Chapter 8
Radiographic Assessment
Introduction
• Bedside CXR’s are most common (as opposed
to taking the baby to the X-ray dept)
• Viewed using picture-archiving and
communication system (PACS); useful for
quick assessment without radiologist
interpretation
• AP Frontal and lateral views most common
Indications
• Identifying position of lines and tubes (OG,
UVC, UAC, ETT…)
• Visualizing lung fields; correlated with physical
assessment
• Post intubation, post surfactant delivery,
sudden distress…
• FBAO
Indications
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Air Leaks
Pneumothorax
Pneumomediastinum
Pneumopericardium
Pneumoperitoneum
Subcutaneous emphysema
Pulmonary Interstitial Emphysema (PIE)
Air embolism
Causes of Air Leaks
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Over-vigorous resuscitation
Intubation/IPPV/NCPAP
‘Fighting’ ventilator
High PIP
Long I.T
MAS; RDS; Pneumonia; Pulmonary hypoplasia;
BPD; tachypnea
Radiographic Technique
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Frontal
Lateral
Posteroanterior
Anteroposterior
Lateral decubitus
Forced expiratory-FBAO
Oblique
Fluoroscopy
Frontal AP
Right and Left Lateral
Lateral Decubitus
Lateral Decubitus
• Useful in determining mobile pleural fluid and
also to better identify a pneumothorax
Normal Chest Anatomy
• Bone and metallic orthopedic hardwear
appear bright white due to greater absorption
of light
• Air little absorption, less exposure on film,
appears black
• Soft tissue organs and fluid appear as shades
of gray
• Incorrect exposure alters normal gray scale,
appear whiter if under exposed
Reading a CXR
• An accurately positioned chest x-ray will
demonstrate the lung apices, lung bases,
medial and lateral lung fields, and the
costophrenic angle of each lung. An air filled
trachea is seen superimposed in the midline
of the upper thoracic vertebrae. The heart
silhouette should be seen without rotation
and the lower thoracic vertebral bodies
slightly transparent through the mediastinum.
•Right clavicle
(A)
•Right scapula
(B),
•Right fourth
anterior rib (C),
right eighth rib
(D),
•Right
costophrenic
angle (E),
•Left lung apex
(F),
•Aortic arch (G),
hilum (H), heart
(I),
•left lung base
(J), Right
hemidiaphragm
(white arrow).
Reading a CXR
• The PA or AP chest radiograph displays a wide
range of structures with many
superimpositions having various radiographic
densities. Furthermore, overlying mediastinal
or bony structures may obscure portions of
the lungs. Therefore, it is important that
image quality be optimal and positioning
accurate for diagnosis of subtle abnormalities.
Reading a CXR
• Heart is composed of soft tissue of waterlike
density, clearly demarcated by a distinct edge
from adjacent air-filled lung
• If the lung becomes waterlike from loss of air,
atelectasis, filled with fluid/puss/PNA… the
heart edge is no longer seen
• Called a silhouette sign- two normal structures
lose their distinct edge and blend together
PNA- Heart edge missing
Normal CXR good heart edge
•ANATOMY
Location Size & Placement
•Lungs
•Heart
•Thymus
•Vessels
•Chest wall
•H
•E
•A
•R
•Half the lateral diameter
•Plumper in newborns
•T
•T
H
Y
M
U
S
•C
•H
•E
•S
•T
Reading a CXR
• AP view accentuates heart size
• Pulmonary artery and veins form confluent
areas on either side of the heart called the hila
• Enlargement of the hila= increased pulmonary
vessels or enlarged lymph nodes
• Aortic Knob also seen
• Mediastinum= heart, aorta, pulmonary
branches, great vessels, thymus, vena cava
•
Close up of upper thorax in a patient with Coarctation of the Aorta.
The red arrows point to rib notching caused by the dilated intercostal arteries.
The yellow arrow points to the aortic knob, the blue arrow to the actual
coarctation
and the green arrow to the post-stenotic dilation of the descending aorta
.
Normal CXR good heart edge
Good Technique
• This is a good radiograph of the infant chest. Notice that the exposure
technique adequately penetrates the thoracic vertebrae.
• The head is straight so that the clavicles are not rotated. When performing
a pediatric chest x-ray, it is important that the chest is not rotated.
Structures such as the trachea should appear over the cervical and upper
thoracic vertebrae. This is because the heart must be presented
anatomically and its border with the thymus seen.
• Good alignment can help identify abnormal anatomical shifts due to
congenital disorders (e.g. tetrology of fallot, dextrocardia, etc).
• Proper collimation was applied vertically to include the nasogastric tube
(blue arrow) and umbilical catheter (red arrow). Overall, this is an
excellently positioned and exposed chest x-ray. I would suggest that the
proximal portion of the NG tube be moved upward in the future and chest
lead moved from the lower lung field.
Critique?
• At first glance this radiograph may appear to be acceptable; however it is
not.
• The main reason this radiograph should be repeated is motion artifact and
quantum mottling. grainy image appearance (termed quantum mottling)
• Notice that the vascular lung marking are ill defined and the bronchi are
not aerated. This is because the exposure was taken on expiration.
Generally, pediatric radiographers know to watch the inspiration indicator
on the ventilator rather than the patient so that exposure is made on full
inspiration.
• When an infant is not on a ventilator the abdomen rises with inspiration
and falls with expiration. The other issue is that the head is not in
anatomic position, which causes a misrepresentation of the location of the
tip of the endotrachael tube.
Critique Continued
Alignment of the part is lacking in all directions. While this
critique does not normally reference the absence of a position
marker it should be noted that this is a serious breach when
imaging infants.
Congenital variations such as dextrocardia, situs inversus, and
others such as transposition syndromes are diagnosed because
position markers alert the physician.
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Obviously there is mild chest rotation, wire artifact, and poor vertical collimation
of the chest.
These three radiographs show why it is important to carefully evaluate ventilated
pediatric chest x-rays for motion artifact. On the left is the radiograph being
evaluated. The middle radiograph shows the same chest x-ray in black bone
window or what is called a positive image (black and whites are reversed). Notice
that the lung markings are not seen on the middle radiograph. Compare this to the
lung markings seen on the right radiograph. Observe how the lung markings and
the heart are well defined on this radiograph. Also observe how motion artifact
produces a faint heart shadow and lack of clear lung markings (middle radiograph).
Now back to the original radiograph, which is a negative. Does motion artifact now
stand out to you? When this radiograph is repeated turn the head to anatomical
position, collimate vertically, and make the exposure at peak ventilator inspiration.
Case Study
• A toddler was brought to the emergency department for
increasing respiratory distress over the past few days. He has
also had fevers, and was started on antibiotics by his family
doctor with no improvement.
• In the emergency department he had SaO2 of 89% and was
treated with oxygen. Prominent wheeze, with decreased air
entry and occasional crackles were noted, predominantly on
the right-side of his chest. He showed no response to
repeatedly nebulized bronchodilators.
• Given this lack of response to therapy, chest radiographs were
ordered:
•A foreign body in
the right main
bronchus. There is
atelectasis
(collapse)
predominantly
affecting the right
lower lobe (note
the distinct right
heart border on the
AP film, and
patchy opacities
below the foreign
body on the lateral
film).
•Round-shaped foods are
the most frequently
aspirated objects:
•Peanuts, grapes, raisins,
and hot dogs…
•Nonfood objects include
all sorts of items — such
as metal dowels from
Swedish furniture.
Conformable objects are
the most difficult to
manage and remove.
Balloons are the objects
most likely to result in
death.
FBAO
• Large objects tend to lodge in the upper airway and
trachea (about 20% of airway foreign bodies). They
are likely to cause obvious and dramatic signs of
upper airway obstruction such as dyspnea, drooling,
stridor, and cyanosis — which may ultimately cause
death unless expeditiously removed.
• More common are smaller objects that pass through
the subglottic space. They will usually lodge in a
bronchus — usually the right main bronchus — or in
a more terminal part of the airway.
FBAO Symptoms
From the history:
• Coughing or choking episodes while eating solid foods (classically nuts), or while
sucking a small plastic toy or similar object. This history should never be dismissed
— a foreign body is almost always present in the symptomatic child.
• Persistent coughing and wheezing.
• Delayed presentations may shows symptoms of infection due to secondary
tracheitis, bronchitis, atelectasis or pneumonia.
• If foreign body ingestion was unwitnessed, there may be no history of aspiration
(about 15% of cases).
On examination there may be:
• no physical signs
• reduced breath sounds over all or part of one lung
• Wheeze: beware of the sudden onset of a first wheezing episode in a toddler in
whom there is no history of allergy, especially if it follows a choking episode.
• Features of a secondary tracheitis, bronchitis, atelectasis or pneumonia if
presentation is delayed
FBAO
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Chest radiographs may show:
radio-opaque foreign bodies
obstructive hyperinflation (asymmetric)
collapse/ atelectasis
normal (15% of lower airway foreign body aspirations)
Some clinicians prefer full inspiration and full expiration films to check for
hyperinflation (impossible in the uncooperative toddler). An alternative is to
perform lateral decubitus films, looking for the absence of of decreased lung
volume when the obstructed side is dependent. The films should include the
nasopharynx to the chest.
A normal chest radiograph does not exclude the presence of a foreign body
Bronchoscopy is indicated for all patients with a suspected inhaled foreign body,
even if the chest radiograph is ‘normal’ — unless the child is completely
asymptomatic with a normal physical and radiographic examination.
Peanut Rule
• rule -- children cannot eat peanuts if they are
unable to touch their opposite ear by reaching
over their head. Corresponds to about their
fifth birthday
Silhouette Sign
Evaluating Normal Structure
Normal Thymus
Evaluating the Lungs
• Lungs
– Lobes
– Fissures
• Inspiration
• Trachea and mainstem bronchi
Positioning of Lines and Tubes
• Endotracheal tubes
– Between thoracic inlet and carina
• Vascular catheters
Airway Obstruction
Airway Obstruction (cont.)
Airway Obstruction (cont.)
Respiratory Distress Syndrome
Pneumothorax
Incidence of Pneumothorax
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1-1.5% of all newborns
Affects 5-14% of babies admitted to NICUs
Males > Females
Terms = Pre-terms
Spontaneous pneumothorax : 10/15,000
Bilateral in 10-21%
Mortality 20%
Clinical Presentation
• Signs of respiratory distress: grunting, ↑RR,
cyanosis/desaturation/respiratory acidosis
• Apnea, bradycardia, ↓BP (obstructed shock)
• Displaced apex beat
• Change in breath sounds
• ↑Ventilatory requirements
• All occur suddenly
Diagnosis
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Patient Assessment
Tansillumination
CXR: Lateral decubitis, AP
Direct needle aspiration
Treatment
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Conservative therapy +/- 100% oxygen
If no underlying lung disease
No complicating therapy
No distress
No continuous air-leaks
Resolve in 24-48 hrs
OXYHOOD, or NC at 100%
Treatment
Needle aspiration
• Equipment
• 21-23 G butterfly needle
• Cleaning solution
• Syringe & 3-way tap
• Procedure
• Clean skin
• Insert needle 2nd/3rd ICS MCL
• End of tubing under water & watch for bubbles or
• Apply continuous suction to syringe until rapid flow of air
• http://www.capefearvalley.com/outreach/outreach/modul
es/airleaks/pages/Procedures.htm
•http://www.youtube.com/
watch?v=rls9R8iFuck
Pneumomediastinum
Pulmonary Interstitial Emphysema
Meconium Aspiration Syndrome
Group B Streptococcal Pneumonia
Diaphragmatic Hernia
Atelectasis
Pneumonia
Cystic Fibrosis
Acute Respiratory Distress Syndrome
Chest Trauma
CDH
Hour long video on interpetation
• http://www.youtube.com/watch?v=H9wbwQrX7c