Dr. Joshua Copel: "This is Josh Copel and I'm in Atlanta, Georgia at the Ob/Gyn Ultrasound 2000 course. I'm here talking with Ilan Timor, who is a Professor of Obstetrics and Gynecology at NYU Medical Center, and with Dr. Beryl Benacerraf, who's a Professor of Obstetrics, Gynecology, and Radiology at Harvard Medical School. The topic that we're going to spend a few minutes talking about right now is the use of 3-D ultrasound in obstetrics and gynecology. The first question I'd like to pose for both of you is whether 3-D ultrasound can currently be considered a standard of care in obstetrical and gynecologic ultrasound?"

Dr. Ilan E. Timor: "I have what is perhaps a very personal opinion on this one, and I would say no. The reason is that there are very few 3-D ultrasound machines scattered around the country, and they are located mainly in centers that have special interests in doing three-dimensional ultrasound. The second reason is that not everyone has the proper training to extract the most information that these machines can give. I am optimistic that in the future, this will be the standard care. How long that will take? I don't know."

Dr. Joshua Copel: "Beryl, do you have a feeling about that?"

Dr. Beryl Benacerraf: "I agree with Ilan that this is not currently the standard of care. I don't think there's anything right now that 3-D adds in the usual and customary type of indications that we do obstetrical ultrasound for, and I think it's only in special cases where it's really needed."

Dr. Joshua Copel: "When is 3-D ultrasound most useful? We can break that down into both obstetrical and gynecologic exams, and maybe one of you could take obstetrics and the other gynecology."

Dr. Ilan E. Timor: "Why don't we take both because we may have different views on some of the things, or maybe we can complement each other. So let's see - Beryl will probably take obstetrical?"

Dr. Beryl Benacerraf: "Okay. In obstetrics I think it is helpful to look at the surface of the fetus in certain areas such as the fetal face, for example, and also the fetal sutures. It's very difficult with 2-D to look at the sutures and see whether perhaps they're fused prematurely, where with 3-D, it's very easy. It is helpful for the fetal face as well, not so much because it is needed to make the diagnosis of a cleft lip, for example, but once you make the diagnosis it's helpful to show the parents what we're dealing with. And it shows the referring physician and plastic surgeon what we're dealing with so that he or she can help the parents plan for the surgeries that are necessary. That's for obstetrics. For gynecology, I think that the multiplanar reconstruction of the coronal plane of the uterus is absolutely crucial. I actually think that it's more helpful in gynecology, currently, than it is in obstetrics."

Dr. Ilan E. Timor: "I wouldn't disagree at all with what you said, I would only complement it. Let me start first with the gynecology part. Really, I think the money at this point is in scanning the uterus mostly for anomalies, for better visualization of the origin of polyps which gives the gynecologist a good notion of where to go, and if he or she does hysteroscopic-directed surgical procedures. The other use for gynecology would be to look at the extent of the fluid in the pelvis because it gives a somewhat better notion of the amount of fluid that coats the different organs in the pelvis, which are used sometimes. But going back to obstetrics, my main use of three-dimensional ultrasound is looking at the fetal brain. It is really astonishing how you can fine tune the diagnosis by doing a transvaginal scan through the anterior fontanel, image the brain, and then look for the normal structures in a daily occurrence or pathology and pinpoint the exact location from where the pathology arises."

Dr. Joshua Copel: "In that situation you're talking about using the multiplane reconstruction only, which is really not what people think about at first when they think about 3-D. They think about the surface rendering of the face and things. But I think it's important for people to remember that the multiplanar may turn out in the long run to be even more important. At a recent meeting that I was at in Florida, I think it was John Hobbins who showed a case of a fetus with a neural tube defect in which they used volume rendering to identify at exactly which level of the spine the defect had occurred. They felt it was easier than it would have been with two-dimensional ultrasound, and that leads me to my next question. Right now, do you think there is anything that 3-D offers that is unique in its ability to diagnose that we can't do with 2-D ultrasound, but which 3-D allows us to do?"

Dr. Beryl Benacerraf: "I don't think there's anything in obstetrics that you cannot diagnose without 3-D. I think there are things in gynecology that you can't diagnose without 3-D. That is, for example, the difference between a septate and a bicornuate uterus, which is extremely difficult and sometimes not accurately done in only 2-D. So I think uterine anomalies are one area where 3-D is really necessary. I think the other important thing about 3-D is it enables the patient to essentially be rescanned by somebody else. You can take your volume of, say, the uterus and the volume of each ovary, send the patient home and essentially rescan that patient in any plane that you want later on, and that's something that even cineloop equipment does not give you the opportunity to do."

Dr. Ilan E. Timor: "Once again, I think it's wrong to pit the 2-D ultrasound against the 3-D ultrasound and see which can do better or whether you can live without the 3-D ultrasonography. Basically, in almost every case, we can make the diagnosis. We have seen enough of the 2-D cases that we can make the diagnoses. What we do every single day with every single case when we scan and not look at static pictures is reconstruct a three-dimensional picture in our own brain. But once again, if you have the volume, you heard Beryl say that you can rescan the patient, and you can send it over to somebody else, but then you can always fine tune the diagnosis a little better by adding this modality. So it's not which is better and whether you are looking now for an exclusive diagnosis that the 3-D can do. The more you do it, the better you get, and the more places you will apply it. Eventually, when every single machine has the 3-D in it, because that will happen, then you will be right there to perform the 2-D and the 3-D scan. And once again, in my hands the brain scan without the 3-D and without that marker dot that I'm navigating around to see the structures is absolutely irreplaceable."

Dr. Joshua Copel: "Let me close with this question, and it's sort of a popular question because what the patient wants to see is the baby's face. What percentage of obstetrical patients are you able to get a nice picture of the face with current 3-D technology?"

Dr. Beryl Benacerraf: "I would say very few. I can get a better 2-D picture of the baby's face than a 3-D picture because you can get around the fact that the hands are in front of the face or that there's placenta coming in on the side. There are certain obstructions to seeing the face, and you can get around those with a 2-D image, but with a 3-D image it is very unforgiving while trying to get a really good picture of the face. I would say it's probably less than 10% of the time, and perhaps even less than 5% of the time."

Dr. Ilan E. Timor: "Once again, the more you do it, the more percentages you will be able to see. I wouldn't discuss the number of cases in which you can or cannot, however. I would rather discuss something else in this regard. Don't attempt to reconstruct the fetal face before 28 weeks for baby pictures because the amount of fatty tissue that lines the facial structures will be crucial to see a nice 3-D picture. The other thing is to forget the face when you have oligohydramnios, of course, and once again, it sometimes takes a long time to cut away structures, so it's not worth doing it for so-called 'baby pictures.' If you have an anomaly, you invest all the time in getting that lip or whatever you want to see, like problems of tumors in the mouth, to see where they come from. But basically, we do not invest time if we don't see it right away, as Beryl said, and which would be in the vicinity of maybe 15%-20%, we don't invest time in that. It's just badly invested time."

Dr. Beryl Benacerraf: "I think this is important, and you brought up a good point about doing surface reconstruction on the early fetus, or on an early second-trimester fetus. I have not found that helpful. I have found that surface reconstruction is only helpful in the third trimester."

Dr. Joshua Copel: "I thank you both for your time in this interview. It's interesting technology. We'll probably be posting these interviews periodically and getting new opinions as we go. Thank you very much."

Comments on this interview can be sent to Ultrasound@obgyn.net