Fetal Gastrointestinal System

Gallbladder and Gallstones

What else can we see in utero?

I'm sure that most people who have done obstetrical ultrasound will have seen this.

And this is a transverse image in the upper abdomen.

And here we have the gallbladder and right in the fundus of the gallbladder, the echogenic lesion with posterior shattering.

And of course this is a little gallstone.

Now sometimes you can see the focal gallstones like this and other times the gallbladder will completely be chockfull of all of this echogenic debris.

Both of them represent gallstones.

The gallbladder does start to contract in the third trimester.

So if you don't see the gallbladder in the third trimester, it could be completely normal just going through the phase of contraction.

It may be due to atresia of the gallbladder or it could be supporting evidence for cystic fibrosis.

Gallstones, as we just saw, can occur in utero.

And these resolve spontaneously usually post nat in the immediate postnatal period.

They do not need to be imaged in the neonate and choli doco cysts get a lot of press.

They get talked about a lot, but they're extremely rare.

Duplicated Gallbladder

So here's an example of a fetus where we could see the beautiful gallbladder in the right upper quadrant, but then we also identified this structure that also looks like a beautiful gallbladder in the right upper quadrant.

And on this image with the color, you can see there's no flow in either structure and this fetus did indeed turn out to have a duplicated gallbladder.

Something else that you don't see very commonly in a fetus.

Spleen Abnormalities

This time we're looking in the left upper quadrant.

So here's the stomach and posterior to the stomach right here.

We again see a well-defined an coic structure, and this is completely con centered within the spleen.

And this is a splenic cyst.

So cysts of the spleen are extremely unusual.

Any sort of abnormality in the spleen is very unusually seen in the fetus, but there's no reason why you can't see it.

You just have to remember to go look for it.

Once again, not one of the things on our protocol of the fetal survey.

The spleen can be absent.

Typically that's related to the asplenia hetero taxii syndromes.

And in those instances, the stomach will be located very far posteriorly or possibly anteriorly in the midline because of the hetero taxii syndrome.

Splenomegaly can occur in utero if there's severe iso immunization of the fetus with hemolytic anemia.

It can also be seen in infection and metabolic problems and neoplastic instances, particularly in fetal lymphoma.

Ventral Wall Defects

A few minutes now on ventral wall defects.

These fetuses present with high a FP levels due to the skin defect and it's important to evaluate the cord insertion and the bladder in all of these fetuses.

Gastroschisis

So here we have an example of a anterior abdominal wall lesion here, seen a little better here.

And you can see these free floating loops of bowel coming out just to the right of the umbilical cord.

And these loops float around with no surrounding membrane and are very closely related to the site of the cord insertion here.

This of course, is gastroschesis the defect, as I just said, it does occur to the right of the umbilicus.

This is a sporadic defect with no genetic associations and no recurrence risks.

It does tend to occur in younger mothers, meaning in particular mothers under the age of 20 to make the diagnosis of gastroschesis, we look for free floating bowel in the amniotic fluid.

Now what that means is there is no membrane over the bowel, therefore you will never see ascites because if there's ascites in the fetus, it will be completely, easily released into the amniotic fluid.

And the presence of ascites means you're not looking at gastroschesis.

There can be an inflammatory pseudo membrane over the bowel in up to 20%, but that's typically not seen as a discreet thin, covering membrane.

These fetuses often have other issues with the GI tract because of the fact that when gastroschesis occurs, the bowel does not have its ability to do its normal protrusion out into the base of the cord, the 270 degree rotation and the return to the fetal abdomen where it can then lay down from the ligament of trites in the left upper quadrant all the way down to the cecum in the right lower quadrant.

That's the process that prevents ulous and mal rotations.

And because this bowel has protruded out of the abdomen, it's at high risk for mal rotations and ulous and other GI anomalies in these fetuses, despite the fact that the only thing they have wrong is GI tract anomalies.

They tend to have postnatal complications in a very high percentage of these fetuses.

They spend a lot of time in the hospital and a small number of these fetuses lose a lot of small bowel.

Here's another example of a patient with gastroschesis at 33 and a half weeks, and you can see these fluid filled dilated loops of small bowel freely floating out in the amniotic fluid.

And notice in this instance that the stomach in this fetus, these images were done at the same time, same day.

The stomach is quite small.

So this fetus, this mom was going along and we're waiting for the pregnancy to continue.

And she came back into the hospital at 35 weeks complaining of decreased fetal movement.

Now of course, this was nine o'clock on a Friday night, and which is of course when all of these things tend to happen and there's a radiology resident on call and he called me up and said, I don't think I can scan this patient.

I've never scanned gastroschesis. I won't know what to do.

I won't know what to look for. So I said, that's okay.

Give it a try. Go back and look at the priors and then look at today and then call me up and tell me what you think.

So he scanned today after looking at the priors and he said, you know, it's very different now.

The gastroschesis doesn't have any fluid in it.

There's no dilated loops anymore and the stomach is huge and those are really, really good observations.

And so he also noted that the biophysical profile score was two.

The fetus was not moving.

So this was an unhappy fetus who is no longer putting any fluid into this gastroschesis loops and who has is now giving us evidence of a possible gastric outlet.

Obstruction. The fetus was delivered that night, and indeed the bowel was navy blue, but at delivery as soon as the bowel was lifted up straight and the blood flow could be restarted.

It pinked right up every time they let go of the bowel and let it drop to the side back to navy blue.

So we were lucky enough in this instance to pick up the acute ischemia that was happening in this fetus as the gastroschisis progressed.

Omphalocele

Another anterior abdominal wall defect we need to be aware of is this one.

In this instance we see a piece of liver, this homogeneous liver sticking out from the abdominal wall.

This is the anterior surface of the chest and you have the stomach back here.

And in this instance we do see this thin membrane covering over the top of this loop of liver that's sticking out.

So now of course we're looking at falle and em.

Falle is a midline defect with a covering membrane.

And in this instance we do see the ascites because the membrane outlines it for us.

The umbilical cord inserts into this mass of the emale and the opposite of gastroschesis.

Emale occurs more often in older moms, particularly over the age of 40.

Here's an emale that was seen as early as 13 weeks.

It's a profile sagittal view of the fetus.

And you can see this little tiny thing sticking out right here in the anter abdominal wall.

And here it is, on the transverse view.

And this was a onic twin gestation and the upper twin has the emale.

Another example of an emale in this instance with just bowel in it instead of just liver in it.

And you can see the covering membrane and the umbilical choroid inserting just into the side here.

Al Seals have a high association of chromosomal abnormalities if there is no liver present in the mass, like this case I just showed, if there's liver out in the emale, the risk of chromosomal abnormalities are associated, is much lower regardless of whether there's a chromosomal abnormality or not.

When there's an emale present, there is a high association of other anomalies in the fetus.

You wanna be very careful that you're getting a good look at these kids.

In particular, congenital heart disease will be present in over 50%.

Another example of a fetus with a ga with a falle.

Here's the fetus here.

You can see some spine back here and notice this enormous, falle almost as big or even bigger than the body of the fetus itself.

And with the color doppler, we can see that the umbilical cord runs right into the seal and along the inferior edge of it.

Well, we know we have to look around, up in the brain we can see a choroid plexus cyst.

And when we went to look at the extremities, we had bilateral clenched fists and everyone should be expecting that the chromosomes would indeed come back.

Trisomy 18, Remember that al seals can be associated with syndromes including the penology of Cantrell, which is the combination of emale, ectopic cordes, sternal diaphragmatic and pericardial defects, as well as with beck with Weidemann syndrome.

And the things we can see in beck with ween include macroglossia, big livers, spleens and kidneys, cystic placentas and macrosomian.

Here's a fetus with, again, a very large falle.

Here's the lower portion of the chest.

You can see the ribs here and a little bit of stomach and the entire liver is out in this vase seal.

Here's the sagittal view of the same fetus and you can see the liver here.

And if you're looking very carefully at one end of the clip, I wonder if you notice that a little tiny bit of the heart and I'll move my pointer out to the other side, has protruded past the anterior margin of the sternum.

Here's a magnified transverse view of the chest and I hope you can appreciate that.

The chest wall should stop right here.

But on this four chamber view, you can see that at least a third of the ventricular chambers have protruded out through the anterior wall in this fetus with penology of Cantrell.

In contrast to this fetus, again, here's the upper abdomen.

A big falle stomach is here, gallbladder is out.

There's a loop of bowel out right here and there's a big piece of the right lobe of the liver that's out in this fetus.

Again, when you see an in fall seal, you look around, here's a sagittal view of the face and here's the chin and protruding from the mouth.

An enormous tongue.

This fetus had macroglossia was unable to keep its tongue in its mouth during the exam and this fetus had Beckwith Weidemann syndrome.

Conclusion

So here we are at the end of the talk on the GI tract, this fetus, and I hope we've given you something to chew on.

Thank you.