Siemens technology delivers true real-time 3D ultrasound

Image acquisition and display mimic live TV

When Siemens Medical Solutions introduced its lightweight Sonoline Antares ultrasound system in mid-2001, the company emphasized ergonomics and ease of use as much as image quality. That emphasis shifted during the 2002 RSNA meeting, when the company added its fourSight technology to the system, giving it a real-time 3D capability that Siemens calls 4D.

Other companies have introduced systems described as providing real-time 3D imaging. For the most part, however, these systems blurred the line separating true real-time and near-real-time imaging. Some say the ability to perceive image motion is the minimum requirement. Others say a minimum frame or volume rate must be achieved to constitute real-time. Siemens has gone a step further with its new release, comparing fourSight to live TV.

"FourSight 4D is acquired in real-time and viewed in real-time," said Lars W. Shaw, director of worldwide marketing for Siemens general ultrasound imaging. "It is akin to seeing a live broadcast on television."

Volumes appear as soon as the transducer is placed on the patient with no lag time, he said. The technology received FDA clearance in mid-November and was officially introduced during the RSNA meeting.

Because the volumes are acquired and displayed continuously, Siemens calls fourSight technology 4D imaging. This performance is achieved using specially designed solid-state transducers that rapidly move a curved array across a series of planes, grabbing multiple 3D volumes and eliminating the need for freehand scanning, although freehand 3D is still possible with the system.

Siemens predicted that the transducer technology would set a new standard for diagnostic ultrasound. The fourSight transducers that facilitate real-time scanning are about 20% lighter than others on the market, with small, ergonomically designed handles that support a variety of grip positions. Their design has enabled clinicians to achieve high volumes-per-second scan rates and excellent reliability, according to company executives.

"The processing speed of the Sonoline Antares, combined with the speed of the mechanically driven transducer, allows for continuous acquisition of 3D volumes (multiple volumes per second), which results in the real-time continuous display of 3D images," said John Pavlidis, president of the Siemens ultrasound division.

FourSight is an outgrowth of work completed by the Siemens ultrasound research and development group, which developed the company's SieScape panoramic imaging and 3-Scape real-time 3D imaging techniques, as well as the ultrasound system processing capabilities that were essential to achieving 4D. Siemens' corporate research division was enlisted as a partner in the project because of its prior role in the development of volume-rendering 3D and 4D imaging software for other modalities, including CT and MRI.

"The development of fourSight 4D imaging has been a large, complex project involving many key groups throughout Siemens," Pavlidis said.

The company hopes to sell "more than a couple hundred" Antares equipped with fourSight in the coming year, Shaw said. Marketing efforts will focus initially on hospitals, clinics, and private physicians, particularly ob/gyns who deal with high-risk patients. Other ob/gyns, radiologists, and vascular specialists will be targeted as well.

Presentations will be made at various medical and imaging conferences and the company's direct sales force will contact the existing installed base. Shipping is expected to begin in late summer, Shaw said.

Initial applications for the technology are expected to involve fetal imaging, specifically face, limb, and biophysical profile assessment, Pavlidis said. Other applications may follow, including uterine exams and abdominal imaging to evaluate liver and renal masses. Additional imaging applications may be developed as the technology matures and finds its way into other hospital departments.

The fourSight package will include 3D and 4D imaging features such as flexible image formats that allow a one-to-one, two-to-one, or four-to-one display to facilitate surface rendering. It will support real-time multiplanar reformatting, real-time volume rendering, real-time volume editing tools, and flexible storage and retrieval.

The Antares platform, which Siemens originally billed as the next generation of ultrasound platforms in terms of performance and size, is ideally suited for integration of the fourSight technology, according to the company. The system design, which is built around maximum information signal acquisition (MISA) technology, is robust and adaptable, allowing clinicians to perform rapid multidimensional analysis.