CHICAGO — The new O-mode form of ultrasound, which improves visualization behind structures and eliminates the need for beam formation, also weighs and costs less than conventional ultrasound, according to researchers presenting here at the Radiological Society of North America 100th Annual Meeting.
"We were quite impressed that, for the little bit of work that we did, we got such images," said Richard Barr, MD, from the Northeast Ohio Medical University in Youngstown. "The technology is actually not extremely complex," he explained, and said he expects that the small hand-held O-mode device will be available next year.
Dr. Barr presented a proof-of-concept study that confirmed that O-mode imaging is possible in a clinical setting.
The beam focuser required for traditional B-mode ultrasound imaging is considered to be important, but can lead to many of the limitations and artifacts seen in conventional scans. In contrast, the O-mode technique does not require a beam focuser.
The novel technique mimics a "single transducer lateral motion" along a known trajectory. This allows the Doppler effect to be evoked artificially from the "moving" transducer.
The result is an echo in different radiofrequency shifts that comes from the different scatterers located at the same depth but at different lateral positions, Dr. Barr explained. The technique makes it possible to visualize a Doppler shift between the Z particles.
O-mode provides constant lateral resolution that is independent of depth of penetration. It therefore significantly decreases the shadowing from small pockets of gas, allowing for the use of new imaging windows.
It also allows for exact lateral localization by exchanging the traditional ultrasound focusing procedure along the line of sight with signal processing of frequency-modulated signals that come from each depth.
Proof of Concept
To test the effectiveness of the O-mode method, Dr. Barr and his team used the technique to scan various organs of 10 patients.
When the images, which received very little post-processing, were reviewed by a board-certified radiologist, all were deemed to visualize deep structures at least as well as conventional B-mode ultrasound.
In addition, O-mode imaging can be performed in real time at 30 to 40 frames per minute, a rate typical of that seen with other systems, Dr. Barr pointed out.
"That's interesting," said session moderator Jason Stafford, PhD, from the University of Texas MD Anderson Cancer Center in Houston. He told Medscape Medical News that he is eager to read more about the technique.
The next step will be to "implement a small device that will be for the market," said Mati Shirizly, PhD, chief executive officer of Orcasonix, the company that will be manufacturing the O-mode ultrasound. The small device will likely retail for approximately $5000.
"Eventually, we will want to put this technology into a high-end system," Dr. Shirizly told Medscape Medical News. He said he thinks the technique will be particularly useful for imaging the hearts of obese patients.
However, during his presentation, Dr. Barr acknowledged that the O-mode technique still requires improved contrast resolution and improved image processing. Because the O-mode does not yet include image processing, it is difficult to truly compare it to conventional ultrasounds. "At this point, it really is hard to do a comparison of apples to apples. It really is apples to oranges," he said.
This study received funding by Orcasonix, the company that will manufacture the O-mode ultrasound. Dr. Barr is a consultant at Siemens AG. Dr. Stafford has disclosed no relevant financial relationships. Dr. Shirizly is a shareholder at Orcasonix.
Radiological Society of North America (RSNA) 100th Annual Meeting: Abstract SSA21-09. Presented November 30, 2014.