Hey, everybody, this is Rishi Agrawal, and in this video, I'm going to be
talking about three different patterns of radiation fibrosis
that you'll commonly see in the chest, but not due to lung cancer.
And those three are mediastinal radiation,
breast radiation and head and neck radiation.
So let's first start with mediastinal radiation.
And I have this example here of a patient who's received mantle field radiation.
The term mantle field radiation is a description
of the area of the body that was radiated.
And it's not really used that much these days because the field
of radiation is quite large.
And today, the radiation fields
that are used to treat lymphoma are much more targeted.
But mantle field radiation is something that you'll still see
because patients received it, you know, in the 70s and 80s,
and you'll still see those patients getting imaging today.
But it covered the axilla, the supraclavicular region
and the mediastinum.
And so this would be the approximate area
that would receive radiation in a patient who got mantle field radiation.
So let's take a look at this chest X-ray and see what we can discern.
The first is that the borders of the mediastinum
are not as crisp and clean as we usually see in a normal patient.
And that's because the lung adjacent to the mediastinum has fibrosis in it.
And so it's not a completely air filled lung.
Therefore, the borders are going to be fuzzy
because you have something of soft tissue
density touching, something of another soft tissue density.
So in this case, we have the aortic arch here, which we can see,
but it's not as well defined as it normally should be,
because you have this fibrotic lung right next to it.
And the same thing is on the other side, the SVC the borders of the SVC
are not as well-defined as we normally have them.
And if we follow that up, you could see that reticulation extends to the apices
and it extends along the lateral border of the upper lungs.
So all of this this whole area here is radiation fibrosis.
The other clue here is that in a normal patient,
if we have a line that bisects the hila, then there should be
an equal amount of space above that line as there is below that line.
But in this patient, you could clearly see that
there's a lot less lung above that line compared to below that line.
So we have upper lung predominant fibrosis.
And there's a few different causes of upper lung predominant fibrosis.
And I did a whole video about that.
So if you want to learn more about that, then click the link above.
But in this case, we have upper lung fibrosis because of radiation.
The third finding that we have in this patient
is that the minor fissure is displaced upward, and it's actually hard
to see the minor fissure But I think that this is part of it right here,
and that's too high than it should be.
And it's also slanted.
And it shouldn't be slanted.
It should be horizontal.
The minor fissure is also called the horizontal fissure,
because it goes from right to left, about right here.
And so that's another sign
that we have upper lung predominant fibrosis in this patient.
Let's take a look at the lateral view.
So on the lateral view, we have our landmark here,
which is the lucent circle of the left upper lobe bronchus.
And that also is too high.
So just as we saw that the hila are retracted upward on the frontal view.
This is a sign that the hila are retracted upward on the lateral view as well.
Let's take a look at the CT on this patient.
Here's the coronal CT of this patient.
And you can see, first of all, that this is the minor fissure.
It was what we were suspecting on the chest x ray.
So it's too high and it's slanted.
So those are both signs that there is right upper lobe fibrosis.
And you could see the radiation fibrosis
in the para-mediastinal portions of the upper lobes.
And so this is why our upper lobes
were fuzzy or ill defined on the chest x ray.
It's because we have something of soft tissue density, fibrotic lung,
next to another thing of soft tissue density, the mediastinum.
And you can see also that that radiation fibrosis extends to the apices.
And along the lateral portions of the upper lungs
consistent with this person's history of mantle field radiation.
Let's take a quick look at the axial images.
So the axial images really just show the same thing, reticulation,
traction bronchiectasis, which is a hallmark of radiation
fibrosis and obscuration of those mediastinal contours.
In this patient with mantle field radiation, the radiation field goes down
quite a bit, so it almost goes down to the level of the inferior
pulmonary veins, you could see there's a little bit of radiation
in the para-mediastinal portions of the lower lobes as well.
Let's take a look at another example.
This is another patient who received radiation due to lymphoma.
And this person didn't receive mantle field radiation,
but they did receive radiation to their mediastinum.
And the fibrosis in their lungs
adjacent to the mediastinum is not quite as bad as the previous patient.
But it is still fuzzy along the left side
of this mediastinum and a little bit on the right as well.
The other thing you'll notice is that this left hilum is retracted,
superiorly a little bit asymmetrically compared to the right side.
So the left is usually higher than the right a little bit,
but this is a little bit too much.
So if we were to draw a line that goes through that left hilum,
you could see that there is less lung above that line
than there is below that line.
The other clue here is that
this patient has a large lymph node in their anterior mediastinum.
And you could see it better on the lateral view.
And that large calcified lymph node is from the treated lymphoma.
Let's take a look at this person's CT.
Here's their CT and you could see there's
little bit of radiation fibrosis with that hallmark traction
bronchiectasis in the lungs right next to the mediastinum.
And when we go to the soft tissue windows, you could see that there is this large
calcified lymph node in the mediastinum along with some other smaller ones.
So that is a classic appearance of treated lymphoma.
Now, let's take a look at some patients with breast radiation.
This is a patient who's had breast cancer.
And there are a couple different findings
that tell us that this patient has had treatment for breast cancer.
One is that we have these clips in the left chest wall axillary region.
The second is that the left
breast is slightly smaller than the right breast due to surgery.
And this chest x ray was read as an asymmetric opacity
in the left apex and a chest CT was recommended.
And if you could see that there is a little bit of hazy opacity here
at the left apex and it's a little bit more dense compared to the other side.
So let's take a look at what the chest CT looks like.
This is the patient's chest
and you'll see a couple of findings on the soft tissue windows.
The first is that
this patient has a little scar in the left breast from the lumpectomy.
And the second finding is that you have clips in the left axilla.
And when we look at the lung windows, what you'll see is a little bit
of radiation fibrosis in the subpleural part of the anterior left upper lobe.
And it's a little bit of reticulation, some mild traction bronchiectasis.
And that's because when this patient's radiation fields are being planned,
the radiation field includes a little bit of the
part of the left lung just deep to the breast.
So it would be something like this
and we'd get a little bit of the lung
and it would cover the entire breast, obviously.
OK, so that's why this patient has a little bit of radiation
fibrosis in the lung.
Now, when we scroll up, this patient also got radiation to the supraclavicular
region and radiation to the supraclavicular
region will give you this characteristic appearing fibrosis at the lung apex.
And on the axials it looks sort of like a mass, but
it's unusual that it's a little bit wedge shaped here.
And when we look at the coronal images,
you could see that it has sort of a plaque like appearance.
Now, if this patient didn't have a history of supraclavicular radiation,
I would be suspicious that this is a lung cancer.
But I'm comfortable calling this radiation fibrosis given that history.
Now, if this patient had radiation therapy like three years ago
and all of a sudden this area of fibrosis starts to get bigger,
then I would be concerned that the patient has developed
some sort of tumor in the radiation field.
So it's very important to make sure that after a certain amount of time,
usually about a year, the radiation fibrosis
should stabilize and you shouldn't really get any changes in it.
And you certainly shouldn't get any growth or nodularity of the fibrosis,
because that would make you suspicious
for either a primary tumor in the radiation field or recurrence.
I just want to show you one other patient
with lung radiation fibrosis from breast radiation.
This is a different patient who's had radiation due to breast cancer.
And I just wanted to show you this one because you can see that
this patient has more radiation fibrosis than the previous patient.
So you could see varying degrees of fibrosis,
depending on the type and quantity of radiation.
And here it is on the sagittal images, you could see that
reticulation and traction bronchiectasis.
This is a patient who's had cancer to the base of their tongue,
and they received radiation therapy to their oropharynx and to the right neck.
And on the chest CT, There's a little bit of ground
glass and reticulation at the right apex.
And it's mainly in the anterior part of the apex.
It's very subtle.
But you could see that it's present because it's asymmetric.
And this fibrosis is a little bit different than what you might see
in a patient who has apical fibrosis from granulomatous disease
because fibrosis from granulomatous disease tends to be a little bit
more circumferential around the apex rather than along the anterior aspect.
And it tends to be bilateral, of course.
Also, it tends to be a little bit nodular, so on the coronal images,
what you'll see are little projections
that extend from the apex down caudally.
This patient's fibrosis is very plaque-like and flat up against the apex.
But this is a characteristic appearance
of radiation fibrosis from head and neck cancer.
I'll show you one other patient.
This is a patient who had a right to tonsillar cancer and they received
radiation therapy to the right tonsil as well as to the bilateral neck.
And I wanted to show you this case, because it was a little bit
more conspicuous than the radiation fibrosis that I just showed you.
But you could see it has that same appearance where there's fibrosis
that tends to be confined to the anterior part of the apices.
And it has that characteristic traction bronchiectasis.
And on the sagittal images, again,
you can see that typical plaque like appearance that you'll see
in patients who've received radiation therapy to the neck.
OK, that's all I have for you today.
If you have any questions about this topic or any topic, please let me know
in the comments below. Thanks.