B-Mode Ultrasound Speckle Tracking for Blood Flow Quantification
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Solution Overview
Problem
Existing blood flow imaging methods using Doppler ultrasound and contrast agents are limited by spatial resolution, sensitivity to user variability, and reliance on assumptions about flow direction, making them inadequate for accurate quantification of blood flow dynamics.
Innovation Solution
Utilizing multi-transmit, coherent image formation techniques in B-mode ultrasound to generate speckle patterns in blood regions, which are tracked over time to determine two or three-dimensional velocity vectors without the need for contrast agents, allowing for accurate quantification of blood flow parameters such as velocity, vorticity, and vortex characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Doppler ultrasound is used to measure blood velocity, then velocity measurement is achieved, but spatial resolution is reduced compared to B-mode anatomy imaging
Solution Approach 1:
The patent combines Doppler ultrasound velocity measurement capabilities with B-mode imaging spatial resolution by processing B-mode speckle patterns to extract velocity information. This merging allows the system to achieve both accurate velocity measurement and high spatial resolution simultaneously, eliminating the need to choose between the two separate imaging modes.
Solution Approach 2:
The patent uses speckle patterns in B-mode images as an intermediary to transfer velocity information from blood flow to the imaging system. By tracking the motion of speckle patterns over time, the system can derive velocity vectors while maintaining the high spatial resolution inherent in B-mode imaging, thus mediating between velocity measurement and spatial resolution requirements.
2Measurement precision
If contrast agents are used for blood flow imaging, then flow visualization is improved, but the system becomes overly sensitive to user variability and image acquisition parameters
Solution Approach 1:
The patent enables the blood flow itself to serve as the imaging agent by utilizing the natural acoustic scattering properties of blood cells to generate speckle patterns. This self-service approach eliminates the need for external contrast agents, thereby removing the sensitivity to user variability in contrast agent injection and the short half-life limitations, while maintaining reliable flow visualization.
Solution Approach 2:
The patent replaces expensive and sensitive contrast agents with the inherently present blood cells that naturally produce speckle patterns. This substitution uses readily available biological material (blood cells already in the patient's system) instead of requiring external disposable contrast agents, improving reliability by eliminating dependence on external agent quality and administration consistency.
3Device complexity
If Doppler ultrasound assumes conservation of mass to compute velocity vectors, then velocity computation is simplified, but accuracy is reduced outside certain heart phases
Solution Approach 1:
The patent inverts the conventional approach by not assuming conservation of mass to compute velocity, but rather directly measuring velocity vectors from speckle pattern displacement and deriving flow field properties from these measurements. This reversal allows accurate velocity computation without relying on the conservation of mass assumption, enabling precise measurements across all heart phases including those with significant net flow.
4Measurement precision
If microbubbles are tracked for contrast agent imaging, then blood flow can be visualized, but the short half-life and lack of retro-reflection make the method overly sensitive to insonification direction
Solution Approach 1:
The patent uses the blood cells themselves to generate the necessary scattering signals for flow visualization, eliminating the need for microbubble contrast agents. This approach provides consistent signal generation regardless of insonification direction, as blood cells naturally scatter ultrasound waves in all directions, thereby removing the sensitivity to beam orientation that plagues microbubble-based methods.
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
Enables high-resolution, user-independent quantification of blood flow dynamics within the heart, providing accurate velocity vectors and vortex information without the limitations of traditional Doppler or contrast agent imaging, facilitating improved heart disease diagnosis.
Implementation Method 1
B-mode images generated with a multi-transmit, coherent image formation produce swirling or other speckle patterns in the blood regions
Implementation Method 2
These patterns, as represented in specially formed B-mode images, are tracked over time to indicate two or three-dimensional velocity vectors of the blood
Data Source
AI summary
For quantification of blood flow by an ultrasound system, B-mode images generated with a multi-transmit, coherent image formation produce swirling or other speckle patterns in the blood regions. These patterns, as represented in specially formed B-mode images, are tracked over time to indicate two or three-dimensional velocity vectors of the blood at a B-mode resolution. Various visualizations may be provided at the same resolution, including the velocity flow field, flow direction, vorticity, vortex size, vortex shape, and/or divergence.