Congenital Lung Malformations

8/13/2019 Congenital Lung Malformations

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History case

A boy of 7 years the last 2 years was repeatedly treated for right

inferior lobe bronchopneumonia.

On the plain chest X-ray, there is a well defined opacity at the level

of the inferior lobe of the right lung. The shadow adjoins to the

mediastinum.


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Suspected diagnosis???

Pulmonary hypoplasia,

Congenital lobar emphysema,

Pulmonary sequestration, Congenital pulmonary airway

malformation,

Bronchogenic cyst.


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Congenital lung malformations

Jalba Alexandru,

MD, PhD,

associate professor

Chisinau 2013

N. Testemitanu State University of Medicine and Pharmacy

Department of Pediatric Surgery, Orthopedics and Anesthesiology


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Background

o The aim of this lecture is to provide a concise approach to congenital lung

malformations.

o Discussed issues:

o bronchogenic cyst,

o pulmonary agenesis and hypoplasia,

o polyalveolar lobe,

o alveolocapillary dysplasia,

o sequestration including arteriovenous malformation (AVM) and

o scimitar syndrome,

o pulmonary lymphangiectasis,

o congenital lobar emphysema (CLE), and

o congenital cystic adenomatoid malformation (CCAM) (sin.

congenital pulmonary airway malformation(CPAM)) and other lung

cysts.


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Background

o Although they secrete the amniotic fluid, the lungs are unnecessary as

organs of respiration in fetal life.

o However, their development must occur so that air exchange may take

place at birth.

o The lungs go through

o embryonic,

o pseudoglandular,

o canalicular,

o saccular, ando alveolar phases (Fig. 1).


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Background

Fig. 1. Lungs development.


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History of the procedure

o Surgery for congenital lung malformation was made possible relatively

recently.

o Early 20th century thoracic surgery consisted of mainly thoracoplasty to

collapse a tuberculoid lung or to drain an empyema.

o Only with the regular use of endotracheal intubation and mechanical

ventilation in the 1950s did intrathoracic procedures become routine.

o These techniques were not widely applied to newborns until the 1950s.

o Although Evarts Graham performed pneumonectomy with mass ligature

of the hilum, Churchill was the first to regularly perform lobectomy

with hilar dissection.

o Gross and Lewis successfully treated a patient with congenital lobar

emphysema with lobectomy in 1943.


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o Bronchogenic cysts are increasingly excised thoracoscopically.

o Rodgers vigorously promoted endoscopic surgery, which has become

prevalent with the plethora of new instrumentation available and with

the expansion of minimally invasive laparoscopy and thoracoscopy.

o Most thoracic surgical procedures, such as resection of masses

(neurogenic tumors, bronchogenic cysts) and pulmonary lobectomy, are

now accomplished with minimally invasive surgery, although the

benefits of this approach for cystic adenomatoid malformations are

unclear.


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o Fetal surgery has been advocated for

cystic adenomatoid malformation with

hydrops, although it has been abandoned

for congenital diaphragmatic hernia

(CDH).

o The extrauterine intrapartum (EXIT)

procedure involves delivery of the baby

in which the umbilical circulation is left

intact if the baby has a congenital high

airway obstruction. This procedureallows relief of the obstruction while

providing gas exchange across the

placenta (Fig. 2).

Fig. 2.EXIT procedure.


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Classification by site of origin

Trachea and Bronchi Pulmonary parenchyma Vascular

Agenesis

Congenital pulmonary airway

malformations (preciously

congenital cystic adenomatoid

malformation)

Hemangioma

Atresia, stenosisBronchopulmonary

sequestration

Arteriovenosus

malformation

Tracheal bronchus Congenital lobar emphysema Scimitar syndrome

Esophageal bronchus/lung

(communicating

bronchopulmonary malformation)

Agenesis Congenital pulmonary

lymphangiectasia

Bronchogenic cyst Aplasia Lymphangioma

Enteric duplication cyst Hypoplasia Congenital chylotorax

Neuroenteric cystBronchiolar cysts (cystic

bronchiectasismultiple)

Bronchial cysts (peripheral) Lobulation abnormalities


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Epidemiology

o Frequency: Congenital lung malformations represent 5-18.7% of all

congenital anomalies. This range may be an underestimate because of

the high frequency of undetected or asymptomatic lesions.


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Generalities

o Although congenital lung malformations are rare, they are important

disorders because they may lead to considerable morbidity and mortality

(eg, infection, hemorrhage, respiratory failure).

o Prognosis depends on the size of the lesion, and the degree of functional

impairment.

o Small lesions may remain asymptomatic.

o Failure to recognize a malformation may lead to inappropriate

intervention.

o For example, placement of a chest tube to manage suspected tension

pneumothorax in a patient with congenital lobar emphysema may lead

to lung contusion and ventilation through the chest tube instead of into

the remaining healthy lung.


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Generalities

o Healthy lung is composed of an orderly system of tubes (airways) and sacs

(airspaces or alveoli) in a strict relationship to pulmonary blood vessels

(arterial from the right ventricle and venous return to the left atrium) (Fig.3).

Fig. 3.Lung vasculature


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Generalities

o Also present is a systemic blood supply (aorta to superior vena cava) and

lymphatic drainage (Fig. 5).

o Congenital lung malformations arise whenever one or more of these

structures are abnormal or when their relationships are altered.

Fig. 5.Pulmonary and systemic blood supply of the lungs


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CERTAIN LUNG

MALFORMATIONS


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Bronchogenic cysts

o Bronchogenic cysts are also known as foregut duplication.

o They arise from an abnormal budding of the ventral foregut.

o Approximately 85% are mediastinal, and 15% are intrapulmonary (Fig. 6).

Fig. 6.Bronchogenic cysts.


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Bronchogenic cysts

o The peripheral cysts are multiple and appear late in gestation.

o They may be filled with air or fluid, or they may have air-fluid levels.

o The cysts can be central or peripheral.

Fig. 6.Bronchogenic cysts.


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Bronchogenic cysts

o Many are asymptomatic, but incidental findings may be observed on

chest radiography (Fig. 7, 8).

Fig. 7. Bronchogenic cyst of the mediastinum


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Bronchogenic cysts

o Many are asymptomatic, but incidental findings may be observed on

chest radiography and (Fig. 7, 8).

Fig. 8. Bronchogenic cyst. CT scan demonstrates a thin-walled cyst in the right upper lobe.


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Bronchogenic cysts

o Infection, hemorrhage, and, in rare cases, malignancy can occur.

o Respiratory distress may result in a stridor or wheeze.

o Airtrapping may lead to emphysema, atelectasis, or both.

o Dysphagia, chest pain, and epigastric discomfort can occur.


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Pulmonary agenesis and hypoplasia

o In lung agenesis, the entire lung and bronchial tree may be absent on one

side.

o The bronchial tree may form without development of the alveoli.

o Pulmonary hypertension complicates lung agenesis because of a

combination of factors: normal blood volume passing through reduced

lung tissue, hypoxemia leading to pulmonary vasoconstriction, and any

associated left-to-right shunting cardiac lesion.


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o Intrathoracic or extrathoracic lesions can cause pulmonary hypoplasia.

o Therefore, prolonged rupture of membranes, renal dysplasia,

neuromuscular diseases, and congenital diaphragmatic hernia can lead to

lung hypoplasia.

o Reduced urine volume during fetal life may retard lung growth.

o Secondary pulmonary causes include cystic adenomatoid malformation

and sequestrations.

o Secondary extrapulmonary, intrathoracic causes include congenital

diaphragmatic hernia, hydrothorax, pleural effusions, and tetralogy of

Fallot (due to poor lung blood flow).


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o Extrathoracic causes include renal dysplasia and neuromuscular disorders(ie, poor breathing).

o Bilateral renal agenesis leads to oligohydramnios and poor development

of the terminal airways secondary to decreased swallowing of the

amniotic fluid.

o The urinary proline aids in the formation of collagen by the fetal lung.

o Thyroid transcription factors also regulate lung development.

o The lung hypoplasia in congenital diaphragmatic hernia is complicated by

pulmonary hypertension.

o Pulmonary aplasia leads to respiratory distress, which may vary

according to the degree of alveolar involvement. Pulmonary hypoplasia

may be primary when the entire lung or when one lobe is reduced in size.


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o Both pulmonary agenesis andhypoplasia may be accompanied

by renal anomalies, which are

usually apparent soon after birth

and associated with respiratory

distress. Cardiac defects occur in

50% of patients.

o Pulmonary agenesis is

differentiated from lung aplasia

by the absence of the carina in

the latter (Fig. 9).Fig. 9. A.Normal lungs.

B.Pulmonary aplasia, with complete absence of both bronchial andalveolar tissue.

C. Pulmonary agenesis with a bronchus reminiscence and

D, Pulmonary dysplasia. Some bronchial elements are present, butthere are no alveoli.


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o Lung agenesis is less common than aplasia, about 75% of cases affect

the left side, and it is lethal in half of all patients.

o It may be associated with other manifestations of the syndrome of

abnormalities of the Vertebrae, Anus, Cardiovascular tree, Trachea,

Esophagus, Renal system, and Limb buds (VACTERLsyndrome).

o The survival rate is better with left-sided lung agenesis than with right-

sided agenesis because the right lung is the larger of the two.


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o In pulmonary hypoplasia,

development of the distal lung

tissue is incomplete (Fig. 10).

o The earlier the delivery of a

child, the higher the incidence of

lung hypoplasia.

o In babies delivered before 28

weeks' gestation, the incidence

approaches 20%.Fig. 10. A to C. Pulmonary hypoplasia. Three conditions of differentembryogenesis that all result in a smaller than normal lung.

A,Alveolar tissue not functional.

B,Reduced size of one lung.

C,Hypoplasia resulting from lobar dysplasia.

D to F.Pulmonary ectoplasia. Part or all of one lung is attached to theesophagus and usually is supplied by a systemicartery. D, Bronchoesophageal fistula. E, Sequestration of right lowerlobe. F,Sequestration of lower lobe and dysplasia of upper lobe.


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o Pulmonary hypoplasia resultsfrom conditions that restrict lung

growth, such as

oligohydramnios, Potter

syndrome (with bilateral renal

agenesis or dysplasia),

abnormalities of the thoracic

cage, Scimitar syndrome (right-

sided pulmonary hypoplasia),

and diaphragmatic hernia

(usually left-sided hypoplasia).Fig. 10. A to C. Pulmonary hypoplasia. Three conditions of differentembryogenesis that all result in a smaller than normal lung.

A,Alveolar tissue not functional.

B,Reduced size of one lung.

C,Hypoplasia resulting from lobar dysplasia.

D to F.Pulmonary ectoplasia. Part or all of one lung is attached to theesophagus and usually is supplied by a systemicartery. D, Bronchoesophageal fistula. E, Sequestration of right lowerlobe. F,Sequestration of lower lobe and dysplasia of upper lobe.


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o More than 50% of patients have associated cardiac, gut, or skeletal

malformations.

o They may have a small thoracic cage, decreased breath sounds on the

affected side, and a mediastinal shift to the side of the lesion (Fig. 11,

12).

o Therefore, aplasia of the right lung can be confused with dextrocardia.

o Patients may present with lung infections, dyspnea upon exertion,

and/or scoliosis.


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Fig. 11. Pulmonary hypoplasia. (a) Schematic illustrates pulmonaryhypoplasia. (b)Anteroposterior chest radiograph of a 7-month-old infant shows opacityof the left hemithorax and small left lung (arrows) with ipsilateral displacement of themediastinum, secondary to repaired Bochdaleck hernia.

a b


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a b

Fig. 12. Pulmonary hypoplasia. (a)Anteroposterior radiograph shows opacity of the right hemithorax anda shift of the mediastinal structures to the right, due to pulmonary hypoplasia secondary to rightdiaphragmatic agenesis. (b) Angiographic MR image of a 10-year-old boy shows a hypoplastic rightpulmonary artery (arrows).


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Pulmonary isomerism

o Pulmonary isomerism is an anomaly of the number of lung lobes.

o In the common variety of pulmonary isomerism, the right lung has 2

lobes, whereas the left has 3.

o This anomaly may be associated with situs inversus, asplenia,

polysplenia, and/or anomalous pulmonary drainage.


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Azygous lobe

o An azygous lobe is a

malformation of the right

upper lobe caused by an

aberrant azygous vein

suspended by a pleural

mesentery.

o An azygous lobe is a

radiographic curiosity

without clinical

significance that occurs

in 0.5% of the general

population.

Fig. 13. A. A 15-year-old boy receiving chemotherapy for osteogenic

sarcoma of the left femur. The chest radiograph showed an azygous lobeof the lung with a thin fissure (arrows) separating it from the rest of theright upper lobe. Computed tomography (Panels B and C) revealed thefissure (Panel B, white arrows and Panel C, asterisk) and a small nodulein the posterior right upper lobe, 1 cm in diameter (Panel B, blackarrow). Evaluation of a specimen from a thoracoscopic lung biopsy(Panel D) showed that the membranous fissure (asterisk) contained theazygos vein (arrowheads) and divided the apex of the right hemithorax.The lung nodule was found to contain metastatic osteosarcoma.


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Pulmonary sequestration

o If an accessory lung bud forms early enough, it leads to the formation of

sequestration in the normal lung tissue.

o Development late in gestation leads to extrapulmonic sequestration.

o Both types obtain their blood supply from the aorta or its branches.

o Patients may present with exercise intolerance due to these vascularshunts.

o Sequestrations may also be connected to the GI tract.


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o Pulmonary sequestration

accounts for 6% of all

congenital lung malformations

and mostly occurs in the lower

lobes.

o A sequestration is a

bronchopulmonary mass without

a normal bronchial

communication and with normal

or anomalous vascular supply

from the systemic circulation.

o Sequestered lung may be

intralobar or extralobar.

AORTA

INTRALOBAR EXTRALOBAR

Fig. 14. Pulmonary sequestration


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o Children present with recurrent respiratory problems in the same

anatomic location.

o Associated anomalies include diaphragmatic hernia and eventration.

o Patients may have exercise intolerance if they have large systemic

arterial venous shunts.

o The extrathoracic variety can be associated with hydrops fetalis or

increased lymphatic transudate in the thorax.


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o About 50% of pulmonary sequestration cases are intralobar, and 60% of

intralobar cases occur in the left lower lobe with equal sex distributions.

o Patients with intralobar sequestration usually present late.

o They may have a chronic cough, recurrent pneumonias, or poor exercise

performance.

o Systemic arterial flow may produce a murmur, and shunts may lead to

congestive cardiac failure.

o Squamous cell carcinoma, adenocarcinoma, and rhabdomyosarcoma

may arise in the sequestration.


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o Approximately 95% of extrapulmonary cases are left sided.

o Most extrapulmonary cases are detected in infancy, with boys affected 4

times more than girls.

o Infants usually present with a chronic cough and recurrent chest

infections.

o Radiographs may reveal signs of consolidation.

o If communication with the gut is present, children may present with

vomiting, failure to thrive due to poor oral intake, and abdominal pain.


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Scimitar syndrome

o The constant feature of this

syndrome is partial or total

anomalous pulmonary venous

return to the inferior vena cava.

o This abnormal vein on the chest

radiography creates a gentle

curve bulging into the right

chest from the mediastinum that

some believe resembles the

Turkish sword called a scimitar.Fig. 15.Scimitar syndrome.


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Scimitar syndrome

o Other features of the syndrome are variable and may include

dextrocardia, hypoplasia of the right lung and/or pulmonary artery,malformation of the bronchi, and systemic arterial supply to the right

lung.

o The clinical features vary according to age. Infants almost always

present with congestive heart failure and severe pulmonary

hypertension. Adults are generally asymptomatic.

Fig. 16. Chest x-ray of a five-year-old girl with Scimitar syndrome. The heart (blue outline) is shiftedinto the right half of the chest, and the anomalous pulmonary venous return (red) has a shape reminiscentof a Scimitar.


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Scimitar syndrome

Fig. 17. Scimitar syndrome (MRI).


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Lung hamartoma

o Hamartomas are lung nodules contain cartilage, respiratory epithelium,

and collagen.

o They may be in the lung tissue or the bronchial lumen.

AA BA

Fig. 18. Pulmonary hamartoma. (A)Chest CT scan shows a heterogeneous, sharply marginated lesionwith small focal areas of calcification and fat. These findings are typical features of hamartoma. (B)The chest radiograph shows a solitary pulmonary nodule in the left lung apex. Close inspection of thisnodule shows small foci of increased attenuation within the nodule, consistent with calcium. Thesefindings are typical features of hamartoma.


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Fig. 19. MRI angiography using MIP (Maximum IntensityProjection) reconstruction shows the presence of multiple,bilateral arteriovenous malformations of pulmonary vessels


Pulmonary arteriovenous malformation

o Pulmonary arteriovenous

malformations are abnormal

communications between the

pulmonary arterial and

venous systems without

interposed capillaries (Fig.

19).


Fig. 19. MRI angiography using MIP (Maximum IntensityProjection) reconstruction shows the presence of multiple,bilateral arteriovenous malformations of pulmonary vessels.


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o Arteriovenous malformations with a systemic arterial supply are

unusual in the lung.

o As with arteriovenous malformations elsewhere, they can lead to high-

output cardiac failure.

o Symptoms are unusual in childhood.

o However, by adulthood, 50% of patients have at least exertional

dyspnea.

o Hemoptysis is most common in patients who also have cutaneous

telangiectasis.

o A continuous bruit is often heard over the lesion.


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o The fistulas are usually seen as

well-defined opacities on chest

radiography, and are multiple in

as many as 50% of patients (Fig.

20) and bilateral in 10%.

Fig. 20. Chest X-ray. Pulmonary arteriovenousmalformation.


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o Most of the fistulas are subpleural, and more often occur in the lower

lobes.

o CT findings are usually diagnostic (Fig. 21).

Fig. 21. Right intrahilar pulmonary arteriovenousmalformation.


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o Complications include bleeding, infection, and embolus.

o Patients with cutaneous telangiectasis are likely to have Rendu-Osler-

Weber disease (also known as hereditary hemorrhagic telangiectasia a

genetic disorder that leads to abnormal blood vessel formation in

the skin, mucous membranes, and often in organs such asthe lungs, liver, and brain).

o They are likely to have multiple pulmonary arteriovenous

malformations and progressive symptoms.


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o Treatment is resection.

o If this is not possible, the lesions can be embolized (Movie 1).

Movie 1. Right pulmonary arteriovenousembolization.


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Fig. 22. Alveolar capillary dysplasia: characteristic histologic features of ACD/MPV: thickened alveolarseptae with scarce dilated pulmonary capillaries located away from the alveolar epithelium, with absence ofthe usual alveolar-capillary barrier ( ); medial hypertrophy of small pulmonary arteries and muscularization

of distal arterioles (); congested pulmonary veins malpositioned, adjacent to pulmonary arteries in the sameadventitial sheath (*); lymphangiectasis not present.



Alveolar capillary dysplasia

o In alveolar capillary dysplasia, a fatal condition, the distal arteriolar

blood supply is reduced, the pulmonary veins are misaligned, and the

connective tissue between the alveolar epithelium and the capillary

endothelium is increased (Fig. 22).

A B










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Alveolar capillary dysplasia

o The alveolar circulation is impaired, and the response to nitric oxide is

poor.

o Affected babies do well with venoarterial extracorporeal membrane

oxygenation (ECMO), but they cannot be weaned from it.

o The clinical presentation of alveolar capillary dysplasia is that ofpersistent pulmonary hypertension of the newborn.

o Hypoxemia leads to arteriolar muscular hypertrophy.

o Patients may have associated anomalies in the heart or urinary system.

o Open lung biopsy and cardiac catheterization are suggested as

diagnostic tools to look for or exclude pulmonary capillary blush.


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Pulmonary lymphangiectasis

o Pulmonary lymphangiectasis is a rare disorder in which the normal

pulmonary lymphatics are dilated.

o It may be associated with congenital heart disease in which the

pulmonary venous pressure is elevated.

o Pulmonary lymphangiectasis can also be observed withlymphangiomatosis, in which proliferation of the lymphatic tissue and

channels occurs.

o The disease can also be part of a syndrome of lymphangiomas in many

organs; it is sometimes associated with vanishing bones (Gorhams

disease).

o Pulmonary lymphangiectasis is congenital, but symptoms of respiratory

insufficiency usually do not appear until adulthood.



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(History case)

o A female infant was born at 40 weeks and 3 days of gestation, weighing

2970 g.

o The Apgar scores were 8, 10, and 10 at 1, 5, and 10 minutes,

respectively.

o Within one hour after birth, severe respiratory distress with profoundcyanosis developed while the infant was breathing room air, and

intubation and mechanical ventilation were required.



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(History case)

o An initial chest radiograph showed normal lung volumes with diffuse,

bilateral nodular changes, and a subsequent chest radiograph obtained

on the 17th day of life showed that these changes had become more

prominent (Fig. 23).

Fig. 23. Chest X-ray - pulmonary lymphangiectasia



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(History case)

o Surfactant and antibiotics were administered.

o Lung compliance remained poor, and high-frequency oscillatory

ventilation was begun.

o Congenital heart disease was ruled out, and cultures of blood and

tracheal aspirates were unrevealing.

o After surfactant protein B deficiency was ruled out, an open-lung biopsy

was performed, on the 18th day of life.



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(History case)

o On gross examination, the lung had an irregular surface with scattered

nodular changes (Fig. 24).

Fig. 24. Pulmonary lymphangiectasis. Intraoperative view.



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(History case)

o On microscopical examination, there was subpleural and septal cystic

lymphangiectasia (L, Fig. 25; hematoxylin and eosin, 150). A

denotes artery. These findings are consistent with a diagnosis of

congenital pulmonary lymphangiectasia, which is a uniformly fatal

disease when it manifests in the newborn period. The infant died on the

20th day of life.

Fig. 25. Pulmonary lymphangiectasis.Hematoxylin and eosin, 150.


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Congenital lobar emphysema

o Massive overinflation of one or more lung lobes occurs postnatally in

congenital lobar emphysema (Fig. 26).

Fig. 26. Congenital lobar emphysema


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o Causes are obscure in 50%. Other causes include intrinsic absence or

abnormality (bronchomalacia) of cartilaginous rings or external

compression by a large pulmonary artery. (Compression of the cartilage

usually leads to malacia.)

o Hyperexpansion of a pulmonary lobe is present after birth when, with

negative inspiratory pressure, air can enter the lung.

o However, the air cannot exit easily because positive pressure causes the

softened airway to collapse.

o The remaining normal lung is then compressed.


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o Congenital lobar emphysema primarily involves the upper lobes.

o The left upper lobe is involved in 41% of patients; the right middle lobe,

in 34%; and the right upper lobe, in 21%.

o Involvement of the lower lobes is rare, occurring in fewer than 5% of

patients.

o Congenital cardiac anomalies may be present in as many as 10% of

patients.

o Lesions most commonly occur in whites, in male individuals (male-to-

female ratio, 3:1), and in young infants.


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o Most patients with congenital lobar emphysema present before 6 months

of life.

o Neonates may present with mild-to-moderate respiratory distress.

o Mediastinal shift may be present, with hyperresonance and decreased

breath sounds on the involved side.

o Infants present with cough, wheezing, respiratory distress, and cyanosis.

o Older children may present with recurrent chest infections.

o On images obtained in neonates, the affected lobe may be slightly

opacified, rather than lucent, because it is still filled with fluid.

o Associated cardiac anomalies occur in as many as 10% of patients. See

the images below.


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Fig. 27. Chest X-ray. (front and lateral views) Congenital lobar emphysema on the right side of the chest in aneonate. Film shows marked lucency and hyperexpansion in the middle lobe of the right lung; this finding isconsistent with lobar emphysema. The possibility of tension pneumothorax is unlikely because lung markingsare seen in this region, with splaying of the pulmonary vessels. Compressive atelectasis is present in the leftupper and right lower areas of the lungs. The mediastinum and heart are shifted to the left. The osseousstructures are intact.


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Fig. 28. Same patient as in the previous 2 images. After surgery, the left lungis expanded. A thoracotomy tube is on the right, with a small right-sidedpneumothorax.


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Congenital cystic adenomatoid malformation

o Congenital cystic adenomatoid malformation (CCAM) or congenital

pulmonary airway malformation (CPAM) lately is a defect in thedevelopment of the terminal bronchioles.

o A hamartomatous proliferation of cysts occurs and resembles

bronchioles (airways without cartilage).

Fig. 29. CCAM on chest radiograph in a newborn.Large cystic changes in the left lung, leading to amediastinal shift to the right due to their mass effect.

Fig. 30. Contrast enhanced computerizedtomography of the chest of the patient withcongenital cystic adenomatoid malformation(CCAM)


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o Adenomatoid malformation results when the terminal bronchiolar

component of the advancing endodermal lung bud proliferateshaphazardly because of disruption of humoral factors from the

surrounding mesenchyme.

o Apoptosis in the advancing lung bud is decreased.

o Glial cellderived neurotrophic factor is a growth factor that isabnormally expressed in the epithelial cells of the cystic adenomatoid

malformation.

o Cystic adenomatoid malformations usually appear before 7 weeks'

gestation but can occur in the mid stage of lung development.o The growth is thought to plateau at 28 weeks' gestation.

C i i i f i


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o Communication with the normal airways can lead to overinflation and

compression of the surrounding lung tissue.

o The larger the sonographic volume of cystic adenomatoid malformation

in relation to head circumference, the greater the chance for developing

hydrops because of more severe central venous compression.


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C it l ti d t id lf ti


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o Polyhydramnios may be present if the cystic adenomatoid malformation

presses on the esophagus.

o Pressure on the heart and large vessels may lead to hydrops fetalis.

o In approximately 60% of patients, cystic adenomatoid malformation

manifests soon after the neonatal period.

o It results in recurrent infections because the mucociliary clearance is

poor.

o Malignancy can occur in the cystic adenomatoid malformation

(pulmonary blastoma, rhabdomyosarcoma, and bronchoalveolar

carcinoma). See the images below.



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Fig. 31. Cystic adenomatoid malformation.



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Fig. 32. Initial radiograph in a patient with congenital cysticadenomatoid malformation on the first day of life with opaque lungsand a suggestion that the right lung is slightly more voluminous than

the left lung.



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Fig. 33. Radiograph obtained in the same patient as in the previous image onthe second day of life shows that the physiologic fluid is resorbed andreplaced with an air-containing cystic area occupying the right upper lung.

Fig. 33. Radiograph obtained in the same patient as in the previous image onthe second day of life shows that the physiologic fluid is resorbed andreplaced with an air-containing cystic area occupying the right upper lung.

P l l l l b


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Polyalveolar lobe

o In a polyalveolar lobe, the number of alveoli increased to more than 3

times normal.

o The alveoli are counted microscopically in random lung sections.

o When extra lung fluid is retained, respiratory distress may occur in the

first days of life.o This generally benign anomaly may be associated with some cases of

congenital lobar emphysema.


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INDICATIONS

Bronchogenic cyst


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Bronchogenic cyst

o Resection is recommended because of the potential for infection,

hemorrhage, and respiratory compromise.

o Resection is especially important in the peripheral lesions, which are

usually multiple.

o These can frequently be excised thoracoscopically because they seldomhave a major blood supply.

Pulmonary agenesis and pulmonary hypoplasia


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o Patients with pulmonary agenesis and pulmonary hypoplasia seem to

have one of 3 presentations.

o The first group consists of patients with insufficient lung tissuewho

may have received mechanical ventilation for some time.

o However, ventilator-induced lung injury results in slow decompensationand death.

o The second group of patients is identified serendipitously when chest

radiography is obtained to assess a minor complaint.

o These patients require no intervention.



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o The third group does not have respiratory distress requiring mechanical

ventilation, but they have respiratory limitations to activity or kinking of

the airway with shift of the lung to the contralateral side of the chest.

o In addition to the aplasia or hypoplasia, congenital narrowing of the

upper airway also affects many patients.



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o Resection is recommended, even in asymptomatic patients, to prevent

infection, hemorrhage, shunting from arteriovenous anastomoses, or

compression of normal lung mass leading to respiratory distress.

o Lobectomy can usually be performed.

o For patients with intralobar sequestration, segmentectomy may suffice.o Segmentectomy is relatively difficult, but preserves additional

functioning lung tissue.



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o Resection is recommended, even in asymptomatic patients, to prevent

infection, hemorrhage, shunting from arteriovenous anastomoses, or

compression of normal lung mass leading to respiratory distress.

o Lobectomy can usually be performed.

o For patients with intralobar sequestration, segmentectomy may suffice.o Segmentectomy is relatively difficult, but preserves additional

functioning lung tissue.

Scimitar syndrome


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Scimitar syndrome

o When symptoms of scimitar syndrome are related to anomalous

pulmonary venous return, this return can be redirected surgically.

o Symptoms are often related to the bronchial abnormalities and chronic

infection.

o In these cases, pneumonectomy is indicated.

Hamartoma and


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pulmonary arteriovenous malformation

o Resection is usually performed for diagnosis when a lesion is noted on

chest radiography.

o Symptoms of airway obstruction or high cardiac output are occasionally

indications for surgery as well.



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o Progressive airtrapping leads to respiratory and circulatory compromise

in infancy.

o Emergency lobectomy may be required.



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o A patient with respiratory distress whose chest radiograph reveals a

hyperlucency on one side and mediastinal shift usually has a tension

pneumothorax. However, one must consider congenital lobar

emphysema (CLE), especially in the newborn.

Fig. 34. Bilateral pneumotorax in anewborn.

Fig. 35. Congenital lobar emphysema in a newborn.



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o The diagnosis can usually be determined by looking at the edges of the

hyperlucent area. In pneumothorax, the edges are convex and outline the

chest wall, whereas in congenital lobar emphysema, they are concave

and outline the cystic structure of an overexpanded lobe.

Fig. 34. Bilateral pneumotorax in anewborn.

Fig. 35. Congenital lobar emphysema in a newborn.



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Fig. 36.Bilateral pneumotorax. Fig. 37.Congenital lobar emphysema of the upperlobe of the left lung.



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Fig. 39.Right sided pneumotorax.Fig. 38.Congenital lobar emphysema of the upper lobeof the left lung.

Cystic adenomatoid malformation


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Cystic adenomatoid malformation

o In congenital cystic adenomatoid malformation (CAM), resection of

even asymptomatic masses is recommended because of the risk for

infection, hemorrhage, acute respiratory compromise (which may occur

anytime), and neoplastic transformation.

o This disease is usually segmental; however, as noted for sequestration,

lobectomy may reduce morbidity.


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WORKUP

Laboratory Studies


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Laboratory Studies

o Hemoglobin testing is always valuable in respiratory illness because the

result is an important factor in oxygen delivery and in planning surgery,

which often involves major vessels.

Renal function tests to measure BUN (Blood Urea Nitrogen), serum

creatinine, and electrolyte levels are important because of the frequent

association of renal anomalies with pulmonary anomalies (usually

pulmonary hypoplasia).

Imaging Studies


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(Chest radiography)

Bronchogenic cysts: Bronchogenic

cysts are usually fluid-filled lesions

and are well circumscribed in the

mediastinum.

Solid masses may be difficult to

differentiate from fluid.

Intrapulmonic cysts appear as solitary

nodules unless they contain air.

Large cysts may be difficult to

differentiate from macrocystic cystic

adenomatoid malformation (CAM).

Fig. 40. Mediastinal bronchogenic cyst.

Imaging Studies


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(Chest radiography)

Pulmonary hypoplasia: In pulmonary

hypoplasia, a mediastinal shift to the

side of a homogenous density may be

depicted, with compensatory

herniation of the uninvolved lung.

The associated anomalies (cardiac,

skeletal, gut) may be seen.

Fig. 41. Chest radiograph shows diffuse haziness ofthe right hemithorax (arrow), slight deviation of thetrachea and heart to the right, and poor differentiationof the right heart border.

Imaging Studies

(


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(Chest radiography)

o Pulmonary sequestration: In pulmonary sequestration, an opaque or

cystic lesion is seen, depending on the presence of infection.

Fig. 42. Chest radiograph. The PA view demonstrates a left sidedtriangular density of the medial left lung base. On the lateral view, thetriangular density is seen posteriorly over the left lung base.

Imaging Studies

(


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(Chest radiography)

o Congenital lobar emphysema (CLE):In congenital lobar emphysema,

the involved lobe crossing the midline and the compressed normal lung

can be seen.

Fig. 43. Congenital lobar emphysema.

Imaging Studies

(


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(Chest radiography)

o This appearance does not change during expiration or in the decubitus

position.

o Vascularity of the involved site is attenuated.


Imaging Studies

(


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(Chest radiography)

o The intercostal spaces in the involved site appear widened, and the

hemidiaphragm is flattened. Lucent, anteriorly herniated lung pushes the

lung posteriorly, as seen on the lateral view.


Imaging Studies

(C i )


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(Chest radiography)

o The lesion must be differentiated from contralateral lung hypoplasia and

ipsilateral pneumothorax.


Imaging Studies

(Ch di h )


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(Chest radiography)

o The lesion must be differentiated from contralateral lung hypoplasia and

ipsilateral pneumothorax.

Fig. 44. Left lung hypoplasia. Fig. 45. Left sided pneumothorax.


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Imaging Studies

(Ch t di h )


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(Chest radiography)

o In a newborn, the lung fluid may not have been absorbed, and the mass may

appear fluid filled and homogenous.

Fig. 46. Congenital pulmonary airway malformation.

Imaging Studies

(Ch t di h )


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(Chest radiography)

o In an older child, pneumatoceles may be confused with cystic adenomatoid

malformation.

o Pneumatoceles are postinfectious pulmonary cysts.

Fig. 46. Congenital pulmonary airwaymalformation.

Fig. 47. Chest X-ray with large, expanding,multicystic pneumatocele associated with

Respiratory Syncytial Virus infection.

Imaging Studies

(Ch t di h )


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(Chest radiography)

o They occur after Staphylococcus aureus infection.

o However, they are unlikely to recur in the same area of the lung as where

cystic adenomatoid malformation occurs.


Fig. 47. Chest X-ray with large, expanding,multicystic pneumatocele associated with

Respiratory Syncytial Virus infection.

Imaging Studies

(Ch t di h )


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(Chest radiography)

o Bronchogenic cysts are central or mediastinal (relatively early embryologic

origin) and peripheral or intrapulmonary (late origin).

o The latter are rare (15%) and tend to be multiple.


Fig. 48. Chest X-ray revealing bronchogeniccyst in the posterior right middle lobe.


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Imaging Studies

(Ch t CT i )


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(Chest CT scanning)

o Bronchogenic cysts:In patients with bronchogenic cysts, CT findings are

characteristic.

o The lesions are sharply marginated and nonenhancing. If the lesions are

seen as soft-tissue attenuation instead of water attenuation, differentiating

from lymph nodes may be difficult.

Fig. 50.Chest CT scan. Bronchogenic cyst.

Imaging Studies

(Chest CT scanning)


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(Chest CT scanning)

o Pulmonary hypoplasia: In lung hypoplasia, loss of lung volume and

associated anomalies can be seen.

Fig. 51.Right lung hypoplasia. Chest CT scan showsherniation of left lung to right side with narrow right main

bronchus and shift of heart to right side.

Imaging Studies

(Chest CT scanning)


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(Chest CT scanning)

Pulmonary sequestration: In

pulmonary sequestration, the

findings may be only an unusual

solid attenuation. Therefore, CT

may have little to add tosonographic and plain

radiographic results unless the

anomalous vascular supply can

be visualized with vascular

contrast enhancement.Fig. 52. CT with IV contrast of the thorax showing an IntralobarBronchopulmonary Sequestration. The yellow arrow in framesA and B point to a hyperdense region in the left lower lobe of thelung with small cystic lesions containing air within it. The redarrows in frames C and D show a contrast enhanced vesselarising from the aorta and supplying the area of hyperdensity in

the lung.


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Imaging Studies

(MRI)


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(MRI)

o MRI: MRI is particularly useful

when delineation of blood vessels

is important. It is the study of

choice in difficult cases of

bronchogenic cysts.

o The cysts appear bright on T2-

weighted images and do not

enhance after the administration of

gadolinium-based contrast

material.Fig. 55.MRI in the supine (A, B) and right lateraldecubitus (C, D) positions. Bronchogenic cystmasquerading as pericarditis.

Imaging Studies

(MRI)


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(MRI)

o Pulmonary sequestration: MRI

and magnetic resonance

angiography (MRA) can be

performed to identify pulmonary

pathology, and aberrant systemicvessels. MRI and MRA have been

suggested as the diagnostic

procedures of choice for

evaluating sequestration of the

lung.

Fig. 56. MR-Angiography showing an aberrant vesselfrom the celiac trunk (white arrow) to a lung sequesterin the right lower lobe.

Imaging Studies

(MRI)


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(MRI)

o Cystic adenomatoid

malformation: In cases of

hydrops fetalis in a fetus with a

prenatal, MRI may be beneficial

for planning surgery. Cysts largerthan 3 mm are depicted as areas of

increased signal intensity on T2-

weighted images.

Fig. 57. Congenital cystic adenomatoid malformation. Fetus at22 weeks gestation. a, b and c Fetal sagittal, coronal, andaxial single-shot fast spin-echo MR images of the fetal chestshow a complex hyperintense lesion with cysts inside in theright lung (arrows). CT after birth dshows the lesion, which isproportionally smaller than in the MR images


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Imaging Studies

(Prenatal ultrasonography)


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o Pulmonary hypoplasia: In lung hypoplasia, renal malformations,

oligohydramnios, decreased fetal movements in neuromuscular disease,

dysmorphisms in trisomies, and skeletal dysplasias may be identified. The

thoracic-to-abdomen ratio and lung area are useful parameters. Pulmonary

arterial flow can be measured by using Doppler studies.

Fig. 58. Diaphragmatic Hernia. A. Transverse image through the chest shows the stomach (S) and a largevolume of small bowel (straight arrows) occupying the left chest and displacing the heart (curved arrow) intothe right thorax. No lung is visible, indicating that severe pulmonary hypoplasiais very likely. B. In anotherfetus, a moderate volume of lung (L) is visible in the right thorax even though the heart (long arrow) isdisplaced rightward by the herniation of bowel (short arrows) and stomach (S) into the left thorax.

Imaging Studies



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o Congenital lobar emphysema:In congenital lobar emphysema, a large fluid-

filled lobe may be seen.

Fig. 59. Sagittal section of the thorax showing enlargement of the leftlung. The right lung has normal echogenicity.

Imaging Studies



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o Cystic adenomatoid malformation: In cystic adenomatoid malformation, a

unilateral cystic mass is seen. However, the patient's postnatal clinical course

and chest radiographic findings may be normal, and CT, MRI, and/or MRA

may be indicated.

Fig. 60. 27th week of gestation. Image shows an axial view through the area of cysticadenomatoid malformation of the left fetal lung, type I. Large anechogenic, left-sided lesion(arrow) displaces the heart to the right.

Imaging Studies

(Isotope ventilation scanning)


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(Isotope ventilation scanning)

o Although specific changes occur on isotope ventilation scanning, this

modality seldom adds clinically useful information.

o In congenital lobar emphysema, decreased ventilation initially occurs,

followed by isotope retention.

o Attenuated vascularity results in decreased perfusion.o Sequestration does not fill up at all during the early pulmonary phase, but it

does during the systemic (late) phase.

o The value of radionuclide imaging is limited because of the lack of anatomic

details.

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Congenital Lung Malformations