Download Self-Assessment Examination - American College of Radiology

Self-Assessment Examination
CPI Pediatric Radiology Module 2014
IMAGE-RELATED QUESTIONS
1.
Radiographs of the knee were performed in a 13-year-old boy presenting with knee pain. Based on
these radiographs (Figures 1-1 and 1-2), which one of the following is the MOST likely diagnosis?
A. Osteosarcoma
B. Giant cell tumor
C. Chondroblastoma
D. Unicameral bone cyst
Fig 1-1. Knee. Radiograph. Frontal view.
CPI Pediatric Radiology Module 2014 Fig 1-2. Knee. Radiograph. Lateral view.
1
2.
Scapula radiographs were performed in an afebrile 4-year-old boy with chronic scapular pain. What is
the MOST likely diagnosis based on Figure 2-1?
A. Osteogenic sarcoma
B. Osteomyelitis
C. Unicameral bone cyst
D. Langerhans cell histiocytosis
Fig 2-1. Shoulder. Radiograph. Frontal view.
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CPI Pediatric Radiology Module 2014
3.
Radiographs of the forearm were performed in a 5-year-old boy with pain and arm deformity after a
fall. Based on these radiographs (Figures 3-1 and 3-2), which one of the following is the MOST likely
diagnosis?
A. Greenstick fracture
B. Galeazzi fracture-dislocation
C. Essex-Lopresti fracture
D. Monteggia fracture-dislocation
Fig 3-2. Forearm. Radiograph. Lateral view.
Fig 3-1. Forearm. Radiograph.
Frontal view.
CPI Pediatric Radiology Module 2014 3
NONIMAGE-RELATED QUESTIONS
29.Which one of the following conditions is MOST commonly associated with chordoma in children?
A. Von Hippel-Lindau syndrome
B. Neurocutaneous melanosis
C. Neurofibromatosis type 1
D. Tuberous sclerosis complex
30-32. Regarding fetal imaging, decide which of the following are True or False.
30. Pontine hypoplasia and a characteristic “Z-shaped” brainstem kinking are seen in Walker-Warburg
syndrome. True or False?
31. The cisterna magna should measure less than or equal to 10 mm. True or False?
32. A ratio of a congenital cystic adenomatoid malformation (CCAM) volume relative to fetal head
circumference (CCAM volume ratio [CVR]) of greater than 1.6 suggests a significantly higher risk of
development of hydrops. True or False?
33. Regarding swallowed button batteries identified in the esophagus on conventional radiographs, which
one of the following statements is CORRECT?
A. A 20-mm lithium cell cannot be differentiated from a nickel or penny coin.
B. Aortoesophageal fistula, mediastinitis, and esophageal perforation are complications of delayed button
battery removal.
C. Leakage of alkaline electrolyte is responsible for the battery-induced local injury that develops in
children who ingested lithium batteries.
D. A repeat radiograph should be performed in 4 hours to confirm passage of the battery into the stomach.
34. Regarding pulmonary interstitial emphysema (PIE) in neonates, which one of the following statements
is CORRECT?
A. PIE can be unilateral or bilateral.
B. The radiographic appearance in PIE is the result of hyperexpanded (emphysematous) alveoli.
C. A common treatment for unilateral PIE is to place the infant in the decubitus position with the affected
side up.
D. PIE is more common in full-term infants than in premature infants.
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CPI Pediatric Radiology Module 2014
ANSWER KEY
CPI Pediatric Radiology 2014
28
1.C
25.B
2.D
26.C
3.D
27.A
4.E
28.B
5.D
29.D
6.D
30.True
7.C
31.True
8.A
32.True
9.C
33.B
10.D
34.A
11.B
35.B
12.A
36.True
13.B
37.True
14.D
38.False
15.D
39.True
16.E
40.False
17.A
41.False
18.B
42.C
19.D
43.C
20.B
44.C
21.C
45.B
22.B
46.A
23.C
47.True
24.B
48.False
CPI Pediatric Radiology Module 2014
RATIONALES AND REFERENCES
Answer 1 is C.
The radiographs (Figures 1-1 and 1-2) show a geographic lytic lesion in the epiphysis with a narrow zone of
transition.
Chondroblastoma is a benign neoplasm that occurs almost exclusively in the epiphysis before physeal closure. It
may be centrally or eccentrically located. Chondroblastoma most commonly occurs in the proximal humerus
and around the knee. The talus and calcaneus may also be involved. Patients typically present with joint pain.
Radiographs reveal a lytic lesion with geographic and sclerotic margins (Figures 1-1 and 1-2, annotated).
Fig 1-1. Chondroblastoma. Annotated. Knee.
Radiograph. Frontal view. Lytic lesion with
geographic and sclerotic margins (arrow) within
the epiphysis is characteristic of chondroblastoma.
CPI Pediatric Radiology Module 2014 Fig 1-2. Chondroblastoma. Annotated. Knee. Radiograph. Lateral view. Lytic lesion (arrow) with geographic
and sclerotic margins found within the epiphysis is
characteristic of a chondroblastoma.
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Lobulated margins are best seen on CT and MRI, and extensive bone marrow and soft-tissue edema is seen on
MRI (Figures 1-3 and 1-4). Chondroid matrix is present in 50% of cases. A joint effusion may be present, and
periosteal new bone formation may occur in the metaphysis remote from the epiphyseal lesion. The differential
diagnosis of a lytic lesion in the epiphysis before physeal closure includes chondroblastoma, infection, and
eosinophilic granuloma. Treatment is by curettage and bone graft with a recurrence rate of 15%.
Fig 1-3. Chondroblastoma. Knee. MRI. Coronal
plane. T1 weighted. The lesion has lobulated
margins and the chondroid tissue is hypointense
relative to epiphyseal fat.
Fig 1-4. Chondroblastoma. Knee. MRI. Coronal plane.
Proton density weighted. The lesion has lobulated margins, and the chondroid tissue is hyperintense relative
to epiphyseal fat. Note surrounding high signal marrow
edema, a common finding in chondroblastoma.
Option A is not correct.
Osteosarcomas are metaphyseal lesions. They may extend to the epiphysis but would not originate in the
epiphysis as does the lesion in the test case. Osteosarcomas have a permeative appearance, osteoid matrix,
and aggressive periosteal new bone formation. The narrow zone of transition of the test case lesion as well as
the lack of osteoid matrix or aggressive periosteal reaction suggest that osteosarcoma would not be the most
likely diagnosis.
Option B is not correct.
Giant cell tumors occur between 20 and 40 years of age and are rare before physeal fusion. They are
metaphyseal lesions that extend to the articular margins. They have geographic margins without sclerosis.
The patient’s age as well as the lesion’s epiphyseal location and sclerotic border suggest that giant cell tumor
would not be the most likely diagnosis in the test case.
Option D is not correct.
Unicameral bone cysts are metaphyseal lesions that do not cross the growth plate. They progress distally into
the diaphysis with age with progressive bone growth from the physis. The epiphyseal location of the lesion in
the test case suggests that unicameral bone cyst would not be the most likely diagnosis.
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CPI Pediatric Radiology Module 2014
References:
Gardner DJ, Azouz EM. Solitary lucent epiphyseal lesions in children. Skeletal Radiol. 1988;17:497-504.
Weatherall PT, Maale GE, Mendelsohn DB, Sherry CS, Erdman WE, Pascoe HR. Chondroblastoma: classic and confusing
appearance at MR imaging. Radiology. 1994;190:467-474.
Answer 2 is D.
The shoulder radiograph (Figure 2-1) reveals a relatively sharply circumscribed lytic lesion in the left scapula.
Langerhans cell histiocytosis (LCH) is a rare disease of uncertain etiology, likely a disorder of the immune
system. The hallmark of LCH is the presence of the Langerhans cell, a histiocyte containing Birbeck
granules that are demonstrable by electron microscopy. LCH of bone often presents with pain, swelling, and a
soft-tissue mass. The flat bones (such as the skull, pelvis, ribs, and scapula) are more commonly involved than
the long bones. The plain radiographic appearance of LCH of bone varies based on the phase of the disease
and the site of involvement. An aggressive (ie, permeative) appearance is more common in the early phase of
the disease. Lamellated periosteal reaction or pathologic fracture may also be present (Figure 2-2).
Fig 2-2. Langerhans cell histiocytosis (LCH) of bone. Femur.
Radiograph. Lateral view. Aggressive permeative destruction
with associated periosteal reaction in the proximal to mid femur
in another patient with LCH.
CPI Pediatric Radiology Module 2014 31
With time, the periostitis resolves. Then chronic lesions are better defined and have more sharply
circumscribed borders. Lesions in the flat bones tend to have a less aggressive appearance, even in the early
phase of disease. Involvement in the spine is typically limited to the vertebral body and can lead to its
collapse (vertebra plana). The adjacent disc spaces are well-maintained (Figure 2-3). The lytic appearance of
the lesion and its location in a flat bone suggest that LCH is the most likely diagnosis in this case.
Fig 2-3. LCH of vertebra. Lumbosacral spine.
MRI. T2 weighted. Midline sagittal view.
Complete collapse of the L4 vertebral body
with well-maintained adjacent disc spaces.
There is an extradural mass (arrowhead)
effacing the anterior aspect of the spinal
canal.
Option A is not correct.
Osteogenic sarcoma would be very uncommon in a 4-year-old child. Most children with osteogenic sarcoma
present in the second decade of life (mean age of 15 years). Osteogenic sarcoma occurs most commonly in
the metaphyses of long bones (80%–90% of cases) with a majority occurring around the knee (distal femur or
proximal tibia). Flat bones are involved in only approximately 10% of cases. Most cases (90%) exhibit bone
production radiographically. Therefore, the age of the patient, the location of the lesion in a flat bone, and the
lack of bone production suggest that osteogenic sarcoma is not the correct diagnosis.
Option B is not correct.
While osteomyelitis can cause a lytic bone lesion, the well-defined appearance of the lytic lesion in the test
case would be unusual. Also, the lack of fever and the chronic nature of the pain would also be atypical for
infection.
Option C is not correct.
The well-defined lytic lesion in the test case is compatible with a unicameral bone cyst (UBC), but the
location is unusual. Eighty percent of UBCs in children are located in the metaphysis of the proximal
humerus or proximal femur (much more commonly in the humerus). In older patients (over 17 years of age),
approximately half of UBCs are found in the pelvis or the calcaneus. Because of the location of the lesion in
the test case, UBC would not be the most likely diagnosis.
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CPI Pediatric Radiology Module 2014
References:
Azouz EM, Saigal G, Rodriguez MM, Podda A. Langerhans cell histiocytosis: pathology, imaging, and treatment of skeletal
involvement. Pediatr Radiol. 2005;35:103-115.
Laor T, Jaramillo D, Oestreich AE. Musculoskeletal system. In: Kirks DR, ed. Practical Pediatric Imaging. 3rd ed.
Philadelphia, PA: Lippincott-Raven; 1998:327-510.
Stull MA, Kransdorf MJ, Devaney KO. Langerhans cell histiocytosis of bone. RadioGraphics. 1992;12:801-823.
Answer 3 is D.
The radiographs (Figures 3-1 and 3-2, annotated) show a greenstick fracture of the proximal ulna with volar
apex angulation. The radial head is dislocated anteriorly in relation to the capitellum (the radius and
capitellum are in normal alignment on the anteroposterior view, but not on the lateral view). Monteggia
fracture-dislocation consists of a fracture of the proximal ulna with dislocation of the radial head. It is
important to evaluate all patients with an ulnar fracture for possible radial head dislocation. This can be
performed by drawing a line through the radial neck. The line normally passes through the capitellum. If the
radiocapitellar line does not pass through the capitellum, the radial head is dislocated.
Fig 3-2. Monteggia fracture-dislocation. Annotated. Forearm. Radiograph. Lateral view. The alignment of the radius and the capitellum
(line) is abnormal with the radial head dislocated anteriorly relative to
the capitellum. This is a type I Monteggia fracture-dislocation.
Fig 3-1. Monteggia fracturedislocation. Annotated. Forearm.
Radiograph. Frontal view. The
alignment of the radius and the
capitellum (line) is normal.
CPI Pediatric Radiology Module 2014 33
Bado classified the Monteggia fracture-dislocation into 4 types. In type I, the most common type (accounting
for 60% of fracture-dislocations in this group), there is apex-anterior angulation of the ulnar fracture and
anterior dislocation of the radial head. Apex-posterior angulation of the ulnar fracture with posterior
dislocation of the radial head characterizes a type II Monteggia fracture-dislocation. In type III Monteggia
fracture-dislocation there is a fracture of the proximal ulna with lateral dislocation of the radial head. The
least common type is type IV, which consists of a fracture of the proximal ends of both the radius and ulna
and anterior dislocation of the radial head. Monteggia fracture-dislocation can be associated with injury to
the radial nerve or its branches in approximately 20% of cases.
Option A is not correct.
Although there is a greenstick fracture of the ulna in the test case, it is associated with a radial head dislocation.
Therefore, greenstick fracture is not best answer in this case.
Option B is not correct.
Galeazzi fracture-dislocation is a fracture of the radial shaft and a distal radioulnar dislocation rather than
the ulna fracture and radial head dislocation seen in this patient.
Option C is not correct.
Essex-Lopresti fracture consists of an acute tear of the interosseous ligament of the forearm, comminuted
fracture of the radial head and neck, and dislocation of the distal radioulnar joint.
References:
Bado JL. The Monteggia lesion. Clin Orthop. 1967;50:71-86.
Gardner DJ, Azouz EM. Solitary lucent epiphyseal lesions in children. Skeletal Radiol. 1988;17:497-504.
Rogriguez-Merchan EC. Pediatric fractures of the forearm. Clin Orthop Relat Res. 2005;432:65-72.
Weatherall PT, Maale GE, Mendelsohn DB, Sherry CS, Erdman WE, Pascoe HR. Chondroblastoma: classic and confusing
appearance at MR imaging. Radiology. 1994;190:467-474.
Answer 4 is E.
The lateral radiograph (Figure 4-2, annotated) reveals a subtle longitudinal fracture in the proximal ulna as
well as visualization of the posterior fat pad and elevation of the anterior fat pad consistent with an associated
elbow joint effusion.
Noting an elbow joint effusion in a child with trauma suggests the presence of a fracture. Careful evaluation
of the radiographs reveals a subtle linear lucency in the proximal ulna on the lateral view consistent with a
fracture. Visualization of the posterior fat pad and elevation of the anterior fat pad confirm the presence of an
associated elbow joint effusion.
The fracture is better seen on a follow-up elbow radiograph performed 1 week later due to bone resorption
along the fracture line (Figure 4-3). The vast majority of elbow fractures in children involve the humerus, and
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CPI Pediatric Radiology Module 2014
Bilateral pulmonary hypoplasia occurs with diaphragmatic hernia due to compression of both the ipsilateral and,
to a lesser extent, the contralateral lungs during fetal development. Pneumothorax is a complication of positive
pressure ventilation of the hypoplastic lungs. In diaphragmatic hernia, the chest is not completely separated from
the abdomen, and air within the pleural space can readily enter the peritoneal space as in this patient.
Option A is not correct.
Necrotizing enterocolitis (NEC) is a cause of pneumoperitoneum in preterm patients, but is rare in the first
week of life. Furthermore, there are no other radiographic findings suggesting NEC, such as pneumatosis
intestinalis or portal venous air. The lack of these other signs of NEC and the age of the patient suggest that
NEC is not the most likely cause of the pneumoperitoneum.
Option C is not correct.
Gastroesophageal junction perforation from nasogastric (NG) tube placement may cause pneumoperitoneum,
retroperitoneal gas, pneumomediastinum, or pneumothorax. However, the course of the NG tube does not
suggest malposition of the tube. Furthermore, the presence of a diaphragmatic hernia suggests that
pneumoperitoneum secondary to extension of pleural air through the diaphragmatic defect is a more likely
explanation for the pneumoperitoneum.
Option D is not correct.
Chest tube insertion may cause pneumothorax, but air from a right-sided pneumothorax would not be
expected to reach the peritoneal space through a left-sided diaphragmatic defect.
References:
Chavhan GB, Babyn PS, Cohen RA, Langer JC. Multimodality imaging of the pediatric diaphragm: anatomy and
pathologic conditions. RadioGraphics. 2010;30:1797-1817.
Mehollin-Ray AR, Cassady CI, Cass DL, Olutoye OO. Fetal MR imaging of congenital diaphragmatic hernia.
RadioGraphics. 2012;32:1067-1084.
Answer 29 is D.
Chordoma is unusual in the pediatric population. Chordomas occurring in the pediatric age group are
associated with tuberous sclerosis complex (TSC). TSC-associated pediatric chordomas present earlier (6.2
months of age) than chordomas in the general pediatric population (12 years of age). Chordomas in patients
with TSC are also more likely to involve the sacrum (40%) than in the general pediatric population (9.4%).
Option A is not correct.
Patients with von Hippel-Lindau syndrome are at risk for hemangioblastomas of the brain and spinal cord
and adenocarcinomas of the endolymphatic sac rather than chordomas.
Option B is not correct.
Melanoma ultimately occurs with a high prevalence in patients with neurocutaneous melanosis. There is not
an increased risk of chordomas in patients with this condition.
Option C is not correct.
Neurofibromatosis type 1 patients are at risk for developing gliomas of the optic pathway (usually low grade)
and gliomas within the cerebral hemispheres, brainstem, and spinal cord rather than chordomas.
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CPI Pediatric Radiology Module 2014
Reference:
McMaster ML, Goldstein AM, Parry DM. Clinical features distinguish childhood chordoma associated with tuberous
sclerosis complex from chordoma in the general pediatric population. J Med Genet. 2011;48:444-449.
Answer 30 is True.
Hypoplasia of the pons and a characteristic “Z-shaped” kink in the brainstem are seen in fetuses with
Walker-Warburg syndrome. Patients with this syndrome also have lissencephaly, hydrocephalus, hypotonia,
and eye malformations (including microphthalmos) (Figure 30-1). Patients with this disorder can occasionally
also have testicular defects (such as undescended testicles or testicular dysplasia) and posterior cephaloceles.
Fig 30-1. Walker-Warburg syndrome.
Fetal brain. MRI. T2 weighted. Singleshot turbo spin-echo. Midline sagittal
view. The brainstem has a characteristic
Z-shaped kink (arrows). The brain surface (arrowheads) is abnormally smooth
in this 32-week fetus, consistent with
lissencephaly.
References:
Barkovich JA. Congenital malformations of the brain and skull. In: Barkovich JA, ed. Pediatric Neuroimaging. 4th ed.
Philadelphia, PA: Lippincott Williams & Wilkins; 2005:291-439.
Crombleholme TM, Coleman B, Hedrick H, et al. Cystic adenomatoid malformation volume ratio predicts outcome in
prenatally diagnosed cystic adenomatoid malformation of the lung. J Pediatr Surg. 2002;37:331-338.
Gianluigi P. Ultrasound evaluation of the fetal neural axis. In: Callen PW, ed. Ultrasonography in Obstetrics and
Gynecology. 5th ed. Philadelphia, PA: Saunders; 2008:363-391.
Hung NA, Silver MM, Chitayat D, et al. Gonadoblastoid testicular dysplasia in Walker-Warburg syndrome. Pediatr Dev
Pathol. 1998;1:393-404.
CPI Pediatric Radiology Module 2014 77
Answer 31 is True.
The normal fetal cisterna magna is considered enlarged if it measures greater than 10 mm. The differential
diagnosis of an enlarged fetal cisterna magna includes Dandy-Walker malformation or variant, mega cisterna
magna, and Blake pouch cyst.
References:
Barkovich JA. Congenital malformations of the brain and skull. In: Barkovich JA, ed. Pediatric Neuroimaging. 4th ed.
Philadelphia, PA: Lippincott Williams & Wilkins; 2005:291-439.
Crombleholme TM, Coleman B, Hedrick H, et al. Cystic adenomatoid malformation volume ratio predicts outcome in
prenatally diagnosed cystic adenomatoid malformation of the lung. J Pediatr Surg. 2002;37:331-338.
Gianluigi P. Ultrasound evaluation of the fetal neural axis. In: Callen PW, ed. Ultrasonography in Obstetrics and
Gynecology. 5th ed. Philadelphia, PA: Saunders, an imprint of Elsevier Inc; 2008:363-391.
Answer 32 is True.
A congenital cystic adenomatoid malformation (CCAM) volume ratio (CVR) of greater than 1.6 is associated
with an increased risk of hydrops. In a prospective study of 58 fetuses with CCAM, 7 of 43 patients (16.7%)
with a CVR less than or equal to 1.6 developed hydrops, while 12 of 16 fetuses (75%) with a CVR greater
than 1.6 developed hydrops.
References:
Barkovich JA. Congenital malformations of the brain and skull. In: Barkovich JA, ed. Pediatric Neuroimaging. 4th ed.
Philadelphia, PA: Lippincott Williams & Wilkins; 2005:291-439.
Crombleholme TM, Coleman B, Hedrick H, et al. Cystic adenomatoid malformation volume ratio predicts outcome in
prenatally diagnosed cystic adenomatoid malformation of the lung. J Pediatr Surg. 2002;37:331-338.
Gianluigi P. Ultrasound evaluation of the fetal neural axis. In: Callen PW, ed. Ultrasonography in Obstetrics and
Gynecology. 5th ed. Philadelphia, PA: Saunders; 2008:363-391.
Answer 33 is B.
There are multiple reports of aortoesophageal fistula with exsanguination and death in patients with ingested
button batteries lodged in the esophagus. Mediastinitis and esophageal perforation are also reported. Other
complications include tracheoesophageal fistula, esophageal stricture or stenosis, vocal cord paralysis from
recurrent laryngeal nerve damage, tracheal stenosis, and aspiration pneumonia. Delayed removal has been
implicated in all of these complications. Several patients have had major complications with batteries lodged
in the esophagus for as little as 2 to 2.5 hours (Figures 33-1 and 33-2).
Option A is not correct.
Because a 20-mm lithium cell is very close in diameter to the penny (19.05 mm) and the nickel (21.21 mm), it
cannot be differentiated on the basis of diameter. However, a battery can be differentiated by its morphology.
Batteries have a double-rim or halo effect when seen en face. They have a step-off or stacked appearance in
profile (see Figure 33-1). To distinguish a battery from a coin, it is key to observe the foreign body’s periphery
and adjust the level and window to see the double-rim and scrutinize the contour to identify the stacked
appearance.
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CPI Pediatric Radiology Module 2014
Fig 33-1. Ingested button battery. Chest.
Radiograph. Lateral view. The “step off” or
“stacked” appearance (arrows) of the foreign
body confirms that it is a button battery rather
than a coin. The battery is lodged in the
esophagus at the level of the thoracic inlet.
Thickening of the soft tissues between the
battery in the esophagus and the air column
in the trachea suggests edema.
Fig 33-2. Esophageal ulceration. Esophagram.
Spot image. Lateral view. Exam performed after
endoscopic removal of the battery (same patient
as Figure 33-1). There is ulceration (arrowhead)
of the posterior esophageal wall.
Option C is not correct.
Lithium button batteries are 3-volt cells, while smaller batteries are 1.5-volt cells. The lithium cell can
generate a large external current that induces electrolysis and generation of hydroxide leading to tissue injury.
Furthermore, the batteries contain an organic electrolyte instead of an alkaline electrolyte. Therefore,
electrolysis and generation of hydroxide rather than leakage of alkaline electrolyte is the source of esophageal
injury with lithium batteries.
CPI Pediatric Radiology Module 2014 79
Option D is not correct.
An ingested button battery lodged in the esophagus is potentially life-threatening and merits urgent
communication to facilitate immediate intervention. Communication by telephone or in person assures
receipt of the information. Other forms of communication may also be sufficient. However, these alternate
methods of communication must be documented showing that the information has been delivered in a timely
manner and has been acknowledged. The final report is the best place to describe this communication.
References:
American College of Radiology (ACR) Practice Guideline for the Communication of Diagnostic Imaging Findings. Revised
2010 (Resolution 11). http://www.acr.org/~/media/C5D1443C9EA4424AA12477D1AD1D927D.pdf. ACR Website.
Litovitz T, Whitaker N, Clark L, White NC, Marsolek M. Emerging battery-ingestion hazard: clinical implications.
Pediatrics. 2010;125:1168-1177.
Answer 34 is A.
Pulmonary interstitial emphysema (PIE) can be unilateral (Figure 34-1) or bilateral and can be focal or diffuse.
Fig 34-1. Unilateral pulmonary interstitial emphysema (PIE). Chest. Radiograph. Supine position. Frontal view. Linear and cystic lucencies in
the left lung are due to diffuse unilateral PIE.
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CPI Pediatric Radiology Module 2014