System for determining peripheral artery disease and method of use
Inventors
King, David H. • TAYLOR, Michael Graeme • Kelly, Patrick • Al-Qaisi, Mohammed
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-11607198-B2
Publication Date
2023-03-21
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 is a system for determining peripheral artery disease that captures and digitizes a baseband stereo audio representation of Doppler-shift signals received back from moving blood. Directionality of blood flow is preserved by quadrature detection, and a waveform converter and processor analyzes the audio representation to determine indicia of peripheral artery disease while a display provides at least one visual indicia to a user.
The waveform converter and processor identifies a series of short time samples and converts the short time samples into a frequency domain representation of the baseband stereo audio representation. From the frequency domain representation, the processor produces a directional sonogram by spectral analysis and detects secondary peaks in the directional sonogram between a forward systolic peak and an end diastole of at least one cardiac cycle.
The processor filters the detected secondary peaks based on amplitude constraints, retaining secondary peaks having an amplitude between 5% and 70% of the amplitude of a forward systolic peak of the cardiac cycle, or having an amplitude greater than 2/64th of a maximum reverse flow peak. A monotonicity indicator is generated based on the filtered secondary peaks to support determining whether peripheral artery disease is present and its severity.
The document also states that derived parameter generation is supported, including cuff-free ABI and vascular reserve, as well as algorithmic processing that statistically detects and filters secondary peaks to determine presence or absence of a C-notch or monotonicity.
Claims Coverage
The independent claim defines a complete diagnostic system pipeline with five inventive features: Doppler audio capture and quadrature direction-preserving digitization, frequency-domain conversion to generate a directional sonogram, secondary-peak detection and amplitude filtering between forward systolic and end diastole, generation of a monotonicity indicator, and visual indicia on a display.
Direction-preserving Doppler audio capture via quadrature detection
A Doppler transceiver configured to capture and digitize a baseband stereo audio representation of Doppler-shift signals received back from moving blood by quadrature detection preserving directionality of blood flow.
Directional sonogram generation from frequency-domain conversion
A waveform converter and processor configured to analyze the audio representation by identifying a series of short time samples, converting the short time samples into a frequency domain representation of the baseband stereo audio representation, and producing a directional sonogram by spectral analysis of the frequency domain representation.
Secondary peak detection between forward systolic peak and end diastole
Detecting secondary peaks in the directional sonogram between a forward systolic peak and an end diastole of at least one cardiac cycle.
Amplitude-filtered secondary peaks for monotonicity indicator
Filtering the secondary peaks to those having an amplitude between 5% and 70% of the amplitude of a forward systolic peak of the cardiac cycle, or having an amplitude greater than 2/64th of a maximum reverse flow peak, and generating a monotonicity indicator based on the filtered secondary peaks.
Visual indicia display of peripheral artery disease determination
A display operably coupled to the waveform converter and processor configured to provide at least one visual indicia to a user.
The claim coverage centers on direction-preserving quadrature Doppler audio, conversion into a frequency-domain directional sonogram, detection and amplitude filtering of secondary peaks between a forward systolic peak and end diastole, and generation of a monotonicity indicator for peripheral artery disease determination, with the result presented as visual indicia on a display.
Stated Advantages
Supports determining whether peripheral artery disease is present and its severity.
Cuff-free testing is supported (cuff-free ABI).
Reduced operator training is stated as an operational advantage.
A supporting clinical study is described with sensitivity 95.1%, specificity 98.2%, and accuracy 96.8%, with low false positive and false negative rates.
Documented Applications
Determining whether peripheral artery disease is present and its severity using a Doppler PAD system with a directional sonogram and a monotonicity indicator, with visual indicia provided to a user.
Supporting cuff-free ankle-brachial index (ABI) and vascular reserve derivation as stated in the disclosed summary.
Clinical evaluation against color duplex is documented in the disclosed supporting study.
Interested in licensing this patent?