But 2-D images aren't going anywhere in the near future. In fact, they usually offer better diagnostic information than their 3-D and 4-D counterparts.
"2-D lets you see inside of structures, because you can take slices within [the fetus's body]," Benson explained. "With 3-D you can do a surface rendering, but you can't see inside the baby any better than I can see inside you."
But because the new kinds of scans are created from many stitched-together 2-D images, the 3-D and 4-D imagery represent a valuable diagnostic resource.
The new processes collect data for the entire volume of the fetus and womb. From this imagery, a more conventional, 2-D image can be separated out and can depict any and all desirable angles.
"When we're looking at the fetus or at the uterus, the position of these structures may not be in the ideal plane to get the information that we want," said Barry B. Goldberg, director of the Jefferson Ultrasound Research and Education Institute in Philadelphia, Pennsylvania.
"With these [new processes] it's possible to reconstruct [2-D cross sections] in different planes," he continued. "We can collect a volume of information, decide what plane we want, and manipulate the image plane to get [the visual] that will give us the most information."
Because the data can be stored on a computer, new slices can be created and examined long after the patient has returned homethough computer capabilities are currently too slow to allow this process to become standard procedure.
Third Dimension Offers Doctors a New View
A three-dimensional view can, in some cases, provide its own diagnostic advantages.
"For the first time it is now possible to visualize fetal organs as more than flat images but rather as three-dimensional objects that can be rotated and examined from different angles," said Wesley Lee, of the Division of Fetal Imaging at William Beaumont Hospital in Royal Oak, Michigan.
Lee stresses that 3-D images are a complement to, rather than a replacement for, 2-D ultrasound.
"[This] technology allows doctors to visualize ultrasound images in different ways that may strengthen or refute an initial diagnostic impression using more conventional tests," he said.
Such images are useful at identifying cleft lip, spina bifida, and some genetic syndromes.
As computers become more powerful and processing speed increases, the technology will only improve.
"We're really at the beginning, 3-D and 4-D image quality appears to be improving every month," the Jefferson Institute's Goldberg noted.
Future advances may allow the digital transfer of complete fetus and uterus volume scans. Such transfers of imagery could enable remote consultation and diagnosis for patients in areas lacking advanced health care.
Everyone agrees that the new scans already provide dramatically better visualization for parents, which can result in an even stronger parent-child bond. High-risk obstetrician and gynecologist Jude Crino is the director of the Perinatal Ultrasound Unit at the Johns Hopkins University School of Medicine in Baltimore, Maryland.
"We can see better, but it's also important that the patient can see better," he explained. "When I give a patient a 2-D image, it's not uncommon for them to ask two or three times, 'What is this? Could you point this out?' If you give them a 3-D image, they are immediately able to recognize it, because it looks like a baby."
Campbell notes that in his clinic the effects of the moving, 4-D images are even greater.
"You just see the whoops of joy when the fetus does something like blink," he said. "That's a very powerful impact."
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