiring manual intervention or complex external calibration equipment, thereby improving precision without proportionally increasing device complexity.
3Measurement precision
If spectral analysis and interference suppression are applied, then measurement precision is improved, but loss of information increases due to potential removal of valid signal components
Solution Approach 1:
The patent employs feedback mechanisms where the processed signal is continuously monitored and compared with the original signal characteristics. The system uses similarity metrics to verify that interference removal does not inadvertently eliminate valid blood flow signal components, allowing for real-time adjustment and correction to minimize information loss while maintaining measurement precision.
Solution Approach 2:
The patent replaces physical shielding and filtering mechanisms with a digital signal processing approach. Instead of using complex electromagnetic shielding hardware to prevent interference, the system uses computational methods (spectral analysis, similarity metrics) to identify and remove interference components from the signal, achieving the same protective function through information processing rather than physical barriers.
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
Effectively reduces interference in Doppler flow measurements, improving the accuracy of IPV and APV estimation, enhancing clinical diagnostics and intervention guidance.
Implementation Method 1
By analysis of the difference between the sent and received signals, the blood velocity in a specific sampling area can be deduced as in standard ultrasound pulsed Doppler measurements
Implementation Method 2
an electrical driving pulse can be sent to the PZT which emits an ultrasound pulse and a reflected ultrasound pulse is received by the PZT
Implementation Method 3
an electrical driving pulse can be sent to the PZT which emits an ultrasound pulse and a reflected ultrasound pulse is received by the PZT, which is converted to electrical signal
Data Source
AI summary
Improvements in ultrasound based blood flow velocity measurements are disclosed, including: suppressing interference components from the Doppler spectrum, in order to prevent them from affecting the flow measurements.