| 摘要 |
Apparatus for measuring the volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall. A flexible catheter is provided which has a longitudinal axis adapted to be disposed in the vessel. The catheter has front and back sides. First, second, third and fourth transducers are carried by the catheter. The first, second and fourth transducers are disposed on the front side of the catheter and the third transducer is positioned on the back side of the catheter. The second and fourth transducers are spaced apart a predetermined distance. The first, second and third transducers comprise a first set of transducers and the first, third and fourth transducers comprise a second set of transducers. Instrumentation is connected to the first, second, third and fourth transducers. The instrumentation causes the first, second, third and fourth transducers to emit ultrasonic energy beams therefrom. The first transducer is positioned on the catheter to emit an ultrasonic energy beam at an angle with respect to the longitudinal axis of the catheter. The second and third transducers are positioned in the catheter to emit ultrasonic beams extending generally perpendicular to the longitudinal axis of the catheter. The fourth transducer is positioned so that it emits an ultrasonic beam. The instrumentation receives the signals from the first, second, third and fourth transducers and measures the velocity of profile of the flow of liquid in the vessel by Doppler shift and ascertains the diameter of the vessel in the vicinity of the transducers. The instrumentation is capable of ascertaining which of said first and second sets of transducers provides more accurate velocity profile and diameter measurements of the vessel.
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