Blood pool imaging and analysis technique using ultrasound

A method of imaging moving pools of blood in a human body ultrasound, comprising:

• transmitting an ultrasonic signal of a predetermined frequency into a human body;
• receiving a reflected ultrasonic signal from the human body;
• continuously sweeping the direction of the transmitted ultrasonic signal through a scan angle comprising a predetermined arc;
• comparing the reflected signal to the transmitted signal to determine a difference in frequency therebetween and an elapsed time between the time of transmission and the time of reception;
• generating a color image based upon the difference in frequency, the elapsed time and the scan angle, wherein a frequency shift in one direction is represented by a first color and a frequency shift in an opposite direction is represented by a second color;
• and
• determining the uncertainty of the frequency shift based upon sampling theory and representing all such uncertain received signals as a third color.

An apparatus for imaging with ultrasound moving pools of fluids, having a three-dimensional volume, confined in moving tissues in a human body, comprising:

• means for transmitting a series of ultrasonic signals of a predetermined frequency into the human body;
• means responsive to the transmitted series of ultrasonic signals reflecting from each moving component of the moving tissues and fluids within the human body to create a series of electrical echo signals which correspond to each moving component and which have a frequency different from said transmitted frequency by an amount proportional to the velocity of the moving components of said tissues and fluids from which said series of transmitted signals were reflected;
• processor means responsive to the series of echo signals for:
• calculating the range, position and velocity of each component of said tissues and fluids within the human body,
• categorizing by velocity each component of said moving tissues and fluids;
• determining an area of those fluids having a velocity magnitude relatively greater than the velocity magnitude of the surrounding tissues and relatively greater than those other fluids having a velocity similar to the velocity of the surrounding tissues;
• and
• estimating the three-dimensional volume of the moving fluid represented by said determined area of fluid.

An apparatus for imaging with ultrasound moving pools of fluid confined in moving tissues in a human body, comprising:

• means for transmitting a series of ultrasonic signals of a predetermined frequency into the human body;
• means responsive to the series of ultrasonic signals reflecting from the tissues and fluids within the human body to create a series of electrical echo signals which have a frequency different from said transmitted frequency by an amount proportional to the velocity of said tissues and fluids from which said series of transmitted signals were reflected;
• processor means responsive to the series of echo signals and operative for:
• calculating range, position and velocity information from the echo signals wherein the calculated range, position and velocity information describe the range, position and velocity, respectively, of said tissues and fluids within the human body,
• comparing the calculated velocity information with a predetermined limit which represents a maximum velocity to obtain out of limit velocity information which is greater than the predetermined limit and to obtain within limit velocity information which is less than the predetermined limit,
• generating a color video signal from said calculated range and position information and from the out of limit and within limit velocity information, the color video signal describing the out of limit velocity information by a first color and the within limit velocity information by at least one different second color, and
• adjusting the predetermined limit to identify by the first color those fluids having a velocity with a magnitude relatively greater than the velocity of the surrounding tissues and relatively greater than those fluids having a velocity similar to the velocity of the tissues and to identify by the second color those tissues and fluids having a velocity similar to the velocity of the tissues.