System for determining peripheral artery disease and method of use
Inventors
King, David • TAYLOR, Michael Graeme • Kelly, Patrick • Al-Qaisi, Mohammed
Assignees
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Publication Number
US-11660063-B2
Publication Date
2023-05-30
Expiration Date
Abstract
A system for determining peripheral artery disease and method of use for determining the presence or absence of peripheral vascular disease and the severity of the disease in particular vascular segments. The System for determining peripheral artery disease and method of use includes a continuous wave Doppler transceiver which generates a digitized version of quadrature detected stereo audio and is coupleable to a waveform converter and processor. The waveform converter and processor provides filtering, time domain to frequency domain conversion, gain control, and statistical processing of the converted Doppler Stereo audio and is operationally coupled to a display for presenting results to a technician.
Core Innovation
The invention relates to a cuff-free peripheral artery disease (PAD) determination system that uses a continuous wave Doppler transceiver to capture an audio representation of blood flow through a blood vessel of interest. The Doppler transceiver produces a baseband stereo audio representation of Doppler-shift signals received back from moving blood by quadrature detection that preserves directionality of blood flow, and digitizes the baseband stereo representation into a digitized baseband stereo representation transmitted to a waveform converter and processor.
The waveform converter and processor receives the digitized baseband stereo representation, captures series of short time samples, and provides initial filtering. The processor converts the series of short time samples into a frequency domain representation of the baseband stereo audio representation and performs spectral analysis to produce a directional sonogram.
The processor performs monotonicity detection by detecting the presence or absence of peaks in the directional sonogram between a forward systolic peak and an end diastole for a cardiac cycle, including a secondary peak or a reverse flow secondary peak. A monotonicity detection is generated when a secondary peak or a reverse flow secondary peak is not identified and diastolic flow at the end of the cardiac cycle is positive.
A display coupled to the waveform converter and processor provides visual indicia for a user that include a graphical representation of the directional sonogram, positional indications of features, and a monotonicity indicator.
Claims Coverage
Independent claim clm-00001 defines a Doppler-based PAD determination system with directional sonogram generation and a monotonicity detection rule based on peak presence or absence between a forward systolic peak and end diastole. Dependent refinements add quantitative peak and flow thresholds and derived clinical parameters.
Continuous wave Doppler stereo direction-preserving representation
A continuous wave Doppler transceiver produces a baseband stereo audio representation of Doppler-shift signals received back from moving blood by quadrature detection preserving directionality of blood flow, and digitizes and transmits the digitized baseband stereo representation to a waveform converter and processor.
Directional sonogram via short-time spectral analysis
A waveform converter and processor captures a series of short time samples, provides initial filtering, converts the series into a frequency domain representation of the baseband stereo audio representation, and provides spectral analysis to produce a directional sonogram.
Monotonicity detection using peak presence or absence between systolic peak and end diastole
The waveform converter and processor detects a presence or absence of any peaks in the directional sonogram between a forward systolic peak and an end diastole for a cardiac cycle and generates a monotonicity detection if a secondary peak or a reverse flow secondary peak is not identified and a diastolic flow at the end of the cardiac cycle is positive.
Visual indicia including directional sonogram features and monotonicity indicator
A display coupled to the waveform converter and processor provides visual indicia for a user, wherein the visual indicia includes a graphical representation of the directional sonogram, positional indications of features of the directional sonogram, and a monotonicity indicator based on the monotonicity detection.
Across the independent claim, the inventive coverage centers on capturing continuous-wave Doppler audio with quadrature detection that preserves directionality, converting digitized baseband stereo samples into a directional sonogram through frequency-domain spectral analysis, and applying monotonicity detection based on presence or absence of secondary and reverse-flow peaks between a forward systolic peak and end diastole to drive a monotonicity indicator displayed with directional sonogram feature positions.
Stated Advantages
Provides an automatic PAD determination based on monotonicity detection derived from a directional sonogram feature analysis.
Reports performance versus a Color Duplex gold standard, including sensitivity, specificity, and accuracy.
Provides visual indicia including a graphical representation of the directional sonogram and a monotonicity indicator for a user.
Provides derived cuff free parameters including cuff free ABI, pedal perfusion pressure, and vascular reserve.
Documented Applications
Determining peripheral artery disease (PAD) in a cuff-free manner using continuous-wave Doppler and directional sonogram based monotonicity detection.
Producing derived hemodynamic outputs such as cuff free ABI, pedal perfusion pressure, and vascular reserve.
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