Ebook Diagnostic imaging of infants and children: Part 1

Diagnostic Imaging of
Infants and Children
VOLUME

I


Notice
Medicine is an ever-changing science. As new research and clinical experience
broaden our knowledge, changes in treatment and drug therapy are required.
The author and the publisher of this work have checked with sources believed
to be reliable in their efforts to provide information that is complete and gener­
ally in accord with the standards accepted at the time of publication. However,
in view of the possibility of human error or changes in medical sciences, nei­
ther the author nor the publisher nor any other party who has been involved
in the preparation or publication of this work warrants that the information
contained herein is in every respect accurate or complete, and they disclaim
all responsibility for any errors or omissions or for the results obtained from
use of the information contained in this work. Readers are encouraged to
confirm the information contained herein with other sources. For example
and in particular, readers are advised to check the product information sheet
included in the package of each drug they plan to administer to be certain that
the information contained in this work is accurate and that changes have not
been made in the recommended dose or in the contraindications for adminis­
tration. This recommendation is of particular importance in connection with
new or infrequently used drugs.


Diagnostic Imaging of
Infants and Children

Robert G. Wells,

MD

Pediatric Diagnostic Imaging, SC
PDI Pediatric Teleradiology
Milwaukee, Wisconsin
Director, Pediatric Imaging

Northwestern Lake Forest Hospital
Lake Forest, Illinois
Associate Clinical Professor of Radiology and Pediatrics
Medical College of Wisconsin
Milwaukee, Wisconsin

VOLUME

I

edical
New York

Chicago

Milan

San Francisco

New Delhi

Lisbon

San Juan

Seoul

London

Madrid

Singapore

Mexico City

Sydney

Toronto


� McGrow·H/1/ CompanieS

Copyright©

2013 by The McGraw-Hill

Companies, Inc. AU rights reserved. Except as permitted under the United States Copyright Act of

1976,

no part of this

publication may be reproduced or distributed in any fonn or by any means, or stored in a database or retrieval system, without the prior written permission of the
publisher.
ISBN:

978-0-07-180839-2

MHJD:

0-07-180839-6

The material in this eBook also appears in the print version of this title: ISBN:
MHJD:

0-07-176966-8.

978-0-07-176966-2,

All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an
editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark. Where such designations appear in this book,
they have been printed with initial caps.
McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. To contact a
representative please e-mail us at
TERMS OF USE
This is a copyrighted work and The McGraw-Hill Companies, Inc. ("McGraw-Hill") and its licensors reserve all rights in and to the work. Use of this work is

subject to these tenns. Except as pennitted under the Copyright Act of

1976

and the right to store and retrieve one copy of the work, you may not decompile,

disassemble, reverse engineer, reproduce, modify, create derivative works based upon, transmit, distribute, disseminate, sell, publish or sublicense the work or

any part of it without McGraw-Hill's prior consent. You may use the work for your own noncommercial and personal use; any otber use of the work is strictly
prohibited. Your right to use the work may be terminated if you fail to comply with these tenns.
THE W ORK JS PROVIDED "AS JS." McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY,
ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING

THE

WORK, INCLUDING ANY INFORMATION THAT CAN

BE ACCESSED THROUGH THE W ORK VIA HYPERLJNK OR OTHERWISE, AND EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED,
INCLUDING BUT NO T LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. McGraw-Hill
and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or
error free. Neither McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for
any damages resulting therefrom. McGraw-Hill has no responsibility for the content of any information accessed through the work. Under no circumstances shall
McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability
to use the work, even if any of them has been advised of the possibility of such damages. This limitation of liability shall apply to any claim or cause whatsoever
whetber such claim or cause arises in contract, tort or otherwise.


To Annie,
my loving wife and best friend.
To my sons, Jack, Sam, and Joe,
who have taught me much more than I will ever teach them.
And to Jack Sty,
who one day said to me, "Bob, let's write another book . . .

"


This page intentionally left blank


Contents
Foreword
Preface
Acknowledgments

ix
xi
xiii

.........................................................

...........................................................

..........................................

VOLUME I
PART 1

................................

1 Developmental Abnormalities
of the Lungs and Diaphragm
2 Neonatal Lung Disease
3 Pulmonary Infection

.........................

................................

Abnormalities, and Systemic Disease
5 Pulmonary Neoplasms and Masses

PART 2

179

219

........................................

...................................................

17 Autoimmune Disorders of the Brain

THE CARDIOVASCULAR
.....................................

Heart and Pericardium

...............................

11 Congenital Heart Disease

13 The Vascular System

277
279

................

................................

14 Congenital Abnormalities of the Brain

......

315

403

....................................

THE BRAIN

15 Hydrocephalus

267

...........................

12 Anomalies of the Great Vessels

251

433

485

625

.........

18 Metabolic and Destructive
Disorders of the Brain

21 Head Trauma

PART 4

641

................................

20 Intracranial Vascular Abnormalities

683

.........

797

...........

..............................................

THE SPINE

of the Spine

847
887

................................

22 Developmental Abnormalities

889

.................................................

23 Infection, Inflammation, and
Degenerative Disorders of the Spine

..........

24 Neoplasms and Masses of the Spine
25 Trauma and Surgery of the Spine

977

........

.............

957

1007

VOLUME II
PART 5

THE HEAD AND NECK

26 The Skull and Face

10 Acquired Diseases of the

PART 3

191

.............................................

SYSTEM

75

...........

....................................................

8 The Chest Wall

3

139

........

6 Pulmonary Trauma, Surgery,

7 The Mediastinum

1

45

......................................

4 Chronic Lung Disease, Genetic

9 The Breast

597

·································

19 Intracranial Neoplasms and Masses

THE THORAX

and Toxins

16 Intracranial Infections

27 The Orbit

...........

1043

.....................................

....................................................

28 The Paranasal Sinuses

1045

1091
1137

...............................

29 The Nose, Nasal Cavity,
and Nasopharynx

........................................

30 The Neck, Pharynx, and Trachea
31 The Salivary Glands

................

..................................

32 The Thyroid and Parathyroid Glands
33 The Temporal Bone and Ear

1153

1173

1249

........

......................

1261
1293

487

.............................................

575
vii


viii

Contents

PART 6

THE GASTROINTESTINAL
SYSTEM

34 The Esophagus
35 The Stomach

1 323

....................................

1325

..........................................

1357

..............................................

50 Urinary Tract Calcifications
and Stones

.................................................

51 Urinary System Trauma,
Surgery, and Therapy

.................................

36 The Smalllntestine

1379

52 Renal Vascular Abnormalities

37 The Colon

1447

53 The Female Genital System

....................................

...................................................

38 The Omentum, Mesentery,
and Peritoneal Cavity

.................................

39 The Anterior Abdominal Wall

1495

....................

1503

40 Abdominal Trauma and

Otherlntraabdominal Emergencies

PART 7

THE HEPATOBILIARY
SYSTEM

....................................

41 The Hepatobiliary System
PART 8

THE PANCREAS

42 The Pancreas

PART 9

..........

......................

............................................

THE SPLEEN

43 The Spleen

........................

...........................

1629

1631

.......................................

1 653
1655

..................................................

47 Urinary System lnfection

48 Vesicoureteral Reflux

...........

...........................

.................................

49 Neoplasms and Masses
of the Urinary System

................................

1715

1741
1759
1777
1785

.......................

PART 11 THE ADRENAL CiLANDS
56 The Adrenal Glands

SYSTEM

...................................

58 Dysostoses and Developmental
Deformities

...............................................

59 Metabolic Bone Diseases

Go Systemic Arthritis

1 931

1933

...................................

...................................

57 Skeletal Dysplasias

1925

.........

PART 12 THE M USCULOSKELETAL

.........................

1965

1967

202 9
2073
2113

......................................

61 Hematological and

...........................

of the Extremity Soft Tissues

.....................

65 Musculoskeletal Trauma

2141

.......................

64 Nonneoplastic Abnormalities

Index

2123

.............................

62 Musculoskeletal Infections

..........................

1855
1887

..........................

..................................

63 Musculoskeletal Tumors

................................

46 Diseases of the Renal Parenchyma

Affect Both Genders

1827
1841

...................

55 Genital Abnormalities that

Ischemic Bone Disease

44 Developmental Abnormalities
45 Renal Cysts

1523

1609

PART 10 THE GENITOURINARY

of the Urinary System

1521

1607

.................................................

SYSTEM

1511

54 The Male Genital System

1813

2161

2237

225 9

.............................................................

/-1


Fo rewo rd
Diagnostic Imaging of Infants and Children

by Robert Wells

is a must-have text that I am sure you will keep as a con­

stant friend. It is a one-of-a-kind book, written in a style

pathophysiology. For clinicians, this text is a resource for
reviewing the advantages and disadvantages of various
imaging approaches and for understanding the signifi­

that is concise and informative. Kudos to Dr. Wells for the

cance of imaging findings. The easy-to-read style and the

superlative work.

clear correlation of radiologic findings with disease patho­

This richly illustrated reference covers the gamut of
pediatric diseases and injuries. Extensive integration of

physiology and clinical features make it an excellent choice
for medical students, residents, and fellows.

clinical considerations and review of disease pathogenesis

This text is a terrific source of information across the

help to make sense of imaging patterns and provide the

entire spectrum of pediatric radiology, and I strongly rec­

radiologist with tools to establish a confident diagnosis.

ommend this book to anyone interested in the subject.

Readers of various backgrounds will find this text use­

ful. Radiologists can pull it off the shelf for a quick review

Richard Towbin, MD

of the imaging findings and differential diagnosis of a con­

Radiologist-in-Chief

dition, with additional material available for those desiring

Phoenix Children's Hospital

a more in-depth review of the clinical presentation and

Phoenix, Arizona

ix


This page intentionally left blank


Preface
is designed to be

Because the approach to the individual patient does

an efficient reference source for the practicing radiologist,

not always fit with a disease category system, there are sup­

Diagnostic Imaging of Infants and Children

a learning tool for radiology residents and fellows, and a

plemental features in the text that provide the reader with

cross-specialty resource for all medical providers who care

additional tools. Clinical Presentations sections interject

for children. Technologists in all imaging modalities will

also find it useful. The text is comprehensive, but concise.

discussions of key symptom-based considerations about
the differential diagnosis and imaging procedure selec­

Up-to-date descriptions of the clinical features, pathogen­

tion. In addition, differential diagnosis tables are included

esis, and pathology of diseases provide a solid background

where appropriate.

for understanding diagnostic imaging principles. The con­

Radiologists, pediatricians, pediatric specialists, and

tent encompasses essentially all pediatric conditions for

other health care professionals who care for children face

which diagnostic imaging is clinically important.

the ongoing and evermore complex challenge of choosing

The basic organization of the text is by organ system

the most accurate, least invasive, and most cost-effective

and disease category. For each condition, the reader is pre­

diagnostic imaging techniques for the individual patient.

sented with a brief overview of current information about

The balanced approach of this text provides the reader with

the pathogenesis, epidemiology, and clinical presentation.

tools to make informed decisions in everyday practice.

When appropriate, discussion of the disease pathology is
correlated with the findings on diagnostic imaging stud­

The information in Diagnostic Imaging of Infants and
Children is the result of an exhaustive review of the current

ies. The imaging features with each pertinent imaging

medical literature, blended with the practical knowledge

30

modality are reviewed sequentially. Imbedded "Pathology­

accumulated from nearly

Radiology" tables provide a quick reference for the key

radiologist. My sincere wish is for my fellow radiologists

findings.

years of practice as a pediatric

and clinical colleagues to find this a useful resource as they
strive to provide high-quality care to children.

xi


This page intentionally left blank


Acknowledgments
This book would not exist without the encouragement,

Wisconsin. The potentially chaotic process of preparing

guidance, and support of Dr. Jack Sty. He has been a men­

thousands of images for use in the book ran with preci­

tor, colleague, and friend throughout my career. His enthu­

sion under the guidance of my dedicated and energetic

siasm for excellence is infectious. My love for teaching and

administrative secretary, Sue Armson. Sue passed too

writing has grown under his influence.

early, but her spirit is part of this book.

My partner, Dr. Brian Lundeen, has been instrumen­

I wish to acknowledge Dr. Jeff Rosengarten and the

tal in helping to maintain our clinical practice as I have

other members of the radiology department at Northwest­

balanced my clinical duties with this time-consuming

ern Lake Forest Hospital. High-quality images from this

project. He has also contributed many of the figures in the

institution are scattered throughout the text. Also, thanks

text and assisted with proofing figure legends. Dr. Smita

to Dr. Darin Brannan and the staff at The Children's Cen­

Bailey, now at Phoenix Children's Hospital, has also pro­

ter in Bethany, Oklahoma.

vided key images.
The physician assistants, nurses, and technologists
at our outpatient radiology center, Pediatric Diagnos­

The editors and production staff at McGraw-Hill
have been supportive and professional. Special thanks to
Michael Weitz and Peter Boyle.

tic Imaging, have contributed in various ways, includ­

Finally, the special contribution of my family needs

ing manuscript proofing and acquisition of illustrative

to be recognized. My three sons, Jack, Sam, and Joe, have

images. Special thanks to Darci Grochowski for her assis­

tolerated a father who needed to devote large blocks of

tance with the musculoskeletal chapter.

time to this project. Only my oldest can remember a time

Several dedicated people assisted with photography,

when dad was not working on "the book." They have been

image organization, clinical correlation, and bibliographic

unwavering in their support and encouragement. My dear

research. They include Jessica Mainus-Sohns, Scott Byers,

wife, Annie, is the unnamed coauthor of this book. She

Kevin Cohen, and Monica Godat. Thanks as well to the fi le

has provided encouragement and advice. Her uncondi­

room staff and technologists at the Children's Hospital of

tional support made this book possible.

xiii


This page intentionally left blank

Diagnostic Imaging of
Infants and Children
VOLUME

I


This page intentionally left blank



This page intentionally left blank


CH A PTE R

1

Developmental Abnormalities
of the Lungs and Diaphragm

E M B RYOLOCY OF TH E LU NCS
AND PULMONARY VESSELS . . . . . . . . . . . . . . . . . . . . . .

3

Anomalous Origi n of the
Left Pulmonary Artery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26

Systemic Arterial S u pply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26
26

DEVELOPM ENTAL ABNORMALITI ES
OF TH E LU NCS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Pulmonary Agenesis and Aplasia. . . . . . . . . . . . . . . .

4

Anomalous Pulmonary
Venous Con nection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

P u l monary Hypoplasia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Anomalous Si ngle Pulmon ary Vei n ...... ......

27

Bronchial Atresia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Bronchopu l monary Seq uestration . . . . . . . . . . . . . .
Extralobar Sequestration . . . . . . . . . . . . . . . . . . . . . . . . . .
Intralobar Sequestration . . . . . . . . . . . . . . . . . . . . . . . . . .

9
1o
11

Pulmonary Arteriovenous
M alformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

28

Pulmonary Varix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30

Congen ital Cystic Adenomatoid
M alformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11

COM BI N ED ANOMALI ES OF LU NC
AND PULMONARY VESSELS . . . . . . . . . . . . . . . . . . . . . .

30

P u l monary Bronchogenic Cyst . . . . . . . . . . . . . . . . . . . .

19

Hypogenetic Lung Synd rome . . . . . . . . . . . . . . . . . . . . . .

30

Accessory Bronchus . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . .

20
20

32

Accessory Cardiac Bronchus . . . . . . . . . . . . . . . . . . . .

Bridging Bronchus...................................

21
21
21

DEVELOPM ENTAL LYM PHATIC
DISORDERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DEVELOPM ENTAL ABNORMALITI ES
OF TH E DIAP H RAC M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

33

Congenital Bronchial Stenosis . . . . . . . . . . . . . . . . . . . .

22

Congen ital Diaphragmatic Hernia . . . . . . . . . . . . . .

33

Congen ital Lobar Em physema . . . . . . . . . . . . . . . . . . . .

22

Eventration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

38

H orses hoe Lung . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24

Lung H ernias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25

Congen ital Paralysis of the
Hemidiaphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39

H epatic-Pulmonary Fusion . . . . . . . . . . . . . . . . . . . . . . . . .

39

ANOMALI ES OF PULMONARY VESSELS. . .

25

I nterruption ofthe M a i n
Pulmonary Artery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39

25

Tracheal Bronchus....................................
Esophageal Bronchus...............................

EMBRYOLOGY OF THE LUNGS
AND PULMONARY VESSELS
Fetal lung development can be categorized into the embry­

buds arise from this diverticulum. The developing air­
ways become separated from the esophageal portion
of the foregut by ingrowths of adjacent mesoderm that
form the tracheoesophageal septum. The lung buds elon­

onic, pseudoglandular, canalicular, and saccular phases.1

gate into primary lung sacs, and the 5 secondary bronchi

Embryonic development begins at 24 to 26 days gesta­

develop as outgrowths of the primary bronchi. This com­

tion when a diverticulum arises from the ventral wall of

pletes the embryonic period, at approximately the end of

the foregut. Over the next 2 days, the right and left lung

the fifth week.

3


4 Part 1 The Thorax
The pseudoglandular phase predominantly consists of

syndrome). Developmental arrest occasionally occurs at the

development of the bronchial tree. During this phase, the

segmental level. Segmental bronchial agenesis most often

airways are blind tubules lined with columnar or cuboidal

involves the right upper lobe.8.9

epithelium. The pseudoglandular phase occurs between the
fifth and 16th weeks of gestation. Nearly all of the conducting

The pulmonary arteries develop from the sixth aortic
arch. The proximal part of the sixth aortic arch becomes the

airways are present by the end of the pseudoglandular phase.

proximal segments of the right and left pulmonary arter­

The canalicular phase represents the early stage of

ies. On the left, the connection with the arch is maintained

development of transitional airways. There is decrease

as the ductus arteriosus. Pulmonary arterial development

in mesenchymal tissue within the developing lungs, and

parallels that of the airways during fetal development.

newly formed capillaries and air spaces approximate one

Postrlatal development results in increase in peripheral ves­

another. The canalicular phase occurs between the qth

sel branching commensurate with alveolar development

week and the 25th to 28th weeks.

until approximately 8 years of age. Anomalies of pulmonary

The saccular (or alveolar) phase relates to develop­

artery development include agenesis, hypoplasia, anoma­

ment of the alveoli. Defined acinar morphology is present

lous systemic connection, and arteriovenous malformation.

by the 28th week of gestation. During the final weeks of

During the embryonic phase of fetal development, pul­

fetal development, there is prolific development of alveoli.

monary venous blood drains from the splanchnic plexus

Alveolar development continues in postrlatal life to approx­

into the primordium of the systemic venous system.

imately the age of 8 years.

Pulmonary venous development begins with caudal and

Tracheal cartilage development predominantly occurs

cranial outpouchings of the sinoatrial regions of the heart.

during the pseudoglandular and canalicular periods. Initial

These extend toward the lung buds. The caudal outpouch­

cartilage development occurs during the seventh to eighth

ing regresses. The cranial portion develops as the common

weeks of gestation. Bronchial cartilage development occurs

pulmonary vein. Eventually, the common pulmonary vein

in a centrifugal direction.

incorporates into the left atrial wall. Residual splanchnic

Anomalies of the lung related to abnormal broncho­

pulmonary connections regress. This leaves

4 independent

pulmonary �ung bud) development include agenesis, bron­

pulmonary veins entering the left atrium. Potential pulmo­

chial atresia, tracheal atresia, some instances of congenital

nary venous anomalies include pulmonary varix, systemic

lobar emphysema, congenital cystic adenomatoid malfor­

connection, and agenesis.

mation, pulmonary bronchogenic cyst, tracheal bronchus,

Congenital lung malformations comprise a heteroge­

and accessory cardiac bronchus. The pathogenesis of bron­

neous and overlapping group of anomalies

chogenic cysts apparently involves abnormal epithelial bud­
ding caused by local defects in the mesenchymal substrate. 2

terminology applied to these lesions is often imprecise.

(Table 1-1).

The

There is overlap of the embryological, pathological, clinical,

The faulty development that results in cystic adenomatoid

and radiological features of these various lesions. A num­

malformation occurs later in gestation, and is character­

ber of classification schemes have been proposed in an

ized by disordered development of the bronchioles and fail­

attempt to provide order to the sometimes confusing array

ure of differentiation of the epithelium into a mature form.

of anomalies. Many investigators consider lung anomalies

This may be related to faulty signaling between the bron­

to represent a spectrum of pulmonary and vascular mal­

chioles and peribronchial mesenchyme during the period

development.10 Bush proposed simplified nomenclature

of active bronchial development, which occurs between the

based on the gross anatomy and imaging appearance. The

fifth and eighth weeks.3 The developmental mechanism

5 major categories in this system consist of a congenitally

of pulmonary sequestration involves both abnormal bron­

enlarged hyperlucent lobe, congenital thoracic malforma­

chial budding (supernumerary budding from the foregut,

tions, a congenitally small lung, absent lung, absent tra­

or pinching off from the developing bronchial tree) and

chea, and absent bronchus." Langston has developed a

failure of normal mesenchymal maturation (persistent sys­

classification system based on the pathologic features and

be caused by any developmental abnormality that results in

system. Langston emphasizes the importance of develop­

lobar air trapping, such as a focal anomaly of airway carti­

mental airway obstruction in the pathogenesis of multiple

lage, intrinsic or extrinsic bronchial obstruction, or abnor­
mal supporting stroma of the alveolar wall.6.7

seemingly unrelated lung malformationsP

temic arterial supply).4·5 Congenital lobar emphysema can

presumed embryogenesis. Table

1-1 is adapted from this

A spectrum of anomalies results from arrested devel­
opment of lung; this is termed the

complex.

agenesis-hypoplasia

The temporal stage of the arrested development

is an important determining factor in the nature of the
resultant anomaly. The patterns include agenesis (absence
of bronchus and lung), aplasia (absence of lung, but pre­
served bronchus), and hypoplasia

(rudimentary bron­

DEVELOPMENTAL ABNORMALITIES
OFTHE LUNCS

Pul monary Agenesis and Aplasia
Pulmonary

agenesis i s the complete absence of lung paren­

chus and lung). The agenesis-hypoplasia complex most

chyma, vessels, and bronchial structures in a lung, a lobe,

often involves an entire lung or lobe (hypogenetic lung

or (rarely) both lungs. Pulmonary

aplasia

represents the


Chapter 1 Deve l o p m ental A b n o r m a l ities of the L u n gs a n d D i a p h ragm 5
Table 1-1 . Congenital Lung M alformations

Absent or small lung

Pulmonary hypoplasia
Pulmonary agenesis
Pulmonary aplasia
Bronchogenic cyst
I solated bronchial atresia
B ronchial atresia with systemic vascu lar connection (intralobar sequestration)
Anomalous bronchial connection to the gastroi ntestinal tract
Cystic adenomatoid malformation, large cyst type
Cystic adenomatoid malformation, small cyst type
Extralobar sequestration
Laryngea l atresia
Solid (adenomatoid) cystic adenomatoid malformation
Polyalveolar lobe
·-- ·----- -- ...... ---

_ ...

------------------

---·-· - ·- ·---·------ - ------ ------------------------------------------·

B ronchopul monary malformation

--------- -----------------

-------

-------

Pulmonary hyperplasia and
related lesions

· ------- ------

---------- --- - ----- ------

Congenital lobar overinflation
Vascular anomalies

-------

------------------------------------

Systemic a rterial con nection to normal l u n g
Hypogenetic lung syndrome
Anomalous pul monary venous connection
I nterru ption of main pulmonary artery
Pulmonary arteriovenous malformation

Lym phatic cysts
Enteric cysts
S i m ple parenchymal cysts
-----

M iscellaneous cystic lesions

-------

same constellation of findings except that a rudimentary

Severe cardiac anomalies are more common in patients

bronchus is present. Pulmonary agenesis and aplasia

with agenesis of the right lung than with agenesis of the
left lung.'3·'4

result from a developmental abnormality at approximately

4

weeks of gestational age. The anomaly usually involves

Symptomatic children with agenesis of a lung often

an entire lung. The left upper lobe is the most common site

have anatomic distortion of the airway and vascular com­

of lobar agenesis/aplasia. The contralateral lung typically

pression. In some patients, there is intrinsic airway ste­

has compensatory enlargement, but is otherwise normal.

nosis. Symptomatic newborns exhibit manifestations of

Morbidity and mortality are greater in those patients with

respiratory distress: tachypnea, cyanosis, and impaired gas

right lung agenesis than in those with involvement of the

exchange.

left lung, presumably as a result of more pronounced medi­

Imaging studies demonstrate shift of normal lung to

astinal shift and concomitant torsion of the great vessels

fill the void created by agenesis or aplasia. There is marked

and major airways.

mediastinal shift and the contralateral lung bulges across

More than 50% of children with pulmonary agenesis
or aplasia have coexistent congenital anomalies of the

the midline

( Figure 1-1 ) .

The severity of contralateral

lung herniation varies between patients. If the left lung

cardiovascular, gastrointestinal, skeletal, or genitourinary

is absent, the right cardiomediastinal border sometimes

systems. Patent ductus arteriosus and patent foramen

produces a sharp perpendicular line adjacent to the left

ovale are the most common cardiovascular anomalies in

margin of the sternum as viewed on a frontal radiograph.

these children. The associated skeletal anomalies of the

With agenesis of the right lung, the left cardiomediastinal

limbs and spine tend to be ipsilateral to the lung abnor­

border is shifted to the right of the sternum and the entire

mality. Ipsilateral radial ray defects and hemifacial micro­

cardiac silhouette is contiguous with that of the liver

somia can occur in association with pulmonary agenesis.

The ribs are crowded together on the side of

( Figu re 1-2 ) .


6 Part 1

The

Thorax

A

Figure 1-2 Pulmonary agenesis.
There is no aerated right lung on this anteroposterior chest
radiograph of a newborn infant. The hyperinflated left lung
herniates across the midline

(arrows). There is rightward shift

of the trachea. The outlines of the heart are not visible; the soft­
tissue density of the cardiac structures in the right hemithorax
is contiguous with that of the liver. There are right-sided rib
deformities and spinal segmentation anomalies.

secondary effects on the airway and mediastinal vessels.
The imaging appearance of pulmonary aplasia is identical
to that of agenesis except that a rudimentary bronchus is
present.'5 ·'6
The radiographic findings of lobar agenesis/aplasia
are subtle. Most often, the ipsilateral lung is small and the
remaining lobes are hyperinfl.ated. There may be an abnor·
mal density in the region of the involved lobe that mim­
ics atelectasis. Agenesis of the right middle lobe and right
upper lobe or of the left upper lobe results in a retroster·
nal density that parallels the anterior chest wall on lateral
radiographs. At times, the radiographic appearance of lobar
8

Figure 1-1 Left pulmonary agenesis.
A, B. Anteroposterior and lateral radiographs show a small left
hemithorax and leftward shift of the mediastinal structures. The
left lung is absent. There is marked leftward displacement of
hyperexpanded right lung.

agenesis mimics that of lobar collapse. If the standard
radiographic findings are inconclusive, computed tomog­
raphy is diagnostic. MR can be helpful to demonstrate sec­
ondary airway abnormalities, and to define the mediastinal
vascular anatomy.'5·16

Pul monary Hypoplasia
The definition o f pulmonary hypoplasia i s deficient or

the absent lung. Bronchography and bronchoscopy dem­

incomplete development of the lung, such that there is

onstrate absence of the main bronchus in patients with

decreased size of the lung and a diminished number

agenesis. Cross-sectional imaging with MR or helical CT

of functioning pulmonary units (i.e., cells, airways, and

shows absence of lung parenchyma, bronchial structures,

alveoli). Both lungs are involved in most patients with

and pulmonary and bronchial vessels on the affected

pulmonary hypoplasia. Unilateral or lobar forms also

side. These studies are also valuable for documenting

occur, usually associated with anomalies of the ipsilateral


Chapter 1 Deve l o pmental A b n o r m a l ities of the L u n gs a n d D i a p h ragm

A

B

A An anteroposterior chest radiograph of a newborn with

by polycystic kidney disease, resulting in abdominal distention,

Figure 1-3 Pulmonary hypoplasia.

respiratory distress and abdominal distention shows small­

7

B. An abdominal radiograph shows large flank masses caused

displacement of bowel, and elevation of the diaphragm.

volume lungs, elevation of the diaphragm, and mild cardiomegaly.

pulmonary artery and pulmonary veins. Bilateral pulmo­

newborn, with cyanosis, tachypnea, hypoxia, hypercapnia,

nary hypoplasia typically causes severe, often fatal, neona­
tal respiratory distress.'7 ·18

be rapid progression to death from severe hypoxemia. The

Pulmonary hypoplasia occurs as a primary lesion in

small lungs are difficult to ventilate, and complications of

and acidosis. With severe bilateral involvement, there may

10% to 15% of cases. The more common secondary form is

mechanical ventilation are common; these include pulmo­

associated with one or more other conditions that directly

nary interstitial emphysema, pneumothorax, pneumome­

or indirectly interfere with lung development, usually by

diastinum, and pneumopericardium. Pneumothorax can

compromising the thoracic space available for lung growth.

also develop spontaneously in these infants.

Intrathoracic lesions are most common; these include

The radiographic diagnosis of bilateral pulmonary

congenital diaphragmatic hernia, extralobar sequestra­

hypoplasia is sometimes difficult. Lung aeration can ini­

tion, agenesis of the diaphragm, and a large fetal pleural

tially appear normal on chest radiographs. The small size

effusion or chylothorax. Asphyxiating thoracic dystrophy

of the lungs may not be appreciated until serial radiographs

(Jeune syndrome) is an example of a thoracic cage anomaly

show that the appearance is persistent. The thoracic cage

that compromises fetal lung development. Others include

is usually small and the diaphragm is elevated

short-rib polydactyly syndromes, metatrophic dysplasia,

Unilateral

pulmonary

hypoplasia

( Figure 1 -3) .

appears

radio­

Ellis-van Creveld syndrome, achondrogenesis, and severe

graphically as a small, but well aerated, lung. The ipsilat­

forms of osteogenesis imperfecta. Extrathoracic causes of

eral pulmonary artery is small or absent. Occasionally, an

pulmonary hypoplasia include oligohydramnios (e.g., renal

anomalous draining pulmonary vein is visible (e.g., scimi­

agenesis, severe urinary tract obstruction) and abdomi­

tar syndrome). The hypoplastic lung is oligemic, and blood

nal distention (e.g., ascites, polycystic kidney disease).

flow to the contralateral lung may be increased. The medi­

Diminished pulmonary vascular perfusion as a result of

astinum is deviated toward the side of the hypoplasia; this

a cardiac or vascular anomaly can also lead to pulmonary

is accentuated during inspiration

hypoplasia."'

graphic differential diagnosis includes hypogenetic lung

(Figure 1 -4) .

The radio­

The clinical presentation of pulmonary hypoplasia var­

syndrome, Swyer-James McLeod syndrome, and urlliateral

ies according to the severity of the anomaly. Most often,

absence of the pulmonary artery. Occasionally, there is cys­

there are manifestations of respiratory distress in the

tic distention of the hypoplastic lung (possibly as a result of


8 Part 1 The Thorax

A

B

Figure 1-4 Pulmonary hypoplasia.

obscuration of the right cardiomediastinal border, rightward shill

Anteroposterior and lateral chest radiographs of an asymptomatic

of the mediastinal structures, and lack of appropriate anterior

4-year-old child show diminished size of the right lung, with

extension of the right lung

a developmental defect at the bronchial-alveolar junction),

(arrows) on the lateral view.

Many clinicians also use the term

Potter syndrome

resulting in an appearance that overlaps that of congenital

to refer to similar, but not necessarily lethal, features of

cystic adenomatoid malformation.

infants who are the products of pregnancies in which

The early prenatal detection of clinically significant

there is severe oligohydramnios from causes other than

pulmonary hypoplasia is helpful for parental counsel­

bilateral renal agenesis. A more proper term in this

ing and planning for optimal perinatal management

situation is

Techniques for assessing the fetus with suspected pulmo­

tions account for approximately

nary hypoplasia include various measurements based on

manifestations of the Potter phenotype. These abnor­

Potter phenotype.

These mimicking condi­

8o% of newborns with

sonography and M R I. Sonographic measurements that

malities include cystic renal dysplasia, severe obstructive

can be useful include the ratio of fetal lung area to thoracic

uropathy, autosomal recessive polycystic kidney disease,

area, the ratio of thoracic circumference to abdominal cir­
cumference, and the ratio of lung area to thoracic area.

renal hypoplasia, medullary dysplasia, and Denys-Drash

syndrome. 2 3-25

MR allows estimation of the fetal lung volume, which can

be compared to the expected values for the gestational age

Bronchial Atresia

or evaluated as a ratio of lung volume to estimated body
weight.'9-2 '

Bronchial atresia is a focal obliteration of a proximal seg­

Potter syndrome refers to a constellation of findings that

mental or subsegmental bronchus. The pathogenesis of

occur with bilateral renal agenesis and other conditions

bronchial atresia is unknown, but apparently involves an

that cause severely diminished urine excretion in utero.

insult to a formed bronchus rather than a primary devel­

The findings include severe pulmonary hypoplasia, oligo­

opmental failure. One potential mechanism is an interrup­

hydramnios, and dysmorphic features. The bilateral pul­

tion of the arterial supply of a developing fetal bronchus,

monary hypoplasia in these infants usually results in death

with subsequent ischemia and scarring or discontinuity

in 3000 livebirths _The newborn with Potter syndrome has

more proximal aspect of the developing bronchus. Despite

soon after birth. Potter syndrome occurs in approximately 1

between the cells at the tip of the bronchial bud and the

characteristic features that include hypertelorism, epican­

the presence of an atretic bronchial segment, the distal

thic folds, low-set ears, a flattened nose, micrognathia, and

branches can develop normally. Typically, the abnormality

limb anomalies; the facial appearance in these children is
termed Potter facies. 22

ever, lobar or subsegmental bronchi can also be involved.

involves segmental bronchi at or near their origins; how­