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-12245885-B2
Publication Date
2025-03-11
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
A Doppler-based PAD diagnostic system captures an audio representation of blood flow through a blood vessel of interest using a continuous-wave Doppler transceiver. The system produces digitized quadrature-detected stereo audio that preserves blood-flow directionality and couples to a waveform converter and processor.
The waveform converter and processor analyzes the audio representation to determine a presence of peripheral artery disease by producing a directional sonogram. The directional sonogram is used for cardiac-cycle peak evaluation, including detection of peaks between a forward systolic peak and an end diastole, and filtering secondary peaks to a subset of candidate peaks by amplitude relative to the systolic peak.
The system detects a monotonicity condition to generate a monotonicity indicator based on whether a secondary peak or a reverse flow secondary peak is not identified and whether a diastolic flow at the end of the cardiac cycle is positive. The diagnostic output includes a visual indicia including a graphical representation of the directional sonogram, positional indications of features of the directional sonogram, and a monotonicity indicator.
Claims Coverage
The independent claim recites a Doppler transceiver coupled to a waveform converter and processor to determine peripheral artery disease using directional sonogram peak logic, amplitude-filtered secondary-peak detection, and conditional monotonicity detection, along with a display for visual indicia. Across dependent claim refinements, additional requirements specify Doppler modalities and further signal-processing and quantitative filtering logic for secondary peaks and reverse-flow secondary peaks, as well as the condition for generating the monotonicity indicator.
Directional sonogram based PAD determination from Doppler audio
A waveform converter and processor analyze an audio representation captured by a Doppler transceiver to produce a directional sonogram and determine a presence of peripheral artery disease.
Secondary-peak and peak-absence logic between systolic peak and end diastole
Detect a presence or an absence of any peaks in the directional sonogram between a forward systolic peak and an end diastole for a cardiac cycle.
Monotonicity detection based on absence of specified peaks with positive end-diastolic flow
Generate 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.
Amplitude-filtered detection of secondary peaks
Filter the detection of any secondary peaks to those which have an amplitude between 5% and 70% of the amplitude of a systolic peak of the cardiac cycle.
Directional sonogram and monotonicity indicator visual indicia
Provide at least one 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.
Continuous-wave stereo quadrature Doppler transceiver preserving directionality
A continuous-wave Doppler transceiver configured to capture an audio representation of blood flow through a blood vessel of interest, including quadrature detection that preserves blood-flow directionality.
Frequency-domain spectral analysis to produce directional sonogram
The waveform converter and processor perform spectral analysis in a frequency domain to produce a directional sonogram.
Quantitative amplitude range constraint for secondary-peak filtering
Filter detected secondary peaks to those whose amplitude is between 2% and 85% of the systolic peak amplitude of the cardiac cycle.
Quantitative fractional threshold constraint for reverse-flow secondary peaks
Filter reverse flow secondary peaks, keeping only those that exceed a fraction of the maximum reverse flow peak between 1/28th and 1/16th inclusive.
Conditional generation of monotonicity indicator based on peak absence and positive diastolic flow
Generate a monotonicity indicator when there are no identified secondary peaks or reverse-flow secondary peaks and the diastolic flow at the end of the cardiac cycle is positive.
Overall claim coverage centers on determining peripheral artery disease using a directional sonogram derived from Doppler audio, applying peak detection between forward systolic peak and end diastole, filtering secondary peaks by amplitude relative to the systolic peak, and generating a monotonicity indicator when specified peaks are not identified together with positive end-diastolic flow. Dependent refinements further constrain Doppler modality and define additional quantitative filtering ranges for secondary peaks and reverse-flow secondary peaks, as well as the precise conditional logic for the monotonicity indicator, and require frequency-domain spectral analysis for producing the directional sonogram.
Stated Advantages
Provides a clearer PAD indication.
Reduced technician training.
Documented Applications
Clinical PAD diagnostic use with reported comparison study versus color duplex using a gold standard (225 limbs), reporting sensitivity 95.1%, specificity 98.2%, and accuracy 96.8%.
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