Non-Rectangular Transducer Array for Dynamic Elevation Focusing
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Solution Overview
Problem
Current ultrasound imaging systems face challenges in achieving high image quality and frame rate due to limitations in transducer array design, beam focusing, and signal processing, particularly in obese patients with varying tissue layers, which affect sound wave propagation and delay calculations.
Innovation Solution
A two-dimensional non-rectangular transducer array with a multi-rowed configuration, including a center row and outer rows with specific element arrangements and electrical connections, along with advanced beamforming and coded excitation techniques, allows for improved focusing and signal processing to generate high-resolution images with adjustable trade-offs between image quality and frame rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a 1D transducer array with acoustic lenses is used for elevation focusing, then the beam can be focused in the elevation direction, but the focus is fixed and the beam width varies significantly with depth
Solution Approach 1:
The transducer array is divided into multiple rows of elements (e.g., 3 rows with 64 elements each), where each row can be independently controlled. This segmentation allows different rows to be activated at different depths, enabling dynamic focus adjustment in the elevation direction without requiring mechanical movement or fixed acoustic lenses.
Solution Approach 2:
The system transitions from static acoustic lens focusing to dynamic electronic focusing by controlling which rows are active at different depths. The beamformer can dynamically adjust the effective aperture in elevation by selectively activating rows based on the depth of interest, providing adaptable focus throughout the imaging range.
2Measurement precision
If synthetic transmit aperture with multiple transmissions is used, then image quality increases, but frame rate decreases
Solution Approach 1:
The imaging process is segmented into different depth zones, with each zone imaged using an optimized number of transmissions. Near-field regions use fewer transmissions while far-field regions use more transmissions, allowing the system to achieve high image quality where needed while maintaining higher frame rates in regions where fewer transmissions suffice.
Solution Approach 2:
The system dynamically changes the number of transmissions used for synthetic aperture imaging based on depth, tissue type, and desired image quality. This parameter adjustment allows optimization of the trade-off between image quality and frame rate for different imaging scenarios.
3Measurement precision
If FM modulated pulses with Tukey windowing are used for coded excitation, then signal-to-noise ratio increases, but costly multi-level linear senders or high-frequency transmitters are required
Solution Approach 1:
The patent employs simpler, lower-cost transmitter hardware (bipolar square wave at moderate clock frequencies) that can still achieve high signal-to-noise ratio through software-based signal processing techniques, rather than requiring expensive multi-level linear senders or ultra-high-frequency transmitters.
Solution Approach 2:
The system replaces complex hardware-based signal conditioning (multi-level linear senders, high-frequency oscillators) with software-based signal processing (beamforming, signal accumulation, digital filtering) to achieve the same signal-to-noise ratio improvement.
4Ease of operation
If straight line propagation assumption is used for delay calculations, then calculations are simple, but accuracy deteriorates in layered media with different sound speeds
Solution Approach 1:
The propagation path is segmented into multiple layers corresponding to different tissue types (e.g., subcutaneous fat, muscle, organ tissue). Delay calculations are performed separately for each layer using the appropriate sound speed, and the results are accumulated to obtain the total delay. This layered approach maintains calculation feasibility while significantly improving accuracy compared to straight-line assumptions.
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
The solution provides higher penetration depth, contrast resolution, and detail resolution, while reducing the number of channels and costs associated with high-frequency transmitters, and effectively handles varying tissue layers by using a layered model for delay calculations.
Implementation Method 1
transmit circuitry that actuates the elements to transmit an ultrasound signal into a field of view
Implementation Method 2
receive circuitry that receives echoes produced in response to an interaction between the ultrasound signal and a structure in the field of view
Implementation Method 3
The sound waves refract during their propagation (Snell's law)
Implementation Method 4
a beamformer that processes the echoes, thereby generating one or more scan lines indicative of the field of view
Data Source
AI summary
An ultrasound imaging system (102) includes a transducer array (108) with a two-dimensional non-rectangular array of rows (110) of elements, transmit circuitry (112) that actuates the elements to transmit an ultrasound signal into a field of view, receive circuitry (114) that receives echoes produced in response to an interaction between the ultrasound signal and a structure in the field of view, and a beamformer that processes the echoes, thereby generating one or more scan lines indicative of the field of view.