Fetal Gastrointestinal System

Echogenic Bowel

If you are considering cystic fibrosis, it is important to go back and see if you had this finding earlier on in the gestation, which is the finding of echogenic bowel.

We have a collection of echogenic debris or material in the pelvis, lower abdomen and pelvis of the fetus, and notice that it is equivalent in echogenicity to the adjacent ileum.

So we can describe echogenic bowel in the second trimester when the bowel echogenicity is equal to bone.

In these instances, it is important to analyze the chromosomes in these fetuses because up to 25% of fetuses with echogenic bowel may have aneuploidy, and about half of those fetuses will have trisomy 21.

Now, echogenic bowel, in addition to being associated with aneuploidy, is associated with infections such as CMV.

It's associated with cystic fibrosis and it also can be an indicator of severe early onset IUGR.

One explanation for echogenic bowel is that the fetus has swallowed intra amniotic blood.

So the mom has had a intrauterine hemorrhage, so-called abruption either in the first or early second trimester.

The amniotic fluid has become echogenic.

The fetus swallows all that echogenic debris, which is basically red cells in the amniotic fluid, just like the fetus I showed really at the opening of the talk.

As that debris moves through the gut, it settles down into the pelvis and can become echogenic.

Now 60% of fetuses with echogenic bowel will have an or could have an adverse outcome, and those outcomes could include abnormal chromosomes, spontaneous IUFD, intrauterine growth retardation.

So these fetuses, regardless of what the source is for the echogenic bowel need close follow-up.

And one explanation for that could be that the kids who have intrauterine hemorrhages because they have a placental abruption, maybe they have a lousy placenta and therefore they're getting IUGR and IDs.

And the echogenic bowel is a side effect of this bad placental hemorrhaging process that's going on through the gestation and resulting in these poor outcomes.

Here's a case that we followed.

At 18 weeks we can see the echogenic bowel down in the pelvis and at 19 weeks we can still see the echogenic bowel.

And at 25 weeks a tremendous amount of echogenic bowel, presumably all related to swallowing of intra amniotic blood.

Here's another patient.

Here's the first trimester ultrasound, and you can see when we sort of jiggle the mom's abdomen, the placenta is back here.

The uterine wall is here with a big contraction and in the anterior aspect of the uterus.

Notice the jiggle that happens in this area because this is an isoechoic hemorrhage.

When the patient came back in the second trimester, that isoechoic low anterior hemorrhage has sort of reformed itself into this hypoechoic structure along the inferior wall of the uterus.

And when we look at the fetus, indeed there's the echogenic bowel that has resulted from swallowing the intra amniotic blood that resulted from that first trimester hemorrhage.

GI Duplication Cysts

Moving on in our trip through the GI tract, we're now gonna move towards GI duplication cysts.

These cysts can occur anywhere from the esophagus to the rectum.

They're usually completely cystic, and the cysts can be the lead point for an intussusception or a bowel obstruction.

And on this image here, I wanna point out all the normal cystic things that you see in the upper abdomen of a fetus.

So here's the gallbladder in the right upper quadrant.

Here's a loop of bowel, presumably transverse colon.

Here's the umbilical vein, which I know from turning color on and following its pathway.

And here is a cyst that isn't supposed to be there.

This is the same fetus just showing you a realtime clip.

You can see the gallbladder, you can see the bowel coming across here, the intra hepatic umbilical vein and the cystic structure sitting right here closely related to this loop of bowel, consistent with a small duplication cyst.

Duplication cysts can be of any size.

Here's a much larger one over four centimeters in the fetus.

And you can see it here just pushing the gallbladder over the gallbladders draping over this cyst, which is unrelated to the liver.

This is the postnatal image of that fetus.

And we can see when we scan from the side from the right side of the neonate, here's the skin surface and here's the cyst.

And you've got this bowel signature around the back.

And on the clip here, you can see that the cyst has bowel signature all the way around it, and we can see some good through transmission confirming that it's a cyst.

No air has gotten into this lesion because it is adjacent to the bowel but not part of the bowel lumen.

Liver Lesions

Moving on, here's a lesion that you don't see very often.

This is a transverse view of the upper abdomen.

Here's the stomach, intra hepatic umbilical vein.

This is the liver and there's an echogenic lesion here seen in the left lobe of the liver.

On this coronal view, we see it's a very well-defined discreet lesion within the liver.

Now liver tumors can be seen in utero.

Typically we see a mass and we'll look for central calcifications, which may help us with the differential.

The most common lesion in a fetus would be a hemangioendothelioma.

But we can also identify adenomas, focal nodular hyperplasia, hemangios, hepatoblastoma and metastatic tumors.

In addition, we can see cysts in the liver.

These can be hepatic cysts or choledochal cysts.

And these are typically at the right lower edge of the liver.

Here's the confirmatory fetal MR on the case that I showed you earlier.

Here's the heart, the diaphragm, the liver is here, and here's the hemangioma.

What was on the ultrasound was a hemangioma liver lesion in the liver corresponding to a hemangioma in this fetus.

Here's another coronal image in a different patient, a hundred percent credit goes to my sonographer who identified that there was a lesion in the liver and I think it's pretty darn hard to see.

Taking pictures of the liver is not part of our protocol, but she identified on this coronal image, and again, for some anatomy, here's the stomach and there's the diaphragm.

Sorry.

Here's the heart.

This is the diaphragm.

This is the stomach here, and the liver is here.

And in the right lobe of the liver, you can see this hypoechoic solid mass in the inferior edge of the right lobe.

Well, when we put color on, it makes the mass a lot easier to see and you can appreciate, I think this typical feeding vessel with peripheral rim flow, which we see in hepatic hemangioendotheliomas.

In this patient we can see on the right side, so we're looking at the liver, this anechoic structure right up against the rib cage.

So when something's anechoic, we'd like to call it a cyst, but to call it a cyst we need to have through transmission.

So what do we do?

We turned the mom on her side to try and get a shot at this thing, this two centimeter thing coming from this side so we could get the through transmission.

And here's the image coming in from the right side.

You get this anechoic structure and you have the beautiful through transmission that let us diagnose a hepatic cyst in utero.