5. Development of Respiratory System
◦ The respiratory system is an outgrowth of the
ventral wall of the foregut.
◦ The epithelium of the larynx, trachea, bronchi,
and alveoli originates in the endoderm.
◦ The cartilaginous, muscular, and connective
tissue components arise in the mesoderm.
◦ In the fourth week of development, the
tracheoesophageal septum separates the
trachea from the foregut, into the lung bud
anteriorly and the esophagus posteriorly.
◦ Contact between the two is maintained
through the larynx, which is formed by tissue of
the fourth and sixth pharyngeal arches.
6. Development of Respiratory System
◦ The lung bud develops
into two main bronchi: the
right forms three
secondary bronchi and
three lobes; the left forms
two secondary bronchi
and two lobes.
◦ Faulty partitioning of the
foregut by the
tracheoesophageal
septum causes
esophageal atresias and
tracheoesophageal
fistulas.
7. Tracheal Agenesis
◦ RARE
◦ MATERNAL POLYHYDRAMNIOS.
◦ 3 types
Type 1: Absent upper trachea, & lower trachea
connecting to the oesophagus.
Type2: Common bronchus connecting right and left
main bronchi to the oesophagus with absent
trachea.
Type 3: Right and left main bronchi arising
independently from the oesophagus
10. Tracheomalacia
◦ Traqcheal wall softening
◦ cartilaginous framework of the trachea is unable to maintain
airway patency Dynamic collapse of airway
◦ Primary: by congenital immaturity of the tracheal cartilage.
◦ Secondary: , previously normal cartilage undergoes degeneration.
◦ Congenital (primary): Vascular ring, Tracheo-Oesophageal Fistulas
◦ Fluoroscopy shows an exaggerated decrease in the caliber of the trachea during
expiration
◦ Cine computed tomography (CT) gives better assessement of pathology
11.
12. Tracheo-oesophageal Fistula
• Type A: Corresponds to pure esophageal atresia without fistula.
• Type B: is esophageal atresia with fistula between the proximal pouch and the trachea.
• Type C: is esophageal atresia and fistula from the trachea or the main bronchus to the distal
esophageal segment. (most common)
• Type D: is esophageal atresia with both proximal and distal fistulas
• Type E: is tracheoesophageal fistula without atresia.
13. ◦ Frontal projection shows absence of air in
the gastrointestinal tract; therefore, there is
no distal traacheoesophageal fistula.
◦ This image is similar to that for atresia with
proximal fistula (type B).
14. ◦ Esophageal atresia with distal fistula
(type C).
◦ The catheter is coiled within the
upper esophageal pouch
15. ◦ In types A and B, there is complete absence of gas in the stomach and intestinal tract;
◦ In types C and D, the gastrointestinal tract usually appears distended with air.
◦ Three-dimensional CT and virtual bronchoscopy allow accurate location of the site of
fistula and can show the length of gap between the proximal and distal esophageal
pouches.
◦ Esophageal atresia may be suspected on antenatal sonograms if a combination of
polyhydramnios, reduced intraluminal liquid in the fetal gut, and lack of detection of
the fetal stomach are present.
16. Bronchial Atresia
◦ Congenital: from focal obliteration of a proximal segmental or subsegmental
bronchus that lacks communication with the central airways.
◦ Upper lobe bronchi are frequently affected
◦ Characteristic chest radiographic finding consists of a bronchocele, seen as
rounded, branching opacities radiating from the hilum. The bronchocele may
contain an air-fluid level. The distal lung is emphysematous and produces an
area of hyperlucency around the affected bronchi. CT is better in sensitivity.
◦ In newborns, the affected segment may be seen as a fluid-filled mass.
19. Tracheal Bronchus
• Anomalous bronchus usually exits the right lateral
wall of the trachea less than 2 cm above the
major carina and can supply the entire upper
lobe or its apical segment.
◦ f the anatomic upper-lobe bronchus is missing a
single branch, the tracheal bronchus is defined as
displaced (more common).
◦ If the right upper-lobe bronchus has a normal
trifurcation into apical, posterior, and anterior
segmental bronchi, the tracheal bronchus is
defined as supernumerary.
20. Tracheal Bronchus
• If they end in aerated or bronchiectatic lung tissue, they are
termed apical accessory lungs or tracheal lobes.
• Bronchiectasis, focal emphysema, and cystic lung
malformations may coexist.
• CT may show a small area of hypoattenuation arising directly
from the trachea.
22. Lung Agenesis
◦ Genetic
◦ Teratogenic;
◦ Mechanical factors around 4th week of Gestation
◦ Usually Unilateral
◦ More than 50% of children with pulmonary agenesis have
associated congenital anomalies that involve the cardiovascular
(more frequent patent ductus arteriosus and patent foramen
ovale), gastrointestinal, skeletal, and genitourinary systems
23.
24.
25. Pulmonary Hypoplasia
◦ deficient or incomplete development of the lungs
◦ Compliccation : Pneumothorax
• Pneumothorax often develops spontaneously or secondary to
mechanical ventilation.
• It is characterized by the presence of both bronchi and alveoli in an
underdeveloped lobe.
• It is caused by factors directly or indirectly compromising the thoracic
space available for lung growth, such as a congenital diaphragmatic
hernia in which a defect of the hemidiaphragma allows the abdominal
viscera to herniate into the thoracic cavity with compression of the
ipsilateral lung.
26.
27.
28. • AP radiograph shows opacity of the right hemithorax and a shift of the mediastinal structures to the
right, due to pulmonary hypoplasia secondary to right diaphragmatic agenesis.
• Angiographic MR image of a 10-year-old boy shows a hypoplastic right pulmonary artery (arrows).
29. Scimitar Syndrome
◦ Also called venolobar syndrome and hypogenetic lung
syndrome, is a rare congenital cardiovascular anomaly involving
the right lung.
◦ In its complete form, the syndrome consists of ipsilateral
anomalous pulmonary drainage of part or all of the right lung into
the inferior vena cava, hypoplasia of the right lung,
dextrorotation of the heart, hypoplasia or other malformation of
the right pulmonary artery, and anomalous systemic arterial
supply to the lower lobe of the right lung from the
subdiaphragmatic aorta or its main branches.
30.
31.
32. Congenital Lobar Emphysema
• Lucent mass in the right
upper lobe (arrows) that
displaces mediastinal
structures to the left.
• Lateral view shows a
hyperlucent retrosternal area
(arrows) that corresponds to
the lobar emphysema.
33. LUL involved
in about 45%
of cases,
RML in 30%,
RUL 20%
and two
lobes in 5%
of cases.
34. Congenital Cystic Adenomatoid
Malformation
• Congenital cystic adenomatoid malformation of the lung is an uncommon
cause of respiratory distress in neonates and infants.
• It is characterized by a multicystic mass of pulmonary tissue with an
abnormal proliferation of bronchial structures.
• Pathogenetically, congenital cystic adenomatoid malformation has been
attributed to an overgrowth of bronchioles, with almost complete
suppression of alveolar development between the 7th and 10th weeks of
embryonic life.
35. • This malformation was classified by Stoker et al into three
histologic types.
◦ Type I is composed of variable-size cysts, with at least one
dominant cyst (>2 cm in diameter). This is the most common
(75%) form.
◦ Type II is composed of smaller, more uniform cysts less than 1 cm
in diameter (10% to 15% of all CCAM)
◦ Type III is a solid mass composed of bronchoalveolar micro cysts
36. CCAM Type I - Type I is composed of variable-size cysts, with at least one
dominant cyst (>2 cm in diameter). This is the most common (75%) form.
• Multicystic mass occupying the right hemithorax. (note the variable size
of the cysts, some of them >2 cm) (arrows).
37. CCAM Type I
• 5-year-old child shows a bubbly mass in the left upper lobe with a
dominant air cyst morre than 4 cm in diameter (arrows).
• CT scan of the same patient shows a hypoattenuating, clearly delineated
cystic mass (*) in the left upper lobe.
38. CCAM Type II is composed of smaller, more uniform cysts
less than 1 cm in diameter (10% to 15% of all CCAM)
• Heterogeneous bubbly mass in the left lung displacing mediastinal
structures to the right.
• Coronal T1-weighted image in the same patient shows cysts (arrows)
smaller than 2 cm in diameter.
39. CCAM Type II
◦ Chest CT shows a complex cystic mass in the right upper lobe, smaller
than the type I mass.
40. Type III CCAM is a solid mass composed of
bronchoalveolar microcysts
◦ Radiograph of a premature girl
weighing 700 g shows an
irregular microcystic mass
affecting the left lung and
displacing the mediastinum to
the right.
◦ There is an associated
dextrocardia.
41. Pulmonary Sequestration
• Pulmonary sequestration is defined as an aberrant lung tissue
mass that has no normal connection with the bronchial tree or
with the pulmonary arteries.
• The arterial blood supply arises from the systemic arteries, usually
the thoracic or abdominal aorta, and its venous drainage is via
the azygous system, the pulmonary veins, or the inferior vena
cava.
• Sequestration is divided into two types:
o Extralobar
and Intrapulmonary
42. ◦ Intralobar sequestration is contained within the
lung and has a visceral pleura covering.
◦ It is intimately connected to adjacent lung and is
located within the lower lobe in 98% of cases.
◦ Intralobar sequestration is usually considered an
acquired abnormality of the lung, due to
recurrent infections and bronchial obstruction.
◦ Extralobar sequestration is a mass of abnormal
lung tissue that is surrounded by its own separate
pleura.
◦ It is usually located in the posterior lower chest,
and 90% of extralobar sequestrations are located
on the left side.
43. Pulmonary Sequestration
• Frontal chest radiograph shows a water-density mass (arrows) located
posteriorly in the left lower lobe.
• Aortogram of the same patient shows the feeding vessel (arrows) of the
sequestration arising from the aorta.
44. Pulmonary Sequestration
• Anteroposterior chest radiograph demonstrates a mass located posteriorly
in the right lower lobe (arrows).
• CT scan of same patient shows a complex mass affecting the medial basilar
segment of the right lower lobe (arrow).
45. Bronchogenic Cyst
◦ Bronchopulmonary foregut malformations are anomalies of
pulmonary development that are due to abnormal budding of
the embryonic foregut and tracheobronchial tree.
◦ This abnormality includes foregut cysts, bronchogenic cysts,
enteric cysts, and neuroenteric cysts.
◦ Thought to originate from the primitive ventral foregut and may
be mediastinal, intrapulmonary(typically medial third), or, less
frequently, in the lower neck.
◦ If in a mediastinal location, they may be paratracheal (usually
right-sided), carinal, or hilar. The carinal location is most frequent.
46. • Asymptomatic 5-year-old girl shows a large soft-tissue mass in the right
hemithorax (arrows).
• Contrast material-enhanced CT scan through the upper lobes shows a
well-defined water-density homogeneous mass (*) with no contrast
enhancement.
47. • Rounded mass with an air-fluid level, occupying the entire right middle
lobe, corresponding to a bronchogenic cyst connecting with the bronchus.
• Contrast-enhanced CT scan shows a thick-walled fluid-filled rounded mass
(*) with an air-fluid level, corresponding to the infected bronchogenic cyst.
• Note enhancement of the cystic wall.
48. Pulmonary Arteriovenous
Malformation
• A pulmonary AVM or congenital arteriovenous fistula is an abnormal vascular
communication between a pulmonary artery and a pulmonary vein.
• The etiology is thought to be defective development of the terminal capillary
loops, resulting in the formation of thin-walled, dilated vascular spaces,
usually supplied by one distended artery and drained by one distended vein.
• AVMs can cause physiologic right-to-left shunting if large, which can result in
paradoxical septic emboli.
49. ◦ CT scan of a 36-year-old woman with hemoptysis shows a tubular structure in the right lower
lobe (arrow), representing a large feeding artery and draining vein.
◦ Chest radiographs show round or oval, well-defined nodules, which can be lobulated, ranging
in size from less than 1 cm to several centimeters in diameter, with prominent feeding and
draining vessels.
50. Congenital Diaphragmatic Hernia
◦ Diaphragmatic hernias
include Bochdalek
(posterolateral), Morgagni
(retrosternal), and hiatal
hernias
51. Bochdalek Hernia
• Frontal radiograph of the chest in a
newborn shows herniation of bowel
loops into the left hemithorax with
displacement of the heart to the
right, findings consistent with left
Bochdalek hernia.
• The nasogastric tube (arrows) in the
left hemithorax indicates the
intrathoracic stomach.
52. Morgagni Hernia
• Morgagni hernia in a 2-year-old child.
Lateral chest radiograph shows herniation
of a bowel loop (arrows) in a classic
location through an anteromedial defect.
• Anterior herniation of bowel loops on a
lateral chest radiograph is the typical
finding. Other herniated viscera include
the liver, spleen, and omentum.
53. Congenital Diaphragmatic
Eventration
◦ Abnormal elevation of part or all of an otherwise intact
hemidiaphragm into the chest cavity is termed eventration.
◦ congenital absence of muscle fibers in the region of eventration.
Or focal dyskinesia and weakness from ischemia, infarct, or
neuromuscular dysfunction.
◦ The anteromedial aspect of the right hemidiaphragm is the most
common location for focal eventration and is usually occupied
by part of the liver.
◦ Differential diagnoses for eventration at this location include
Morgagni hernia, pericardial cyst, paraesophageal hernia,
bronchogenic cyst, and tumor.
54. • Focal eventration (arrow) at the anteromedial aspect of the right
hemidiaphragm.
• The eventration contains part of the liver.
55. ◦ Eventration (arrow) at the left
hemidiaphragm at seen at birth.
◦ Complete eventration of a
hemidiaphragm is more common
in males and typically occurs on
the left side.
