Holoprosencephaly

YES Three-dimensional capabilities should be on every ultrasound machine, but 3-D doesn't have to be used on every patient who gets an ultrasound. If I'm in a room that doesn't have 3-D, I will often move to a different room, because I'm using 3-D more and more every day. If it's not on the machine, then you don't have an opportunity to work with it.

There are some problems with resolution, but the technology is changing at an incredibly fast rate. I have no doubt that the resolution will improve very quickly.

The 3-D may be the only way to get a volume or to look at a view that you cannot otherwise get. If it's a question of seeing that view or not seeing it at all, even if it's lesser resolution, I think it is important to see it.

It is vital to learn to work with 3-D now We need to keep up as practitioners with the technology that's coming out. Volume scanning is going to come whether we're ready or not.

There are many, many studies that suggest that 3-D adds to demonstrating fetal defects. Among them, my colleague Dr. Harm-Gerd Blaas did a study on early diagnosis of abnormalities such as holoprosencephaly and found that the use of 3-D and volume reconstructions improved the imaging and understanding of the condition.

I have found it particularly useful in measuring first-trimester nuchal translucency When the fetus is in the wrong position for two-dimensional (2-D) imaging, you can get your third view, nuchal translucency orientation, a longitudinal view of the fetus with 3-D.

There are areas such as the fetal ears, fetal sutures, and uterine shape where our mind's eye reconstruction may not demonstrate the image as well as the actual display would. The display helps us discuss our findings with our colleagues and our patients, who are nor trained to imagine 2-D images in 3-D form.

In one case of conjoined twins, the mother benefited from having the 3-D images to remember the pregnancy even though she could not continue it.

We use 3-D all the time to image the uterus and the adnexa. You can see things there that you can only see otherwise with an MRI. You can see the difference between a bicornuate, a septate, and a unicornuate uterus, which is sometimes not obvious on a standard 2-D image.

In women with abnormal bleeding, we can identify polyps and fibroids and see exactly where the polyp is located. You can use the endometrium as its own contrast agent and identify exactly where a submucous fibroid is located. You can add fluid for 3-D sonohysterography. Looking at the adnexa, you can identify septate cystic masses. You can get beautiful views of the perineum and the structures of the pelvic floor. You can see the relationship between the urethra, the vagina, and the rectum.

Volume imagery and 3-D reconstruction is in its infancy, but it provides a new approach with far more control over the image and data and display than ever before. The possibilities are infinite. Do not be left out.

NO You can define "ultrasound unit" different ways. I think of it as an ultrasound department, not an ultrasound machine. Does every ultrasound department need a 3-D machine? No. Not today but perhaps in the future.

Three-dimensional ultrasound is wonderful. It can show the face or any other part of the body and obtain some ultrasound images not accessible to 2-D scanning. It can help calculate volume. But it does not work in some cases, there are resolution problems, and the diagnoses can be made with 2-D ultrasound alone.

When imaging the fetal brain using 2-D ultrasound, with an axial resolution of 0.4 mm, we can identify the layers of the corpus callosum. A3-D reconstruction of that area in the range plane (perpendicular to the original plane) gives us a resolution of 2-3 mm: Would anybody dare to order diagnostic procedures based on such poor resolution? The answer is no, of course.

We get along quite well with just 2-D ultrasound, as most sonographers do. In the future, we will have 3-D as an additional mode like Doppler, color Doppler, etc. The technology is developing. For now, 3-D ultrasound is an interesting research tool. Besides the significant resolution problem, the cost of the technology outweighs the knowledge gained. This does not justify buying an expensive 3-D machine and investing in additional training of sonographers and doctors.

What does it take to make a 3-D image? One of the leading experts in 3-D ultrasound recently reported on scans of 2,365 fetuses in the first, second, and third trimesters. In 25%-50% of the cases, the fetus was not in a suitable position to obtain a 3-D ultrasound of the face.

The author spent about 3.5-4 minutes per 3-D scan, and he was a superexpert, presumably faster than you or I would be. So if he had 20 patients a day he had to work 1 hour more that day because of the addition of 3-D ultrasound.

It's a time-consuming process, and the images are often difficult to obtain. Another study reported that the investigators required about 30 minutes, and sometimes up to 1 hour, to reconstruct facial anomalies by 3-D ultrasound. And in the end, they reached the same diagnoses obtained by 2-D scanning.

Volumetry is time consuming and provides only marginal improvements. We don't have whole-body volumetry with 3-D ultrasound, only volumetry for parts of the body like the arm or the leg. When we need it, 2-D is sufficient to screen for growth-retarded fetuses, and we have other tests available like Doppler analysis.

Studies done on 3-D ultrasound for different gynecologic indications mainly conclude that the. impact of 3-D on gynecologic diagnosis has been limited so far.

There are no randomized controlled studies of 3-D vs. 2-D ultrasound. The prospects for fetal scanning by 3-D are, at best, speculative.

All diagnoses illustrated by 3-D ultrasound can be made, and are made, by 2-D ultrasound.

COPYRIGHT 2003 International Medical News Group
COPYRIGHT 2003 Gale Group