Feb. 25, 2000 (Miami) -- Despite considerable marketing hype about it, three-dimensional ultrasound has benefits in only a few situations, according to researchers who spoke at a meeting of maternal-fetal medicine specialists. Because some doctors are advertising their new 3-D equipment, it's important for patients to know its intended uses, they say.
Ultrasound is a type of imaging using sound waves to allow safe visualization of the fetus in the womb. Many women have at least one routine ultrasound as part of their prenatal care to be sure that their baby is maturing correctly.
The 3-D technology is best used to get more information about fetal abnormalities already detected with traditional 2-D ultrasound, Ilan E. Timor-Tritsch, MD, tells WebMD. "It's essential for detecting brain [abnormalities] because it can help us pinpoint the diagnosis, while conventional ultrasound only detects [the abnormality's] presence," he says. "However, it should always be used in addition to two-dimensional ultrasound."
The equipment is expensive, the images are time-consuming for the physician to interpret, and insurance usually does not pay for 3-D ultrasound, says Timor-Tritsch, who is a professor of obstetrics and gynecology at New York University. Patients who could benefit from it are usually referred to maternal-fetal medicine specialists. The specialists typically use the images to help pregnant women understand their options after a fetal abnormality is diagnosed, he tells WebMD.
Certain brain abnormalities can be accurately diagnosed with a 3-D scan across the fontanelle, or so-called 'soft spot' in the skull, says Ana Monteagudo, MD, who also spoke at the meeting. She says the anatomy of the fetus's brain is most easily read in the 15th to 16th week of pregnancy. After that time, the growth of the skull bones has progressed so that the ultrasound can no longer see through the fontanelle, says Monteagudo, an associate professor of clinical obstetrics and gynecology at New York University.
She echoes Timor-Tritsch's concern about the misuse of 3-D ultrasound. "It's easy to get the false impression that three-dimensional ultrasound is a better ultrasound, " Monteagudo tells WebMD. "I've had patients call the office asking for 3-D ultrasound to screen for Down's syndrome. When I tell patients that I use two-dimensional ultrasound to screen for Down's, they get upset because they think I'm not giving them optimal care."
"In our practice, we use three-dimensional ultrasound for [abnormalities] only," Feresheh Boozarjomehri, MD, tells WebMD. "We find the images helpful for counseling parents because they can better understand any abnormalities that have been diagnosed." Boozarjomehri, who was not involved in the presentation, is a maternal-fetal medicine specialist at Columbia Presbyterian Hospital in New York.
Timor-Tritsch was critical of media reports that he says have played up the "pretty picture" obtainable with 3-D technology and created patient demand for it. What should matter to doctors and patients is the 3-D technology's role in the diagnosis and evaluation of problems during pregnancy, Timor-Tritsch says. The research on the technology is still limited, and several of the studies involved 2-D ultrasound machines that contained parts that are now outdated.
In the near future, 3-D ultrasound will be found in most hospitals, he says. Now, however, Timor-Tritsch says that the resolution and quality of images remain inferior to those of 2-D ultrasound.