State of the Art X-ray
Interpretation
Pulmonary – Critical Care Associates
of East Texas
Jeffrey M. Shea, MD, FCCP
Objectives
• List the reasons for obtaining a Chest x-ray
• Identify anatomical structures present on a chest
film.
• Recognize a normal chest radiograph.
• Recognize and name the radiographic signs of
atelectasis, consolidation, pneumothorax,
pleural effusions, and hyperinflation frequently
seen in patients with cardiopulmonary disease.
A Chest x-ray is very valuable in
answering the following questions
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Is the heart enlarged or normal?
Are there signs of heart failure and fluid overload?
Does the patient have pneumonia or a collapsed lung?
Is there evidence of emphysema?
Are there findings of an aneurysm involving the aorta?
Is there fluid in the sac that surrounds the lung?
Is there free air under the diaphragm to suggest a hole in
the bowel wall?
• Is there a tumor in the lung that could represent cancer?
• Are there changes of bronchitis or emphysema?
How is a PA Chest X-ray done?
Standard PA or posterior –
anterior Radiograph
•Patient usually upright
•Distance of beam
determines magnification
and clarity
• Place the films on the
view box as though you
were facing the patient
with his left on your right
side.
Standard Lateral Chest
Radiograph
• Left side of the chest against
filmholder (cassette); beam
from right at a distance of six
feet;
• Lesions located behind the
left side of the heart or in the
base of the lung are often
invisible on the PA view
because the heart or
diaphragm shadow hides it
– the lateral will generally show
such lesions
X-rays are a study of densities
• DENSITIES Air < fat < liver < blood < muscle < bone <
barium < lead.
• Air — least dense; most transparent or radiolucent;
unobstructed beam or air-filled densities appear black
– Lungs, gastric bubble, trachea, ? bifurcation of bronchi
• Fat — breasts
• Fluid — most of what you see; vessels, heart,
diaphragm, soft tissues, mediastinal structures
• Mineral — most dense (or radiopaque) of body
structures; mostly Ca++; bones (marrow is aerated),
aortic calcifications such as the aortic knob, ?
calcification of the coronary arteries, old granulomas;
bullets, safety pins, etc.
Different Densities on an ICU Chest X-ray
Anatomy
Silhouette Sign / Air Bronchogram
What am I looking at?
What am I looking at?
Right Upper Lobe
Right Middle Lobe
Right Lower Lobe
Left Upper Lobe
Left Lower Lobe
Normal Cardiac Anatomy
(PA view)
Normal Cardiac Anatomy
(Lateral view)
Pleura
How to Read a Chest X-ray
• Go from general observations to specific details.
– Sometimes a change may be so major that the old saw
about missing the forest for the trees comes true.
• Read the Chest X-ray in a systematic fashion:
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L shoulder
L chest wall
Lower Chest
R chest wall
R shoulder
Cervical spine and soft tissue
Chest / Ribs
Hilum
Lungs
Pleura
LEFT SHOULDER GIRDLE
• Soft tissues - look at overall amount, then
check for the following: calcifications,
obvious mass effect, abnormal air
collections
• Bones - look at each bone for abnormalities
• Joints- are articular relationships normal,
joint spaces narrowed, widened, any
calcification in the cartilages, air in the joint
space, abnormal fat pads, etc.
LEFT SHOULDER GIRDLE
LEFT CHEST WALL
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Look for overall
thickness,
subcutaneous
emphysema,
calcification.
Look for sharp,
distinct muscle fat
planes
BREAST TISSUE
•In males and females, some
asymmetry can occur from
standing with unequal
pressure against the film
holder.
•Notice how the apparent
lung density changes from
the lung area covered by the
soft tissue of the breast to
the lung area inferior to the
breast.
ABDOMEN
• The visibility of structures
is highly variable
• Gastric and bowel gas - Is
amount and location
normal?
• Check for free peritoneal
air
– position of patient will
change location of free
air.
• Look for calcifications
and masses - can they be
localized to a specific
structure.
RIGHT CHEST WALL
• Look for overall
thickness,
subcutaneous
emphysema,
calcification.
• Look for sharp,
distinct muscle fat
planes.
RIGHT SHOULDER GIRDLE
NECK SOFT TISSUES AND
SPINE
• Amount of soft tissue,
presence of calcifications,
subcutaneous emphysema,
position and size of trachea.
• For the cervical spine, check
alignment and note any
major congenital
abnormalities.
• Then look at specific parts of
the vertebra and disc spaces,
checking for erosions, boney
destruction, disc / joint
narrowing or other
abnormalities.
THORACIC SPINE AND RIB
CAGE
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Concentrate on the skeletal
detail -- "look through" the
mediastinum and lungs.
First check overall
alignment of the spine and
symmetry of the rib cage,
double check bone density
(this is a gross estimate).
RIBS
• Compare individual ribs
side to side
1. Posterior rib
2. Anterior Rib
Hilum (pleural = hila.)
• "lung root;" medusa-like tangle of arteries
and veins on either side of the heart
shadow.
• Irregular medial shadow in each lung
where the bronchi and pulmonary arteries
enter.
• Other structures in these areas,
particularly lymph nodes, are normally so
small as to be unapparent.
Pulmonary hilum
FRONTAL VIEW OF THE HILA
• On the frontal view most
of the hilar shadows are
the left and right
pulmonary arteries.
• The left pulmonary
artery is always more
superior than the right,
thus making the left
hilum appear higher.
• Calcified lymph nodes
may be visible within the
hilar shadows.
LATERAL VIEW OF THE HILA
Hilar Adenopathy
Hilar Adenopathy
Lungs
LUNGS
• Compare overall size
of one lung to the
other,
• Look for major areas
of abnormal lucency
or density
Pleura
Pleura
• Check the frontal view for minor fissure
thickness and location, and on the
lateral view, look for minor and major
fissures
• These are normally fine delicate
structures that do not show up on the
digitized images.
Pleura
Stomach Anatomy
Let’s look at
some examples
Terminology
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Silhouette sign
Atelectasis
Consolidation
Pneumothorax
Pleural effusion
Nodule
Hyperinflation
Loculated
Lateral Decubitus
Silhouette Sign
When two objects of the same
density touch each other, the
edge between them disappears
A
B
Using the Silhouette Sign
•Right middle lobe silhouettes right heart
border
•Lingula silhouettes left heart border
•Right lower lobe silhouettes right
hemidiaphragm
•Left lower lobe silhouettes left
hemidiaphragm
Silhouette Sign
Silhouette of the Right Heart
Border
Right middle
lobe Infiltrate
showing
obliteration of
the right heart
border
Atelectasis = collapse
(volume loss)
• To diagnose atelectasis,
there must be evidence of
volume loss such as
displacement of a fissure
or hilum.
Atelectasis of right lung – shift of the mediastinal
structures TOWARDS the side of opacification
Tension Pneumothorax
Pleural Effusion
Loculated Hydropneumothorax
Pulmonary Nodule
Hyperinflation
Hyperinflation
Pneumonia
Final Exam
Conclusion
• Should be able to look at a CXR and
determine whether it is normal
• Identify obvious abnormalities on the CXR,
including boney, soft tissue, cardiac and
pulmonary pathology
• Be able to understand basic radiology
terminology