The role of ultrasound in obstetrics has come a long way over the past several decades. Some 35 years ago, pregnant women caught glimpses of their babies in-utero via ultrasound. Today, a mother-to-be and her family no longer view ultrasound as an amenity. Rather, they expect it even look forward to it.
As a resident in the Department of Obstetrics and Gynecology at The Pennsylvania Hospital (Philadelphia) in the early 1980s, Joshua A. Copel, M.D., quickly became acquainted with what he described as this most exciting, new thing, full of possibilities, probabilities and promise for obstetrical medicine. Twenty years later, his opinion has not changed. Ultrasound has continued to be the most exciting, new clinical thing in obstetrics … in the last 50 years, he believes.
Today, Copel is professor of obstetrics and gynecology and section head of maternal-fetal medicine at Yale University School of Medicine (New Haven, Conn.). He specializes in fetal therapy and high-risk obstetrics, and concentrates his clinical and research expertise in a number areas, including prenatal diagnosis by ultrasound. A member of various professional organizations, Copel serves on the American Institute of Ultrasound in Medicines (AIUM of Laurel, Md.) board of governors, as AIUMs liaison to the American College of Obstetrics and Gynecology ACOG of Washington, D.C.), and on AIUMs education committee. He is the recipient of numerous awards in obstetrics and teaching and he sits on the editorial boards of several publications, including Clinics in Diagnostic Ultrasound and Ultrasound in Obstetrics and Gynecology. Copel also is a regular Internet columnist at Now That Youre Pregnant, Womens Health, www.drkoop.com/family/womens/.
Medical Imaging spoke with Copel about the current and expanding role of ultrasound in obstetrics.
What is your experience with obstetrical ultrasound?
I come into this with a bias, because I was on a trajectory from the start of residency with an interest in ultrasound and prenatal diagnosis. I was doing my residency in the very early 1980s and ultrasound was the most exciting, new thing in obstetrics. It has continued to be the most exciting, new clinical thing in obstetrics, outside of laboratory research, in the last 50 years.
What do you cite as some of these exciting new developments? The evolution from 2D to 3D?
Improvements in image quality, penetration, signal processing, uses of Doppler and color Doppler. That is not to say that there isnt a role for 3D ultrasound, but I think that practically there is a lot more going on in ultrasound every day. It has been the window into seeing the fetus in a way we never could before.
What, then, is the status of ultrasound in obstetrics? Is it considered routine? Is it necessary in every case? If so, why?
If you look at statements by the American College of Obstetrics and Gynecology, they are careful to avoid any statement that an ultrasound must be performed in every pregnancy. And while I think that it has continued to be very elusive to try and show improvements in a lot of outcomes from the use of ultrasound, I believe that there are improvements. The literature is starting to show them, but if youre using strict cost/benefit-type approaches, improvements have been difficult to prove. I know that I cant put a dollar amount on the value of a family knowing about a congenital abnormality for them and planning for the delivery at a place that can take care of the baby. But there is a lot that goes into proving the cost/benefit approach. You have substantial costs just because 97 percent of fetuses are normal; some proportion of congenital abnormalities isnt detectable prenatally. The quality of ultrasounds varies, so the detection rates vary; and there are many ways to manipulate the figures to come up with different calculations for whether the costs exceed the benefits or whether the benefits exceed the costs.
My wife had ultrasounds during her two pregnancies. There was no way that we would not have done that. I believe that in many parts of the country it is considered pretty routine for all pregnant women to have an ultrasound. Certainly, I believe there is benefit when it is done well. The RADIUS study, an extensive study published a number of years ago here in the United States, reported that primary care-type settings had about a 16 percent detection rate of anomalies and that the rate was about twice that at tertiary-care-type settings. Part of the lesson from that was if you do not do ultrasounds well, you are not going to find things. If someone is going to have only one ultrasound done during pregnancy, she ought to have it done by the most experienced available team at finding fetal abnormalities in order to maximize the benefits to her for having the ultrasound.
How accurate is ultrasound in detecting these abnormalities?
Its all over the map. Some things are not recognizable until very late in pregnancy. Some mild forms of dwarfism, for example, may not be detectable until very late in pregnancy; some are detectable very early. Some types of congenital heart disease are made obvious even as early as 14 to 16 weeks. Others may not be detectable until after birth. It varies widely, and there are long, thick books listing different types of abnormalities, so it is hard to digest that down to a single, hard-and-fast rule.
From a comment you made earlier about coming to ultrasound with a bias, I would guess that you are enamored with the technology.
I would not let a member of my family go through pregnancy without the best possible ultrasound imaging study at least once during the pregnancy. I should not say would not let I cannot control what somebody else does but I would encourage, and I have encouraged my sister, sister-in-law and cousins when they have been pregnant to get a good-quality ultrasound study for reassurance.
Even if a woman and her family have no reason to suspect there could be a problem?
Most congenital abnormalities occur in families with no history of other abnormalities. Two to 3 percent of babies are born with major congenital abnormalities. A lot of these are either recessive genes or multigene disorders where you have to have the right combination of genes from both parents, in which case there will not be a family history. With a recessive gene there will not be a family history. How did two blue-eyed parents have a brown-eyed child? Well, they each have a recessive gene for blue eyes.
Ninety-seven percent of pregnancies are problem-free, but in most of the congenital abnormalities I see, when I am counseling the family, it is very common for the Mom to say to me, I dont smoke, I dont drink, I dont take drugs, and I have no family history. How can this happen to me? And that is far more typical than someone coming in and saying, Oh, I understand. This is because of my family history. Actually, it is funny that very often when there is a family history those are the folks who assimilate the information most easily, at least for the more minor abnormalities. It is not at all uncommon to find a club foot, and someone in the family says, Yeah, my cousin had it, my uncle had it.
How does 3D ultrasound differ from 2D?
I have had limited experience with 3D ultrasound. There are two major flavors that it comes in right now, and one is a sculpture-type picture, called surface-rendering. That is dramatic, but from my limited experience and what I understand from other people, getting those beautiful face pictures of a fetus is the exception rather than the rule. It is very dependent on the fetal position, gestational age, the amount of amniotic fluid, where the placenta is, whether the baby has its face mashed up against the placenta. It is still tricky to get.
The second, and in the long run, possibly the more important way that 3D is used is what is called multiplanar imaging; that is, taking the volume of information that is represented by the 3D image and being able to slice it anyway you want to create 2D tomograms. But you are not limited to where you can put the transducer anymore. You can come at it from different angles, just like a CT scan or an MRI. In either of those, ultimately the X-ray imager is going in a helix, a circle in multiple planes around the body, but then you can take all that information and say, I dont want to look axially, I want a coronal view, or a tangential view. You are able to re-create those. In situations where you cannot get exactly the plane you want, particularly in gynecology, looking at abnormal shapes of the uterus may be important in trying to understand the morphology of abnormal ovaries or in the fetus. The fetus just may not be cooperative and is not giving you the right plane to do a measurement. Being able to create a new plane may be very, very helpful.
What is the difference between a 2D real scan and 3D virtual scan?
In 2D, we are in real time; the movement is on the screen. In 3D, so far, the processing is not fast enough to be able to see the fetus like a hologram in front of you. It may get there. That is part of its continuing development.
Do you consider 3D ultrasound an improvement? If so, how is it an improvement for the patient? For the physician? For the hospital?
I think that it is a works-in-progress. It is not something that every institution has to get yet. The 3D machines have to perform as well as the 2D machines in 2D imaging, as well as being able to do 3D. In processing, that is, how you create the image. The 3D image has to be fast enough that it doesnt slow down patient flow to be practical. Nobody wants to get huge magneto-optical disks full of information and then have to spend hours off-line, after the patient has left, interpreting them. Nobody has the time to do that anymore; we have to move on to the next patient. We cannot stay here until 2 oclock in the morning to interpret all the images, so it has to be very user-friendly and quick.
Are there any tradeoffs with 3D ultrasound?
So far, the machines have been either clunky add-ons to existing good machines or new machines that have not had, as I understand it, quite the quality of imaging that the high-end 2D machines have. I think there are constant improvements. There are some new things coming down the road that may radically change the equation and allow for easy adaptation of basically off-the-shelf, high-end ultrasound machines in the not-too-distant future.
What kind of additional certification and/or training will be required to operate the newer ultrasound technology?
Many of us do not like the idea that accreditation will, effectively, be mandatory; I think it will be. I say that I do not like the idea, even though I am the AIUMs vice chair of accreditation.
Nobody likes to have to jump through more hoops. We do enough. We take admission exams for medical school. We take exams all through medical school, then we take national boards, then we take specialty boards and, in my case, subspecialty boards, and those are both written and oral exams, and we have to get continuing certification.
No one wants more, but the insurance companies are going to require it, if we do not. So, if we have some national accreditation processes that allow people to show their certificates and say to insurance companies, Look I have been through a process that ensures that I have been educated, that I have adequate equipment, that I have a safe lab, that I keep good records so far that has worked. All the insurance companies that have thought about their own accreditation have accepted that people can get either AIUM- or ACR-accredited, and that stands for them. And I think that is one way the insurance companies think they possibly can reduce their costs they will not pay for scans done in non-accredited facilities. It could be a private office, a hospital, a university-based practice like ours it does not matter. So I think that is coming. It may get more complex over time in terms of different types of scans, the high-end scans that we do here vs. the basic scans that people do in offices. I do not know if that will get broken out in types of accreditation or not.
What do you predict for the future of ultrasound in obstetrics?
It is not going to go away. Ultrasound is a powerful tool for the obstetrician, but it does not substitute for prenatal care; it is just one part of prenatal care. People need to have their blood counts checked, they need to get their weight and blood pressure checked, they need to have good counseling about nutrition, about risk factors and about wearing seatbelts. There are a lot of components to prenatal care. People tend to focus on ultrasound; they love having them. Everybody wants to see the baby, and I agree. I loved seeing my own kids when my wife had ultrasound. But it is only one part of prenatal care. It is a part of good prenatal care for me, but I dont set the national standard. The American College of Obstetricians and Gynecologists clearly says that it is not required to have an ultrasound but, as I have said before, I cannot imagine my wife or anyone in my family going through pregnancy without having the best possible ultrasound performed.