Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-9681853-B2
Publication Date
2017-06-20
Expiration Date
Abstract
The velocity of fluids containing particles that scatter ultrasound can be measured by determining the Doppler shift of the ultrasound scattered by the particles in the fluid. Measuring fluid flow in cylindrical vessels such as blood vessels is an important use of Doppler ultrasound. This invention teaches using various configurations of cylindrical diffraction-grating transducers and cylindrical non-diffraction-grating transducers that suppress the Doppler shift from non-axial components of fluid velocity while being sensitive to the Doppler shift produced by axial velocity components. These configurations thus provide accurate measurement of the net flow down the vessel, even when the fluid flow is curved or not parallel to the vessel wall.
Core Innovation
The invention provides an ultrasonic transducer apparatus for receiving a signal indicative of a velocity of a fluid containing ultrasound scatterers flowing through a lumen having an axis. The apparatus includes a cylindrical non-diffraction-grating transducer configured to be wrapped around the circumference of the lumen and coupled to electrode elements for exciting an ultrasound beam perpendicular to the axis, and a cylindrical diffraction-grating transducer disposed in close proximity and coupled to electrode elements, configured to be wrapped around the circumference to form a receiving beam.
The receiving beam wavefronts from opposite walls of the cylindrical diffraction-grating transducer form multiple equiphase planes perpendicular to the axis of the cylindrical diffraction-grating transducer. When the cylindrical non-diffraction-grating transducer is excited, a scattered signal corresponding to ultrasound scatterers in the fluid crossing at least one of the equiphase planes is received at the cylindrical diffraction-grating transducer, and the scattered signal is indicative of a velocity of the fluid along the axis of the lumen.
In additional embodiments, the apparatus uses a cylindrical diffraction-grating transducer with either a first and second cylindrical non-diffraction-grating transducer excited at first and second frequencies different from each other, or a cylindrical non-diffraction-grating transducer with first and second cylindrical diffraction-grating transducers forming first and second sets of multiple equiphase planes. These configurations enable receiving scattered signals having changing phases with respect to the ultrasound beams, and the scattered signals correspond to scatterers crossing at least one of the multiple equiphase planes to indicate velocity along the lumen axis.
Claims Coverage
The provided independent claims cover three core inventive aspects: a wrapped cylindrical non-diffraction-grating transducer and nearby wrapped cylindrical diffraction-grating transducer forming multiple equiphase planes to determine axial velocity; a Doppler technique method using the same wrapped cylindrical transducer relationship to receive velocity-indicative scattered signals; and apparatus embodiments using multiple diffraction or non-diffraction grating transducers with differing frequencies and/or multiple equiphase-plane sets to receive phase-changing scattered signals indicative of axial velocity. The claims identify 3 independent claims in this excerpt (clm-00001, clm-00005, clm-00011, clm-00015).
Wrapped cylindrical transducer pair forming equiphase planes perpendicular to lumen axis
A cylindrical non-diffraction-grating transducer adapted to be wrapped around the circumference of the lumen and coupled to electrode elements for exciting an ultrasound beam perpendicular to the lumen axis, together with a cylindrical diffraction-grating transducer disposed in close proximity and coupled to electrode elements, configured to be wrapped around the circumference to form a receiving beam whose wavefronts from opposite walls form multiple equiphase planes perpendicular to the axis.
Scattered signal from scatterers crossing equiphase planes indicating axial velocity
The cylindrical non-diffraction-grating transducer and the cylindrical diffraction-grating transducer are configured to receive, at the cylindrical diffraction-grating transducer, a scattered signal corresponding to the scatterers in the fluid crossing at least one of the equiphase planes, wherein the scattered signal is indicative of a velocity of the fluid along the axis of the lumen.
Doppler technique receiving using cylindrical grating transducer pair with equiphase planes
Disposing a cylindrical diffraction-grating transducer in close proximity to a cylindrical non-diffraction-grating transducer; exciting, from the non-diffraction-grating transducer, an ultrasound beam perpendicular to the axis; and receiving, by the diffraction-grating transducer, a scattered signal indicative of a velocity of the fluid along the axis, where the transducers wrap around the circumference of the lumen to form a receiving beam whose wavefronts from opposite walls form multiple equiphase planes perpendicular to the transducer axis, and the diffraction-grating transducer receives the scattered signal corresponding to the scatterers crossing at least one equiphase plane.
Multi-frequency non-diffraction grating arrangement with diffraction-grating receiver and changing-phase scattered signals
A cylindrical diffraction-grating transducer with a first cylindrical non-diffraction-grating transducer disposed in close proximity on one side and exciting at a first frequency a first ultrasound beam perpendicular to the axis, and a second cylindrical non-diffraction-grating transducer disposed in close proximity on the opposite side and exciting at a second frequency different from the first; where the receiving beam wavefronts form multiple equiphase planes perpendicular to the diffraction-grating transducer axis and the apparatus receives scattered signals having changing phases with respect to the first and second ultrasound beam, corresponding to scatterers crossing at least one of the multiple equiphase planes and indicative of velocity along the lumen axis.
Separate first and second sets of equiphase planes using one non-diffraction and two diffraction grating transducers
A cylindrical non-diffraction-grating transducer wrapped around the circumference and exciting an ultrasound beam perpendicular to the axis, a first cylindrical diffraction-grating transducer configured to form a first receiving beam whose wavefronts form a first set of multiple equiphase planes perpendicular to the axis, and a second cylindrical diffraction-grating transducer configured to form a second receiving beam whose wavefronts form a second set of multiple equiphase planes perpendicular to the axis; where the system receives a first scattered signal at the first diffraction-grating transducer and a second scattered signal at the second diffraction-grating transducer, each corresponding to scatters crossing at least one of the respective sets of equiphase planes and each indicative of velocity along the axis.
Across the independent claims in the excerpt, the coverage centers on wrapped cylindrical non-diffraction and diffraction grating transducers configured to form multiple equiphase planes perpendicular to a lumen axis, and on receiving scattered signals corresponding to ultrasound scatterers crossing at least one equiphase plane to indicate axial fluid velocity; further embodiments extend this to multi-frequency excitation with phase-changing scattered signals and to apparatus having first and second sets of equiphase planes.
Stated Advantages
Documented Applications
No documented applications found
Interested in licensing this patent?