Ultrasound that works like 3-D movies

Parents-to-be soon might don special glasses in the ultrasound lab to see their developing fetuses in the womb "in living 3-D, just like at the IMAX movies," maintain researchers at Duke University's Pratt School of Engineering, Durham, N.C. The same team that developed real-time, three-dimensional ultrasound imaging says it now has modified the commercial version of the scanner to produce an even more realistic perception of depth. Paired images seem to pop out of the screen when viewed with the 3-D glasses.

The researchers created an updated version of the image-viewing software found on clinical ultrasound scanners, making it possible to achieve a stereo display with no additional hardware. "To our knowledge, this is the first time it's been made possible to display real-time stereo image pairs on a clinical scanner," indicates Stephen Smith, professor of biomedical engineering. "We believe all 3-D scanners could be modified in this way with only minor software changes."

The new imaging capacity can improve the early diagnosis of certain types of birth defects of the face and skull and improve surgeons' depth perception during ultrasound-guided medical procedures, including tumor biopsies and robot assisted surgeries done through tiny "keyhole" incisions.

Human depth perception largely is the result of stereo vision--the slightly different perspectives of the same scene that are observed by the left and right eyes. The brain processes the information to produce a sense of depth, a phenomenon that cannot be achieved when viewing a single, flat image.

Stereophonic images solve that problem by taking two "snapshots" of the same object from slightly different angles, mimicking the normal difference between left- and right-eye views. Special glasses or goggles then can be used to fuse the two images into one, gaining a 3-D effect. This principle lies behind 3-D movies and the familiar View-Master toy. With practice, some people can "defocus" their eyes and fuse the paired images without the aid of any special viewing device.

"Thousands of 3-D ultrasound systems in clinics could be upgraded with such new software, and stereoscopic goggles could be issued to them as well," Smith notes. "Keepsake DVDs of the fetal exam could also be viewed at home in 3-D stereo."

The goggles soon would become obsolete, he adds, as new monitors capable of fusing stereo 3-D images without them now are in development.

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COPYRIGHT 2008 Gale, Cengage Learning