Patent ID: 6346081
Filing Date: 2002-02-12
Classification: A61B

Abstract:
An apparatus for determining the velocity of a fluid flowing through a lumen comprising:a first diffraction grating transducer and a second diffraction grating transducer operable in a first mode for providing a first cooperating pair of intersecting ultrasonic beams; the first diffraction grating transducers responsive to a continuous wave signal for driving the first diffraction grating transducer at a first frequency and first phase, the first and second diffraction grating transducers operable in a second mode for providing a second pair of cooperating intersecting ultrasonic beams, the first diffraction grating transducer responsive to a continuous wave signal for driving the first diffraction grating transducer at a first frequency and second phase, the second diffraction grating transducer operative as a receiver for receiving reflected signals associated with the first and second signal beams means for focusing the intersecting beams to intersect in a first predetermined region of the lumen through which dynamic particles are undergoing velocity analysis, and the second beams to intersect in a second predetermined region of the lumen through which dynamic particles are undergoing velocity analysis; and means responsive to the reflected signals for comparing with the first frequency and the first and second phase to determine the velocity of the fluid.