Motion detection using ping-based and multiple aperture doppler ultrasound
Inventors
Specht, Donald F. • Brewer, Kenneth D. • Smith, David M. • Call, Josef R. • Le, Viet Nam • RITZI, Bruce R.
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Assignees
Member
MAUI ImagingMAUI Imaging develops ultrasound-based medical imaging solutions designed to overcome the limitations of traditional ultrasound, particularly in visualizing anatomy beyond bone, air, and metal barriers. Founded in 2006, the company has pioneered Computed Echo Tomography (CET) to enable diagnostic imaging in settings where conventional CT or MRI are impractical. With over 160 patents granted and FDA clearance for its K3900 system, MAUI Imaging targets applications in trauma medicine, critical care, neurosurgery, and interventional radiology, aiming to enhance timely diagnostics and interventions in both civilian and military environments.
MAUI Imaging develops ultrasound-based medical imaging solutions designed to overcome the limitations of traditional ultrasound, particularly in visualizing anatomy beyond bone, air, and metal barriers. Founded in 2006, the company has pioneered Computed Echo Tomography (CET) to enable diagnostic imaging in settings where conventional CT or MRI are impractical. With over 160 patents granted and FDA clearance for its K3900 system, MAUI Imaging targets applications in trauma medicine, critical care, neurosurgery, and interventional radiology, aiming to enhance timely diagnostics and interventions in both civilian and military environments.
Publication Number
US-11826204-B2
Publication Date
2023-11-28
Expiration Date
Abstract
A method of full-field or “ping-based” Doppler ultrasound imaging allows for detection of Doppler signals indicating moving reflectors at any point in an imaging field without the need to predefine range gates. In various embodiments, such whole-field Doppler imaging methods may include transmitting a Doppler ping from a transmit aperture, receiving echoes of the Doppler ping with one or more separate receive apertures, detecting Doppler signals and determining the speed of moving reflectors. In some embodiments, the system also provides the ability to determine the direction of motion by solving a set of simultaneous equations based on echo data received by multiple receive apertures.
Core Innovation
Ping-based (whole-field) Doppler ultrasound imaging detects Doppler signals without predefining Doppler range gates by transmitting unfocused spherical or semicircular Doppler pings to insonify an entire field of view. Echoes are received on one or more separate receive apertures while the motion speed is estimated from detected Doppler frequency shifts. In-phase and quadrature processing is used to form Doppler-related echoes for timing-based speed calculations.
Direction and vector Doppler are obtained using multiple-aperture ultrasound probe data by solving simultaneous equations based on the received echoes and per-pixel acoustic-path relationships. Separate receive apertures provide different acoustic paths per pixel, enabling computation of a direction and a 2D velocity vector for one or more pixels. Adjustment factors are computed per pixel to account for the first acoustic path and the second acoustic path associated with the transmit aperture to each receive aperture.
The document further describes storing raw echo data with associated TX data in memory so that later re-processing can be performed with different image windows, motion axes, and Doppler parameters. Pixel localization is supported via multiple apertures with dynamic beamforming and accumulation. Additional discussion includes test-segment evaluation with optional correlation to contemporaneous B-mode and/or automatically cycled operation, non-Doppler motion estimation using high-frame-rate ping imaging, and geometry-based, data-independent correction factors related to acoustic path geometry to improve minimum speed and subsequent vector estimation.
Claims Coverage
The independent claim (clm-00001) covers imaging a moving object with Doppler ultrasound using a multiple-aperture probe that computes per-pixel adjustment factors and then computes an object velocity vector from echoes received at first and second receive apertures. The claim set includes dependent inventive features refining the angle-based adjustment factors, velocity direction and magnitude representation, a specific magnitude computation, automated determination of an axis of predominant motion, and configuring the unfocused spherical wavefront pulse to insonify an entire region of interest.
Multiple-aperture probe with per-pixel acoustic paths
providing a multiple aperture ultrasound probe comprising a first transmit aperture, a first receive aperture, a second receive aperture, and an imaging field that comprises a plurality of pixels, wherein each of the plurality of pixels comprises a first acoustic path to the first receive aperture and a second acoustic path to the second receive aperture
Per-pixel adjustment factors for acoustic paths
computing a plurality of adjustment factors for the first acoustic path and the second acoustic path for each of the plurality of pixels
Unfocused spherical wavefront insonification using the transmit aperture
transmitting a first unfocused spherical ultrasound wavefront pulse from the first transmit aperture towards the moving object
Echo acquisition at first and second receive apertures
receiving echoes of the first unfocused spherical ultrasound wavefront pulse at the first receive aperture and receiving echoes of the first unfocused spherical ultrasound wavefront pulse at the second receive aperture
Velocity vector computation from echoes and adjustment factors
computing an object velocity vector at one or more of the plurality of pixels based on the received echoes at the first and second receive apertures and one or more of the plurality of adjustment factors
Per-pixel angle-based adjustment factors
computing the plurality of adjustment factors by calculating, for each pixel, a first angle between a first transmit aperture and a first acoustic path and a second angle between the first transmit aperture and a second acoustic path
Velocity magnitude computation as a distinct quantity
computing the magnitude of an object velocity vector
Magnitude as half-sum of two velocity measurements
calculating the magnitude of an object velocity vector as half the sum of two velocity measurements taken along specified first and second acoustic paths through particular transmit/receive apertures and pixels
Automated determination of an axis of predominant motion
automatically analyzing multiple measured velocity vectors to determine an axis of predominant motion
Insonification of an entire region of interest
configuring the first unfocused spherical ultrasound wavefront pulse to insonify an entire region of interest
Overall, the claim set focuses on computing per-pixel adjustment factors derived from first and second acoustic paths provided by a multiple-aperture ultrasound probe, transmitting an unfocused spherical wavefront pulse, receiving echoes at first and second receive apertures, and computing an object velocity vector (including direction and magnitude refinements). Dependent claims further specify angle-based adjustment factor computation, a half-sum magnitude computation, optional automated determination of a predominant motion axis, and insonification of an entire region of interest.
Stated Advantages
Documented Applications
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