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Method and apparatus for investigating a circulatory system in living biological structures

  • US 4,848,354 A
  • Filed: 03/11/1988
  • Issued: 07/18/1989
  • Est. Priority Date: 05/13/1983
  • Status: Expired due to Term
First Claim
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1. Method for generating a multidimensional map of blood velocities in the circulatory system of living species, using the Doppler effect of backscattered ultrasound, the flow map being shown in real time on a display device, with the ability to select small sample volumes in the map where an approximate spectral analysis of the Doppler signal can be shown on a display as a function of time together with the moving flow map in real time to illustrate the time variation of the blood velocities in the sample volumes selected, comprising the steps of:

  • (a) transmitting a pulse type ultrasonic beam which is swept in two or more dimensions through a region of the biological structure which is to be investigated;

    (b) sampling the backscattered ultrasonic signal in a plurality of sample volumes along each beam direction of the transmitted ultrasonic pulses;

    (c) determining a velocity parameter of the blood flow for each sample volume and beam direction by means of the Doppler principle;

    (d) assigning a coded presentation on a display screen, displaying said velocity parameters for each sample volume and beam direction as a flow map;

    synthesizing continuous substrate signals from segments of said backscattered signal from selected sample volumes to produce a continuous representation of the signal from these sample volumes;

    (e) audibly presenting and frequency analyzing said continuous representation to estimate the variation of the blood velocities in said selected sample volumes as a function of time; and

    (f) displaying said frequency analyzed signal on a display.

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