Flow rate measurement
First Claim
1. A method of measuring fluid flow rate in a system having a conduit through which fluid flows, comprising:
- adding a substance which provides a plurality of bubbles of known size to said system upstream of said conduit;
impelling a sonic pulse across said conduit, from a position opposite and spaced from said conduit, as said bubbles pass therethrough;
measuring the degree of attenuation of a sonic signal defined by said pulse which passes across said conduit, said attenuation being due to the presence of said bubbles; and
determining the fluid flow rate from the degree of attenuation of said sonic signal.
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Accused Products
Abstract
A method is presented for measuring fluid flow rate in a system having a conduit through which the fluid flows. The method is particularly useful for measuring blood flow rate in a cardiovascular system. A substance which provides a plurality of microbubbles is added to the fluid flow system upstream of the measurement position in the conduit. An ultrasonic pulse is generated from a position opposite and spaced from the conduit as the microbubbles pass therethrough. A reflected ultrasonic image, created by reflection of the pulse from at least the wall of the conduit which is distal from said position, is measured. The fluid flow rate within the conduit is determined from these ultrasonic images using dye dilution techniques. In a living being, the pulse is preferably generated adjacent the rib cage or in the esophagus and the conduit is preferably the heart or the pulmonary artery, whereby, the blood flow rate determined is equal to the volumetric cardiac output rate.
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Citations
9 Claims
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1. A method of measuring fluid flow rate in a system having a conduit through which fluid flows, comprising:
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adding a substance which provides a plurality of bubbles of known size to said system upstream of said conduit; impelling a sonic pulse across said conduit, from a position opposite and spaced from said conduit, as said bubbles pass therethrough; measuring the degree of attenuation of a sonic signal defined by said pulse which passes across said conduit, said attenuation being due to the presence of said bubbles; and determining the fluid flow rate from the degree of attenuation of said sonic signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification