Patents Assigned to Applied Physiology and Medicine
  • Patent number: 5348015
    Abstract: This disclosure relates to a noninvasive means for detecting, counting and characterizing emboli moving through the arterial or venous circulation. An ultrasonic transducer is applied to the skin or other tissues of the subject at sites such as over the temporal bone on either side of the head of the subject, on the neck, on the chest, the abdomen, arm, leg, within the esophagus, or surgically exposed organs or blood vessels. Using standard ultrasonic Doppler techniques, Doppler-shifted signals are located which are proportional to the blood flow velocity in the blood vessel(s) of interest. Spectral analysis is performed on the received signal using the fast Fourier transform or other appropriate technique to determine the frequency components in the Doppler shift spectrum. Further analysis of the spectra is used to delineate and characterize Doppler shift signals due to blood from Doppler shift signals due to emboli having a variety of compositions.
    Type: Grant
    Filed: September 17, 1992
    Date of Patent: September 20, 1994
    Assignee: Applied Physiology and Medicine
    Inventors: Mark A. Moehring, Mark A. Curry, Merrill P. Spencer, John R. Klepper
  • Patent number: 4109642
    Abstract: Continuous wave ultrasonic sound waves from a transmitter and receiver are highly focused to a width of approximately 1 millimeter or less and are transmitted and received through intersecting paths within the tissue of a patient. A doppler flow detector produces an image of the moving blood within the vessel. The transmitter and receiver are systematically scanned over the subject and the detected images are converted into visually intelligible pictures.An improved circuit for more clearly defining the flow picture of the moving blood particles utilizes a conventional directional doppler circuit plus a multiplier-differentiator-low pass filter circuit to automatically eliminate venous flow signals. A grey scale oscilloscope provides brightness intensity on the visual picture proportional to the velocity and direction of the blood flow for detecting stenosis in the vessel.A recording technique is disclosed for detecting atherosclerotic thickening of the artery wall.
    Type: Grant
    Filed: March 25, 1974
    Date of Patent: August 29, 1978
    Assignee: Institute of Applied Physiology & Medicine
    Inventors: John M. Reid, Merrill P. Spencer