Multi-Aperture Doppler Ultrasound for Full-Field Motion Vectors
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Solution Overview
Problem
Conventional scanline-based Doppler ultrasound methods are limited in detecting motion transverse to the scanline, require predefined range gates, and impose restrictions on B-mode frame rates, making it difficult to accurately quantify blood flow velocities and visualize motion in three dimensions.
Innovation Solution
The use of ping-based Doppler ultrasound techniques with multiple aperture probes allows for unfocused ultrasound signals to be transmitted and received without predefined range gates, enabling detection of motion in two dimensions and improving lateral resolution of B-mode images by using beamforming and Doppler frequency analysis to determine the speed and direction of moving reflectors within a region of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If scanline-based Doppler ultrasound methods are used, then motion along the scanline axis can be detected, but motion transverse to the scanline cannot be detected
Solution Approach 1:
The patent extends motion detection from one dimension (along the scanline axis) to two dimensions by using multiple apertures arranged at different angles. Each aperture detects motion along its specific axis, and the combination of these measurements enables reconstruction of complete 2D motion vectors, including transverse components that were previously undetectable.
Solution Approach 2:
The ultrasound probe is divided into multiple apertures (e.g., first aperture, second aperture, third aperture) positioned at different orientations. Each aperture functions as an independent detection channel, segmenting the overall motion detection task into multiple parallel measurements that can be combined to achieve comprehensive 2D motion analysis.
2Measurement precision
If conventional Doppler methods are used, then blood flow velocity can be measured along the scanline, but true magnitude of flow velocity vector cannot be estimated
Solution Approach 1:
The system transitions from measuring only the scalar velocity component along a single scanline to measuring velocity vectors with both magnitude and direction in two dimensions. By combining measurements from multiple apertures at different angles, the complete velocity vector is reconstructed, preserving both speed and flow direction information.
Solution Approach 2:
The system uses the measured velocity components from multiple apertures to calculate the true magnitude of the flow velocity vector through vector addition. The relationship combines the velocity components along different axes to provide feedback about the complete flow characteristics, enabling accurate estimation of true velocity magnitude and direction.
3Productivity
If scanline-based imaging is used, then B-mode images can be produced, but frame rates are restricted by the need to acquire multiple scanlines
Solution Approach 1:
The patent combines the functions of multiple scanlines into a single imaging operation by using multiple apertures simultaneously. Instead of sequentially acquiring multiple scanlines to construct an image, the system uses multiple apertures to capture motion information across the entire field of view in one operation, merging multiple measurement tasks into a single parallel process.
Solution Approach 2:
The system transitions from a sequential scanline-based imaging approach to a parallel multi-aperture approach. By arranging apertures at different angles and positions, the system achieves complete motion detection and B-mode imaging capabilities simultaneously, eliminating the time-consuming sequential acquisition process and enabling higher frame rates.
4Measurement precision
If predefined range gates are used in Doppler methods, then motion detection can be localized, but flexibility in analyzing different regions is reduced
Solution Approach 1:
The ultrasound field is divided into multiple test segments corresponding to different spatial regions, each associated with specific apertures. This segmentation allows independent analysis of motion characteristics in different areas without requiring predefined range gates, providing both localized precision and flexible region-specific analysis capabilities.
Solution Approach 2:
The system dynamically selects and processes data from different aperture combinations based on the region of interest. Instead of being constrained by fixed range gates, the system can adaptively configure which apertures to use for analyzing specific test segments, providing dynamic flexibility in region analysis while maintaining measurement precision through targeted aperture selection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the detection of motion vectors in two dimensions, improves lateral resolution, and eliminates the need for predefined range gates, allowing for more accurate and efficient blood flow velocity estimation and visualization.
Implementation Method 1
In the case of a moving object, successive echographic returns will arrive at different times with respect to the transmit pulse. For example, echographic returns that are received at intervals less than the stationary round-trip time may represent reflectors moving towards the TX/RX probe, while returns received at intervals longer than the stationary round-trip time may represent reflectors moving away from the TX/RX probe. This is the result of the well-known Doppler Effect
Implementation Method 2
beamforming the received echoes to determine a display position for each of a plurality of reflectors within the region of interest
Data Source
AI summary
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.