Ultrasonic Doppler Velocity Estimation Using Multidirectional Coherent Compounding
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Solution Overview
Problem
The multidirectional plane wave coherent compound technique in ultrasonic diagnostic systems suffers from increased aliasing velocity, leading to misrecognized blood flow direction and underestimated flow rates, particularly when applied to color Doppler imaging, which limits the frame rate and accuracy of blood flow observation.
Innovation Solution
The implementation of a method that involves continuously transmitting ultrasonic waves in multiple directions and applying a Moving Target Indicator (MTI) filter to unequal interval data sequences to extract blood flow signals, followed by complex addition of these signals to improve velocity estimation and reduce aliasing, thereby enhancing the accuracy of blood flow velocity measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multidirectional plane wave coherent compound technique is applied to color Doppler imaging, then frame rate is improved, but aliasing velocity decreases leading to misrecognized blood flow direction
Solution Approach 1:
The patent divides the processing into two separate coherent compound stages: first performing coherent compound on reception signals to obtain initial beamformed signals, then performing second coherent compound on the beamformed signals to obtain final compounded signals. This segmentation allows optimization of each stage independently, maintaining high frame rate while improving velocity measurement accuracy and reducing aliasing.
Solution Approach 2:
The patent introduces beamformed signals as an intermediary between the raw reception signals and the final color Doppler processing. The beamformed signals serve as a mediator that preserves the high frame rate benefits of multidirectional plane wave transmission while providing a stable basis for accurate velocity estimation in the second coherent compound stage.
2Productivity
If plane wave is transmitted in multiple directions with repetition period T, then frame rate is improved, but aliasing frequency becomes 1/A times the original frequency
Solution Approach 1:
The patent employs periodic transmission of plane waves in multiple directions with repetition period T, and performs coherent compounding over these periodic transmissions. By structuring the transmission and processing in periodic cycles, the system maintains high frame rate while the coherent compounding across periods A reduces the effective aliasing frequency impact through constructive interference of the periodic signals.
Solution Approach 2:
The patent changes the processing parameters by performing coherent compound not only across different directions but also across multiple repetition periods. By adjusting the compounding window to span multiple periods and directions, the system transforms the aliasing problem into a manageable parameter that can be compensated through the extended coherent compounding process.
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 effectively suppresses the decrease in aliasing velocity, improving the accuracy of blood flow velocity estimation and maintaining high frame rates, thus providing more reliable color Doppler imaging results.
Implementation Method 1
an ultrasonic probe 101. The plurality of vibrators 101a generates an ultrasonic wave
Implementation Method 2
a method of applying a plane wave coherent technology to a color Doppler is known. Such a method is also referred to as an 'Ultra Fast Doppler method'
Data Source
AI summary
An ultrasonic diagnostic apparatus of an embodiment includes an ultrasonic probe and processing circuitry. The ultrasonic probe repeatedly performs scanning in which a plane wave or a diffused wave is continuously transmitted a plurality of times in the same direction in a plurality of directions. The processing circuitry performs processing of applying a moving target indicator (MTI) filter to an unequal interval data sequence in the same direction obtained by the scanning and extracting a blood flow signal in each of the plurality of directions, performs processing of generating an autocorrelation signal by performing an autocorrelation operation on a plurality of blood flow signals in the same direction for each of the directions, and estimates a velocity value of blood flow on the basis of a complex signal generated by performing complex addition of a plurality of autocorrelation signals generated for the plurality of directions.