Examination of the Fetal Heart with Ultrasound - HD

Introduction

Good morning or good afternoon
or good evening, wherever you may be.
I'm Dr. John McGann.
I'm from the University of California Davis Medical School,
which is located in the fabulous city
of Sacramento, California.
I'm gonna talk to you about
what everybody should know about examination
of the fetal heart with ultrasound.

CPT Codes and Guidelines

In speaking about some of the guidelines
and the certain CPT codes that are being used
for examination in the fetal heart, probably the two
most common are what is called a 7 6 8 0 5
and a 7 6 8 1 1. 7 6 8 1 1 is,
which most people do for what is called a level one
or sometimes a level two ultrasound.
And what we do there is look at the four chambers as well
as the outflow tracks.
And a 7 6 8 1 6 is a follow-up.
This is also the different guidelines.
A-C-R-A-I-U-M, acog,
they all have very similar guidelines
for practice parameters for obstetrical ultrasound,
including looking at the four chamber view of the heart,
looking at the left and the right ventricular outflow tract.

Task Force Recommendations

However, there was a task force formed
and they had the results
of the task force published in the Journal
of Ultrasound in Medicine in 2014.
They called themselves the 7 6 8 1 1 task force.
What they basically said is this exam
that we looked at previously,
which was the four chamber view
of the heart plus the outflow tracks, they expanded
and they thought it should be expanded.
Now none of this has been officially adopted
by the CPT codes,
but this is what the task force recommended.
What they called is a basic would be what
previously would be included as the 7 6 8 1 1, not the
expanded 7 6 8 1 1.
So they included obviously the four chamber view
of the heart and the left
and the right ventricular outflow tracts.
So basic exam would include is shown here,
a four chamber view of the heart as well as outflow tracks.
One thing that I will
talk about is when we do outflow tracks, I always like
to do them in real time.
So in real time I can see the relationship of the RVOT
and the LV OTs to make sure
that they crisscross one another.

Detailed Views

They've expanded that to include not only those views
but also a view of the aortic arch.
What they call is a bi caval view called the superior
inferior vena Caval view, A three vessel view
of the heart plus a three vessel
and tracheal view, view of the lungs, integrity
of the diaphragm and evaluating the ribs.

Aortic Arch and Bi-Caval Views

If we look at some of these detailed views on the left is
what is called an aortic arch view.
So this is the candy cane view looking at the aortic arch
and through there you can see branching
of the vessels towards the head.
The other view on the right is taken
as a bi cable view superiorly.
We have the SVC and inferiorly, we have the IVC
and this is called a bival view in which we look at both.
So these are two additional views that we will,
not talk a lot about these,
but these are two additional views that have been added.

Three-Vessel View

And finally the view
that I will detail is the three vessel view currently
and we've been doing the three vessel view at our
institution in our lab for the last 10 years or more.
And we find it very helpful if in fact we can't see the
normal outflow tracts.
We do this view in real time to show the relationship
of the aorta and the pulmonary artery to either the right
and or the left ventricle.
So the detailed view would include these views
and here we'd also be able to see the trachea.
And if you look carefully
and sometimes you can see the trachea bifurcating into the
right and the left main stem bronchus.
In this view, you see the pulmonary artery, which is over
to one side, then the aorta always centrally
and the SVC over to the right.
We can also look at this higher in which we can see sort
of a V-shaped side in which the pul pulmonary artery
and the aorta come together
and where the pulmonary artery starts to form the,
ductus through this region.

Four-Chamber View: PASS Assessment

To start, we're gonna start
with the four chamber view of the heart.
In this we basically published something called the pass.
So I'm gonna actually put that down smaller
and we're gonna look at P for position.
That is sinus A for the axis of the heart, then S
for the size of the heart and also the size
and thickness of the ventricles.
And then s for is that septum intact or not.
So these are the four things that we're gonna look at.

Position (Situs)

So in this case, the stomach is midline.
We see the portal vein midline.
So what is the diagnosis here?
Is it a STOs versus situ solitude, STO ambiguous
or I just don't know.
So if we look here, this is axia.
So this is called sitis ambiguous.
And if you look here on this chart, this can be due
to polys, Nia or Asplenia.
If you have true sinus solitude,
you whatever the background is for cardiac mal
malformations, whether it's 2%, 3%,
that's our cardiac malformation rate, it increases
with true sinus
and versus totalis in which everything is completely inverse
but not to the same degree
as when you have teter hetero ataxia.
When you have axia, you have markedly increased rate
of cardiac anomalies.
And in this case there was a large AV canal
as you can see here.
And so these are different views
of the AV canal in this case of axia.
So we start looking at the sinus.
Next we look at the axi again, we start again
by looking first at the sinus.
So we see that the stomach is on the left apex
of the heart is also on the left.
From there we look at the two complete ribs
and we try to scan exactly where the ribs are.
We can go ahead and we will show you
or I'll show you how what the normal ax is here,
usually about 45 degrees.
So we draw a line from anterior to posterior,
so from the spine anteriorly to the sternum
and then draw another line down the interventricular septum,
that should be about 45 degrees.
It can be too big or it can be too small.
So if you have a cardiac axis greater than 45 degrees,
these are the potential etiologies.
This is a case of Epstein's
abnormality in which you can see the ultrasound on the left
of the diagram on the right.
And then we have a MRI.
But you can see here there's enlargement
of the right atrium usually.
So you have a malposition tricuspid valve usually
and in this case you can see the axis is abnormal.
It's closer to 90 degrees and in fact 45 degrees.
Here we have A-C-P-A-M
and you can see in this case the heart axis isn't too bad
but certainly a, it's above 45 degrees,
but you can see that the heart is depl displaced into the
left hemothorax by this large mass On the right side,
here's an interesting case
and you look here, the axis is about zero.
And there's something very interesting on this case
that I don't know if you can observe,
but if you look carefully such as we see here,
you see a little bump on this 3D image in which there is a
bump seen anteriorly.
And then if you look here, there is an ectopic corti.
So in this case the axis was about 90 degrees
or about zero degrees, excuse me, fi

Size

or third we look at the size of the heart, the ventricles,
and we're gonna go through this.
So in general, the cardiac circumference
to the chest circumference should be less than 0.5.
I use the rules of three
or I subjectively just look at that rules of three,
we look at the heart, we should be able
to place two other hearts.
It's actually about maybe 2.8 hearts in there
into the thorax.
In this case, there's obviously a huge heart if
you look very carefully.
There's also a pleural effusion.
But this, this case is due to a fetal tachycardia.
And so there's basically failure of this heart
and we get a very large heart.
So it doesn't follow that.
Rules of three on the,
and these are the different etiologies.
So I was showing you the arrhythmias.
You can get it from cardiac failure extrinsic such
as epstein's, and then a cardiomyopathy.
On the other hand, look at this heart, this heart
is pretty small.
So if you look there, you have rules of six here instead
of rules of three.
So that heart is compressed, so is it compressed
by bilateral sequestration, C-P-A-M-C cam,
et cetera.
And what this is is congenital high airway obstruction,
which there's obstruction of the tracheal
or bronchial tree here
and you get very echogenic lungs that in fact
ended up compressing the heart
and making for a very small heart.
Looking at the ventricular size in general, it's about a one
to one ratio.
If we get it and we look
and we're right on right ventricle may be of 1.1
to one in terms of the left ventricle,
but in general the size is pretty close.
Look at this case here in which there's tricuspid
intrusion real time.
You can see there's hardly any right ventricle whatsoever,
very echogenic valve here.
There's virtually no flow getting into there.
And usually these are associated with some sort of VSD.
This case is not, we'll show a case that is,
here's another case, looks very similar,
but you can see here blood flow goes from the right side
over to the left side and very little gets through here.
But if you look here, there's a little bit of flow in
through that tricuspid valve into the right ventricle in
this case, right ventricle is still small
and very echogenic,
but it is larger than the case I just showed you.
Finally, you can have hypoplastic left heart
so you can have asymmetry of the heart
where the right ventricle is much larger
than the left ventricle.
And you can see here the discrepancy here.
In addition, the aorta is often affect especially the
ascending aorta in these cases.
Ventricular thickness, you can have cardiac tumors,
thrombus would be rare.
Endo cardio fibro elastosis is rare but not uncommon.
Here's a case that actually has both
and if you look here you can see there is a
cardiac rhabdo myoma.
In addition to that cardiac rhabdo myoma,
there's the cardiac rdo myoma, there's cardiac fibroblasts.
So that heart muscle becomes thickened
because it's trying to pump against something
and it's having a very, very tough time.
So basically hypertrophies in this case,
these cardiac rdo myomas can be small, they can be multiple
or in this case they can be very large.
If they're very large the prognosis is poor.
If they're very small, actually the prognosis is very good,
but they're often associated with tuberous sclerosis.

Septum

Finally, the septum is that intact or not?
And that's sort of the fourth area.
This is the toughest area.
So if you look at all cardiac anomalies, this is the area
that is most commonly missed are VSDs.
And if you look here, you can see maybe a little VSD,
you're not sure where the arrow is when we go ahead
and we put color flow
and it very nicely shows us that in fact,
yes there is a small VSD certainly in cases such
as this a tricuspid atresia, you can see
that the right ventricle
and the left ventricle are discrepant in size.
There is tricuspid reia.
But you look and you wonder is there just a
little hole in the heart?
You go ahead, you do color flow
and you can see yes there is a fairly high VSD.
So there's flow from the left ventricle into the right
ventricle which actually preserves flow.
So it actually helps preserve some
of the right ventricle as well.
Here's a real time of that.
And now you can see that in real time where that small VSD,
you can see there is tricuspid atresia
and you can see normal motion of the,
mitral valve on the left side.
Now if there's a larger defect,
you would think it would be easy.
It isn't always easy.
Remember that in fact that the tricuspid valve is closer
to the apex, slightly offset compared to the mitral valve.
As you see on the left of that example I showed you
of a cardiac arrhythmia
or tachycardia on the example on the right,
if you look carefully here, it almost makes a T
and there is a large VSD,
but you have to look exactly, that's why you have
to get a real time clip.
You cannot take one moment in time or you will get fooled.
And I've seen people fooled with this.
So you take another moment in time
and in fact you see that T configuration in the two valves
with the curved arrow.
You see here there is a very large
endocardial cushion defect
where there's a defect both in the atria as well
as the high in the ventricular septum.
Sometimes these defects can be even larger
and they're easy to, more easier to recognize than this one.
But you can see how subtle it could be in this case.
Also often these little end of the,
the ventricular septum
where there is a BSD will appear bulbous
or almost light bulb in appearance.
Here's a complete AV canal
and you can see here between opening of the valves
and closing of the valves, get that complete T appearance
and you can see there's no ventricular atrial septum here,
a fairly large AV canal.
Here's another complete AV canal
and you can see sort of this bulbus appearance.
Some people say it's a light bulb appearance,
but you can see
where the ventricular septum ends when there is a large
ventricular septal defect or an AV canal.
You can see it very nicely here,
this large AV canal in real time you can watch closely
as the two valves come together almost form
that T configuration where they actually touch together.

Remember the hardest job is those of you
that do a screening job.
So if you have to do the four chamber view of the heart,
that is the toughest job.
So in addition,
basically the IUM says now it's recommended
that you do a right and a left ventricular outflow tract
and there may be other anomalies
that you can detect when in fact you do a outflow tract
views tetrology below some
of the Ts you can see transposition.
So a lot of these sort
of things you can see when you do outflow track views.
Here's very nice outflow track views,
but they're not in real time
and I always emphasize obtaining things in real time.
So they look like they crisscross here,
but it's nice to have real time.
So again, you want to go ahead and you see the RVOT
and then you want to see the L-V-O-T-R-V-O-T coming straight
down LVOT.
That comes more parallel to the long axis here.
And so this is a case of a normal
but things in real time.
So you gotta see the R-V-O-T-L-V-O-T in real time
and here's such an example where it could be missed.
So this was called left ventricular outflow tract.
This was called the right ventricular outflow tract.
Guess what? This was detransposition,
no real time images at all.
And the worst thing in this case, there was no BSD.
So this is all a ductal dependent defect.
So if that ductus ever closes
after birth, there's no way for blood
to get shunted from right to left.
So this is very difficult.
This example shows you even though the stenographer thought
this was normal documented,
the RBOT documented the LBOT did not do it in real time.
So in the, this relationship was more
parallel than perpendicular.
Here's a case of transposition of the great arteries
and the one thing you're gonna notice here,
this left ventricular outflow tract goes back to the ductus
but it bifurcates,
there should be no reason why the aorta bifurcates and forms
and basically fills the left pulmonary artery.
You also know the R-V-O-T-L-V-O-T tend to be more parallel
and we call this the baby birds beak image.
So if you see something coming out of the left ventricle
that bifurcates looks like this, that isn't a good sign.
That means whatever is coming out is bifurcating,
it probably cannot be the aorta.
Here it is in real time.
The RVOT and LVOT are very close together
and you can see something coming out of the L-L-V-O-T
that does bifurcate.
That's the pulmonary artery.
Again, real-time images are important.

Three-Vessel View

Now this three vessel view, it has five views.
It's originally described by gel in 2001.
We've been doing this view since about 2003 or 2004.
And basically if we can't get the normal outflow
tracts, we always do this.
So again, you would just start at the bottom
for sinus four chamber view of the heart,
then you B bring your transducer up
and I do it in real time
to take a look at the more superior portion of the heart.
This is what it should look like.
Pulmonary artery usually can bifurcate be the largest
structure over on the left side.
Then aorta, then SVC over here on the right side.
And usually you can see this bifurcate often you'll see the
pulmonary artery as I show you,
come towards the descending aorta and the ductal view.
And then right here you're gonna see the aorta.
These two often come together
as they go into the descending aorta.
Another view of this
and you can see back here's sort of the ductus view,
the pulmonary artery coming back, you can see the trachea
and you can actually see the trachea bifurcate
that I'll show you in some real time images.
So when we look at that three vessel view, number one, look
for the crisscross
and then look for the number of vessels, the alignments,
the size relationship to the trache, et cetera, et cetera.
So a normal relationship again should be crisscross.
I'm gonna show you a couple real time images.
They each show you something different.
So in the first image you can actually see the crisscross
with the aortic coming over from the left
side to the middle.
And then you can see the pulmonary artery bifurcating a
little bit and it also will come down here
to the descending uh aorta.
Here's another view that shows you a little bit different
where the two vessels come together
and whoever did this did a great job
because they first showed us, the stomach showed us the LVOT
and the RVOT and the apex pointing over to the left.
Then as they come up from there,
and you can see in real time the RVOT goes down
to the region of the ductus and then you have the LVOT.
If you look carefully just adjacent to the aorta,
you can see a little teeny structure
and that little teeny structure right there is gonna be the
trache and the trachea.
You can actually see bifurcate in this view.
Again, real time is really what I would like to emphasize.

Abnormal Three-Vessel Views

So I'm gonna look now and my final portion is abnormal.
Three vessel view. Either aorta is greater than the
pulmonary artery, pulmonary artery greater than the aorta.
If they're parallel to vessels or four vessels.
Here's normal. Here's a case lent to me by Dr. Roy Philly.
What is the diagnosis here?
So the pulmonary artery is much smaller than the aorta.
We would have this and tetrology of fall low.
So we see a very small pulmonary artery, a larger aorta
'cause the orders aorta is overriding
and if you look at this image, they match up perfectly.
So if you look at the aorta size here, pulmonary artery,
it's just absolutely perfect here.
So this is a great example of tetrology of fall low.
Here's another example of tetrology of flow in which I have
aorta, SVC
and a very small little twig coming off
the pulmonary artery.
So again, there's discrepancy in the size,
width in this case the aorta greater than the
pulmonary artery.
Well next pulmonary artery greater than the aorta.
So you can have a left ventricular outflow abnormality such
as in this case we have double outlet
of the right ventricle.
Normal on the left side,
pulmonary artery is much larger than the aorta in this case.
And you had aortic atresia in this case.
Another interesting case,
which the pulmonary artery is much bigger
than it normally would.
So you can compare that to the descending aorta,
certainly it's much larger.
So this is a different sort of case.
And this is a case of pulmonic stenosis.
So if you had pulmonic stenosis, you would get posts,
stenotic dilatation,
you can see here in this image vessels crisscrossing,
but you see a very large or very dilated pulmonary artery.
So pulmonic stenosis would be another example
where the PA would be greater than the aorta parallel.
So again, TGA, so you end up here,
you can see transposition in this case
in which the two vessels are parallel.
So the LV gives off to the pulmonary artery
and the RA gives off to the aorta.
And you can see they're not crisscrossing, they're parallel
as we see in this example.
Finally, if in fact the aorta is much greater than the
pulmonary artery, such as in this case of severe tetrology
below in which it was almost a truncus,
but there was a little bit of a pulmonary artery at top.
The pulmonary artery is very, very small.
You see the aorta and the SDC in this case
then in this case where the pulmonary artery is much
greater than aorta.
And this is a case of a severe hypoplastic left heart.
We virtually have no ascending aorta
and this can be very difficult if they want
to do any surgical repair
because there's no ascending aorta in which anybody can tie
into Finally four vessels,
you can have a duplicated SVC.
So this is my example of a duplicated SVC
with other cardiac disease in which there's a duplicated
SVC, you can see that here in this diagram as well.

Summary

So again, hardest job is deciding is this
scan good or not?
After that, then a referral is made
and we start just from the four chambers.
Yes, we start from the simplest.
If you do that, you pick up 65 to 70%
of all major cardiac defects.
Then you add to see if things crisscross.
If you add that, you add another 20 cents
or 20% worth, you're up to 85%.
Three vessel view can add a little bit more,
especially if you don't see that crisscross.
Those are the real things
that I think you gotta get is those first three things.
Aortic arch fuse, you can do that or ductal arch
and then you can try that, by cable view.
So again, in summary, the three vessel view axial plane,
you have to see that in real time.
You want to see the size of the vessels, the location
of the vessels with the pulmonary artery,
slightly larger than the aorta and bigger than the SVC,
and then see that relationship of the vessels to each other.
So I've hope you enjoy this update
or latest update of how to look at the fetal heart,
starting first with the four chamber view,
the heart proceeding to the outflow tracks,
and then to some of these newer views.
So thank you very much and I hope you've enjoyed this.