1. ROLE OF IMAGING IN
PEDIATRIC CHEST DISEASES
(STUDY OF 60 CASES)
A
DISSERATATION SUBMITTED TO
THE GUJARAT UNIVERSITY
FOR THE DEGREE OF
DOCTOR OF MEDICINE
(BRANCH-IX)
RADIODIAGNOSIS
GUIDED BY:
DR. P.A.AMIN
(M.D.)
PROFESSOR AND HEAD OF THE DEPARTMENT,
DEPARTMENT OF RADIOLOGY,
B.J. MEDICAL COLLEGE AND CIVIL HOSPITAL,
AHEMEDABAD-380016
SUBMITTED BY:
DR. RUSHABH G. SHAH
APRIL-2010
1

2. INTRODUCTION
Pediatric chest radiology is a complex subject and hence a full understanding of
all the relevant pathologies is necessary. Clinically the pediatric patient with a thoracic
disorder usually presents with fever, wheezing, shortness of breath, tachypnea ,
hoarseness, stridor, cough with or with out expectoration, feeding problems in newborn
patients etc. However, these signs and symptoms of thoracic disorders in pediatric
patients are relatively non-specific and often caused by multiple disorders of varying
pathogenesis. For example, wheezing can be caused by infection (viral or bacterial),
toxic exposure (inhalation), trauma (aspirated foreign body) or congenital anomalies
(such as tracheal compression by a vascular ring, such as a double aortic arch).
Radiation exposure in the first 10 years of life is estimated to produce a risk of
total aggregated detriment 5–7 times greater than exposure after the age of 50.
The role of diagnostic imaging is to provide the clinician probable underlying
etiology of the patients’ symptomatology with the knowledge of the relative advantages
and disadvantages of the various modalities for the wide range of disorders in infants
and children keeping the dosage of radiation minimum to the patient.
2

3. AIMS AND OBJECTIVES
(1) To describe different modalities available for imaging of pediatric chest with their
advantages and disadvantages.
(2) To present a brief overview of the various chest pathologies in neonate and
children
(3) To consider radiological appearances of various chest pathologies
(4) To discuss current approaches for radiologic analysis and diagnosis of these
pathologies
(5) To consider role of imaging for providing anatomical operative planes for
surgeons.
3

4. ANATOMY OF LUNG
THE LUNGS
Each lung is divided into lobes surrounded by pleura. There are two lobes on the left:
the upper and lower, separated by the major (oblique) fissure; and three on the right: the
upper, middle and lower lobes separated by the major (oblique) and minor (horizontal)
fissures. The fissures are frequently incomplete, particularly medially, containing
localized defects which form an alveolar pathway for collateral air drift and the spread of
disease.
For a fissure to be visualized on conventional radiographs, the X-ray beam has to be
tangential to the fissure. In most people, some or all of the minor fissure is seen in the
frontal projection, but neither major fissure can be identified. In the lateral view, both the
major and minor fissures are often identified, but usually only part of any fissure is seen;
in fact, it is very unusual to see both left and right major fissures in their entirety.
The major fissures have similar anatomy on the two sides. They run obliquely anteriorly
and inferiorly from approximately the fifth thoracic vertebra to pass through the hilum
and contact the diaphragm 0–3 cm behind the anterior costophrenic angle.
The minor fissure fans out anteriorly and laterally from the right hilum in a horizontal
direction to reach the chest wall. On a standard chest radiograph, the minor fissure
contacts the chest wall at the axillary portion of the right sixth rib.
THE CENTRAL AIRWAYS
The trachea is a straight tube that, in children and young adults, passes inferiorly and
posteriorly in the midline. In subjects with unfolding and ectasia of the aorta the trachea
may deviate to the right and may also bow forward. In cross-section the trachea is
4

5. usually round, oval, or oval with a flattened posterior margin. The trachea divides into
the two mainstem bronchi at the carina. In children the angles are symmetrical. The
main stem bronchi further divide into lobar bronchus and then into segmental bronchus
dividing lungs into segments.
Nomenclature approved by the Thoracic Society is given as below:
UPPER LOBE
Right Left
1. Apical bronchus 1. Apicoposterior bronchus
2. Posterior bronchus 2. Anterior bronchus
3. Anterior bronchus
MIDDLE LOBE/LINGULA
4. Lateral bronchus 4. Superior bronchus
5. Medial bronchus 5. Inferior bronchus
LOWER LOBE
6. Apical bronchus 6. Apical bronchus
7. Medial basal (cardiac) 8. Anterior basal bronchus
8. Anterior basal bronchus 9. Lateral basal bronchus
9. Lateral basal bronchus 10. Posterior basal bronchus
10. Posterior basal bronchus
5

6. MODALITIES FOR PEDIATRIC CHEST IMAGING
CHEST X RAY: - TECHNICAL FACTORS, VARIATIONS AND ARTEFACTS
Chest radiograph is usually the first imaging modality used for thoracic signs and
symptoms.
• Technical Factors of chest x ray in pediatric patient
A. LUNG VOLUME:-
Findings of a good inspiratory film:
• Heart projects below the dome less than 1/3rd
• Flat domes of diaphragm on frontal view
• Vertically oriented hemidiaphragms on lateral view
• Anterior 6th
/ 7th
rib crossing the diaphragm
• Triangle of air behind heart
B. POSITION OF THE PATIENT:-
In supine position, the vascular supply to upper and lower lobes is equal since
gravity has no effect as compared to child sitting or standing when due to gravity upper-
lobe vessels are less distended than lower-lobe vessels.
Findings of a rotated film:-
• Anterior ribs- not equidistant from ipsilateral pedicles
• Medial aspects of clavicles- asymmetrical in relation to midline
• Position of carina to the left of right pedicles (normally approx. right
pedicles)
• Ribs seen posteriorly
• Differential aeration of lung field
6

7. C. PROJECTION OF THE X RAY:-
In supine film, there is inherent magnification of mediastinal structures and
absence of the effect of gravity on pulmonary vascularity.
D. ADEQUACY OF EXPOSURE:-
In properly exposed film, the detailed spine and pedicle through the heart and the
pulmonary vessels in the peripheral lung are visible. If only the spine but not the
pulmonary vessels are seen, the film is overexposed.
E. THYMUS:-
The mediastinum of infants including neonates appears abnormally wide or
misshapen, due to the variable appearance of the thymus. Enlargement of the thymus
may occur after an acute illness—normal ‘thymic rebound’, and may simulate
mediastinal mass. Features of normal thymus : lower attenuation structure allowing
vessels to be seen through it, uniform reflectivity on US and not displacing the trachea.
• Technical factors of chest x ray in neonate:
1. PA projection: - difficult to take in neonate.
2. AP projection: - supine, tube–film distance is 36–40 in.
3. Lateral projection :- by turning patient to one side “cross table lateral
view”- particularly for free air .
The normal appearance of neonatal chest differs from older pediatric chest. It is almost
cylindrical in shape, having horizontal ribs with higher anterior portions of diaphragm.
• Difficulties in interpretation of neonatal chest x ray due to technical and
anatomical factors:-
1. A normal neonate breathes at a rate of 30–50/min, and it is therefore difficult to get a
“good inspiratory film”.
2. The trachea in the neonate and young infant is “too long” for the contracted chest in
expiration and therefore buckles.
7

8. 3. Skin folds can be seen as curvilinear densities projecting over the lung bases laterally
mimicking a pneumothorax.
4. A rotated film can simulate abnormal mediastinal shift.
5. “Ductus bump”:- Frontal views in an infant shows “bump” in the upper mediastinum
caused by the superimposition of the main pulmonary artery, left pulmonary artery, and
ductus arteriosus. The latter gradually retracts, and the mass disappears by 3rd
day.
• Neonatal Chest with Normally Positioned Tubes and Lines
The position of the tubes and lines on a neonatal chest x-ray should be:
1. Nasogastric tube tip: within the stomach
2. Feeding tube tip: within the third portion of the duodenum
3. Central venous line tip
From subclavian/jugular/antecubital approaches: within superior vena cava.
From a femoral approach: low in the inferior vena cava (below L3) or at the
junction of the inferior vena cava and right atrium
4. Umbilical artery catheter (UAC) tip: either high (between T7 and T11) or low
(Below L3). On the lateral film the UAC dips into the pelvis from the umbilicus
through one of the paired umbilical arteries and then courses through the
internal iliac artery and then into the common iliac artery and aorta. UAC
projects over the left side of the spine on the AP film.
5. Umbilical venous catheter (UVC) tip: at the junction of the right atrium and the
superior vena cava.On the lateral film the UVC extends cephalad from the
umbilicus through the umbilical vein and then courses into the portal vein,
across the ductus venosus, and into the inferior vena cava. The UVC projects
over right side of the spine on the AP film.
8

9. FLOUROSCOPY
It has limited role due to high radiation dose, but may be useful for assessment of
diaphragmatic movement, air trapping, oesophageal lesions.
ULTRASONOGRAPHY
USG should be considered as a second line modality for the evaluation of those
processes which are intrathoracic but peripheral in location as there is no sound
transmission through air filled lungs3
. USG is useful for presence and characterisation of
pleural effusions, chest wall leisons, peripheral lung lesions and anterior mediastinal
mass in young childern.
COMPUTED TOMOGRAPHY
CT is often considered when radiography is insufficient for the diagnosis or for
surgical planning. CT provides excellent global assessment of thoracic and intrathoracic
structure with the help of IV contrast media. HRCT provides early information regarding
diffuse pulmonary parenchymal disease. Relative disadvantages are need of sedation in
younger childern, artefacts due to cardiac and respiratory motions , less tissue contrast
due to paucity of mediastinal fat and risks of IV contrast.
MRI
MR imaging is considered as a problem solving tool in evaluation of chest wall,
spinal, paraspinal region and cardiovascular disease.
NUCLEAR MEDICINE
Nuclear medicine help delineate cardiac function, lung ventilation/perfusion,
pulmonary embolism and inflammtory lung disease.
9

10. CLASSIFICATION OF PEDIATRIC CHEST PATHOLOGIES
Α) MEDICAL CONDITIONS:-
NEONATE INFANTS AND YOUNG CHILDERN
Transient tachypnea of newborn Infections
Hyaline membrane disease AIDS
Aspiration syndrome Aspiration pneumonia
Neonatal pneumonia Hilar adenopathy
Pulmonary Hemorrhage Cystic fibrosis
Complication of Therapy- Interstitial lung disease
Early:-
Pneumothorax
Pneumomediastinum
Pulmonary interstitial emphysema
Late:-
Bronchopulmonary dysplasia
Wilson- Mikity syndrome
Β) SURGICAL CONDITIONS:-
1. LUNG:-
Congenital:-
Abnormal lung bud development: - Congenital lobar emphysema
Unilateral pulmonary agenesis
Pulmonary hypoplasia and
Hypogenetic syndrome
Abnormal separation of lung bud: - Sequestration
Hamartomatous lesions: - Congenital cystic adenomatoid
Malformation (CCAM)
Lung cysts
Hamartoma
Vascular anomalies Congenital AV malformation
10

11. Infective:-
Lung abscess
Hydatid cyst
Neoplastic:-
Metastasis
Pulmonary sarcoma/blastoma
2. AIRWAY:-
Congenital:-
Tracheo-esophageal fistula
Tracheal stenosis
Tracheomalacia
Infective:-
Bronchiectasis
Obstruction:-
Foreign body inhalation
3. MEDIASTINUM:-
Developmental:-
Lymphangioma
Anterior thoracic meningocele
Duplication cyst
Mediastinal mass: described below
4. PLEURAL AND CHEST WALL:-
Infective: - Empyema
Neoplastic:-
PNET (Primitive neuroectodermal tumor)
Ewing’s sarcoma
Rhabdomyosarcoma
5. DIPHRAGM:-
Diaphragmatic eventration
Diaphragmatic herniation
11

12. CLASSIFICATION OF MEDIASTINAL MASSES
For classification of mediastinal masses, mediastinum is divided into three
compartments. For this various classifications have been given but most common
followed radiographically is as mentioned below:
Anterior: - The space in front of the heart and great vessels
Middle: - The space between the anterior and posterior mediastinal components,
including heart, airway, esophagus, and lymph nodes
Posterior: - Everything behind a line that passes through 1 cm behind anterior border of
vertebral body
12

13. Category Anterior Middle Posterior
Congenital Normal thymus
Cystic Hygroma
Morgagni Hernia
Foregut Duplication Cyst
Bronchogenic Cyst
Esophageal duplication cyst
Neurenteric cyst
Cystic Hygroma
Hiatus hernia
Achalasia
Cardiomegaly
Vena caval enlargement
Bochdalek
Hernia
Foregut cysts
Hiatal Hernia
Inflammatory Lymphadenopathy Lymphadenopathy
Tuberculosis, sarcoidosis,
Histoplasmosis, Metastasis
Lymphoma
Paravertebral
abscess
Neoplastic Lymphoma & leukemia
Germ cell tumours
Thymoma
Thymolipoma
Extension of those arising from
Anterior mediastinum
Ganglion cell
tumour
Lymphoma
Mesenchymal
tumours
Vascular Aortic aneurysm Aortic
aneurysm
Azygous &
hemiazygous
enlargement
Other Paravertebral
Hematoma
Extramedullary
Hematopoesis
13

14. RADIOLOGICAL APPEARANCES OF COMMON PEDIATRIC CHEST
DISEASES
Respiratory distress syndrome( RDS, or hyaline membrane disease, HMD):-
a. Preterm
b. Diffuse ground glass opacities- fine reticular shadows throughout
c. Accentuation of air bronchogram
d. Confluent shadows obscuring diaphragmatic and cardiac contour
e. Effusion is very rare
f. Traditionally low volume
Neonatal pneumonia:-
a. Any pattern possible (focal opacity, multifocal opacity, focal or diffuse ground
glass opacities)
b. Asymmetry of the findings is more favouring
c. Normal or increased lung volume
d. Term or preterm appearing child
e. Small to moderate pleural effusion is much more common
Aspiration syndromes: can be amniotic fluid alone, blood, or fluid with meconium—the
latter results in most severe changes)
a. Generally, term neonate
b. Patchy areas of hyperinflation and atelectasis (or other heterogeneous
opacities)
c. Pneumothorax or pneumomediastinum
d. Effusion is not typical
Transient tachypnea of the newborn (TTN) or retained foetal lung fluid
a. Term neonate
b. Increased lung volume
c. Streaky, predominantly central opacities
d. Usually symmetrical, more on right side
e. Small pleural effusion
f. Radiographic resolution by 48-72 hrs of age
14

15. Pneumothorax:-
Air in pleural cavity, usually anterior and medial to lung
Increased radiolucency of hemithorax
Increased sharpness of mediastinal border from superior extent to diaphragm
Compression of thymus
Pneumomediastinum:-
Air in mediastinum, able to dissect into various spaces
Not associated with respiratory distress
Oval or round lucency on either side of diaphragm
Not extend to diaphragm due to its anterior location
Elevation of thymus
Pulmonary interstitial emphysema (PIE):-
Air leaking into the interstitial space and spreading throughout the lymphatics
and along the perivascular sheaths
Radiological appearance is of small bubbles of air radiating out from the hilum.
When severe, the lungs are overinflated.
PULMONARY INFECTIONS:-
Most common cause of respiratory related morbidity in pediatric patient.
Etiologies acco. To different ages:-
Congenital(at birth) Newborn(less than 1 mth)
Group B streptococcus Group B streptococcus
Gram –ve organisms Gram –ve organisms
Congenital viruses Staph. Aureus
Toxoplasmosis Chlamydia Trachomatis
Listeria Monocygenes Pneumocystis carinii
Viruses
15

16. Early years (1 to 5 yrs) Older children (more than 5 yrs)
Viruses Viruses Streptococcus pneumoniae
Mycoplasma pneumoniae
H. Influenzae Strepto. Pneumoniae
Staph. Aureus H. Influenzae
Radiological appearance:
X RAY:-
Bacterial Pneumonia
Focal (more common than multifocal) opacity
Ill-defined margin
Air space involvement: air bronchogram (hallmark of airspace disease)
Lobar or segmental distribution
Normal lung volumes
Associated pleural effusion or empyema
Hilar adenopathy
Viral pneumonitis
Generally symmetric: centralized or diffuse
Interstitial Involvement
Peribronchial thickening
Streaky hilar opacities
On lateral, these superimpose to create full looking hila
Pitfall: may look like adenopathy
Hyperinflated lungs
Atelectasis
Hilar adenopathy
16

17. Appearance specific to organism:-
Staph. Aureus: - Severe, necrotizing, segmental and lobar consolidation
Associated with cavitation and pneumatocele
Associated with pleural effusion and empyema
‘Ghost cavities’ may persist after resolution
Pertussis: - Classical finding is of shaggy heart border due to sublobar
Consolidation
Pneumocystis carinii pneumoniae:-
Most common opportunistic infection in children with HIV
Affects children between 3 months to 7 months
Radiographic appearance includes increased interstitial
markings, which spread from an initial perihilar distribution to the
periphery. Alveolar opacities often accompany progression of
interstitial disease
Round pneumonia:- In children less than 8 years of age in whom the collateral
pathways of circulation are not well developed, pneumonia can
have a very round appearance and mimic a mass8
.In a child
with fever and appropriate symptoms, round pneumonia should
be the primary diagnosis when a round mass is seen on chest X
ray. Follow-up after antibiotic therapy needed to exclude an
underlying mass, such as a bronchogenic cyst. Most cases are
related to Streptococcal pneumoniae infection.
Fungal infection:- usually non specific, but hallmark is the prescence of nodules6
.
USG:-
The role of USG for in infectious processes is primarily limited to evaluation of
the presence and of characteristics of pleural fluid, or in confirming that an opacity is
parenchymal and not pleural.
17

18. CT:-
CT is used in evaluation of parenchymal infections that are not responsive to
therapy and associated with progressive consolidation or development for large pleural
fluid collection.
CT examination is the second-line modality in evaluation of pulmonary infectious
process following serial radiographs.
Findings include necrosis, cavitation, pleural abnormalities (bronchopleural
fistulae, fluid collections) or chest wall involvement.
IV contrast-enhanced CT is useful to define adjacent vessels, potential
enhancement of viable lung which may be atelectatic, or absence of enhancement of
consolidated lung suggesting necrosis.
It also gives the best assessment of the nature and extent of infection, including
the presence of pneumatocele formation.
PULMONARY TUBERCULOSIS:-
Lung is the most commonly involved organ by Mycobacterium.
Radiological manifestation includes:-
Primary pulmonary complex:
Consolidation:- usually single, < 2cm, homogneous with illdefined margins
Tuberculoma:- round/oval mass like opacity, more in upper lobes and on
right side
Satellite lesions in 80%, cavitation and calcification in 10 to 50%
Lymphnode:- In 96% of pts.
On same side, usually hilar or bronchial, then others are involved
CT usually shows > 2cm in size with central area of low density
with rim enhancement of irregular thick wall with preserved or
obliterated perinodal fat. Other patterns are homogenous
enhancement, uniform rim enhancement.
Airway involvement:- Atelectesis due to either primary endobronchial TB or
extrinsic compression by lymph node.
Pleural involvement:- Pleural effusion – absent or mild
18

19. Progressive primary disease:-
Consolidation:- lobar or segmental
Collapse
Pleural involvement:- may be massive, can lead to empyema
Bronchogenic spread:- confluent multiple foci of alveolar shadows
Miliary tuberculosis: - tiny, pinpoint opacities uniformly through out both lung
Fields, more at bases.
Post primary lesion:-
Calcification, both parenchymal and nodal
Fibrosis
ASTHMA:-
Should be performed to exclude complication
Findings are signs of overinflation and bronchial wall thickening and peribronchial
cuffing.
CYSTIC FIBROSIS:-
Autosomal recessive disease associated with chronic pulmonary sepsis and
malabsorption (pancreatic exocrine insufficiency, cirrhosis, and gut involvement).
Early radiographic features include air trapping and bronchial wall thickening,
features that are radiographically indistinguishable from asthma or recurrent
pneumonia.
Later a diffuse interstitial pattern, bronchiectasis, cyst formation and changes of
pulmonary hypertension occurs.
LOBAR COLLAPSE:-
It is one of the common radiological manifestation of various pediatric chest
conditions. When these lobes collapse, they retain their hilar attachment, and the
other lobes often expand to compensate. The patterns of the lobar collapse are
identified in two ways: by seeing the collapsed lobe in a recognizable pattern,
and by noticing subtle shifts of intrathoracic structures such as the fissures
19

20. between lobes of the lung and loss of normal radiological borders (silhouette
sign)
Things to determine when an opacity is seen that appears to be a lobar
collapse to identify the lobe involved and its probable etiology:
● Shift of mediastinum
● Deviation of major and minor fissure
● Silhouette of normal structures e.g. cardiac borders, diaphragmatic contour
● Pulled up or pulled down hila
● Elevation of dome of diaphragm
A common cause of lobar collapse in children is mucus plugging in postoperative and
asthmatic patients. Always look for foreign bodies by carefully examining the right and
left main-stem bronchi. Masses such as lymph nodes (due to tuberculosis,
other infections, or lymphoma), or extrinsic masses such as bronchogenic cysts, can
also cause lobar collapse.
CONGENITAL LUNG MALFORMATIONS
Solid mass-like Air-filled mass-like
Bronchogenic cyst CCAM
Pulmonary sequestration Congenital diaphragmatic hernia
Rarely, CCAM: more often air-filled CLE
Diaphragm elevation
Pneumatocele
CONGENITAL LOBAR EMPHYSEMA (CLE):-
Age & Sex: - less than 6 mths, male preponderance
Symptoms and signs:- Respiratory distress
Chest x ray:- Primary imaging tool
Predilection for the upper lobes and right middle lobe.
20

21. Sequence of appearance: within 24 hrs, alveoli appear distended
and opaque, then gradually distends with air and shows acinar
shadowing, a reticular interstitial pattern and finally becomes
hyperlucent. Adjacent lobes are compressed, the ipsilateral
hemidiaphragm is depressed, and rib spacing is increased.
Differntial diagnosis:-
Attenuated lung markings seen in the overinflated lobe, helps to
differentiate it from a pneumothorax. With a pneumothorax, the
lung collapses around the hilum.
Other differential diagnosis include secondary lobar emphysema;
congenital lung cysts (including type I CCAM); pneumatoceles; and
the Swyer-James syndrome (unilateral hyperlucent lung).
CT scans:- demonstrates involved lobes or segments.The affected lobe is
overdistended and hypodense, with attenuated vascular markings.
Peripherally situated septa and vascular structure20
.
No cysts or soft tissue are seen. CT is useful to exclude secondary
causes of lobar overinflation,i.e a vascular ring or a mediastinal
mass lesion.
CCAM(Congenital cystic adenomatoid malformation):-
CCAM results from a failure of normal bronchoalveolar development.There is
communication between the individual cysts within the CCAM and also with the
tracheo-bronchial tree.
Classification of Stocker11
:-
Type I CCAMs: Most common, approx. 70%21
contain one or more cysts measuring over 2 cm in
diameter, surrounded by multiple smaller cysts.
Appearance:-
A multicystic lesion,although there can be one dominant cyst
21

22. Mass effect can cause contralateral mediastinal shift,
inversion of the ipsilateral hemidiaphragm,and compression
and atelectasis of both ipsilateral and contralateral
pulmonary lobes. The involved lobe may herniate across the
midline to the opposite side
Type II CCAMs: 15 o 20%
contain cysts measuring up to 2 cm in diameter.
Asso. With other anomalies-renal ,cardiac & lung
Type III CCAMs: usually contain cysts less than 0.5 cm in diameter
seen as a homogeneous, soft tissue density mass.
Location:- Equal frequency in the upper and lower lobes, less often in right
middle lobe.Typically, they are unilobar, but multisegmental CCAMs
have been reported
Antenatal ultrasound examinations:-
An echogenic mass, which may/ may not contain cysts
May be associated with the development of maternal
polyhydramnios or fetal nonimmune hydrops fetalis.
CT scan:- Document the involved pulmonary segments or lobes
appears as a multicystic mass, with few air fluid levels and
fluid filled cysts.
Overinflation and lack of definite air bronchogram differentiates
it from necrotizing pneumonitis2
.
Differential diagnosis:-
Diaphragmatic hernia ( Intact diaphragm & normal bowel pattern)
Pulmonary sequestration
CLE
Bronchogenic cyst
22

23. SCIMITAR SYNDROME:-
Commonly affects right lung, which is hypoplastic and is drained by anomalous
vein that extends below the diaphragm to join IVC, hepatic or portal vein.
Chest Xray:- Small affected lung with small hilum with ipsilateral mediastinal shift
Curved turkish sword continuing below the diaphragm
BRONCHOPULMONARY SEQUESTRATION:-
Congenital mass of nonfunctioning lung tissue lacking communication with
tracheobronchial tree
2 types
Intralobar Extralobar
Presents with recurrent pneumonia Coincidental mass
Systemic bld supply Systemic bld supply
Drains into left atrium into systemic veins
Have normal pleural covering separate pleural covering
Older age infancy
Mostly in lower lobe,on left side on left side,conti with diaphragm
Features:
Spherical or triangular basal opacity, may be associated with emphysema of
surrounding lung tissue
Demonstration of abnormal vascular supply by angiography, CTA or MRA.
Cystic parenchymal lesion can be a presentation.
LUNG ABSCESS:-
Due to necrosis, suppuration and cavitation in localized infection in lung
Early stage:- discrete pneumonic consolidation on chest x ray
At this stage, CT may demonstrate low density area in area of
consolidation with no air bronchogram in region of abscess
Late stage:- Cavitary leison with air fluid level and thick and shaggy wall
23

24. HYDATID CYST:-
Due to infestation with Echinococcus
CxR:- shows spherical or oval well defined homogenous opacity.
May be single, multiple, unilateral or bilateral
Rarely calcify.
USG shows characteristic cystic mass with floating membranes in lesions
abutting chest wall or diaphragm
CT or MR shows fluid content of cyst and floating membranes.
PULMONARY METASTASIS:-
In children, due to Wilm’s tumour, rhabdomyosarcoma, osteosarcoma , ewing’s
sarcoma, germ cell tumours, neuroblastoma, lymphoma and leukemia
TRACHEO-OESOPHAGEAL FISTULA:-
Most important congenital malformation of oesophagus
5 types, H type being commonly associated with respiratory distress
Demonstration by injecting contrast at various levels of esophagus
BRONCHIECTASIS:-
Localized irreversible dilatation of bronchial tree
Cystic fibrosis,most important cause in children
3 types:- cylindrical, varicose and saccular
CxR:- multiple cystic spaces with/without air fluid level, tramline shadows
due to bronchial wall thickening
CT(HRCT)- detects type, distribution, severity and extent of disease
Cylindrical:- dilated thick walled bronchi towards the periphery
On end on along with artery, signet ring sign
Varicose:- beaded bronchial lumen
Saccular:-marked dilatation of bronchi with cluster of cysts
FOREIGN BODY:-
24

25. Most common cause of respiratory distress < 3yrs of age.
More on right side. Opaque being 5-15%
Findings:- Partial blockade- unilateral hyperlucency due to air trapping and
obstructive emphysema
Complete Blockade:- atelectasis with mediastinal shift to same side
Expiratory films, decubitus films with involved side dependent and fluoroscopy is
useful.
EMPYEMA:-
Due to bacterial infection, secondary to septic pulmonary emboli, lung abscess or
spread from adjacent infectious process
Fluid rich in protein and tend to loculate
CxR:- d/d from lung abscess & consolidation important
USG:- septation with echoes within fluid
CT:- localize site & extent of fluid collection, determine adequacy of tube
drainage, and to d/d between pulmonary and pleural lesion
Lenticular , obtuse angle of interface with chest wall and changes with change in
position of the patient.
Demonstrates “split pleura sign” and compression of adjacent structures.
D/D from lung abscess:- round shape, thick irregular wall,acute angle at interface
with chest wall and absence of evidence of lung compression, shows air bubbles
in wall.
Parietal pleural enhancement, parietal pleural thickening greater than 2 mm,
extrapleural thickening and increased attenuation of the extrapleural space, and
adjacent chest wall edema favours empyema more than transudative effusion
in
parapneumonic effusion.14,15
.
PNET(ASKIN’S and EWING’S SARCOMA)
Most common chest wall tumours in children
Locally aggressive and associated with rib destruction and pleural effusion19
25

26. Diffucult to d/d between two, only histology is useful.
DIAPHRAGMATIC HERNIA:-
Bochdalek’s hernia Morgagni’s hernia
More on left side More on right side
Posterolateral Anteromedial Earlier presentation
Late presentation
Large in size Small in size
Cystic/complex mass(solid mass if x ray has been taken before air enters bowel)
in hemithorax with mediastinal shift,failure to visualize stomach, abnormal
position of stomach and abdominal viscera and abnormal position of NG tube.
D/D from CCAM:- position of stomach normal,in diaphragmatic hernia either
stomach is not visualized or central in abdomen.
EVENTRATION OF DIAPHRAGM:-
d/t thin diaphragm, usually partial involving ½ to 1/3 of hemidiaphragm
usually anteromedial portion of right hemidiaphragm
CxR:- Elevated hemidiaphragm with smooth hump blending with contour of
hemidiaphragm
Poor or paradoxical movement
MEDIASTINAL MASSES:-
Cysts and Cystic Conditions Fat-containing masses
True thymic cysts Thymolipoma
Germ cell tumours Germ cell tumour (usually mature teratoma)
Lymphatic malformation Vascular malformations
Lymphoma
Thymoma
Foregut duplication cysts
Calcification
Germ cell tumour
26

27. Thymic cysts
THYMIC MASSES:-
Normal thymus
Thymic cysts:- developemntal, unilocular or multilocular
Thymoma:- 5-8%, after 10 yrs of age, calcification in 10%
GERM CELL TUMORS:-
2 age peaks: 2 yrs and adolescence
80% teratoma and benign, rest others
Calcification & areas of fat, displacement of adjacent structure
CYSTIC HYGROMA:-
Mostly in neck, 10% extend in mediastinum
Low attenuation cystic mass with insinuation in surrounding structures
NEUROGENIC TUMOURS:-
Neuroblastoma (malignant, < 5yrs), ganglioneuroblastoma(5-10yrs)
Ganglioneuroma(benign, >10yrs)
X ray:- paravertebral soft tissue mass with calcificaiton in 30%
Thinning, separation of ribs and enlargement of intervertebral foramina
CT:- Calcification in 90%12
, inhomogenous enhancement
FOREGUT CYSTS:-
Bronchogenic cysts:-
Round/oval, unilocular, homogenous water density mass with well defined
borders
Types:-paratracheal, carinal, hilar and paraoesophageal
Oesophageal duplication cyst:-
Larger, to the right of midline extending in posterior medistinum
Approximately 60% of EDCs are located in the distal third of the esophagus, 17%
are in the middle third, and 23% are at the cervical level22
.
Neurenteric cyst:-
Maintains connection with spinal canal, more on right side
27

28. Vertebral body anomalies are associated.
LYMPHOMA
Hodgkin’s disease NHL
Usually > 10 yrs Any age in children
Mostly localized. Mediastinal in 85% Disseminated in > 75%
Displacement is more likely Compression is more likely
Lung involvement in 10% of cases Pulmonary involvement is higher
INTERSTITIAL LUNG DISEASE:-
HRCT is the best investigation available for the evaluation of interstitial lung disease in
older children.
Findings are similar to that of adults: ground glass opacity, tree-in-bud, lobular air
trapping, reticular opacities, and centrilobular nodules.
Indications of HRCT in children:-
Infantile cellular interstitial pneumonitis and pulmonary interstitial glycogenosis
Chronic pneumonitis of infancy
Persistent tachypnea of infancy
Surfectant protein abnormality
Systemic disease: glycogen storage disorder, hemosiderosis, connective tissue
disorder
APPROACH TO EARLY DIAGNOSIS IN PEDIATRIC CHEST X RAY6
Large cystic hemithorax Large lucent hemithorax Large opaque hemithorax
CCAM Pneumothorax Pleural fluid
CDH Partially obstructed CDH
PIE lung CCAM
Pneumatocele Compensatory hyperinflation Neoplasm
28

29. REVIEW OF LITERATURE
1. In a 1986 publication, Swischuk LE, Hayden Jr CK9
et al evaluated the ability of
radiographic patterns of infection to predict whether or not a child had bacterial
pneumonia based on clinical criteria, such as rapid or short duration of illness, high
fever, high white blood cell count, and rapid response to antibiotics .There was no
analysis for organisms performed. They reported that the radiographic presentation
predicted which children meet the clinical criteria for bacterial illness with an accuracy
rate of 90%.
2. A study published by Ramnath et al 16
suggested a very simple ultrasound grading
system in which parapneumonic effusions were graded as low-grade
(anechoic fluid with no septations) or high-grade (presence of echogenic fronds,
septations, or loculations) Those patients with high-grade parapneumonic effusions, as
demonstrated by ultrasound, and treated with aggressive therapy had a 50% decrease
in duration of hospital stay as compared with those who were conservatively managed.
3. In one study done by Donnelly LF, Klosterman LA studying role of imaging in
persistent or recurrent pneumonia, IV contrast-enhanced CT identified an underlying
suppurative cause of the persistent illness in 100% of patients15,17
.
4.In a study done by Stigers KB, Woodring JH1
et al given lobar predilection of CLE,
most common site being left upper lobe(43%) followed by right middle lobe (32%) and
right lower lobe (20%).
5. Frush DP, Donnelly LF4
et al concluded that Helical CT is the imaging modality of
choice in sequestration in demonstration of systemic arterial supply and characterization
29

30. of lung lesion. They also demonstrated association of other anomalies with extralobar
sequestration in 65% of cases they studied.
6. Donnelly LF, Klosterman LA5
et al studied patients with cavitary necrosis and showed
that 41% of these patients were detected on x ray as compared to CT.
7. In evaluating trauma, Sivij CJ, Taylor GA7
et al showed that chest trauma is
responsible for 25% of deaths occurring in children due to trauma.
8. Siejel MJ10
et al stated that mediastinal lymphnodes generally are not seen on CT or
MR in children prior to puberty and their presence should be considered abnormal.
9. Whitsett JA, Pryhuber GS, Rice WR18
et al studied acute respiratory syndrome in
neonate and showed that approximately 50% of neonates born between 26 and 28
weeks and 20–30% of neonates born at 30–31 weeks of gestation develop RDS.
10. Conran RM, Stocker JT23
et al studied 50 cases of extralobar pulmonary
sequestration and showed its association with type II CCAM in 50% of cases.
11. Macpherson RI22
studied Gastrointestinal tract duplications anomalies and showed
distribution of esophageal duplication cyst: 60% in distal third, 17% in middle third and
23% in cervical third.
12. Billmire DF26
et al while studying germ cell tumours showed that Germ cell tumors
account for 6% to 18% of mediastinal tumors.
13. Fishman SJ25
et al showed that cystic hygroma are rare causes of mediastinal
masses.
30

31. 14. Meza MP, Benson M, Slovis TL24
et al showed of all pediatric mediastinal masses
studied, 30% to 40% occur in the posterior mediastinum. Most (85%–90%) of these
masses are of neurogenic origin.
31

32. MATERIALS AND METHODS
Sixty patients were selected based on clinical suspicion from May2007 to
October2009. Patients below the age of 14 years have been considered. All patients
underwent chest xray as first line of investigation on bases of symptomatology.
Followed by this depending upon the need of the clinician further investigations were
carried out. Though heart is within the thoracic cage, I have excluded cardiovascular
system from my study to concentrate more over respiratory system problems. Those
patients were selected in whom more than one imaging modality was used for the
purpose of evaluation of condition.
X rays of patients were taken most of the times in PA position with appropriate
exposure factors either making the child stand or holding the infant by their parents and
keeping them protected with lead aprons. Rest of times supine AP x-ray was taken.
US was next investigation in patients having suspected pleural effusion.US was
performed on a Esaote, Philips unit, using 3.5 and 5.0 MHz transducers.
CT scan was performed when further evaluation was deemed necessary and
when the investigation was affordable and accessible to the patient. It was carried out
on helical CT unit of Schimazdu, civil hospital, Ahmedabad.
MRI was performed on Philips Gyroscan 0.5 T machine for the evaluation of
infective process involving spine and spinal canal.
Ultrasound guided fluid aspiration was done when indicated.
As most of the patients with pediatric chest diseases conservatively treated, they
were followed up to know the outcome of the therapy. In surgical conditions,outcome
and follow up whenever available were recorded. Imaging findings were correlated with
surgical and histopathological findings whenever available. The role of radiology played
in each case was critical.
32

33. OBSERVATION AND ANALYSIS
Table 1: Age distribution
Age group No. of patients
Less than or equal to 1 mths 3
1 mth to 1 yr 8
1 yr to 5 yr 24
5yr to 9 yr 17
9yr to 14 yr 8
Total 60
Out of the 60 patients, most common age of presentation with pediatric chest disease is
1 yr to 5 yr(40%).
Table 2 : Sex distribution
Sex of patient No. of patients
Male 41
Female 19
Total 60
Out of studied 60 patients, majority are males (68%) as compared to females (32%).
Table 3: Presentation with respiratory symptoms
33

34. Symptom No. of patients Percentage
Fever 41 68%
Cough with or without sputum production 48 80%
SOB or breathing difficulty/ choking 26 43%
Chest pain 12 20%
Major symptoms in pediatric chest symptomatology are cough with or without
expectoration (80%) followed by fever( 68%).
Table 4: Etiological classification of pediatric chest pathologies
Disease Group No. of Patients Percentage
Congenital 10 15
Inflammatory 41 70
Traumatic 1 1.6
Neoplastic 2 3.3
Interstitial 1 1.6
Other 6 10
Total 60 100
In studied patients, major group of disease involving pediatric chest is inflammatory
(70%) followed by congenital (15%).
Table 5 : Regional involvement of pediatric chest
34

35. Region of chest involved No. of patients
Parenchymal 23
Pleural 7
Airway 6
Mediastinum 3
Diaphragm 3
Chestwall 1
Diaphragm and parenchymal 2
Pleural and parenchymal 14
Multicompartemental 1
Total 60
Most common region of chest involved in studied 60 pediatric patients is pulmonary
parenchyma (38%) followed by both pleural and parenchymal (23%) and pleural
disease(12%).
Table 6: X ray – CT correlation in relation to pulmonary and mediastinal pathology
PATHOLOGY X RAY CT
Airbronchogram 9 16
Soft tissue opacity in patient with
consolidation
16 20
Collapse 7 20
Cavity 5 5
Mediastinal shift 12 17
Associated lymph node 0 6
Calcification in lung parenchyma 1 1
35

36. Calcification in mediastinal mass 1 3
Pneumomediastinum 0 1
Table 7:- X ray – CT correlation in pleural pathology
Pathology X ray CT Total no. of pt undergoing both x ray and
CT with pathology
Pleural effusion 15 17 17
Pneumothorax 6 8 8
CT showed effusion and pneumothorax in all patients as compared to x ray
demonstrating same in 88% and 75% of patients respectively.
Table 8:- X ray – USG correlation in pts with pleural effusion
Pleural fluid X ray USG Total No. of pts
undergoing both x
ray and USG
Present 8 12 12
X ray was able to detect pleural fluid in 67% of patients as compared to USG in patients
undergoing both x ray and USG.
36

37. Table 9:- USG –CT correlation in pleural collection in pts undergoing both USG
and CT*
Pleural collection USG CT
Fluid present 10 10
Septation 8 0
Echoes 7 0
USG showed presence of septation and echoes in majority of patients as compared to
CT which was not able to demonstrate the same in any patient.
*- Total number of patients undergoing USG and CT—10
Table 10:- X ray and CT correlation in pts with pleural effusion
Pleural fluid X ray CT
Present 15 18
X ray demonstrated pleural fluid in 83% of patients as compared to CT in patients
undergoing both X ray and CT.
Table 11:- X ray and CT demonstrating both pleural and pulmonary pathology
Pathology X ray
37

38. Only pleural pathology 6
Only parenchymal pathology 1
Both pleural and pulmonary pathology 7
Total no. of patients detected by CT having both
pleural and pulmonary pathology
14
X ray was able to detect both pleural and pulmonary involvement in 50% of patients
studied.
DISCUSSION
In this study, 60 patients of pediatric age group with chest disease were studied by
various radiological methods based on clinical methodology.
• Most common age being presented with pediatric chest disease is between 1 yr to 5
yr (40%).
• Pediatric chest diseases are found to be more common is males in this study (68%).
• Most common symptomatology was found to be cough with or without expectoration
(80%) and fever (68%).
• Among the basic disease groups, the most common disease group is inflammatory
41 cases (70%) followed by congenital 10 cases (15%), foreign body 4 cases (7%),
rest comprising of neoplastic (2 cases), interstitial and traumatic and nonneoplastic
mediastinal mass (1case each).
• In this study, most common region of chest involved were pulmonary parenchyma
23 cases (38%), both pleural and parenchymal pathology 14 cases(23%), pleural
pathology 7 cases(12%) and airway involvement 6 cases(10%). Rest comprising of
mediastinum and diaphragmatic involvement in 5 cases each.
38

39. Congenital lesions:-
• Out of 10 cases of congenital origin, 5 are diaphragmatic in origin, 3 being
diaphragmatic hernia and 2 being eventration of diaphragm. Other four are
CCAM, CLE, lung aplasia, TOF with esophageal atresia and bronchopulmonary
sequestration.
• In diaphragmatic hernia, herniation of bowel loops noted in all cases and spleen
noted in one case which was better demonstrated on CT. Bowel loops were
easily visualized with barium examination.
• In CCAM and CLE, CT was useful to determine the lobar involvement and
guiding the surgeon.
• Esophageal atresia was seen as a curling of IFT in esophagus. There was
presence of gas in stomach, so the diagnosis is TOF with esophageal atresia.
• One case of bronchopulmonary sequestration appeared as patch of
consolidation on chest x ray and revealed to be a soft tissue density mass
supplied independently from a systemic artery arising from aorta. Thus CT was
essential for diagnosis.
Inflammatory lesions:-
• Out of 41 patients having inflammatory etiology, majority cases are of only
parenchymal involvement 17 cases (41.5%), both parenchymal and pleural
pathology 14 cases (34%), only pleural pathology 7 cases (17%), 2 cases of lung
involvement with mediastinal node involvement and one case of airway
involvement.
• Amongst these cases, 3 were in neonatal age group having bilateral diffuse
reticulonodular opacity diagnosed as respiratory distress syndrome.
39

40. • In this study, x ray was able to define the various characteristics such as ABG,
soft tissue opacity, collapse, and mediastinal shift in 56%, 80%, 35%, and 71 %
of patients respectively as compared to CT.
• In collapse which was not diagnosed on x ray were mostly resorptive in nature
and segmental in distribution.
• X ray did not demonstrated mediastinal lymph nodes in 6 pts detected having
lymph nodes on CT.
• X ray was able to demonstrate cavitary lesions in all 5 patients as their sizes
were large.
• For detection of pleural fluid, USG as well as CT shown better accuracy than x
ray.
• Out of 8 pts with pneumothorax, x ray diagnosed in 6 cases (75%) as compared
to CT in all patients.
• While for characterization of pleural fluid, USG showed presence of echoes and
septations in 8 patients. CT was not able to detect echoes and septations in any
patient.
• X ray showed simultaneous detection of both pulmonary and parenchymal
pathology in 50% of patients as compared to CT (7 out of 14 cases).
• One case of airway involvement showed bronchiectasis and it showed presence
of fluid levels on HRCT.
• Thus CT is useful in inflammatory lesions to characterize the lesion, extent of
involvement, associated pleural fluid and mediastinal nodal involvement and any
associated complication e.g. Brochopleural fistula, pneumatocele formation.
Airway involvement:-
There were 3 cases of hyperinflation on x ray among which CT was done in two cases
and showed presence of soft tissue density foreign body in one case. Another case was
diagnosed as ? Obstructive emphysema/?? CLE and was found to be foreign body on
bronchoscopy.
Another case showed presence of metallic foreign body in bronchus.
40

41. Traumatic lesions:-
• One studied case of trauma showed presence of bilateral subcutaneous
emphysema on x ray was found to be associated with pneumothorax and
Pneumomediastinum on CT.
Neoplastic lesions and mediastinal masses:-
• Out of 60 patients studied, two cases (3.6%) of neoplasm and 3 mediastinal
mass (5%) were found out.
• A case of neoplasm presented with opaque hemithorax on x ray showed large
necrotic chest wall neoplasm with invasion of pulmonary and mediastinal
compartments, diagnosed as PNET.
• Mediastinal masses were thymic germ cell tumour, bilateral paravertebral
abscess and pericardial cyst.
• One case of thymic germ cell tumour showed presence of calcification and fat in
the region of thymus and thymus was not seen separately from the lesion.
• The pericardial cyst was having partially calcified rim.
• Bilateral paravertebral abscess with calcification had same component in
epidural region of spinal canal with kyphoscoliosis of spine. Intraspinal extension
was better shown on MR examination.
Other:-
• One case of patient undergoing multiple blood transfusions noted having bilateral
diffuse alveolar opacities and was diagnosed as having idiopathic pulmonary
hemosiderosis.
41

42. CONCLUSION
Various imaging modalities such as X ray, USG, Flouroscopy, CT scan and MRI
are available for diagnosis and evaluation of pediatric chest lesions. They have many
advantages and disadvantages in common. It is difficult to isolate a single modality with
distinct advantage over others.
Chest radiography is the first and often only (e.g. for pneumonia) imaging
modality used to assess thoracic signs or symptoms providing a survey of lung
parenchyma, cardiovascular structures, mediastinum and chest wall structures.
Though air being highly reflective, USG is considered invaluable in evaluation of
pleural fluid, pleural masses, diaphragmatic lesions and evaluation of thymus as being
noninvasive and non radiating.
CT is though expensive and having higher radiation dosage, it is quite useful in
management of the patient with pediatric chest lesions demonstrating extent of the
lesion, particularly in congenital lung malformation. Simultaneous assessment of cross
sectional anatomy can be done. With IV contrast, it provides enhancement of vascular
structures. CT provides crucial diagnosis in conditions having similar appearance on
radiograph e.g. between pneumonia and sequestration, between pneumonia and AV
42

43. malformation having appearance of consolidation. Thus CT provides an excellent
anatomical guidance to the pediatric surgeon.
Need for longer duration of sedation and sophisticated softwares, MRI is
considered as a reserved modality particularly in evaluation of foregut malformation and
neurogenic tumours or inflammatory processes involving spine.
BIBLIOGRAPHY
1. Stigers KB, Woodring JH: The clinical & imaging spectrum of findings in CLE.
Pedia. Pulmonol 14: 160-170,1992
2. Nuchtern JG, Harberg FJ. Congenital lung cysts. Semin Pediatr Surg
1994;3:233–43.
3. Coley BD (2005) Pediatric chest ultrasound. In: Frush DP (ed) Pediatric
chest imaging, W.B. Saunders, Philadelphia, PA, pp 405-418
4. Frush DP, Donnelly LF: Pulmonary sequestration spectrum: A new spin with spiral CT.
AJR Am J Roentgenol 169: 679-682, 1997.
5. Donnelly LF, Klosterman LA: Cavitary necrosis complicating pneumonia in children
AJR Am J Roentgenol 171: 253-256, 1998.
43

44. 6. Brown MJ, Miller RR, Muller NL: Acute lung disease in immunocompromised host: CT
and pathological examination findings.
Radiology 190: 247-254, 1994.
7. Sivit CJ, Taylor GA: Chest injury in children with blunt abdominal trauma: Evaluation
with CT.
Radiology 171: 815-818, 1989.
8. Rose RE, Ward BH. Spherical pneumonias in children simulating pulmonary and
mediastinal masses. Radiology 1973;106:179– 82
9. Swischuk LE, Hayden Jr CK. Viral vs. bacterial pulmonary infections in children (is
roentgenographic differentiation possible?).
Pediatr Radiol 1986;16:278–84.
10. Siegel MJ. Mediastinum In: Pediatric body CT
Lippincott Williams and Williams 1999:101-110
11. Stocker JT, Madewell JE, Drake RM. CCAM: classification and morphologic
spectrum. Hum Pathol 1977; 8:155– 71.
12. Strollo DC, Rosado-de-Christenson ML, Jett JR. Primary mediastinal tumors. Part II:
tumors of middle and posterior mediastinum. Chest 1997;112: 1344– 57.
13. Waite RJ, Carbonneau RJ, Balikian JP, et al. Parieta pleural changes in empyema:
appearance at CT. Radiology 1990;175:145– 50.
14. Muller NL. Imaging of the pleura. Radiology 1993; 186:297– 309.
15. Kendrick T, Ling H, Subramaniam R, et al. The value of early CT in complicated
childhood pneumonia. Pediatr Radiol 2002;32:16– 21.
44

45. 16. Ramnath RR, Heller RM, Ben-Ami T, et al. Implications of early sonographic
evaluation of parapneumonic effusions in children with pneumonia. Pediatrics
1998;101:68–71.
17. Donnelly LF, Klosterman LA. The yield of CT of children who have complicated
pneumonia and noncontributory chest radiography.
AJR Am J Roentgenol 1998;170:1627– 31
18. Whitsett JA, Pryhuber GS, Rice WR, et al: Acute respiratory disorders.In:
Neonatology: pathophysiology and management of the newborn, 4th edn.
Philadelphia: JB Lippincott; 1994:429-452.
19. Fink IJ, Kurtz DW, Cazenave L, et al: Malignant thoracopulmonary small-cell (Askin)
tumour. Am J Roentgenol 1985; 145:517-520.
20. Patz Jr EF, Mu¨ ller NL, Swensen SJ, et al. Congenital cystic adenomatoid
malformation in adults: CT findings.J Comput Assist Tomogr 1995;19:361– 4.
21. Berrocal T, Madrid C, Novo S, et al. Congenital anomalies of the tracheobronchial
tree, lung, and mediastinum: embryology, radiology, and pathology.
Radiographics 2003;24:e17– 62.
22. Macpherson RI. Gastrointestinal tract duplications: clinical, pathologic, etiologic, and
radiologic considerations. Radiographics 1993;13:1063– 80.
23. Conran RM, Stocker JT. Extralobar sequestration with frequently associated CCAM,
type 2. Pediatr Dev Pathol 1999;2:454– 63.
24. Meza MP, Benson M, Slovis TL. Imaging of mediastinal masses in children.
Radiol Clin North Am 1993;31:583– 604.
45

46. 25. Fishman SJ. Vascular anomalies of the mediastinum.
Semin Pediatr Surg 1999;8:92– 8.
26. Billmire DF. Germ cell, mesenchymal, and thymic tumors of the mediastinum.
Semin Pediatr Surg 1999; 8:85– 91
46