Vector Projectile Imaging Ultrasound Flow Vector Estimation
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Solution Overview
Problem
Conventional ultrasound color flow imaging struggles with accurately mapping flow dynamics in tortuous vasculature due to beam-flow angle dependence, particularly in bifurcation geometries like the carotid arteries, leading to uncertain velocity estimates and challenging diagnostic interpretations.
Innovation Solution
The development of Vector Projectile Imaging (VPI) employs high-frame-rate broad-view data acquisition, multi-angle Doppler analysis with regularization, and dynamic visualization of color-encoded vector projectiles and speckles to provide accurate, time-resolved, and quantitative tracking of spatiotemporally varying flow trajectories in complex vascular geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ultrasound color flow imaging based on axial Doppler estimation is used, then real-time 2-D maps of axial flow velocity can be provided, but accurate mapping of flow dynamics in tortuous vasculature becomes unreliable due to beam-flow angle dependence
Solution Approach 1:
The patent transitions from single axial velocity measurement to two-dimensional velocity vector estimation by incorporating lateral velocity component measurement. This is achieved through multi-angle plane wave imaging that captures flow information in both axial and lateral directions, enabling accurate velocity estimation in tortuous vasculature where beam-flow angle varies.
Solution Approach 2:
The imaging system performs multiple functions simultaneously: it acquires multi-angle plane wave data for velocity vector estimation, generates B-mode anatomical images, and produces color flow overlays. This multi-functional approach allows the system to provide comprehensive vascular assessment including both structural and flow information in a single imaging session.
2Measurement precision
If multi-angle Doppler analysis is implemented to resolve beam-flow angle dependence, then velocity estimation accuracy improves, but system complexity and data processing requirements increase
Solution Approach 1:
The system uses periodic plane wave transmissions at multiple angles (e.g., -15°, 0°, +15°) to acquire flow information. By transmitting plane waves at regular angular intervals and processing the periodic return signals, the system achieves accurate velocity vector estimation while maintaining manageable data processing requirements through the structured periodic nature of the acquisitions.
Solution Approach 2:
The multi-angle plane wave imaging approach allows the system to self-determine the beam-flow angle by analyzing the velocity vectors estimated from multiple transmission angles. The system automatically resolves the angle dependence issue without requiring external angle measurement devices or manual angle calibration, as the velocity vector direction itself provides the angle information.
3Loss of time
If high-frame-rate data acquisition is used to capture pulsatile flow dynamics, then temporal resolution improves, but data processing load and computational requirements increase
Solution Approach 1:
The system employs periodic plane wave transmissions at high frame rates to capture pulsatile flow dynamics. By transmitting plane waves at regular intervals and using coherent compounding of the periodic signals, the system achieves high temporal resolution for capturing rapid flow changes during the cardiac cycle while managing computational load through efficient signal processing of the periodic data.
Solution Approach 2:
The system performs preliminary clutter filtering and velocity estimation on the multi-angle plane wave data before final image reconstruction. By pre-processing the high-frame-rate data to extract velocity information and remove tissue clutter early in the processing pipeline, the system reduces the computational burden on subsequent processing stages while preserving the high temporal resolution needed for pulsatile flow analysis.
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
VPI offers enhanced accuracy and consistency in flow vector estimation and visualization, enabling effective tracking of multi-directional and pulsatile flow patterns, even in curvy vascular geometries, with frame rates exceeding video display limits and providing detailed spatiotemporal insights.
Implementation Method 1
a data acquisition unit, which transmits, via an ultrasonic array transducer, repeatedly a group of M plane waves pulsing events fired in sequence
Implementation Method 2
transmits... plane waves pulsing events fired in sequence into a tissue and which generates beamformed data frames
Implementation Method 3
performing slow-time frequency shift estimation on each of the MN ensembles
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
Apparatus and methods are provided for complex flow imaging and analysis that is non-invasive, accurate, and time-resolved. It is particularly useful in imaging of vascular flow with spatiotemporal fluctuations. The apparatus is an ultrasound-based framework called vector projectile imaging (VPI) that can dynamically render complex flow patterns over an imaging view at millisecond time resolution. The VPI apparatus and methods comprise: (i) high-frame-rate broad-view data acquisition based on steered plane wave firings; (ii) flow vector estimation derived from multi-angle Doppler analysis coupled with data regularization and least-squares fitting; and (iii) dynamic visualization of color-encoded vector projectiles with flow speckles displayed as adjunct.