The Fetal Thorax - HD

Introduction

Hello, my name is Dr. Mary Frady. I am from Brigham and Women's Hospital in Boston, Massachusetts and Harvard Medical School.

And today's lecture will be on the fetal thorax.

Normal Fetal Lung Development

It's important to remember as we start talking about the thorax, that what we really care about is normal fetal lung development.

And that depends on several things. First, there has to be sufficient intrathoracic space or room for the lungs to grow. There has to be adequate amniotic fluid. We also have to have a normal balance of fluid between the pressure in the trachea and the lungs and the pressure with the amniotic fluid. There can't be holes or leaks in the system. We depend on fetal breathing movements to move the amniotic fluid into the lung and back out.

The most important thing to remember about normal lung development is that there is no type of imaging that can predict lung maturity. Just looking at the lungs with an ultrasound cannot tell us whether those lungs are mature or not.

So one of the things we do need to see again, is fetal breathing movements. And so here we have movement of breathing movement of a 15 week fetus. You can see the diaphragm going up and down, and of course, the more familiar fetal breathing movement at 33 weeks.

Pulmonary Hypoplasia

Now, pulmonary hypoplasia, this is not a sonographic diagnosis. However, the ultrasonographer can suspect that there is going to be fetal pulmonary hypoplasia when there is prolonged severe oligohydramnios due to either ruptured membranes or some sort of GU pathology. Also severe IUGR fetuses or at increased risk for pulmonary hypoplasia or a fetus with a visibly small thorax or a fetus with a normally sized chest, but an intrathoracic mass or marked cardiomegaly compressing the lungs.

So let's look at a couple examples here. And the, in this case, we see that there's a very small chest with a big heart. The ribs are bent. This is a patient with osteogenesis imperfecta and these lungs are hypoplastic.

In this case, we have a case of short lim Polydactyly syndrome. Again, big heart here, little tiny lungs. And in this third case, campic dysplasia. Very, very tiny thorax notice in all three of these cases, there is no oligohydramnios yet. We know we have pulmonary hypoplasia.

Pulmonary Agenesis

The extreme form of pulmonary hypoplasia would be pulmonary agenesis. And this is true absence of one of the lungs. It's pretty rare, and it would be asymptomatic if it's a unilateral process. If in the unilateral case, the heart and mediastinum will shift over to the agen to the side with the agenesis, but the other lungs should develop normally.

Here's a case of a patient who came in, and you can see in the thorax we see the heart here and we see normal lung or a little tiny small lung on one side, tiny small lung on the other side. And this is a bad sign, unexplained severe polyhydramnios.

Well, so now we're gonna look and see if we can establish what's going on in those chests. And on the right side, we see that the right hemi diaphragm is quite elevated because here are the ribs and you follow the rib cage. The rib cage goes all the way down to here, and the diaphragm is markedly elevated. Only about half of that thorax is filled with a little small lung on the right, on the left side, again, we're trying to find the diaphragm. We thought maybe it was way up here, but this is almost certainly shadowing from one of these ribs. It's an elevated stomach.

And, this fetus died in the delivery room, turned out to have agenesis of the left lung, hypoplastic right lung, and complete tracheal atresia leading us to tracheal bronchial atresia. This is also known as chaos, standing for congenital high airway obstruction syndrome.

Congenital High Airway Obstruction Syndrome (CHAOS)

It's thought that it may be due to a vascular insult to the developing mainstem bronchus or trachea. What happens is, beyond the point of impact, the distal bronchi and trachea become mucus filled and dilated, and that normal fluid secreted by the lungs is unable to be passed out through the mouth or through the nose. So the bronchi are distended and dilated, and what we see in utero is an epigenic mass, if it's a peripheral process or the entire lung will become epigenic. If it's a central process, the lungs become markedly enlarged, very echogenic. And if it's a central process, the expansion of these lungs by all of the little tiny pockets of fluid will cause e in, inversion of the diaphragm.

Now, it could be due to a web across the trachea, could be due to tracheal stenosis, trache atresia. But in any case, there's an inability for the fetus to inhale fluid, and there's increased intrathoracic pressure that cannot be released out into the amniotic fluid. These patients will often present with ascites because of, the increased intrathoracic pressure prevents return of blood to the heart through the inferior vena cava and polyhydramnios from that increased pressure.

Now, when a fetus has tracheal or bronchial atresia, there is often an associated esophageal fistula. If there's an esophageal fistula that's sort of a pop-off valve, and that will prevent us from being able to diagnose tracheal atresia prenatally.

Here's an example of a fetus with tracheal atresia at 17 weeks, and we see these markedly enlarged echogenic lungs. The diaphragms are inverted down towards the pelvis here, the iliac bones here, and you can see that these lungs extend well below the level of the ribcage. And if you look transversely at the four chamber view, you can see this poor little heart is completely compressed on both sides by these massively enlarged and dilated lungs.

Here's a case at 19 weeks where the process is unilateral. So a mainstem bronchus is a retic, and you can see this huge, huge dilated, distended, left lung being fed blood supply from the heart that's been pushed way, way over to the right and only a little tiny bit of right lung left over here. Here's the sagittal view on the left, and again, you can see that the this side is markedly enlarged and homogeneously echogenic as compared to the right side. The diaphragm is elevated, the heart is pushed over to the right and there's barely any, lung available for normal development.

This is a patient who came in at 35 weeks and one, the first thing we'll notice here is that there's polyhydramnios at 35 weeks, but when we look at the chest, the heart seems fine, it's in a normal location, it's got a normal access. Both lungs appear to have developed symmetrically and there's a nice, volume of lung tissue on both sides of the heart. Go down to the abdomen and we see a nice stomach bubble. Notice here there's a two vessel umbilical cord, so we have a two vessel umbilical cord and unexplained polyhydramnios. You do need to be worried when you have polyhydramnios that is unexplained.

This child went on to deliver and, also died in the delivery room. The autopsy showed that this fetus had complete tracheal bronchial atresia, so, tracheal esophageal atresia. So the esophageal atresia is responsible in part for the polyhydramnios, but why don't we see the big distended lungs from the tra atresia? Well, in addition to the tra atresia, there was a fistula from the right main stem bronchus to the distal esophagus to this, to the, end of the esophagus beyond the esophageal atresia. And so the pulmonary fluid was able to decompress down into the stomach. So it gave us a normal lung appearance, a normal stomach, and yet impossible for this fetus to survive.

Chest Masses

So let's move on and start talking about some chest masses. The prognosis for the fetus with a chest mask depends on first the name of the type of diagnosis, whether there are any associated anomalies, and mostly it depends on what the anatomic and physiologic changes are that are caused by the mass. Does the mask cause pulmonary hypoplasia? Does the mass create hydro drops in the fetus? All chest masses are potentially life-threatening. The fetuses with larger masses and the presence of hydrops, of course not surprisingly, have the worst outcome.

Congenital Pulmonary Airway Malformations (CPAM)

So starting with congenital pulmonary airway malformations, and these had previously been called congenital cystic adenoid malformations, this is the most common congenital lung lesion occurring, responsible for about 75% of what we see in the chest. It's a hamartoma lesion thought to be due to an overgrowth of overgrowth of mesenchymal tissue. This insult is felt to occur before 17 weeks during the pseudo glandular sl stage of lung development.

So these CPAs, as we now call them, they have no side preference. Right side is as common as the left side. Most of the time it just involves one lobe. And when it does involve one lobe, it is typically the lower lobe, but an upper or the right middle lobe can also be involved. CPAs have a pulmonary blood supply and they are con connected to the bronchial tree, although that is an abnormal connection.

Traditionally, we talked about three types of C cams and then, that was expanded to five subtypes more recently. But a better way to think about these CAM lesions are, is whether we're looking at a macrocystic lesion with cysts that measure over five millimeters in size or a microcystic lesion, where all of the cysts are so tiny that the appearance becomes the solid echogenic look of little tiny, cysts.

Now, the category, the true category is gonna be determined by the pathologist when the lesion is out. And the category determined by the pathologist postnatally may differ from the type we assign as, in the fetus. CPMs typically grow rapidly between 20 and 26 weeks, and then they either plateau and the fetus continues to grow, or these masses can even regress and shrink away Cysts in the lesion can go away and the lesions can completely resolve in utero.

Well, when this happens, it complicates a little bit the category that the cyst that you're going to name the lesion if you have a big cyst and then it turns into a small cyst. How do you know if you see the fetus for the first time and you see a small cyst? Maybe it was always a small cyst, maybe it used to be a big cyst. So it turns out that the name of the lesion is really much less important than the behavior of the lesion.

So the traditional macrocystic or type one CPAs is a small number of large cysts, and these can measure anywhere from two to 10 centimeters or even greater. They often involve the entire lobe or even the entire side. When these are resected, the outcome for these fetuses is quite good. And in addition, it is possible to aspirate or drain the large cysts, the type one large cysts in utero to improve the pulmonary development of the remaining lobes.

Here's an example of the type one or the large cyst. Now, initially, when you look at this study, you could think to yourself, gosh, this sure looks like the CS shaped stomach that we see in the chest during a diaphragmatic hernia, and here's the heart being pushed off to the right side. However, if we go to a coronal image, which is the way you should be looking at all of your chest lesions to evaluate the diaphragm, we can see that the diaphragm is intact. It runs across this hypoechoic line all the way across under the heart, and it is intact. And this is certainly not a diaphragmatic hernia. If we had any question, we can actually look. And here's the stomach in the left upper quadrant. So this cannot be the stomach. The cystic lesion in the chest is certainly not the stomach, the diaphragm's intact. Here's the spleen, here's the fetal stomach, and this is a cystic, adenoid malformation with a single large cyst.

Another example of, CPAM at 27 weeks. In the top right here, we see three distinct cysts within a slightly echogenic and enlarged and expanded, right chest as we follow at 30 weeks. Now we see that the cysts are about the same size, but the fetus is actually much bigger, the cysts are about the same size. And when we get to 35 weeks, you can see that indeed the cysts have been shrinking as the fetus has been growing and this child had a very good outcome.

Now, another type that we can consider are the, is the type of CPAs with smaller cysts, a large number of smaller cysts. With these cysts all being under one centimeter. Other malformations are reported to be more common with this type, even up to 60%, including tracheal, esophageal fistulas, renal issues, diaphragm issues, CNS issues. Multiple anomalies suggest that this is a earlier insult and possibly a different etiology and background. And the lung process in these fetuses is probably less important than the combination of all the other abnormalities.

Another example of a, A-C-P-A-M with smaller size cysts, we're at 19 weeks here, and you can see a small cyst tucked down low, and the costophrenic angle, here on the left side and on the sagittal view, you see the little cysts tucked down here in the back in the left lower lobe. And here again, small cysts at 19 weeks. Another example of a fetus with small cysts and more larger cysts. So here we have a combination of both and notice that the heart is being pushed way over to the right side. This is going to be more of an issue because it's such a large lesion. Another patient farther on, we see small cysts. The heart is not quite as displaced though in this instance. So this is a left-sided lesion with several small cysts. When we look at it, Sally, we can see that the diaphragm is intact and also that the blood supply is coming from the lungs. It's a pulmonary blood supply. So we're confident we're looking at A-C-P-A-M.

The last type to talk about is the microcystic type or the solid type. This is the type that's composed of innumerable tiny cysts, which are so small. We don't see the individual cysts. We just see the lesion as an echogenic mass. And you can think about this type lesion, the sonographic appearance, the way we think about hemangiomas in the liver or autosomal recessive, polycystic kidney disease where we know we have little tiny cystic spaces, but they're not large enough to discreetly resolve any koic fluid. And what we're appreciating is the reverberation of the sound wave from the walls of all of these little tiny lesions.

Now, the microcystic type often involves the entire lobe, but usually not the entire lung. Here's a patient with a subtle lesion, and you have to be careful with these. They can be quite subtle. In this instance, it almost looks like there's increased through transmission from the fluid in the heart, giving you this, in this area of brightness behind the, behind the heart, but on the right side. But if we look at the lesion on the coronal image, we can see that the diaphragm is inverted by this discreet white lesion. Now we look with the color doppler and we can see that it has a pulmonary blood supply, and we can confirm that this is a coronal image of the descending aorta, and we can confirm that the lesion, which is on the downside, it's on the right side here. Here's the stomach. So the upside's, the left, and the downside is the right. Here's the lesion, and there's no systemic blood supply here. That's an entirely pulmonary blood supply. Again, A-C-P-A-M MICROCYSTIC type.

The prognosis of CPAS is again related to the behavior of the mass over time. So we do watch these fetuses closely to try and predict what's going to happen. The size of the mast, does it continue to enlarge or does it turn around and start to shrink? And is it causing the presence of hydro drops? 50% of these lesions will resolve at ultrasound. Interestingly, when the newborns are scanned, the half that are theoretically resolved, 40% of the, those patients will still have A-A-C-P-A-M or the lesion can still be find found postnatally. 50% of the lesions will stay around, but we usually see that they get smaller.

So here's a fetus with a very, very large, solid appearing, echogenic lesion, on the right side coming across the anterior mediastinum, flattening or almost e inverting the diaphragm. That is a significantly sized lesion at 23 weeks, but at by 34 weeks, we can see that the heart is completely midline and that you don't even see any sort of shift or mass at all by 34 weeks.

In contrast, here's a fetus, with a similar lesion at 22 weeks. And again, it's a very large right-sided lesion with a small cystic space in it, and the heart is pushed way to the left. But even at the time that we saw this fetus at 22 weeks, we could see that there was a pleural effusion. And then in the abdomen there is also ascites outlining the liver. That was 22 weeks when the fetus came back at 26 weeks, the lesion is bigger, you can see that it's crossed the mediastinum crossed the midline and the superior mediastinum at the apex and has gotten quite large. And by 29 weeks, the amount of ascites in the abdomen had increased significantly, and this fetus did not have a good outcome.

Pulmonary Sequestration

So let's move into sequestration. Well, in sequestration, there's a part of bronchial mass, which has become separated from the bronchial tree. So there is no bronchial connection in a sequestration. This is also a solid echogenic lesion, and it's characterized by the fact that it does come from, by the type of pleural origin that it has sequestration receive their blood supply from the descending aorta. In contrast to CPAs whose blood supply comes from the pulmonary artery, we can, we do now know that cysts can be present in sequestration. And if that cyst is present with a systemic blood supply, we'll be looking at a hybrid lesion combination of sequestration and CPAM sequestration can be categorized as extra lobar. Most fetal sequestration are extra lobar that have an individual pleura. Almost all of these are on the left and down low 10 to 15% can be, below the diaphragm or even in between the leaves of the diaphragm. The intra lobar type is much more common in adults where this, sequestration shares the visceral pleura with the lung. And those are pretty similar right and left sides, and it, it's not all that important for us in the prenatal diagnosis. We cannot tell intra lobar and extra lobar apart prenatally.

So here's a patient with an echogenic mass on the left side in the lower uh, lobe. And so the next thing we're gonna do is look at the lesion sagittal, take an image of the descending aorta and look for the blood supply coming from the descending aorta. And the blood supply is very characteristic. You'll see that a branch will come off the aorta and then turn around and go back the way it came from, unlike all the other branches of the aorta that come out and stay at the level or, head down inferiorly like the superior mesenteric artery goes inferiorly or the renal arteries go to the side, the blood suppli to a sequestration actually takes a u-turn, turns around and goes back up into the echogenic lesion. And you can appreciate that Here on this, power doppler image, the chest is here and you can see the, aorta coming down and then the vessel turning around to supply this large lesion, another small echogenic mass.

Now sometimes these echogenic masses are found in the upper abdomen rather than at the base of the lung. So here in the upper abdomen, immediately next to the stomach, we have stomach. Here we have spleen here, and then there's this well-defined echogenic mass that's almost surrounding the aorta with, we put put on the color doppler. And we can see the blood supply is coming right off the aorta, two vessels actually coming into this area of sequestration. And on this, coronal clip, you can see here's the beautiful diaphragm coming across. And here's the, sequestration protruding through the esophageal, hiatus to make a little tiny mass down on the left side, infra diaphragmatic portion of it.

This is a different patient with a very well-defined discreet mass, again in the left upper quadrant. And when we scan, sagittal again, now what we wanna know is, is the diaphragm intact? And is this lesion above or below the diaphragm? We can see a beautiful diaphragm. And then you can see the lesion is below the diaphragm and you're talking about an echogenic lesion in the left upper quadrant. The next thing you wanna do is after you ensure that the diaphragm is intact, you wanna find the left kidney, make sure it's not a renal lesion, and then you wanna find the left adrenal gland and make sure it's not an adrenal process. And then you're left with a sequestration as the most likely etiology.

Here's the same patient on day of life one, and now the fetal head is to the left. These are the lungs, and you can see here's the spleen and here's this echogenic lesion. Pretty easy to see with a beautiful left kidney, not part of the lesion, a very discreet plane between the lesion and the kidney, and also a beautiful adrenal gland tucked in here, completely normal and appearance again with a discrete plane separate from the adrenal gland and still the systemic blood supply coming off the aorta into this, infra diaphragmatic sequestration.

Another fetus, this is a neonate again. We're back in the nicu and you can see this lesion that was picked up behind the left lobe of the liver. Very discreet, triangular lesion. What are we gonna do? Let's go over and make sure that we have a beautiful adrenal gland and a beautiful kidney separate from the lesion, which is seen right here.

Hybrid Lesions

So I did mention earlier a little bit about hybrid lesions, and these are combination lesions that are part CPAM and part sequestration. What happens is when the pathologists look at these lesions, they're finding a lot of overlap and that at least 50% of the surgically resected lesions have some of both, types of abnormalities. So it seems like, the name again is less important. It's important to figure out where the blood supply is. So we can predict how what type of surgery might be necessary.

Both lesions, both CPAs and sequestration, seem to increase in size to about 24 weeks when they peak and then turn around and decrease. They both seem to be able to be traced to some sort of bronchial atresia versus a plug, some sort of a, injury to the bronchus that prevents it from being either, partially or completely connected to the true bronchial tree. And there has to be some overlap with the, spectrum of true bronchial atresia, which we started out looking at. The important thing to remember is it's again, the composition. The name is not what influences the prognosis. So the name becomes less important.

Here's a patient with an echogenic lesion this time, again on the left, pushing the heart to the right, it's got some cystic spaces, it ought to be a CPA, but yet when we turn color on, we see very clearly that the blood supply is off the aorta. So is it A-C-P-A-M? Is it a sequestration again, as we follow it at 38 weeks, you can see the cystic spaces are much smaller. It does not appear to be affecting the, curve of the diaphragm or the development of the lungs. The blood supply is still systemic, a hybrid lesion, but the child did fine.

Congenital Diaphragmatic Hernias

Uh, so now we'll change, gears a little bit and move into congenital diaphragmatic hernias. This is the most common intrathoracic extra cardiac anomaly we see. Over 90% of them are blike hernias, which happen in the back as opposed to more gagny hernias, which happen anteriorly 80% of the time hernia, diaphragmatic hernias are on the left side. What happens is, these hernias occur at eight to 10 weeks when the bowel has gone out into the, base of the, umbilical cord to do its 270 degree rotation, and it returns back into the, abdominal um, cavity. However, the diaphragm has not completely closed and then, material can move up into the thorax. This is more common on the left because the presence of the liver on the right seems to give the seems to protect that right hemi diaphragm. And the right diaphragm tends to do a better job at closing than the left side.

Diaphragmatic hernias present as a complex intrathoracic mass. They often will cause mediastinal shift. They will push the heart to one side or the other. A big clue is that there, the stomach or if it's a right-sided hernia, the gallbladder is not in the dire in the abdomen where it's supposed to be. We used to just look for the stomach in the wrong spot and, infer that there was a diaphragmatic hernia. But currently with the, ex, excellent equipment that we have available to us, we actually can look at the diaphragms. And the diaphragms are now included in the, guidelines for the performance of an obstetrical ultrasound. So we do either a sagittal or coronal look at both right and left diaphragms.

When there is a diaphragmatic hernia and fetal breathing begins, the, you will see it during the breathing movement that rather than the abdominal contents moving inferiorly, as the diaphragm comes down, if there's a hernia, the contents will come down on the side that is normal and they'll move up on the side where the hole is. As the pressure sucks, the abdominal contents up into the thoracic cavity.

So here's a patient with a, diaphragmatic hernia, and we can see there, there's a big cystic structure behind the heart. The heart is pushed over to the right. There's a cystic structure here. We're not quite sure what it is, but if we look carefully, this is the same patient with an image from the other side. If we look carefully, we can see this is all peristalsing bowel. So this could only be diagnosed with a video clip or real time, in the room. This could not be, as confidently diagnosed with a static image.

Again, here's that paradoxical movement. This is a sagittal view of the fetus. This is the abdomen here. Where's the stomach? This is the chest. And this is the fetal arm that's up over its head. Here's the shoulder. So as the fetus hiccups, you see the diaphragm goes down with each hiccup, but the kidney, which is right here, goes up with the hiccup. So that's the paradoxical movement. The kidney should be going down as the stomach goes down during the hiccup, but it moves the opposite direction.

Another patient with, diaphragmatic hernia. We can see, on the, on the right side that the diaphragm is beautiful intact. You see this black skinny line running along the top of the liver on the right, but when we go over to the left, you only see the diaphragm, partially over here. And then when we look at the breathing movement, we can see this sort of cork corkscrew or curly cue. The top part is going down and the bottom part is going up through the hernia. As the movement rotates, the abdominal contents up into the chest.

Another patient with a diaphragmatic hernia, the heart is pushed to the left and we see a lot of bowel in the front and a solid appearing structure here in the back, wondering what that could be while postnatally, we scanned the newborn and we can see that this is a big piece of liver. And the hole in the diaphragm is right here. And you can see the liver has protruded up into the, the chest. And here's the aerated lung around the edge of the liver.

Now, congenital diaphragmatic hernias do not go away once this fetus develops polyhydramnios or if there's, IUGR at the same time, the prognosis for the child is ominous. A in addition, seeing the presence of liver in the thorax implies that it's a poor prognosis, typically because it's a larger hernia. Clues to liver in the chest. If the liver has come up, it typically comes up anteriorly and pushes the stomach posteriorly. When the liver is down, the stomach is often anterior in the hernia. But the best thing to do is turn on the color doppler and see what the portal vein is doing.

So here's a case where the, here's the heart pushed over to the side, and we have an anterior stomach, so there shouldn't be any liver in this case. This is peristalsing bowel in the back. But if we look on the coronal view and follow the liver all the way across, here's the abdomen here. And you can see the liver that there's a piece of liver right here that goes up. It's just in complete continuity right here. The whole left lobe has gone up into the hernia.

There are associated in abnormalities in 50% of fetuses with congenital diaphragmatic hernia. These could be structural or they may be due to a karyotype abnormality. So often there will be pulmonary hypoplasia because the lungs are compressed and are unable to grow. There's often a hypoplastic left heart sequence as the heart is compressed over to the opposite side. There can be malrotation of the bowel if the bowel has gone up into the chest and there can be associated CNS abnormalities. A fetal echo is required in all fetuses with diaphragmatic hernias. And about 10 to 20% have, aneuploidy is found when you see a diaphragmatic hernia. And again, we have the heart pushed over to the right big stomach and more abdominal contents in this hernia. Make sure you take a good look around this fetus had bilateral club feet. Here's the fetus scene At 28 weeks, again, the heart pushed way over to the right side, a big hernia. This one had large bowel and small bowel. And when we look at the profile view, you can see micrognathia and the hand, which was up in front of the face looking somewhat abnormal on the static, but clearly abnormal on the video clip. There were only two fingers on this hand. So be sure to look for associated abnormalities.

Another diaphragmatic hernia. You can see the stomach is a little bit flattened. There's bowel loops in the back and there is probably a piece of liver in the front. What do we do? We look for the portal vein turning and coming across the diaphragm. And on the color doppler here, power doppler, you can see a branch of the portal vein crossing this, the hole. Here's a little piece of the diaphragm. Here's the hernia herniated liver going through. And the color power doppler helps confirm that liver being above the diaphragm.

So here's a different patient. We got a phone call from the newborn, intensive neonatal intensive care unit. They called down and said, we just took this, baby gram and there's a diaphragmatic hernia. And you, well, the first thing you say is, and did we tell you it was gonna be there? And they said, no, you did not. And you say, well, let's go up and scan. And we did. We went up. And here's the right lobe, here's the liver. And you can see the nice echogenic lung. And as the child breathes, the lung moves up and down and clearly that diaphragm on the right is beautiful. And we go over to the left side, we see that paradoxical movement, movement. Here's the spleen here. The diaphragm should be right across here, but we see all of this complex material and, the big hole right here. And here's the diaphragmatic hernia.

Well, the first thing you do, and I think everybody does this, all imagers will do this, is say, well, let's go back and look at the pictures of this fetus. And here's the image of the diaphragm at 26 weeks in the same fetus. And we read this out as normal, no diaphragmatic hernia. And I agree with that reading. Here's the liver, here's the stomach, the hernia, the two, the sorry, the diaphragm, the two lungs, no hernia at this time. However, at 28 weeks on this, which was a biophysical profile, not a survey image, we can see again bladder here, stomach here, little bit of diaphragm, big hole. And that was not identified on this study, was not an anatomic survey, but you gotta look every time you scan a fetus, you gotta take a look around.

Pleural Effusions

So now we'll move into, change gears a little bit and move into pleural effusions. Pleural fluid is always abnormal. Pleural fluid can cause a mediastinal shift just like a solid mass. The important thing to do is to figure out whether you're looking at a pericardial effusion or whether it is really a pleural effusion. And typically, if you look in the back away from the heart, that will be, a good clue, to say that you're not looking at a pericardial effusion.

So here's a fetus with a extremely large, pleural effusion, pushing the heart over, causing mass effect. And this certainly will cause pulmonary hypoplasia. You can see on the video clip this little tiny, left lung and the heart being pushed way over to the right by this large, large pleural effusion.

Well, most pleural effusions, unilateral pleural effusions are due to kofax kalhor in the neonatal, intensive care unit or in a, in the newborn baby. When you tap the fluid, you'll see a milky appearance. That's the characteristic appearance of a kofax. That's due to the chylomicrons that, carry lipids. And once the child has been fed, those lipids will be carried and the pleural effusion will turn white. However, in utero in a, fetus, the effusion will be clear or yellow. Kofax is more common in boys than girls. It's more common on the right than the left, and we don't know what causes it. However, we do know that if the fetal thoracic duct is bilateral and during the fetal evolution, the right side reabsorbs at the top and the left side reabsorbs at the bottom. And typically there's only one crossover. But in, in many fetuses there are multiple cross connections. So there's a lot of opportunity for there to be a little hole in, in the thoracic duct and a leak of the, Kyle.

So here's a fetus who came in with this big pleural effusion on one side. But notice that in this case we also have ascites and also in this case there's a small pleural effusion on the other side. And look at the marked skin thickening around the thorax and the marked skin thickening around the head. So now we don't have just a straightforward unilateral pleural effusion. We have fluid in multiple components as well as skin thickening. And this indeed will be high drops most of the time. When you see bilateral pleural fluid, it is going to be in, the presence of hydros. It can also be associated with aneuploidy in particular Trisomy 21 and Turner's syndrome or 45 xo. It's also associated with particular syndromes. The most common being noonan syndrome fetuses with bilateral pleural effusions have a worse prognosis. And remember that it is still possible to have a kofax, be present bilaterally. But once we see bilateral, we're much more concerned that there's going to be another underlying cause.

Here's a fetus who came in with bilateral pleural effusions, and you can see on this coronal image the subpulmonic component of the pleural fluid on both sides. And you can see, actually that this fluid is separating into the, right, lower and middle lobes. You can see the, the fissure right here and this fetus with the pudgy hands, didn't wanna let us see its face, but turned out to have trisomy 21.

Another different case. Here's the heart, the lungs, and bilateral pleural effusions. You can see them again, it's nice to take these coronal images. You can see the diaphragm is intact and you get a sense for how large this pleural effusion is when you see it outlining the entire lung. Two weeks later, when this child came in, the both sides now had pleural fluid. The amount of pleural fluid had increased bilaterally, and this child ended up with noonan syndrome.

Pleural effusions can increase over the pregnancy or may resolve. This can be spontaneous. The resolution can be spontaneous, or sometimes after we do one thoracentesis, of the fetus, that will solve the problem and the pleural fluid will never come back. It's important to remember that a pre-delivery tap may be necessary with pleural fluid. It is much easier for the neonatologists to manage the child without pleural fluid. It's, much more stable to do the tap, in, in utero prior to delivery so that the pediatricians receive a baby who's able to aerate both lungs and sometimes even just, being able to expand both lungs will put enough pressure on the pleural fluid and the thoracic duct to seal off the, kofax and they'll have a much better time in the, newborn nursery. If necessary, we can place a shunt in utero and that may improve a fetus with hydro drops. The size of the pleural effusion and how what the timing is during the pregnancy will predict how we will treat it and how well the fetus will do.

So here's a fetus who came in with large bilateral pleural effusions. And so the determination was made to that. We were quite concerned that there was going to be a pulmonary hypoplasia here. So we decision was made to tap these, pleural effusions. So here we are tapping the right pleural effusion. You can see the needle coming in and we drained all of the fluid off on the right. And then we, rolled the mom and put a needle in on the other side and tapped the left side completely dry. And here's a video clip of the chest immediately following these two traps. And we were patting ourselves on the back because wow, we got rid of both of these pleural effusions, not a drop left. These lungs are gonna do great. She came back in the next day, pleural effusions, both back skin thickening. This fetus did not have a good outcome.

Now we can see these pleural effusions quite early. We can see them in the first trimester indeed. And here's a yolk sac here, and you can see the bilateral pleural effusions in this first trimester embryo. You can see the sagittal view of the effusion here. And this is certainly not a good sign when you see pleural effusions, at 10 weeks. But if you notice also the cardiac activity is very irregular and bradycardic and this, embryo, did not survive.

Unique Cases in the Fetal Thorax

Couple last things as I finish up just a few unique things to show you in the chest. Here you see the heart beating here. This is a, a third trimester fetus. And you can see these bright echogenic spots throughout growth lobes. And this is something that you won't see very often. This is a fetus who had undergone an interventional procedure to open a stenotic aortic valve where the needle is placed from outside through the mom, through the placenta, through the amniotic fluid, through the chest wall into the left ventricle, A wire placed through the aortic valve, a balloon placed over the wire and the aortic valve opened. And at the time of the, placement of these catheters, air was released into the ventricles and out to the lungs. And these are little tiny, pockets of air throughout both lungs following that interventional procedure. And that resolved within um, 15 minutes.

Here's another instance of, is a magnified view of something you won't see very often. A magnified view of the ascending aorta. And we know it's the aorta. You can see the branches going off up into the head and it turns the corner and descends here. And there's a fluid collection posterior to the descending aorta in the upper chest. When we put color on that, we can fill the aorta and see that this is not a vascular structure here it is transversely. So it's a cystic structure in the posterior mediastinum, often, almost certainly either a, duplication cyst, a bronchial duplication cyst, or a lymph lymphatic malformation.

Another case, seen at 37 weeks, by, a member of my department. And a mass was seen in the thoracic wall. Here's the apex of the heart. And you can see a little hypo coic, abnormality in the subcutaneous tissue of the chest wall at 37 weeks. Unclear etiology while I was able to scan the patient three weeks later when she came in for a biophysical profile. Here's the apex of the heart. And you can see that again, that hypoechoic structure right there. Notice there's another hypoechoic structure right here. And this is a female fetus, and this is a little bit of breast tissue seen bilaterally, so completely normal finding.

Conclusion

And with that, I hope you've enjoyed this, discussion of abnormalities of the fetal thax. Thank you very much.