# US 10,945,700 B2 · Non-invasive estimation of intravascular pressure changes using vector velocity ultrasound (US) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,945,700 B2 - Document ID: US10945700B2 - Status: Granted - Kind: B2 - Application number: 15/555,333 - Filed: 2015-06-04 - Published: 2018-02-08 - Granted: 2021-03-16 - Earliest claimed: 2015-03-02 - Assignees: B-K Medical Aps - Applicants: B-K Medical Aps - Inventors: Jacob Bjerring Olesen; Jorgen Arendt Jensen; Carlos Armando Villagomez-Hoyos - Web page: https://patentgrep.com/patent/US10945700B2 ## CPC - A61B 8/04: Measuring blood pressure - A61B 5/021: Measuring pressure in heart or blood vessels - A61B 8/06: Measuring blood flow - A61B 8/0883: {for diagnosis of the heart} - A61B 8/0891: {for diagnosis of blood vessels} - G01F 1/66: by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters - G01S 15/8984: {Measuring the velocity vector} - A61B 8/488: {involving Doppler signals} - A61B 8/5223: {for extracting a diagnostic or physiological parameter from medical diagnostic data (for algorithms to analyse biomedical images G06T7/0012)} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A method for determining pressure gradients with ultrasound data includes acquiring ultrasound data of a vessel and generating a velocity vector profile for flow in the vessel with the ultrasound data. The method further includes computing an acceleration with the velocity vector profile. The acceleration includes at least a temporal acceleration, and computing the temporal acceleration includes reducing noise from the velocity vector profile and determining the temporal acceleration from the noise-reduced velocity data. The method further includes determining the pressure gradients with the computed acceleration. The method further includes displaying an ultrasound image of the vessel with indicia indicative of the pressure gradients superimposed thereover. ## Claims ### Claim 1 A method for determining pressure gradients with ultrasound data, the method comprising: acquiring ultrasound data of a vessel; generating a velocity vector profile for flow in the vessel with the ultrasound data; computing an acceleration with the velocity vector profile, wherein the acceleration includes at least a temporal acceleration, and computing the temporal acceleration includes: transforming the velocity vector profile from a time domain to a frequency domain; selecting a sub-set of the frequency components that satisfy predetermined energy criteria; processing the selected sub-set by differentiating the selected sub-set; transforming the differentiated selected sub-set back to the time domain, thereby reducing noise from the velocity vector profile and determining the temporal acceleration from the noise-reduced velocity data; determining the pressure gradients with the computed acceleration; and displaying an ultrasound image of the vessel with indicia indicative of the pressure gradients superimposed thereover. ### Claim 2 (depends on 1) The method of claim 1, wherein the pressure gradients are generated using the Navier-Stokes equation. ### Claim 3 (depends on 1) The method of claim 1, wherein the selecting of the sub-set of the frequency components further includes selecting based on a complexity of the velocity vector. ### Claim 4 (depends on 3) The method of claim 3, wherein the transforming of the differentiated selected sub-set back to the time domain includes employing a trigonometric function that reconstructs the data back into the time domain. ### Claim 5 (depends on 3) The method of claim 3, wherein transforming the velocity vector profile to the frequency domain includes applying a Fourier transform to the velocity vector profile. ### Claim 6 (depends on 3) The method of claim 3, wherein the selecting of the sub-set of the frequency components further includes selecting the sub-set of frequency components based on an ability to recover a predetermined percentage of the velocity profile from the sub-set. ### Claim 7 (depends on 3) The method of claim 3, wherein selecting the sub-set of the frequency components include selecting a sub-set of the frequency components based on a signal-to-noise ratio of the velocity vector profile. ### Claim 8 (depends on 3) The method of claim 3, wherein selecting the sub-set of the frequency components include selecting a sub-set of the frequency components with an energy ins a predetermined range. ### Claim 9 (depends on 1) The method of claim 1, wherein the acceleration further includes a spatial acceleration. ### Claim 10 (depends on 1) The method of claim 1, further comprising: receiving an identification of a plurality of points of interest on the ultrasound image, wherein the plurality of points of interest are respectively located behind a constriction of the vessel, within the constriction, and before the constriction; determining a pressure drop based on the pressure gradients for the plurality of points of interest; visually identifying the plurality of points of interest on the displayed ultrasound image; and displaying the determined pressure drop. ### Claim 11 (depends on 1) The method of claim 1, further comprising: receiving a signal identifying a set of pixels in the image for a line along a long axis of the vessel; determining a pressure drop by integrating over the pressure gradients corresponding to the identified set of pixels; repeating the acts of receiving and determining for each image frame; and visually presenting the pressure drops as a function of time. ### Claim 12 (depends on 11) The method of claim 11, further comprising: repeating the acts of receiving, determining, repeating and presenting for a plurality of different lines along the long axis of the vessel each image frame to produce a plurality of pressure drops; and visually presenting the plurality of pressure drops as a pressure map. ### Claim 13 (depends on 1) The method of claim 1, wherein the velocity vector profile is one of a 2-D or 3-D velocity vector profile. ### Claim 14 (depends on 1) The method of claim 1, further comprising: generating the velocity vector profile based on at least one of a transverse oscillation, a plan wave, or a synthetic aperture algorithm. ### Claim 15 An apparatus, comprising: a velocity estimator that processes ultrasound image data acquired by an ultrasound imaging system and generates velocity vector fields based thereon; a temporal acceleration processor that processes the velocity vector fields and generates a temporal acceleration, wherein the temporal acceleration processor filters the velocity vector fields while determining the temporal acceleration by: decomposing the velocity vector fields into a series of sinusoids; discarding a sub-set of the sinusoids that do not satisfy predetermined energy criteria; differentiating the remaining sinusoids; and reconstructing the differentiated data back to the time domain; a spatial acceleration processor that processes the velocity vector fields and generates a spatial acceleration; a pressure change estimator that estimates pressure gradients for the ultrasound data based on a model and the temporal and spatial accelerations; and a display configured to display ultrasound image data and the pressure gradients estimates. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the model is based on the Navier-Stokes equation. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein the remaining sinusoids include a set that recover the velocity vector fields to a predetermined percentage. ### Claim 18 (depends on 15) The apparatus of claim 15, wherein the spatial acceleration processor fits a second-order polynomial to a subset of adjacent data points by a linear least-squared approach and then calculates convolution coefficients from a least-squared model to approximate first-order derivatives to generate the spatial acceleration. ### Claim 19 (depends on 15) The apparatus of claim 15, further comprising: determining one or more pressure drop based on the pressure gradients. ### Claim 20 A non-transitory computer readable storage medium encoded with computer executable instructions which when executed by a processor of the computer causes the processor to: acquire ultrasound data of a vessel; determine a spatial acceleration based on velocity vector fields for the ultrasound data; transform the velocity vector fields to the frequency domain, producing a sum of sinusoids; differentiate a sub-set of the sinusoids satisfying a predetermined energy of interest, producing a sum of cosines; reconstruct the sum of cosines to determine a temporal acceleration; and determine a pressure change with the Navier-Stokes equation based on the spatial acceleration and the temporal acceleration; and display an ultrasound image of the vessel with indicia indicative of the pressure change superimposed thereover.