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Developmental Lung Malformations in Children
Recent Advances in Imaging Techniques, Classification System,and
Imaging Findings
Paul G. Thacker, MD,* Gary R. Schooler, MD,w Michael J. Caplan,
MD,zand Edward Y. Lee, MD, MPHy
Abstract: Congenital lung anomalies represent a diverse group
ofdevelopmental malformations of the lung parenchyma,
arterialsupply, and venous drainage, which may present anywhere
fromthe prenatal period through adulthood. It is imperative for
radio-logists to be aware of imaging techniques and imaging
appearanceof these anomalies across the pediatric age range. This
reviewpresents the spectrum of these lesions that are often
encountered indaily clinical practice. Each anomaly is discussed in
terms ofunderlying etiology, clinical presentation, and imaging
character-ization with emphasis on the most up-to-date research and
treat-ment. Knowledge of these areas is essential for accurate,
timelydiagnosis, which aids in optimizing patient outcomes.
Key Words: congenital lung anomalies, prenatal imaging, com-
puted tomography, magnetic resonance imaging
(J Thorac Imaging 2015;30:2945)
LEARNING OBJECTIVESAfter completing this CME activity,
physicians should
be better able to:1. Distinguish the most commonly encountered
congenital
lung anomalies encountered in thoracic imaging2. Analyze the
most common anatomic locations of con-genital lung anomalies
3. State other developmental anomalies associated withcongenital
lung anomalies
Congenital lung anomalies (CLA) have an annualincidence of 32 to
42/100,000 population13 and represent aheterogenous group of
developmental abnormalities yield-ing a wide variety of imaging and
clinical manifestations.Many will be detected during early
childhood, whereasothers will remain occult into adulthood. It is
thus imper-ative for radiologists to be cognizant of the proper
imaging
techniques and imaging appearances for each lesion togarner
timely and accurate evaluation and diagnosis.
This article provides practical imaging techniques inthe
evaluation of CLA. In addition, this article includes up-to-date
information of underlying etiology, clinical pre-sentation,
characteristic imaging ndings, and currenttreatments. Future
directions, which can lead to improvedunderstanding and evaluation
of CLA, are also discussed.
PRACTICAL IMAGING TECHNIQUES ANDEVALUATION
Detailed descriptions of the imaging characteristics foreach
lesion are provided under the respective sections.However,
usefulness analysis and description of the availableimaging
modalities are informative. Four modalities arecurrently used for
the imaging evaluation of CLA, inclu-ding chest radiography (CR),
ultrasound (US), computedtomography (CT), and magnetic resonance
imaging (MR).
CRDespite CLA often being detected by prenatal US or
MR, CR remains the initial imaging modality for the detec-tion
and characterization of these lesions postnatally, even ifpatients
are asymptomatic. If obtainable, posteroanterior andlateral
radiographs are the technique of choice. However, in avery young
patient, a lateral radiograph may not be feasible,and a single
anteroposterior radiograph must suce.
Radiographic ndings vary depending on the lesiontype and size.
However, general principles can provide aclue to the presence of a
CLA and include: (1) focal opacity/mass; (2) focal lucency; (3)
thoracic asymmetry; (4) vascularabnormalities; (5) airway
anomalies; and (6) other con-genital lesions involving the spinal
column, heart, andgastrointestinal tract.2,3 The presence of 1 or a
combinationof these ndings may help in further imaging
recom-mendations or sometimes point to a denitive diagnosis.
USUS has become an integral tool of maternofetal med-
icine and is the modality of choice for fetal screening.
Fetallungs appear uniformly hyperechoic compared with theliver.
Focal increased areas of echogenicity or cyst mayprovide an early
clue to the presence of an underlying CLA(Fig. 1). However, the rst
clue is often cardiomediastinalshift with the heart serving as an
important landmark in thefetal chest, occupying a thoracic volume
of 25% to 30% onthe 4-chamber view.4 Postnatally, US provides a
widelyavailable and radiation-free modality for CLA
evaluation,usually following initial radiographs.
Optimal acoustic windows in the neonate and youngchild include
the parasternal, transsternal, and intercostal
*Assistant Professor of Radiology and Radiological
Science;zAssociate Professor of Pathology and Laboratory
Medicine,Medical University of South Carolina, Charleston, SC;
wPediatricRadiology Fellow, Department of Radiology; and yChief of
Divi-sion of Thoracic Imaging, Director of Magnetic Resonance
Imag-ing, Department of Radiology, Boston Childrens Hospital
andHarvard Medical School, Boston, MA.
All authors and sta in a position to control the content of this
CMEactivity and their spouses/life partners (if any) have disclosed
thatthey have no nancial relationships with, or nancial interests
in,any commercial organizations pertaining to this
educationalactivity.
Correspondence to: Edward Y. Lee, MD, MPH, Chief of Division
ofThoracic Imaging, Director of Magnetic Resonance
Imaging,Department of Radiology, Boston Childrens Hospital and
HarvardMedical School, 300 Longwood Ave. Boston, MA 02115
(e-mail:[email protected]).Copyright r 2014 by
Lippincott Williams & Wilkins
REVIEW AND SA-CME ARTICLE
J Thorac Imaging Volume 30, Number 1, January 2015
www.thoracicimaging.com | 29
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approaches utilizing a high-resolution 10 to 15MHz linear-array
transducer.5 At least 2 orthogonal planes are acquired,with Doppler
used for aberrant vascularity evaluation. Withincreased patient
age, US becomes limited because of decreasedsonographic windows,
and US may simply add to increasedcost while providing little
additional diagnostic information.
CTAfter CRs, CT, specically multidetector CT (MDCT),
is generally recommended in CLA evaluation. MDCTadvantages
include fast acquisition times, high spatial res-olution, and
exquisite detail of multiplanar (MPR) and 3-dimensional (3D)
reconstructions.2,6 Disadvantages includeits relatively high doses
of radiation and respiratory motionin the subset of children unable
to cooperate with breath-holding. These disadvantages have
progressively decreasedwith newer-generation scanners and low-dose
techniques.
Optimal scan coverage is of utmost importance forCLAs.
Generally, coverage extends from the thoracic inletto the
diaphragm. In specic situations, for example,extralobar
sequestration and type 2 pulmonary arteryslings, coverage may be
extended. Technical parameters willvary on the basis of the CT
scanner model, patient size, andimaging protocol. However, some
general parameters fortube current, kilovoltage, collimation, and
table speed areworth considering. Given the wide range of
pediatricpatient sizes, both tube current and kilovoltage are
variedon the basis of patient weight. For patients
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Postnatally, the respiratory system becomes air lled,resulting
in marked trachea, bronchial, and lung hypointensityon all pulse
sequences, providing little anatomic detail outsideof pathologic
abnormalities. However, denition of aberrantvascularity remains
exquisite, particularly after gadoliniumadministration. It should
be noted that gadolinium should onlybe utilized if necessary in the
early neonatal period, given therelative renal insuciency of
newborn kidneys.
In addition to standard descriptive anatomic informa-tion, MR
can provide useful physiological data beyond whatis available by
other modalities. Residual lung volumes oftenrepresent the
predominant driver of morbidity and mortalityin patients with large
CLAs.14 Phase contrast imaging cangive useful ow dynamics within
some vascular CLAs.15
Lastly, MR is limited in the full evaluation of thepulmonary
parenchyma given the low proton density of lungtissue and resultant
weak MR signal. To compensate,hyperpolarized gases, for example,
3He and 129Xe, have beeninvestigated as methods to improve lung MR
signal.1618
Thus, both structural and functional information can beobtained
with ventilation imaging. However, research inchildren has been
largely conned to those with asthma andcystic brosis.18 As such,
the utility of hyperpolarized gas forCLA evaluation has not yet
been demonstrated.
SPECTRUM OF IMAGING FINDINGS
Branching Anomalies
Developmental Interruptive LesionsAgenesis, Hypoplasia, and
Aplasia. Fetal lung under-
development is classied into 3 categories: lung agenesis,lung
aplasia, and lung hypoplasia.2,3
Currently, the cause of pulmonary agenesis and apla-sia remains
unknown. With pulmonary agenesis, there iscomplete absence of all
normal pulmonary structuresaecting either one or both hemithoraces.
In pulmonaryaplasia, a rudimentary bronchus is present, whereas
thelung parenchyma and pulmonary vasculature are absent.When
aecting both hemithoraces, pulmonary agenesis/aplasia is uniformly
fatal. However, patients with unilateralpulmonary agenesis/aplasia
may remain asymptomatic intoadulthood.
In contrast, the pulmonary artery and bronchus arepresent but
hypoplastic with a variable degree of lungparenchyma in pulmonary
hypoplasia. Pulmonary hypo-plasia is divided into 2 subcategories.
In primary pulmo-nary hypoplasia, there is no identiable cause.
Secondarypulmonary hypoplasia results from limited fetal
pulmonarydevelopment produced by varied intrinsic and
extrinsiccauses, such as congenital diaphragmatic hernia,
oligohy-dramnios, thoracic dystrophies, and congenital
pulmonarymasses.2,3
The imaging appearance of pulmonary agenesis,aplasia, and
hypoplasia is dependent on the amount ofpulmonary structures
present. On all imaging scans, theaected hemithorax is
asymmetrically small with hemi-diaphragm elevation and variable
amounts of mediastinalshift. Hyperination of the contralateral lung
may bepresent and can herniate across the central chest (Fig.
3).
Bronchial Atresia (BA). BA results from subsegmentalor segmental
bronchial obstruction with normal formationof the airway distal to
the obstruction. The exact cause ofthe obstruction remains elusive
with 2 theories proposed.One theory holds that BA results from
obliteration of theconnection between the primitive bronchial cells
and the tipof the bronchial bud. A second theory postulates that
BAresults from a focal ischemic insult causing focal bronchiallumen
disconnection.3
Historically, BA was thought to be an isolated anomaly.This is
no longer the case as multiple associated congenitalanomalies have
recently been described. In a study by Ried-linger et al,19 BA was
present in 50% of congenital lobaremphysema (CLH) cases, 70% of
congenital pulmonary air-way malformations (CPAM), 82% of
intralobar sequestra-tions, and 100% of extralobar sequestrations.
The associationof BA with sequestrations and CPAMs has led to the
phrasebronchial atresia sequence to encompass this maldevelop-ment
spectrum.19 Generally, pediatric BA patients present withrecurrent
infection or respiratory distress with severity relatedto the
degree of parenchymal disease. With little or noparenchyma
involvement, patients may remain asymptomatic.
Classically described on CR, BA appears as a round oroval
opacity, most commonly in the apical or apicoposte-rior upper lobe
segments, although it may occur in anysegment. These opacities
represent impacted mucous distalto the atretic bronchus. With
distal air trapping, a focalhyperlucency lung segment may be seen.
If there is anassociated congenital mass, mucus impaction and
airtrapping may be obscured. In this case, the CR appearancewill be
that of the associated mass. If additional imaging isnecessary, CT
is often the next modality utilized. Distal tothe atretic bronchus,
mucous-lled bronchi will appear asdilated, tubular opacities.
Hyperinated lung will be seendistal to the impacted bronchi and is
thought to result fromcollateral air drift through pores of Kohn
and the pulmo-nary interstitium2,3,6,20,21 (Fig. 4). Current
treatmentinvolves resection because of increased infection
risk.
FIGURE 2. Sagittal T2 image through the fetus shows a
trian-gular-shaped hyperintense mass (*) representing a CPAM,
whichresides posterior to the heart within the left lower lobe.
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Foregut Duplication Cyst. On gestational day 26, lungdevelopment
begins as a ventral diverticulum from theprimitive foregut. Foregut
duplication cysts result fromdefective foregut budding and comprise
a spectrum ofabnormalities including esophageal duplication and
bron-chogenic, and neurenteric cysts. Dierentiation is based
onhistologic examination with bronchogenic cysts
containingrespiratory epithelium and esophageal duplication
cystsdemonstrating squamous epithelium and/or pseudos-tratied
epithelium22 (Fig. 5A). Esophageal duplicationcysts may contain
other ectopic gastrointestinal tract tissueincluding ectopic
gastric mucosa with the associated risk forhemorrhage.23
Bronchogenic cysts occur in the paratracheal, hilar,and
subcarinal regions in 65% to 90% of cases, mostcommonly in the
subcarinal region6,2426 (Fig. 5B). In 12%of cases, bronchogenic
cysts occur intraparenchymally.27
Esophageal duplication cysts occur in a similar distributionand
may be intimately associated with the esophagus. Iflocated in the
middle mediastinum and associated with thefocal cleft in the
adjacent vertebral body, a neurenteric cystmay be diagnosed.
Typically, small lesions are asymptomatic and inci-dentally
detected. With large lesions, patients may becomesymptomatic, often
presenting with respiratory symptoms,dysphagia, or chest pain.
Cysts may become infected if incontinuity with the esophagus or
tracheobronchial tree; thismanifestation occurs more often in older
children and is lesscommon in infants and neonates.
On prenatal US, foregut duplication cysts appear asunilocular,
cystic masses most commonly found in themiddle mediastinum.28 If a
prenatal MR is performed, theyusually manifest as
well-circumscribed, smooth masses withheterogenous T1 signal and T2
hyperintensity.4 If cysticuid is hemorrhagic or signicantly
proteinaceous, dupli-cation cysts may be uniformly T1
hyperintense.
Yet, foregut duplication cysts are often rst identiedon CR,
manifesting as round or oval, well-circumscribedmasses.2 Splaying
of the main stem bronchi may be seen.Generally, CT is performed for
further evaluation oncedetected on CR and these lesions share a
similar CTappearance as smooth, well-dened, rounded or oval
masseswith homogenous internal attenuation if uncomplicated(Fig.
5). Fifty percent of lesions will have CT attenuationvalues close
to that of water.3,6 However, variable attenu-ation can occur
depending on cystic uid protein content.Postcontrast, uncomplicated
foregut duplication cysts have
FIGURE 3. A, Frontal radiograph of the chest in a neonate
showsunilateral agenesis of the left lung. The heart and
mediastinalstructures are shifted into the left hemithorax. Note
the umbilicalvenous catheter, which is deviated to the left of
midline, butremains within the right atrium. B, Axial image from a
contrast-enhanced CT of the thorax reveals absence of the left
pulmonaryartery and pulmonary veins. M indicates main pulmonary
artery;RP, right pulmonary artery.
FIGURE 4. Coronal reformatted image from a contrast-enhancedCT
of the thorax shows hyperlucency within the apicoposteriorsegment
of the left upper lobe, surrounding a tubular opacity(arrow)
extending to the left superior hilum, findings represent-ing
BA.
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minimal or no wall or internal enhancement. With con-current or
prior infection, foregut duplication cysts mayhave a thick or
irregular wall with more robust enhance-ment. Air-uid levels may
also be seen.
If infected or symptomatic, thoracoscopic or opensurgical
resection may be performed. Recent alternatives tosurgical
resection have been proposed and include percu-taneous or
transbronchial cyst aspiration.2
Ectopic or Supernumerary Bronchial LesionsTracheal Bronchus.
First described in 1785 by Sandifort
as an aberrant bronchus originating from the trachea
andsupplying the right upper lobe, the term tracheal bronchusnow
refers to multiple bronchial anomalies whereby anaberrant bronchus
arises from either the main bronchi or thetrachea and supplies the
upper lobe territories.29 Over theyears, additional terms have been
utilized. True tracheal
bronchi originate directly from the trachea, normally within2 cm
from the carina. A displaced bronchus refers to theabsence of a
normal upper lobe bronchus with the trachealbronchus supplying the
entire ipsilateral upper lobe. A pigbronchus refers to when the
right upper lobe bronchus isdisplaced onto the trachea. The
bronchus is termed super-numerary when it supplies the ipsilateral
upper lobe inadditional to a normally bifurcating or trifurcating
upperlobe bronchus.30 Prevalence is 0.1% to 2% on the right and0.3%
to 1% on the left.29,31 A displaced tracheal bronchus ismore common
than a supernumerary type.32
Aected children are usually asymptomatic. However,tracheal
bronchi can be associated with recurrent upperlobe infection,
bronchiectasis, or persistent upper lobeatelectasis. Tracheal
bronchi may occur with other con-genital anomalies including
cardiac anomalies, trachealstenosis, and in Down syndrome.30
Although not often apparent on CR, tracheal bronchimay appear as
a tubular lucency arising from either the tra-chea or main stem
bronchi and tracking into the ipsilateralupper lobe. An ipsilateral
upper lobe opacity can be seen withsuperimposed infection or
atelectasis. Nevertheless, trachealbronchi are almost always rst
diagnosed on cross-sectionalimaging. On CT, tracheal bronchi appear
as a well-denedbronchus arising from the trachea or main stem
bronchi andextending into the ipsilateral upper lobe (Fig. 6).
Super-numerary or displaced subtyping is readily apparent
byevaluating for a normal branching pattern of the mainbronchi. 3D
reconstructions exquisitely demonstrate theaberrant bronchial
anatomy, but their denitive usefulnessfor treatment planning has
yet to be demonstrated. MRimaging occasionally may demonstrate the
presence of atracheal bronchus as a hypointense tubular branch.
As these anomalies are usually asymptomatic, noparticular
treatment is normally needed. However, itspresence is important to
communicate in patients under-going intubation because of the risk
of occluding thebronchus. With recurrent infection, surgical
resection ofboth the bronchus and the lobe it supplies may
benecessary.33
Accessory Cardiac Bronchus. An accessory cardiacbronchus is a
supernumerary bronchus originating from themain bronchi or bronchus
intermedius and coursing in aninferior direction toward the
pericardium. Most endblindly. Overall frequency in the population
is approx-imately 0.08%.29 Accessory cardiac bronchi are
oftenasymptomatic. In older children, they may serve as a sourceof
recurrent infection, and aected patients can presentwith cough and
hemoptysis.29 Cases of aspergillomas andtumors within accessory
cardiac bronchi have beenreported.29,34,35
The role of CR is limited. If infection or tumor ispresent, a
focal soft tissue opacity may be demonstrated,most commonly in the
subcarinal region. Still, cardiacbronchi are almost always rst
demonstrated on CT. Here,cardiac bronchi will appear as a focal
accessory bronchusarising from the inferior aspect of the main stem
bronchi orthe medial wall of the bronchus intermedius.
Theseanomalies then course inferiorly to the adjacent pericar-dium
where they abruptly end in a blind pouch. Infection ortumor appears
as a focal opacity at the tip or surroundingthe cardiac
bronchus.
No treatment is necessary for uncomplicated accessorycardiac
bronchi. If recurrent infection develops or tumor ispresent, a
thoracotomy with surgical resection is warranted.
FIGURE 5. A, Medium-power pictomicrograph of a section froma
bronchial duplication cyst view showing pseudostratified col-umnar
epithelium and glands. B, Coronal reformatted imagefrom a
contrast-enhanced chest CT demonstrates a mediastinalmass (*)
splaying the carina and resulting in obstruction of theleft main
stem bronchus with air trapping (arrows) in the leftlower lobe.
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Parenchymal Anomalies
Congenital Lobar Hyperination (CLH)CLH, also known as congenital
lobar emphysema and
congenital lobar overination, results from intrinsic orextrinsic
narrowing of the bronchial lumen and manifests asoverination of 1
or multiple pulmonary lobes.2,3 Absenceor weakness of bronchial
cartilage represents intrinsiccauses of bronchial narrowing.2
Extrinsic etiologies includeenlarged or aberrant vessels and
mediastinal masses.
There are 2 classications of CLH predicated onalveolar number.
Hypoalveolar CLH has fewer thanexpected alveoli with alveolar
overdistension. In poly-alveolar CLH, the number of alveoli is
increased 3- to 5-fold in the aected lung segment with each
individualalveolus normally inated (Fig. 7A). Thus, the
aectedlobe(s) are overinated because of the increased number
ofnormally inated alveoli.2,3 Presentation often depends ontype,
with hypoalveolar CLH presenting earlier in life.Respiratory
distress is what typically brings patients toclinical attention,
with severity dependent on the amount ofhyperination and associated
compression of mediastinalstructures and adjacent lung.2,6 CLH is
often detectedduring the neonatal period and has a distinct lobe
predi-lection. The most common site is the left upper lobe,with the
right middle lobe being the next most commonfollowed by the right
upper lobe (Fig. 7B). Lower lobeinvolvement is uncommon. Rarely,
CLH may be bilateralor multifocal.36
On fetal US, CLH manifests as a hyperechoic,homogenous mass with
variable associated compression ofthe adjacent normal lung and
mediastinal structures. Onfetal MR imaging, CLH presents as a
homogenous, T2-hyperintense mass.4 With CR, CLH demonstrates a
classictemporal progression in the early neonatal period. Early
on,CR will show a focal mass-like opacity resulting fromretained
fetal uid. As fetal uid is cleared, there is pro-gressive
hyperlucency of the aected lobe(s). The aectedlobe(s) may become
increasingly overdistended withincreasing compression of the
adjacent lung and media-stinum. If detected past the neonatal
period, CLH may be
confused with CPAM. Here, CT can be useful for
furthercharacterization and dierentiation. In large CLH lesions,the
aected lobe(s) will be hyperinated with displacementof the
pulmonary vessels, compression of the adjacent lung,and
contralateral mediastinal shift. Ipsilateral hemi-diaphragm
compression and rib interspace splaying may beseen.6
CLH is treated surgically, with timing dependent onlesion size
and the degree of respiratory compromise.6,3740
Care must be taken during operative ventilation to
avoidpreferential aeration of the aected lobe with
associatedprogressive hyperination and
respiratory/cardiovascularcollapse from tension physiology. With
successful surgicalresection, patients have an excellent
prognosis.39
CPAMCPAMs are a heterogenous group of cystic and non-
cystic anomalies and are the most common CLA,
FIGURE 6. Anterior view from a volume-rendered 3D CT imageof the
lungs and airway demonstrates the entire course ofa tracheal
bronchus (arrow) and its relationship to the distaltrachea.
FIGURE 7. A, Pictomicrograph at low-power magnificationreveals
an increased number of alveoli, which are normallyinflated and
without features of maldevelopment consistent withpolyalveolar CLH.
B, Coronal reformatted CT image demon-strates hyperlucency of the
left upper lobe in this patient withCLH.
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representing about 30% to 40% of cases.4144 CPAMs arethought to
result from early airway maldevelopment fromintrauterine airway
obstruction,2,4 supported by histologicand pathologic changes of
exuberant primary bronchiolarovergrowth in communication with an
abnormal bronchialtree lacking cartilage.2,24,32,37,4547 Arterial
supply normallyarises from the pulmonary artery with pulmonary
venousdrainage. Patients present early in life with
respiratorydistress. If presenting in later life, they often
manifest asrecurrent infection involving the same segment of the
lung.However, a substantial portion of CPAMs may remainasymptomatic
throughout life and are only incidentallydetected.
CPAM classication was rst proposed by Stockeret al in 197746 and
was recently updated by Stocker,47
expanding from 3 to 5 types. With this expansion, the
oldnomenclature of cystic adenomatoid malformations wasreplaced by
CPAM. This term is more accurate given thatonly 3 of 5 types are
cystic and only 1 type has adenomatoidchanges. The revised Stocker
classication includes 5 types(0 to 4), with classication predicated
on histologic sim-ilarities to the developing bronchial tree and
airspace aswell as cyst size.47 Type 0 CPAMs have severe acinar
dysgenesis aecting all lung lobes and are uniformly
fatal.Solitary or multiple macrocysts (>2 cm) characterize type
1CPAMs and are of bronchial or bronchiolar origin (Fig. 8).Type 2
CPAMs have single or multiple cysts of bronchiolarorigin measuring
between 0.5 and 2 cm (Fig. 9). Type 3CPAMs have multiple microcysts
measuring r0.5 cm andare predominately solid. This type is the only
adenomatoidCPAM type and has a bronchiolar-alveolar duct
origin.Type 4 CPAMs have a distal acinar origin and are
char-acterized by large air-lled cysts. Type 4 CPAMs
areindistinguishable by imaging from type 1
pleuropulmonaryblastoma.2,4,47
CPAMs are often rst identied on prenatal US. OnUS, the overall
mass size and associated compressive eectson the adjacent normal
lung and mediastinal structuresmay be assessed. In some cases,
CPAMs may be sub-categorized prenatally, adding important
prognostic value.Types 1 and 2 (macrocystic) CPAMs appear on
prenatalUS as echogenic masses with variable-sized cysts.4 Type
3CPAMs are indistinguishable on prenatal US from othersolid CLAs,
appearing as a homogenous echogenic mass.Occasionally, associated
anomalous vascularity may be
FIGURE 8. A, Coronal reformatted image from a contrast-enhanced
CT of the thorax in a patient with a type 1 CPAMshows a large
air-filled cyst within the right upper lobe. B, Grosssurgical
specimen showing a large cyst with a trabeculated wallin a type 1
CPAM.
FIGURE 9. A, Axial image from a contrast-enhanced CT of
thethorax in a different patient with a type 2 CPAM reveals a
mul-ticystic mass in the right lower lobe. Note that none of the
air-filled cysts measure >2 cm in diameter. B, Low-power
magnifi-cation view of microcystic, dilated bronchiole-like
structures in atype 2 CPAM.
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seen. In such cases, a hybrid lesion is diagnosed
(furtherdiscussed below).
CRs are often utilized in the postnatal period, andimaging
manifestations are dependent on the underlyingtype. The single
exception to this principle is type 0 CPAMs,which generally receive
no postnatal imaging given therapidly deteriorating clinical
course. On CR, type 1 CPAMsappear as a mixed solid and cystic lung
mass with at least 1cyst measuring >2cm. If a single
large/dominant cyst ispresent, they may be dicult to distinguish
from CLH.Similarly, type 2 CPAMs are mixed cystic lung masses
withcysts measuring 0.5 and 2 cm.4,47 Alternatively, type 2CPAMS
may manifest as a persistent area of consolidationwith cysts only
demonstrable on cross-sectional imaging.2
Much like their prenatal sonographic appearance, type 3CPAMs
appear on CR as solid-appearing focal opacitiesindistinguishable
from other solid CLAs. Type 4 CPAMsare indistinguishable from type
1 pleuropulmonary blasto-mas, appearing as a large cystic
lesion.
After initial chest radiographs, CT or MR imaging isoften
utilized for further characterization and treatmentplanning. With
these modalities, the imaging appearanceclosely correlates with
that of their CR appearance withcyst presence and size determining
type classication(Fig. 8A). These cysts may be completely air lled
or con-tain air-uid levels.6 On MR, if the cysts are uid
lled,typically the uid is hyperintense on T2. Conversely, if
thecysts are air lled, they usually appear diusely hypointenseon
all pulse sequences. Type 3 CPAMs are composed ofinnumerable
microcysts, which are in general notindividually discernible on CT
or MR. Thus, type 3CPAMs almost always appear on CT and MR as a
focalsolid lesion with diuse homogenously increased T2 signalon
MR.4
Treatment for symptomatic patients is operative, which isnow
often performed via thoracoscopy with either a lobec-tomy or
segmentectomy performed. Treatment for asympto-matic patients
remains controversial. Most believe that electiveresection is
prudent given the associated risks of hemorrhage,recurrent
infection, and potential risk for malignancy.6
Vascular Anomalies
Anomalies of the Pulmonary ArteryInterruption (Absence) of a
Main Pulmonary Artery.
The primitive sixth aortic arch gives rise to the proximalaspect
of the main pulmonary artery. Failure of the for-mation of the
sixth aortic arch results in proximal inter-ruption of the
pulmonary artery. Given their dieringembryological origin, the
hilar and distal pulmonaryarteries form normally.6,4851 Vascular
supply to theaected lung results from collateralization of ow
throughbronchial and intercostal arteries with enlargement of
thecontralateral pulmonary vessels. However, overall ow tothe
aected lung is diminished, resulting in ipsilateralpulmonary
hypoplasia. Venous drainage of the aected sideis usually normal.6
Patients typically present withhemoptysis from bronchial arterial
enlargement, pulmo-nary hypertension, or recurrent infection,
although patientsmay remain asymptomatic.50,51
Proximal interruption of the pulmonary artery maymanifest in a
similar manner on CR as mild to moderatepulmonary hypoplasia with
small lung size, volume loss,and mediastinal shift. The
intraparenchymal vascularity isdiminished, and the ipsilateral
hilum may appear small or
absent. With collateralized arterial supply, there may alsobe
increased peripheral reticular vascular markings. On CT,the focal
absence of the proximal pulmonary artery isshown to best advantage
with termination of the pulmo-nary artery usually within 1 cm of
its origin from the mainpulmonary artery. Recently, MDCT
angiography with 3Dreconstructions has been shown to have
particular utility indepicting not only the focal discontinuity of
the pulmonaryartery but also the extent of arterial
collateralization,contralateral pulmonary artery enlargement, and
associatedcentral airway anomalies.10
Early treatment is key, as it may improve aected lungand
pulmonary arterial growth. Surgical intervention con-sists of
grafting or direct anastomosis of the main and hilarpulmonary
artery segments. In older patients presentingwith recurrent
hemoptysis or pulmonary hypertension,embolization of collateral
vessels may be warranted.2,6
Anomalous Origin of the Left Pulmonary Artery Fromthe Right. If
the left sixth aortic arch is completely obli-terated during
development, the left pulmonary artery mayarise anomalously from
the posterior right pulmonaryartery. This rare congenital anomaly
is commonly referredto as a pulmonary sling, with the term sling
deriving fromthe left pulmonary artery having a looping
appearancearound the trachea as it passes between the trachea
andesophagus from right to left. Patients generally present atan
early age with upper and lower respiratory symptomsincluding
episodic apnea, stridor, and respiratorydistress.2,3
Anomalous origin of the left pulmonary artery fromthe right
occurs in 2 varieties. Type 1 is associated with anormally
positioned carina at the T4 to T5 vertebral level,with
characteristic compression of the posterior trachealwall, anterior
esophageal wall, and the right main stembronchus. In type 2
pulmonary artery slings, the trachea iselongated with inferior
carinal displacement, generally tothe T6 level. The carina takes on
a T-shaped morphologywhereby the main bronchi arise perpendicularly
from thecarina giving them a horizontal course. In 50% of
cases,there is diuse tracheal stenosis with complete
cartilaginousrings. Fifty percent of patients with a type 2
pulmonarysling will have congenital heart defects.52
Pulmonary sling imaging manifestations are depend-ent on type
and associated anomalies. Classically, on con-trast esophagram
there is an external impression on theposterior aspect of the
trachea and the anterior aspect ofthe esophagus, the only vascular
anomaly to cause thisappearance. A complete vascular ring is formed
when aligamentum arteriosum is present, encircling and com-pressing
the trachea while sparing the esophagus.
On CR, the right lung may be hyperinated owing toright main stem
bronchus compression. On the lateralradiograph, the posterior
tracheal wall may be compressedby a soft tissue opacity interposed
between the trachea andbronchus, with anterior tracheal
displacement. MDCT with3D reconstructions have been shown of value
in the eval-uation of pulmonary slings and is the current
imagingmodality of choice6,10 (Fig. 10). MDCT demonstrates
theanomalous origin and course of the left pulmonary artery.3D
reconstructions of the airway demonstrate the cong-uration and
extent of tracheal stenosis. Paired inspiratoryand expiratory views
are of great value in demonstratingassociated tracheomalacia. In
type 1, both axial and sagittalimages can demonstrate the anterior
esophageal impressionand compression of the posterior tracheal
wall. With
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intravenous contrast, the looping anomalous course of theleft
pulmonary artery can be seen. Associated right lunghyperination is
best depicted with expiratory images.6 CTfeatures of a type 2
pulmonary sling include a T-shapedcarina with caudal displacement
of the carina to the T6level. Long-segment tracheal stenosis may be
demonstratedand is seen to best advantage on coronal reformations
and3D reconstructions (Fig. 10B). When assessing type 2pulmonary
slings, it is prudent to image the entire course ofthe trachea, as
the stenosis can be diuse. Demonstratingthe extent of stenosis is
helpful for planning surgicalintervention.6
Although less often utilized, MR imaging can readilydemonstrate
the left pulmonary arterys anomalous origin
and course. Right lung hyperination can be detected byasymmetric
hemithorax volumes. Tracheal narrowing canalso be depicted,
although generally with less denitionthan that seen on MDCT.
Surgical division and reimplantation of the left pulmo-nary
artery is the treatment of choice. With long-segmenttracheal
stenosis, tracheoplasty may be necessary. Alter-natively, stenosis
resection with end-to-end anastomosis maybe utilized for
short-segment tracheal stenosis.53,54
Anomalies of the Pulmonary VeinPulmonary Vein Stenosis (PVS).
Etiologies for PVS
include both acquired and congenital causes. Congenitallesions
can be life threatening and are rarer, resulting fromuncontrolled
broblast growth with thickening and nar-rowing of the pulmonary
vein.6 Pediatric patients oftenpresent with symptoms of pulmonary
edema such asshortness of breath, cyanosis, and fatigue.
Correlating with patient symptomatology, CR demon-strates signs
of reduced pulmonary venous drainage,pulmonary venous hypertension,
and pulmonary edema.Recently, Mayhew et al55 evaluated CR ndings in
41 infantswith known PVS. The most common CR ndings
includedincreased interstitial opacity (100%), reticular opacity
(85%),and ground-glass opacity (71%). Although these are non-specic
signs of pulmonary edema, given the population ageand the very high
percentage of these ndings, the authorsconcluded that PVS should be
considered particularly whenthese ndings are heterogenous or
unilateral.55
Although PVS may be depicted on MR, CT is oftenutilized for
cross-sectional imaging as it better demonstratesassociated lung
parenchymal changes. The aectedpulmonary venous segment is usually
at or near its junctionwith the left atrium (Fig. 11). With disease
progression,pulmonary vein thickening and narrowing may extend
intoadjacent distal intraparenchymal pulmonary vein
segments.Pulmonary parenchymal changes follow that of
unilateralpulmonary edema. Recently, the utilization of 3D
recon-structions in the pediatric population has been shown
tosignicantly increase diagnostic accuracy, diagnostic
value,condence level, and intraobserver agreement.56
Due to the potential life-threatening consequences ofPVS,
accurate and prompt diagnosis is paramount. Treatmentstrategies
depend on disease extent. Focal or short-segmentPVS is treated with
percutaneous balloon dilatation andstenting. In long-segment
stenosis, lung transplantation maybe required.
Partial Anomalous Pulmonary Venous Return (PAPVR).PAPVR occurs
when 1 or more pulmonary veins retain anembryologic connection to
the primitive splanchnic system ofcardinal veins.57 The anomalous
drainage pattern is varied,and these anomalous veins may drain into
the vena cavae, thecoronary sinus, azygous vein, a persistent left
vertical vein, ordirectly into the right atrium. A concurrent sinus
venosusdefect may be present, particularly in patients with right
upperlobe PAPVR.52 PAPVR results in a right to left shunt.
Ifhemodynamically signicant, patients will present with symp-toms
of pulmonary overcirculation and pulmonaryhypertension.
Imaging ndings of PAPVR are dependent on locationand number of
the anomalous pulmonary vein/veins, wherethe veins drain, and
ndings of pulmonary overcirculation.In general, CRs are limited for
the evaluation of PAPVR(with the exception of scimitar
syndromediscussed later).In the presence of a hemodynamically
signicant shunt,
FIGURE 10. A, Axial image from a contrast-enhanced CT of
thethorax reveals the aberrant left pulmonary artery (arrow)
arisingfrom the right pulmonary artery in a patient with a
pulmonaryartery sling. The pulmonary artery courses posterior to
the tra-chea and anterior to the esophagus to reach the left lung.
B,Anterior view from a volume-rendered 3D image of the tracheaand
proximal bronchi shows diffuse narrowing of the intra-thoracic
trachea (arrow) due to complete cartilaginous rings anda T-shaped
configuration of the carina characteristic of a type 2pulmonary
artery sling.
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CRs may demonstrate pulmonary arterial and right
heartenlargement.
Both CT and MR can clearly demonstrate the numberand course of
the anomalous pulmonary veins (Fig. 12). Themost common PAPVR
involves a vertically oriented anom-alous left upper lobe pulmonary
vein, which courses lateral tothe aortic arch with drainage into
the left innominate vein.This type is also the most common to not
have an associatedcongenital heart lesion.52,58 CT and MR can also
demon-strate the associated sinus venosus defect, appearing as
afocal defect in the posterior-superior atrial septum. On
CT,intermixing of contrast-enhanced and noncontrasted bloodacross
this defect may be demonstrated. On MR, a jet owvoid may be
demonstrated to pass through the defect.
PAPVR is usually associated with an excellent prog-nosis.
Surgical correction with patch placement is per-formed if a sinus
venosus defect is present. If the anomalousdrainage is to the
superior vena cava, the patch can beextended to separate the
pulmonary from systemicdrainage.30
Combined Anomaly of the Pulmonary Artery andPulmonary Vein
Pulmonary Arteriovenous Malformation (AVM).AVMs are a
consequence of a segmental maldevelopmentof pulmonary capillaries
resulting in direct communicationof a pulmonary arterial branch
with its associated/adjacentpulmonary vein. An alternative and more
accurate term forpulmonary AVMs is pulmonary arteriovenous
stulae.Nevertheless, common convention refers to these lesions
aspulmonary AVMs.
Pulmonary AVMs are most often congenital with asmall population
being acquired, typically in patients withchronic liver disease,
those who have had prior surgery forcongenital heart disease, and
in patients with prior atypicalinfection, for example,
tuberculosis.3,6,5963 CongenitalAVMs are classically associated
with Osler-Weber-Rendu,also known as hereditary hemorrhagic
telangiectasis(HHT), an autosomal dominant disorder.
Patients with HHT often come to clinical attention dueto
symptoms or for screening in the setting of an HHTfamily history.
The classic symptom triad includes epistaxis,family history, and
telangiectasias, particularly nasal. Strokeor cerebral abscess may
occur from right to left shunting.Thirty-ve percent of HHT patients
have 1 or morepulmonary AVMs3 and may also have AVMs in otherorgans
such as the liver, pancreas, and gastrointestinal tract.
Pulmonary AVMs manifest on CR as nodular orlobulated
well-circumscribed soft tissue opacities, with 50%to 70% occurring
in the lower lobes.6 Solitary or multipleAVMs may be present.
Occasionally, a tubular or curvi-linear opacity may be seen to
extend from the lesion with acourse directed toward the ipsilateral
hilum, representingthe draining vein, the feeding artery, or both.
Generally, theintraparenchymal nature of these lesions is
apparent,
FIGURE 11. A, Axial image from a contrast-enhanced CT of
thethorax in a patient with PVS demonstrates narrowing (arrows)near
and at the level of pulmonary vein insertion involving veinsfrom
both lungs. B, Posterior view from volume-rendered 3D CTimage from
the same patient shows narrowing (arrow) of the leftpulmonary
vein.
FIGURE 12. Coronal image from contrast-enhanced MRangiography
demonstrates drainage of the upper and middlelobe pulmonary veins
(arrow) into the superior vena cava justabove the level of the
right atrium, findings consistent withpartial anomalous pulmonary
venous return.
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although pulmonary AVMs may project over the media-stinum on
both frontal and lateral projections, makingexact localization
dicult.3
After CR, MDCT is often performed and representsthe modality of
choice for assessing number, size, andlocation as well as the
associated vascular supply. Contrast-enhanced examinations are
preferable. However, AVMsmay be seen on noncontrast CT obtained for
alternativereasons and manifest as a focal, serpiginous or
lobulated,intraparenchymal soft tissue nodule or mass. On
post-contrast imaging, pulmonary AVMs robustly enhance, andthe
feeding and draining vascular pattern becomes readilyapparent. In
lesions with complex angioarchitecture, 2D-MPR and 3D
reconstructions may be valuable in fullyelucidating the vascular
supply (Fig. 13).
The quantity of right to left shunting throughpulmonary AVMs is
the predominant driver of bothsymptoms and need for intervention.
Generally, treatmentis oered when feeding arteries reach a diameter
of 3mm orgreater, even if asymptomatic. Treatment options
includeballoon occlusion, coil embolization, and surgical
excision.
Combined Lung and Vascular Anomalies
Hypogenetic Lung (Scimitar) SyndromeHypogenetic lung syndrome,
classically known as sci-
mitar syndrome, consists of right-sided PAPVR, right
lunghypoplasia, heart dextroposition, and anomalous right
lungsystemic arterial supply.4,6,24,32,64 The anomalous pulmo-nary
vein may drain into the portal venous system, thehepatic venous
system, or, most commonly, the inferiorvena cava. Other congenital
anomalies are common andoccur in up to 25% of cases.2 Clinical
presentation is
dependent on patient age. Older children often present
withrecurrent infection in the right base. Young infants
oftenpresent with symptoms of right to left shunting andpulmonary
overcirculation from the anomalous pulmonaryvenous drainage. Some
patients may remain asymptomatic.
Scimitar syndrome is largely detected postnatally,although there
are a few reports within the literaturedescribing prenatal
detection.6567 CR often is the rstpostnatal imaging study. Unlike
many of the afore-mentioned anomalies, scimitar syndrome is rather
unique inthat its denitive diagnosis can be made by the
radiographalone. The anomalous pulmonary vein appears as a
curvi-linear, tubular soft tissue opacity coursing in a
verticalorientation in the lower right hemithorax. The right
hemi-thorax is small in size, and the right lung is hypoplastic
andhyperlucent (Fig. 14).
Despite the ability of CRs to make the denitivediagnosis, most
patients undergo cross-sectional imaging,that is, CT or MR. CT and
MR are benecial in demon-strating the anomalous pulmonary vein
course, caliber, anddrainage pattern. The scimitar vein most
commonly drainsinto the inferior vena cava and less commonly into
thehepatic veins, portal veins, right atrium, superior vena
cava,and the azygous vein.3,6,32,42,68 With angiographic
techni-que, the anomalous arterial supply may also be
demon-strated. 3D reformations are helpful in demonstrating boththe
venous and arterial anomalies in a single image.6 Otherassociated
nonvascular anomalies are readily demonstratedon CT including
hypoplasia of the right lung with alteredlobulation and bronchial
branching anomalies.2,6,69 Post-operatively, CT is helpful in
evaluating reimplantationcomplications, for example, thrombosis and
stenosis.
Treatment is largely reserved for symptomaticpatients,
especially with a left to right shunt ratio >2:1. Theanomalous
systemic arterial supply is often embolized withsurgical
reimplantation of the anomalous pulmonary veinto the left
atrium.2,6
Pulmonary SequestrationPulmonary sequestrations represent the
second most
common congenital pulmonary anomaly.4 It is composedof
dysplastic pulmonary tissue, contains no normal con-nection to the
tracheobronchial tree, and receives a systemicvascular
supply.24,6,32,42,48,7072 Pulmonary sequestrationsare traditionally
divided into 2 categories, that is, intralobarversus extralobar, on
the basis of its venous drainage pat-tern and pleural investment.
Intralobar sequestrationscomprise 75% of sequestrations. They do
not have theirown pleural investment but rather share pleura with
theadjacent normal lung. Generally, intralobar sequestrationsdrain
through the ipsilateral pulmonary venous system.4 Itremains
controversial whether or not these represent truecongenital
anomalies in all cases, with some authors argu-ing that they are
acquired as a result of recurrent localizedinfection, resultant
bronchial obstruction, and eventualparasitization of the adjacent
systemic vascular supply.However, with prenatal imaging advances,
evidence sup-ports that at least a subcategory is congenital as
there hasbeen increased detection of intralobar sequestrations in
thefetal lungs. In contrast, extralobar sequestrations are
gen-erally considered to be a congenital anomaly and accountfor 25%
of sequestrations.2,3,6,32,48,70,72 Extralobar seques-trations
drain through the systemic venous system andcontain their own
pleural investment. Regardless of type,pulmonary sequestrations
receive a systemic arterial supply
FIGURE 13. Coronal reformatted maximum intensity projectionCT
image in an HHT patient reveals a right lower lobe pulmonaryAVM
(arrow) with its associated feeding pulmonary artery (a)
anddraining pulmonary vein (v).
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most commonly directly from the thoracic or abdominalaorta with
less common supply from the celiac, splenic,intercostal,
subclavian, and coronary arteries.4,48
The presentation depends on the sequestration type.Extralobar
sequestrations most often present in the neo-natal period or in
early infancy as a focal mass on imaging.Intralobar sequestrations
present later in childhood as afocus of recurrent
infection.2,6,32,48,70,72
Like most congenital pulmonary anomalies, but partic-ularly with
pulmonary sequestrations, imaging plays a keyrole in diagnosis and
surgical planning. On prenatal US,sequestrations appear as a
hyperechoic homogenous lesion,most commonly in the lower left
hemithorax.4 Doppler maydemonstrate systemic arterial supply
distinguishing seques-trations from other CLAs. Sequestrations
appear on prenatalMR as a homogenous T2-hyperintense mass.
Althoughgadolinium is often not utilized, the arterial supply may
beseen as a serpiginous, tubular signal void arising from
theaorta.4,42
After the prenatal period, the imaging appearance
ofsequestrations is more variable and depends on type, con-current
or prior infection, and other anomalies. US has alimited role
postnatally. However, it does have value and maybe utilized to
demonstrate the aberrant arterial supply to aprenatally detected
mass and conrming the diagnosis.Depending on institutional and
surgeon preferences, additionalimaging may not be obtained.
However, a large majority ofpatients have a postnatal CR, often
followed by CT.
Pulmonary sequestrations appear as a focal opacity ormass in the
lower lobe in 98% of CRs.6,32 Occasionally, theaberrant systemic
artery may be demonstrable.24 Withrecurrent infection,
intralesional necrosis may develop, anda more cystic appearance
with or without air-uid levelsmay be seen.2,6
After the initial CR, MDCT with 3D reconstructionsis generally
utilized for both diagnosis conrmation andpresurgical planning
(Fig. 15). The mass itself can have avariable appearance ranging
from a complex cavitary masswith intracystic air-uid levels to a
heterogenouslyenhancing solid lesion. In 50% of cases,
sequestrations canbe categorized into intralobar and extralobar on
the basisof the venous drainage pattern.73,74 Extralobar
sequestra-tions most commonly drain into the azygous system andless
commonly through the portal system, subclavian veins,and internal
mammary veins.6,70,73 Intralobar sequestra-tions typically drain
through the inferior pulmonary vein.6
A recent study consisting of 46 pediatric patients showedthat
axial CT images allow accurate diagnosis of the types,location,
associated mass eect, and anomalous arteries ofCLAs. However,
supplemental MPR and 3D MDCTimages add additional diagnostic
value.10
A variant of sequestration known as a hybrid lesion isworth
noting. Hybrid lesions represent a midpoint on aspectrum between
CPAMs and pulmonary sequestrations.On CT, hybrid lesions show
characteristics of a CPAMwhile having an anomalous systemic
arterial supply.
MR and MR angiography provide nonradiationalternatives for the
evaluation of pulmonary sequestrations.However, they are less often
utilized given the limited def-inition of pulmonary parenchyma.
Depending on the his-tory of infection, sequestrations appear on
postnatal MR assolid lesions with both T1 and T2 hyperintensity,
which isconsidered to result from internal airway mucus
impac-tion.7577 MR angiography images with or without the useof
gadolinium have been shown to be eective in thedepiction of the
aberrant arterial supply.3,75,78
Management is predominantly surgical given the riskfor recurrent
infection and the small risk for associated
FIGURE 14. A, Frontal chest radiograph demonstrating a
largeanomalous pulmonary vein (S). B, Coronal T2-weighted
imageshows the anomalous pulmonary vein (S) draining into
thejunction of the inferior vena cava (IVC) and right atrium
(RA).
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malignancy.2,30 Recently, embolization of the anomalousarterial
supply has been suggested as an alternative tosurgery with a
reported high rate of success.3,79,80
FUTURE DIRECTIONSAlthough much knowledge has been gained over
the
last several decades regarding CLAs, there are still areasthat
need further elucidation. Precise etiologies remainelusive for a
large portion of these lesions. Further research,particularly in
molecular biology and genetics, may helpshed light into why and
when these abnormalities occur.Continued research and utilization
of advanced imagingtechniques with particular emphasis on
nonradiationalternatives may be helpful in future imaging. One
partic-ularly fruitful area is in the advancement of chest
MRimaging in which imaging times are progressively decreas-ing with
ever-increasing spatial resolution.12 However, MRremains decient in
lung parenchymal detail when com-pared with CT, although this
particular drawback is cur-rently the subject of research, with
recent studies supportingfast-imaging MR sequences as comparable to
CT forthoracic abnormalities. Lastly, the establishment of a
con-sensus between our obstetric, pediatric, and surgical
col-leagues in terms of optimal management for each lesioncould be
helpful in standardizing practice and ultimatelyimproving patient
outcomes.
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54. Ho AS, Koltai PJ. Pediatric tracheal stenosis. Otolaryngol
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SA-CME EXAM30:1Developmental Lung Malformations in Children:
Recent Advances in Imaging Techniques,
Classification System, and Imaging FindingsINSTRUCTIONS FOR
OBTAINING AMA PRA CATEGORY 1 CREDITSt
The Journal of Thoracic Imaging includes CME-certied content
that is designed to meet the educational needs of its readers.This
article is certied for 1.5 AMA PRA Category 1 CreditsTM. This
activity is available for credit through 12/22/15.
Accreditation StatementLippincott Continuing Medical Education
Institute, Inc., is accredited by the Accreditation Council for
Continuing MedicalEducation to provide continuing medical education
for physicians.
Credit Designation StatementLippincott Continuing Medical
Education Institute, Inc., designates this journal-based CME
activity for a maximum of 1.5AMA PRA Category 1 CreditsTM. This
activity is available for credit through 12/22/15.Physicians should
only claim credit commensurate with the extent of their
participation in the activity.
To earn CME credit, you must read the article in The Journal of
Thoracic Imaging and complete the quiz, answering at least70
percent of the questions correctly. For more information on this
JTI SA-CME educational oering, visit the LippincottCMEConnection
portal at http://cme.lww.com/cme/public/journals/123 to register
online and to complete the free CMEactivity online.
Questions marked with an asterisk are ABR Self-Assessment Module
(SAM) questions. Participants can claim credit for theSAM
regardless of the test outcome. Notify the ABR of the SAM
completion, or visit the ABR website at www.theabr.orgto set up or
log in to your personal database to record the number of SAMs you
completed. The SAM ID number will beprinted on the CME certicate
for your records. If you wish to include the ID number in your ABR
database, contact aMOC Specialist at the ABR oce for instruction by
calling 520-519-2152.
SA-CME EXAMINATION
After completing this SA-CME activity, physicians should be
better able to:1. Distinguish the most commonly encountered
congenital lung anomalies encountered in thoracic imaging2. Analyze
the most common anatomic locations of congenital lung anomalies3.
State other developmental anomalies associated with congenital lung
anomalies
*1. In contrast to pulmonary agenesis, which of the following is
present in patients with pulmonary aplasia?a) Pulmonary arteryb)
Pulmonary veinc) Rudimentary bronchusd) Hypoplastic lower lobe
Please see the following reference for further study:1. Thacker
PG, Rao AG, Hill JG, Lee EY. Congenital lung anomalies in children
and adults: current concepts and imaging
ndings. Radiol Clin North Am. 2014;52:155181.
*2. What is the most common location of bronchogenic cysts?a)
Anterior mediastinumb) Subcarinal regionc) Right lower lobed) Left
paratracheal space
Please see the following reference for further study:1. McAdams
HP, Kirejczyk WM, Rosado de Christensen ML, Matsumoto S.
Bronchogenic cyst: imaging features with
clinical and histopathologic correlation. Radiology. 2000;
217:441446.
*3. Which of the following is the most common congenital lung
anomaly?a) Congenital lobar hyperinationb) Congenital pulmonary
airway malformationc) Extralobar sequestrationd) Pulmonary
aplasia
Please see the following reference for further study:1. Azizkhan
RG, Crombleholme TM. Congenital cystic lung disease: contemporary
antenatal and postnatal management.Ped Surg International. 2008;
24:643657.
Thacker et al J Thorac Imaging Volume 30, Number 1, January
2015
44 | www.thoracicimaging.com r 2014 Lippincott Williams &
Wilkins
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*4. What is most commonly associated with interruption of a main
pulmonary artery?a) Anomalous venous drainageb) Tracheal bronchusc)
Congenital lobar hyperinationd) Pulmonary hypoplasia
Please see the following reference for further study:1. Lee EY,
Boiselle PM, Cleveland RH. Multidetector CT evaluation of
congenital lung anomalies. Radiology. 2008;247:
632648.
*5. Which of the following is most commonly associated with
pulmonary sling?a) Complete tracheal ringsb) Right aortic archc)
Diaphragm duplicationd) Tracheoesophageal stula
Please see the following reference for further study:1. Fiore
AC, Brown JW, Weber TR, Turrentine MW. Surgical treatment of
pulmonary artery sling and tracheal stenosis.Ann Thorac Surg. 2005
Jan;79(1):3846.
*6. Which pulmonary vein is most commonly involved in partial
anomalous pulmonary venous drainage?a) Left superiorb) Left
inferiorc) Right superiord) Right inferior
Please see the following reference for further study:1. Ho ML,
Bhalla S, Bierhals A, Gutierrez F. MDCT of partial anomalous
pulmonary venous return (PAPVR) in adults. JThorac Imaging. 2009
May;24(2):8995.
*7. Which of the following is most commonly associated with
pulmonary arteriovenous malformation?a) Marfan syndromeb)
Birt-Hogg-Dube syndromec) Down syndromed) Osler-Weber-Rendu
syndrome
Please see the following reference for further study:1.
Cartin-Ceba R, Swanson KL, Krowka MJ. Pulmonary arteriovenous
malformations. Chest. 2013 Sep;144(3):103344.
*8. Which of the following is mostly likely to be diagnosed
denitively on chest radiography alone?a) Intralobar sequestrationb)
Bronchogenic cystc) Scimitar syndromed) Partial anomalous pulmonary
venous drainage
Please see the following reference for further study:1. Korkmaz
AA, Yildiz CE, Onan B, Guden M, Cetin G, Babaoglu K. Scimitar
syndrome: a complex form of anomalous
pulmonary venous return. J Card Surg. 2011 Sep;26(5):52934.
J Thorac Imaging Volume 30, Number 1, January 2015 Developmental
Lung Malformations in Children
r 2014 Lippincott Williams & Wilkins www.thoracicimaging.com
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