Vantage Volume Imaging Solutions
Verasonics offers researchers versatile, comprehensive solutions
Verasonics offers a variety of options for researchers in need of high-channel count ultrasound systems. Previous solutions provided Volume Imaging Packages that utilized either one or four Vantage™ 256-channel research ultrasound systems to interrogate a volume of tissue or material. Verasonics also offers a 512-channel solution using two Vantage 256 systems synchronized for phase-accurate data acquisition.
This two-system solution enables faster data acquisition than is possible with the single system solution. It provides opportunities to directly connect to all elements in custom transducers that have between 256 and 512 elements. The solution also provides customers the opportunity to connect to higher element probes by using the Multiplex adaptor. Customers with a Vantage 256 system now have the ability to upgrade to 512 channels with the addition of another Vantage system and appropriate software, licenses and accessories.
The two-system Volume Imaging package includes 512 transmit and receive channels, synchronized with the Verasonics synchronization module, a license for two-system RDMA data transfer, example scripts for volume acquisition with matrix arrays, and LINUX-based host controllers. It is compatible with the UTA 1024-MUX or UTA 256 Direct adapters.
Single system, 256-channel solution:
The Vantage system software includes example sequence programs (scripts) for the 1024-element matrix array (Vermon) when used with a single Vantage system and the 1024-MUX adapter. The 256 channels of the Vantage system can be connected to different subsets of matrix array elements on transmit and receive to obtain synthetic aperture ultrasound data. This data can be processed by the Vantage system software to yield a volume image or reconstructions of the volume data set.
Multi-system solutions:
To acquire data from the matrix array at a faster rate or with more flexibility, two or four Vantage systems can be synchronized to provide up to 1024 channels of acquisition data. A researcher can start with one Vantage system and acquire additional systems later that can be synchronized to provide direct connection between channels and elements. The UTA 256 Direct adapter provides direct element-to-channel connection (without multiplexing) for 512- and 1024-channel configurations. A custom rack is provided with the four-Vantage system solution along with high-performance, rack-mounted-computers. This solution efficiently utilizes the space with ergonomic considerations to accommodate all host adapters and cables, and synchronization module. This solution also provides installation and additional scripting support.
The software components of the Vantage Volume Imaging Package include a graphical user interface (GUI) to program all systems from the “primary” Vantage system. Scripts for distributed beamforming on each computer enables real-time display of orthogonal planes, with options for offline reconstruction of the 3D data volume. It also includes example scripts to help you get started with the matrix arrays offered by Verasonics.
Also available from Verasonics is a cost-effective version of the Vantage 256 for use in high-channel-count applications. The Vantage 256 EC “External Clock” has all the transmit and receive capabilities of the standard Vantage systems but will only function when it is paired with a “Primary” system from which it obtains a clock signal. Although the Vantage 256 EC is intended to be used only in multiple-system arrangements, it can easily be upgraded to full capability should the researcher need another independent Vantage system.
Verasonics Volume Imaging Package with four rack-mounted Vantage 256 systems with UTA 256-Direct Adapters and a 1024-element matrix transducer. The rack also provides space for four high-performance, host controller computers in an ergonomic, space-saving arrangement.
Examples of Verasonics Volume Imaging solutions
using 1024-element matrix array transducers
| 256-channel solution | 512-channel solution | 1024-channel solution |
|---|---|---|
| 1 Vantage system | 2 Vantage 256 systems (1 of these may be the External Clock configuration) | 4 Vantage 256 systems (up to 3 of these may be the External Clock configuration) |
| Data acquisition using 4:1 multiplexing | Data acquisition using 2:1 multiplexing | Data acquisition directly from each element (no multi-plexing) |
| OS: Windows | OS: LINUX Ubuntu | OS: LINUX Ubuntu |
| Designed for bench or table-top installations | Designed for bench or table-top installations | Designed for rack-mounted installations |
| No license required to access scripts for multi-plexed acquisition | Includes RDMA licenses, data cables, sync module, support, scripts | Includes RDMA licenses, rack and rack-mounted computers, data cables, sync module, monitor, keyboard, installation & support, scripts |
Multi-System Sync Module
One of the challenges in combining multiple systems for research or product development is the synchronization of transmit and receive clocks for each system.
Verasonics has developed the Multi-System Synchronization Module that can synchronize up to eight Vantage systems for a total of 2048 channels. The Multi-System Synchronization Module connects to each Vantage system with HDMI cables and the individual 250 MHz system clocks are synchronized to within 2ns.
The Multi-System Vantage configurations define one system as the primary, with one or more secondary systems. Identical scripts are run on each system and the sequences are synchronized using the input/output triggers. Using high-speed serial modules, raw volume data is transferred from each secondary system’s host controller to the primary computer at up to 4GB/s. To further accelerate data transfer and reconstruction processing, a pre-transfer beamforming mode can be enabled on each secondary computer. Data from all secondary system is collected in the primary system computer for final processing and display.
Experiments can be simulated using Vantage software before running the scripts on the Vantage hardware and transducer.
Applications of Volume Imaging with Matrix Arrays
High-element-count transducers and high-channel-count beamforming have many applications, including the rapid acquisition of a data set for a volume of tissue or material. Whereas conventional ultrasound imaging only acquires information along a single line or plane, matrix arrays enable volume imaging to characterize changes in structural properties or physiological events. For example, the deformation of a structure under stress can be better understood if the visualization is not limited to a single plane. Likewise, quantitative analysis of perfusion within tissue (wash-in, wash-out processes) may require that the entire volume be evaluated. Researchers doing functional imaging want to be able to characterize the blood flow changes throughout the area of interest, not only in a single plane.
Another application is in focused ultrasound for therapy research. Scientists working in the field of HIFU not only want to direct the delivery of energy in multiple planes, but also want to know how the tissues adjacent to the treated tissue are responding to that energy. High channel count arrays, controlled by a high-channel-count system, can facilitate both focused ultrasound for therapy, and conventional imaging for guidance and monitoring.
Finally, there is another potential for high-channel-count systems in the area of aberration correction. With conventional 2D imaging there is often image degradation due to echoes produced by out-of-plane structures. These structures are not visible, but the artifacts they produce can create confusing and misleading information. Current techniques for aberration correction can address artifacts that arise from in-plane structures, but not those from structures that lie out of the scan plane. A matrix array transducer, controlled by a high-channel-count system, provides opportunity for the researcher to detect and mitigate these artifacts.
High Element / High Channel Count Systems
As scientists and researchers explore new ways to use ultrasonics, there is an increasing need to employ more elements and more channels. This is particularly true in the field of diagnostic medical ultrasound, where physicians have utilized 3D imaging to better understand complex anatomical structures, and 4D ultrasound (3D in real-time) to depict moving structures such as the valves in the heart.
For imaging moving structures, or to acquire a volume of data at high-speed, the optimal transducer is an electronically-steered phased array that uses a two-dimensional grid of elements. This type of transducer is often called a matrix array and may utilize hundreds or even thousands of elements. Several transducer manufacturers are now making matrix arrays in 8×8, 16×16, 32×32 and even higher element configurations.
There are some clinical ultrasound systems that employ matrix arrays, however these typically utilize only 192 or 256 channels. The transducers are multiplexed, and use “micro-beamforming” techniques to reduce the programming complexity and the volume of data that these probes acquire. Many scientists and researchers, however, would prefer to have a direct connection to every element for maximum flexibility, absolute control and complete data acquisition.
One of the challenges in combining multiple systems for research or product development is the synchronization of transmit and receive clocks for each system. Verasonics has developed a Multi-System Synchronization Module that can synchronize up to 8 Vantage systems for a total of 2048 channels. Multi-System clocks are synchronized to within 2ns by simply connecting via HDMI cables to the Multi-System Synchronization Module.
The unique Pixel-Oriented Processing software of the Vantage system makes it possible to create transmit and receive beamforming delays for virtually any transducer geometrical configuration and element positions, enabling the implementation of novel transducers and systems. The software is extremely flexible and allows for each element to have a separate geometric orientation from other elements in the same experiment or system. This flexibility is compatible with any shape, size or combination of transducers. For example, Vantage enables the user to implement 3D concave (bowl-shaped) transducers, ring arrays, 1D and 1.5D arrays, 2D matrix arrays, multiple simultaneous arrays and sparse arrays, as well as through-transmission ultrasound techniques. Support for new transducer technologies as well as novel imaging techniques and algorithms can be developed and simulated using Vantage software before testing on the Vantage hardware and transducer.
3D volume image of a phantom acquired with the Vantage 256 System with a UTA 1024-MUX adapter and a 1024-element matrix array transducer. The transmit-receive sequence was composed of 25 diverging wide beams located at four virtual sources with multiple transmit and receive apertures.
The Vantage 256 system with the UTA 1024-MUX Adapter.
The transducer is a 1024-element (32 x 32) matrix array made by Vermon.
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