Ultrasound of the Pediatric Chest: Fever, Cough and Respiratory Distress - HD

Introduction

Hello, my name is Harriet Paul Thiel.
I'm a radiologist at Boston Children's Hospital
and Harvard Medical School,
and I'll be talking about ultrasound
of the pediatric chest today.

Role of Ultrasound in Pediatric Chest Evaluation

As most of you know, pediatric chest disorders
are initially evaluated with chest radiography.
However, ultrasound can be very useful when the nature and
or the location of a chest opacity is uncertain.
It's particularly helpful in distinguishing pleural from
parenchymal lesions
and does permit characterization
of pleural fluid collections
as either simple or complicated.
Chest wall lesions can be localized and characterized.
And realtime imaging permits evaluation of the diaphragm
and adjacent structures.
Although mediastinal lesions are usually evaluated with CT
or MRI, ultrasound can be useful in selected cases such
as assessment of the thymus
and vessels, especially in infants.

Ultrasound Windows for Chest Evaluation

This image is from a recent publication,
and shows the various windows that can be used
to evaluate the chest.
So we see here, number one, a supraclavicular approach,
suprasternal, parasternal, transsternal,
which is possible in the very young children
where the bone is thin and can be penetrated by ultrasound.
Intercostal, subxiphoid,
subdiaphragmatic.
And paraspinal.

Normal Lung Ultrasound

Normal lung can be studied with ultrasound,
and it normally shows a strong echogenic interface
of aerated lung and pleura.
And I'm gonna show you a couple of imaging clips.
The upper one was obtained in the sagittal plane
and the lower one in the transverse plane.
And what you can appreciate are these reverberation
artifacts that are projected more deeply within
the lung parenchyma.
And these are known as A lines
and the normal aerated lung moves along the parietal pleural
surface with breathing.
And this is the so-called gliding sign.

Abnormal Lung Findings: Thickened Interlobular Septa

When there are thickened interlobular septa, the ultrasound
interaction with these thickened septa produces the
so-called B lines.
They're also sometimes referred to as lung rockets
or comet tails,
and it's normal to see a few scattered B lines
that may be caused by focal subpleural thickening.
However, if multiple B lines are identified,
this is indicative of interlobular septal thickening.
However, a distinction between fibrosis
and interstitial edema, both of which can lead
to thickened interlobular
septa generally requires clinical correlation
and can't be made by ultrasound alone.

Example: RSV Bronchiolitis in a 43-Day-Old Infant

Here's an example of a 43 day old infant
with RSV bronchiolitis being treated with venous ECMO.
Here we see the venous ECMO catheter,
and you'll notice that the lungs have a very
different appearance.
There's a very coarse appearance
of the pulmonary interstitial in that right lung
and that is reflected in the ultrasound findings here.
On this sagittal view, we see the liver
and above it the lung.
And here you see these multiple vertically
oriented B lines,
and we see them again here in this lower image on the left side.
In contrast, you'll notice
that there's opacification on the radiograph
and on the left side by ultrasound on the sagittal view,
we see the spleen and above it.
The consolidated lung.

Lung Consolidation

Airless lung appears similar to the liver by ultrasound,
and this appearance has been termed hepatization initially
as a pathologic finding,
but we also use that term with ultrasound as well.
The internal architecture of the lung is preserved
and this permits differentiation from masses
or other pathologic processes.
One can appreciate branching linear echogenic foci
that represent air bronchograms when there's fluid
or OID material entrapped within the bronchi.
This produces a hypoechoic branching appearance
and this fishbone appearance
and findings have been referred to as the sonographic
fluid bronchogram sign.

Pleural Fluid Collections

The ultrasound characteristics
of pleural fluid collections will vary according
to the composition of the pleural fluid.
A simple transudate may be anechoic, whereas with
infection and hemorrhage,
there may be mobile echogenic debris seen within the fluid
and empyemas are often septated and have a solid appearance.

Example: Opacification at the Left Lung Base

Here's a patient with
opacification at the left lung base
and we can see with ultrasound on the subcostal view.
We appreciate the spleen, the lung
above it consolidated, having that hepatic appearance,
and then a large anechoic fluid collection.
With color Doppler, we see
that the lung parenchyma is perfused.
There are some small echogenic branching structures
that represent the air bronchograms.
Here's just another transverse view of the spleen
and the clear pleural fluid.

Example: Bilateral Basal Opacification

Here's a different patient with bilateral
basal opacification.
On the right side, we can see the liver, the lung,
and some complex fluid within
the right chest cavity.
Here we have a little clip to show you.
You can see that there is echogenic
debris within that fluid.
And here's the left side, which also shows
a pleural fluid collection
with some echogenic debris within it,
and we can see that clip as well.

Lung-Gap Esophageal Atresia

Lung gap esophageal atresia is
a relatively rare problem,
but at our institution we get a lot of these patients.
And this is a contraption that's
that is seen. The separated portions
of the esophagus are very slowly brought together over time,
and a lot of these patients have
complicated clinical courses.
Here we see that there is opacification
of the right hemithorax on these ultrasound
images, you can appreciate the lung.
Again, there's an anechoic pleural fluid.
We see the air bronchograms, the echogenic
air-filled bronchi,
and on this image clip you can see the lung moving
freely within the pleural fluid.

Another Example: Long-Gap Esophageal Atresia

Here's another patient with a long gap esophageal
atresia with a chest radiograph.
Very similar. Opacification
of the right hemithorax very similar
to the prior one that I showed.
However, the ultrasound features are quite different.
Here you see a well
localized fluid collection with multiple septations
and this was an empyema with some mass effect
on the adjacent lung.

Fluid Color Sign

The fluid color sign has been described.
Mobile fluid collections will show color signal
with color Doppler imaging during respiration,
whereas the sign is absent in non-mobile fluid collections.
And the sign is useful in distinguishing echogenic fluid
collections from organized empyema and fibrothorax.

Example: 17-Year-Old Boy with B-Cell Lymphoma

This is a 17-year-old boy with B-cell lymphoma
and refractory bilateral pleural effusions.
You can see marked opacification of the right hemithorax
and some opacity at the left lung base.
Pleural fluid is identified on each side
by ultrasound and you can see
that there's a very prominent color Doppler fluid sign,
with respiration implying
that these fluid collections are mobile without loculation.

Lung Abscess and Parenchymal Necrosis

Zones of parenchymal necrosis may develop
as lung infection progresses
and enlarging zones of necrosis may lead
to abscess formation.
An abscess demonstrates a thickened wall
and air fluid levels can be seen with cavitation
or communication with the bronchial tree.
Organisms are not inevitably cultured from the sputum
or peripheral blood.
And with ultrasound we can pick up lung abscesses if they
are relatively close to the pleural surface
and certainly ultrasound is also useful in guiding
aspiration and drainage.

Example: Patient with Congenital Heart Disease

This is a patient who had congenital heart disease
and she had developed a refractory pleural effusion.
You can see the opacity at the right lung base
and when we look with ultrasound, we see that
with color there is some perfusion
of the parenchyma at the periphery,
but there are in addition these multiple
hypoechoic rounded areas of necrosis within the lung.

Example: Infant with Neutropenia and Failure to Thrive

Here's another patient where there was a question of
whether all of this opacity at the right lung base
was a pleural effusion in this infant with neutropenia
and failure to thrive with ultrasound.
We could see the liver, the heart,
and then this area of lung
that is perfused peripherally
but demonstrates some central necrosis.
Here are some images from this patient's CT scan.
We see there is some pleural fluid
and a zone of decreased perfusion,
some necrosis within it.
And here we see the coronal
and sagittal reformatted images of this patient's CT
necrotizing pneumonia.

Example: Patient with Large Lung Abscess

Here's a patient with a large lung abscess.
We see a large air filled rounded structure in the apex
of the right lung
and these ultrasound images were obtained at the time of
interventional drainage.
We can see a little bit of needle as it enters
the abscess collection.

Example: 16-Year-Old Boy with Unresponsive Pneumonia

Next we have some radiographs of a 16-year-old boy
with pneumonia that was unresponsive to antibiotics.
On the lateral decubitus view,
we see this area at the left lung base.
Maybe there's a little bit of pleural fluid,
but we did go on and do an ultrasound.
And what we do appreciate is
that there's a very large complex collection here
with outflow.
We see that it is adjacent to
aerated lung on this clip.
And here we have some CT images.
We see that this was empyema elevating the base
of that left lung.
We see some air bronchograms within the lung itself.

Empyema in Children

So a few words about empyema in children.
It's almost never fatal with good outcome regardless
of treatment, whereas in adults mortality rate is about 20%
thought to be due to a higher incidence
of premorbid conditions.
In the adult empyema population,
we are seeing an increased incidence
of empyema in the United States thought to be due
to a combination of both improved diagnosis
and also because of reduction in the prescription of antibiotics
for respiratory infections in the general community,
patients who have pneumonia that's not promptly treated
will may go on to develop empyema
and more often than if they had been treated promptly
with appropriate antibiotic therapy.
Strep pneumoniae is the most frequently isolated pathogen
and the best
outcomes in children are seen when there's early surgical
drainage or fibrinolysis and chest tube drainage.
And here's a pathologic specimen
of an empyema.

Hemothorax

I'd like to say a few words about hemothorax,
which usually develops after blunt or penetrating trauma,
but may be secondary to a bleeding diathesis as well.

Example: Infant with ECMO for Meconium Aspiration

Here's an example of a hemothorax in an infant
who was being treated with ECMO due
to meconium aspiration.
She presented with falling hematocrit and she had three right-sided chest tubes
and they were removed because the source
of hemorrhage was thought to be in the chest.
You can see that there's marked opacification
of both hemithoraces with ultrasound.
You can see that there is this large avascular mass
that's actually has inverted the diaphragm
and is compressing the liver.
And this is a huge hemothorax.
The other side, which is opaque by radiography as well,
has a different appearance.
This is actually the lung
and you can see that its shape is maintained.
And this is the spleen below.
Three images from a CT scan of this patient.
Again, this massive hematoma extending down
into the upper abdomen here, inverting the diaphragm.
Here we see fluid fluid
levels.

Pleural Masses

Pleural masses can also occasionally be diagnosed
with ultrasound.
Most of the time we study these patients with CT or MRI
but occasionally we do perform ultrasound
and we can see it in patients
who have Wilms tumor or sarcomas.
Ultrasound shows solid masses abutting the pleura
and pleural effusion.
Benign causes of pleural masses include infantile hemangioma
and lymphatic malformation.

Example: Young Man with Metastatic Osteosarcoma

Here is an unfortunate young man with metastatic osteosarcoma on the sagittal MR view.
We see the primary tumor in the distal femur
and here is his chest radiograph.
He was in marked respiratory distress.
You can see that there is a chest tube,
but that whole hemithorax is opacified.
By ultrasound we can see
that there are pleural masses.
These are three separate pleural masses as well as complex
pleural fluid, some of which is probably hematized.
We see that there is a fluid color sign here,
but not throughout the fluid in the chest.
Here you can see these septations moving as the patient breathes.
Here are some images from
this patient's CT scan.
You can appreciate the pleural metastases as well,
although I do think that they are better shown
by ultrasound.

Congenital Pulmonary Airway Malformations (CPAMs)

We can also characterize
congenital pulmonary airway malformations or CPAMs.
These are masses of disorganized pulmonary tissue
that can involve either an entire lobe or part of a lobe.
There's a normal communication with the bronchial tree,
with normal vascular supply and drainage.
These are often detected prenatally,
as was the case in this patient.
Patients may be asymptomatic
or they may have associated respiratory
symptoms postnatally.
So we see on this postnatal radiograph of this child,
this very large lobulated mass in the right hemithorax.
Here are some images from the prenatal sonogram.
This whole thing is the lesion
and it you can see it's got both solid
and cystic components.
There is some vascularization which was detectable with color.
Here's a clip
and here we see the extent of this very very large CPAM.
And below it we have part of the liver.
Here again, we're seeing the liver and the right kidney.

Diaphragmatic Hernia

We can use it to study patients with diaphragmatic hernia.
These may be congenital or acquired
and they're often picked up detected prenatally.
The abdominal contents will be found in the ipsilateral
hemithorax and there is discontinuity
of diaphragmatic echoes on ultrasound.

Example: Post-Traumatic Diaphragmatic Hernia

This is a patient who had a post-traumatic
diaphragmatic hernia.
You can see that there is this
abnormal opacity within the right chest
and on the lateral view, I think you can appreciate
that there are some air-filled structures posteriorly.
And here are some images from this patient's sonogram,
a sagittal view of the right chest.
We see the liver, the kidney,
and this collection, this funny collection of air
and air-filled structures in the right hemithorax.
Here we see the liver and again the bowel up in the chest.
And on this clip you can appreciate
that there is some peristalsing bowel here in the
right hemithorax.

Diaphragmatic Paralysis

We can evaluate patients
with diaphragmatic paralysis as well.
This may be due to phrenic nerve injury at the time
of birth or as a result of cardiac surgery.
TE fistula repair, chemical injury from parenteral
fluid extravasation.
It's important
because infants are dependent on diaphragmatic function
for adequate ventilation
because they have relatively poorly developed intercostal
muscles and a mobile mediastinum.
It's rare that patients will require surgery,
but occasionally a diaphragmatic plication will be
required in order to prevent severe lung infections
and mortality in selected patients.
And one big advantage
of ultrasound diagnosis over fluoroscopy is the lack
of ionizing radiation
and the fact that these evaluations can be made in the intensive care unit
in unstable patients.

Example: Normal Diaphragmatic Function

So as a baseline, here's a patient
with normal diaphragmatic function.
The patient was on a ventilator.
On this transverse view we can see the right
and left hemidiaphragms and they are moving normally
and symmetrically when the ventilator, when the patient is
removed from the ventilator, there's still good normal
symmetric function of both hemidiaphragms.

Example: Diaphragmatic Paralysis

Here's a patient with an elevated left hemidiaphragm
and diaphragmatic paralysis, which is shown.
On the ultrasound you can see that there's really no
normal contractility of that left hemidiaphragm.
Here we see the normal right side
with good movement of that diaphragm.
During respiration,

Example: Diminished Motion on Left Side

here's a patient with elevation again elevation
of the left hemidiaphragm on the radiograph.
And on this transverse view of the right
and left sides, we can see there's a little bit of motion.
It's diminished on the left side compared to the right,
but it's not completely paralyzed.
Here we can see it on a sagittal view.
We have the spleen in the stomach
and here on the right, the normal right side with the liver,
with a nice normal function of that diaphragm.

Example: 22-Day-Old Infant with Tachypnea

Here's another patient, 22 day old infant with tachypnea
who has opacification of the right lower right hemithorax.
And we have some images from an ultrasound examination.
Here we see the heart and anterior to the heart
and surrounding it and extending over into the right chest.
We see that there is this complex collection
of fluid-filled structures of varying size.
The patient did go on to have an MRI examination very high signal fluid-filled structures on T two weighted images
and after gadolinium administration there's no enhancement
of the fluid collections, just a little bit
of rim enhancement.
And this patient had a lymphatic malformation.

Lymphatic Malformations

These are abnormal lymphatic channels lined
by normal endothelium and they're present at birth
and they persist throughout life.
However, they may not become evident until adolescents
or adulthood and there does seem to be some
hormonal sensitivity.
They do tend to grow at the time
of the adolescent growth spurt.
This is an image from a
paper we published some time ago where you can see the subcutaneous lymphatic malformation.
These are slow flow lesions
that may be localized or diffuse.
The size of the fluid-filled
structures or abnormal lymphatics may be macrocystic when
they're one centimeter or more in diameter or microcystic.
And they're often combined in terms of their size.
They may be complicated
by intralesional bleeding and infection.
The majority of them are localized to the head
and neck region, but other common sites include the axilla,
the chest, the mediastinum, retroperitoneum, buttocks
and anal genital region.
And they're treated with sclerotherapy and excision.
The large macrocystic lesions are more likely to respond
to sclerotherapy than the microcystic lesions.

Example: Prenatally Detected Infant

Here's an example of an infant who was detected prenatally.
We can see part of the skull here
and a portion of the lesion coming off the skull
at the level of the trachea.
You can see that the lesion surrounds the trachea here
and it consists of cystic spaces
of varying size.
Here's another coronal image that I think shows well
the involvement of the neck
and with extension into the thorax.
Here we see it again on an axial view at birth,
you could see the lesion quite readily in the neck.
And this image was obtained at the time of sclerotherapy by
my interventional radiology colleagues.

Example: Infant with Very Large Malformation

Here's another infant, very large malformation and you can see that they can be so large
that they can really lead to suffocation
and this infant needed to be intubated, have a tracheostomy placed in order to breathe.
And here is one image of the lesion
and again, you can appreciate that the channels are of varying size.
Some macrocystic, others much smaller on the MR.
You can see the distortion of the spine.
There has been a little bit of bleeding.
You can see some blood products on some of these images
and after gadolinium administration, again,
the typical appearance of septal enhancement.
But no, the fluid itself is not enhancing with contrast.

Thymic Cyst

A thymic cyst can present in the mediastinum or the neck.
It's usually asymptomatic and pathologically.
There is thymic tissue within the cyst wall.
The cyst may be congenital or acquired.
The congenital cysts are unilocular
with a thin wall as you see here.
This is a transverse. We see the thymus draped over the great vessels
and then anterior to the thymus.
We see this triangular shaped thin walled structure.
We see it again here on this view
and also on the sagittal CT scan.
Acquired cysts are often post-inflammatory
and they may be multilocular with a thick wall.

Teratoma

A teratoma can also be diagnosed by ultrasound.
It's a germ cell tumor
of the anterior mediastinum located in or near the thymus.
It's usually benign and well circumscribed.
Has a complex appearance as you can see here with multiple little spaces not particularly vascular.
It compresses and displaces the adjacent structures
and can lead to symptoms
and by color Doppler as I've mentioned,
they may be avascular or hypovascular.
And here you see this lesion on a CT scan.

Cardiac Tumors

Here's another patient who presented with tachypnea
and oxygen desaturation and had tuberous sclerosis.
You can see very large cardiac silhouette.
The patient had an abdominal ultrasound
and from the subxiphoid view we got a look at the heart
and you can see that it's just filled with
solid masses.
A very dramatic appearance of the heart by ultrasound.
Here's some images from this patient's MRI examination.
And as you can appreciate,
there are multiple intracardiac tumors involving
all four chambers.
They're large, but they did not appear
to be causing significant outflow tract obstruction.
So this was a patient with tuberous sclerosis
and multiple cardiac rhabdomyomas.

Cardiac tumors in children may be benign
or malignant primary or metastatic.
Primary tumors are rare and about 90% are benign.
Of those primary benign tumors,
rhabdomyomas comprise about 60%
and then the remainder usually teratoma, fibroma,
hemangioma and myxoma. Rhabdomyomas often
regress spontaneously.
And as you saw in the example that I showed you,
tuberous sclerosis is associated
with multiple cardiac rhabdomyomas.
Although as pediatric radiologists we don't do a lot
of cardiac imaging.
I'd like to just show you some other cardiac tumors just to make the distinction
with the rhabdomyoma that I showed you.

Teratoma

Teratoma is the second most common cardiac tumor in
the fetus and neonate.
It's usually attached to the pulmonary artery
and the aorta in the pericardial cavity.
And here you can see one, it's typically cystic
and multilobulated
and it causes mass effect on serous pericardial effusion.
Patients can present with respiratory distress, cyanosis,
and congestive heart failure and cardiac compression
and tamponade may occur.
Here we see a couple of images from a CT scan
and from a cardiac MRI.
And you can appreciate the mass,
which is very well shown on these images as well
as the large associated pericardial effusion.

Fibroma

A fibroma is a solitary tumor usually located in the
ventricular septum.
It's usually clearly demarcated from the myocardium.
Although it can invade the ventricular muscle
and leads to congestive heart failure.
When there's extension into the ventricular conduction
system, there can be arrhythmias
and central calcification can occur due
to a poor blood supply.
It's either there's very large tumor here in the ventricular septum
and here are some image clips from this patient's
MRI examination.
Again, you can appreciate the very very large ventricular mass.

Myxoma

And finally, myxoma, which is a gelatinous pedunculated lesion
on the left atrial septum near the foramen ovale.
Very rarely it can occur in the right atrium.
90% of these are solitary.
They appear inhomogeneous by ultrasound
with small lucencies and calcification
and patients will present with breathlessness syncope.
They may have embolization of a portion of the lesion
CHF and arrhythmias.

Summary

So in summary, I hope I have been able
to show you the utility of chest ultrasound in the diagnosis
of a variety of disorders resulting in fever, cough,
and respiratory distress in children.
And I'd like to thank you for your attention.