Download x-ray examination of the lungs - University of Yeditepe Faculty of

IMAGING OF THE CHEST
Neslihan Tasdelen MD.
Yeditepe University School of Medicine
Department of Radiology
Imaging Modalities
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Direct radiography (Chest x-ray)
Computed Tomography
MRI and US in selected patients...
Chest X Ray
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Positioning:
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Posteroanterior (PA)
Lateral (left)
Anteroposterior (AP)
Lateral decubitus
The x ray enters the patient posteriorly and exit anteriorly with the patient’s chest
on the film cassette. There is 180 cm distance between the x-ray tube and
cassette. Obtained in deep inspiration !!!
The patient’s left side is against the film. The right side is magnified.
Obtained in deep inspiration !!!
The right ribs (red arrows below) are larger due to magnification and
usually projected posterior to the left ribs if the patient was examined in
a true lateral position. This can be very helpful if there is a unilateral
pleural effusion seen only on the lateral view.
The left hemidiaphragm is usually lower than the right. Also, since the heart
lies predominantly on the left hemidiaphragm the result on a lateral film is
silouhetting out of the anterior portion of the hemidiaphragm, whereas the
anterior right hemidiaphragm remains visible. Notice how the right
diaphragm (red arrows) continues anteriorly, while the left diaphragm
disappears (black arrow) because of the silouhetting caused by the
heart. Also notice how the right diaphragm at the blue arrows continues
past the smaller left ribs and ends at the larger and more posterior right ribs.
The PA (posterioranterior) film is
obtained with the patient facing the
cassette and the x-ray tube 180 cm
away.
This distance diminishes the effect of
beam divergence and magnification of
structures closer to the x-ray tube.
AP (anteriorposterior) position the x-ray
tube is 100 cm from the patient.
The heart shadow is magnified because
it is an anterior structure.
PA
AP
The patient can also be examined in a lateral decubitus position.
This could be helpful to assess the volume of pleural effusion and
demonstrate whether a pleural effusion is mobile or loculated.
Is the film technically
adequate?????
The patient should be examined in full inspiration. This greatly helps the
radiologist to determine if there are intrapulmonary abnormalities. The
diaphragm should be found at about the level of the 8th - 10th posterior rib
or 5th - 6th anterior rib on good inspiration.
A patient can appear to have a very abnormal chest if the film is
taken during expiration.
On the first film, the loss of the right heart border silhouette
would lead you to the diagnosis of a possible pneumonia.
On repeat exam with improved inspiration, the right heart border
is normal.
Adequate penetration of the patient by radiation is also required for
a good film. On a good PA film, the thoracic spine disc spaces should
be barely visible through the heart but bony details of the spine are
not usually seen. On the other hand penetration is sufficient that
bronchovascular structures can usually be seen through the heart.
On the lateral view, look for proper
penetration and inspiration by
observing that the spine appears to
be darken as you move caudally.
This is due to more air in lung in the
lower lobes and less chest wall. The
sternum should be seen edge on and
posteriorly you should see two sets of
ribs.
Underpenetrated
Overpenetrated
Rotation ???
If there is rotation of the patient, the mediastinum may look
very unusual. One can access patient rotation by observing the
clavicular heads and determining whether they are equal
distance from the spinous process of the thoracic vertebral
bodies.
In this rotated film skin folds can be mistaken for a tension
pneumothorax !!!!!
Wrong positioning of the heads of the clavicles and the spinous
processes
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INTERPRETATION
BONE
AIR
WATER
TISSUE
Trachea
Carina
Right and left pulmonary
bronchi
Lobar bronchi
Right Lung
*Superior lobe
*Middle lobe
*Inferior lobe
Left Lung
*Superior lobe
*Inferior lobe
Right Lung
Superior lobe
Middle lobe
Inferior lobe
PA View
Extensive overlap
Lower lobes extend high
Lateral View
Extent of lower lobes
*The right upper lobe (RUL)
occupies the upper 1/3 of the
right lung
*Posteriorly, the RUL is adjacent
to the first 3-5 ribs
*Anteriorly, the RUL extends
inferiorly as far as the 4th right
inferior rib
*The right middle lobe
is typically the smallest
of the three lobes,
appears triangular in
shape, narrowest to the
hilum
*The right lower lobe is
the largest
*Posteriorly, the RLL
extends as far superiorly
as the 6th thoracic
vertebra, and inferiorly till
the diaphragm
*The three lobes are
seperated from eachother
by two fissures
*The
minor
fissure
seperates the upper and
middle lobes and is
oriented horizontally
*The major fissure, which
is
oriented
obliquely,
extends above till the 4th
vertebra
*There is no minor fissure on
the left
*There are two lobes: LUL, LLL
Major fissure is similar to the
one on the left side, slightly
inferior in location
*The portion of the left lobe
that corresponds anatomically
to the right middle lobe is
incorporated to the upper lobe
PA View
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Aortic arch
Pulmonary trunk
Left atrial appendage
Left ventricle
Right ventricle
SVC
Right hemidiaphragm
Left hemidiaphragm
Horizontal fissure
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Patient Data (name history #, age, sex, old films)
Routine Technique: AP/PA, exposure, rotation, supine or erect
Trachea: midline or deviated, caliber, mass
Lungs: abnormal shadowing or lucency
Pulmonary vessels: artery or vein enlargement
Hila: masses, lymphadenopathy
Heart: thorax: heart width > 2:1 ? Cardiac configuration?
Mediastinal contour: width? mass?
Pleura: effusion, thickening, calcification
Bones: lesions or fractures
Soft tissues: don’t miss a mastectomy
ICU Films: identify tubes first and look for pneumothorax
Computed Tomography
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An intrathoracic radio-opacity if in anatomic
contact with the border of a mediastinal
structure, will obscure that border.
Air Bronchogram ???
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An air bronchogram is a tubular outline of an airway
made visible by filling of the surrounding alveoli by
fluid or inflammatory exudates.
Etiology; lung consolidation, pulmonary edema,
nonobstructive pulmonary atelectasis, severe
interstitial disease, neoplasm, and normal
expiration.
Solitary Pulmonary Nodule ???
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A solitary nodule in the lung can be totally
innocuous or potentially a fatal lung cancer.
Initial step in analysis is to compare the film with
prior films if available.
A nodule that is unchanged for two years is
almost certainly benign.
If the nodule is completely calcified or has central
or stippled calcium it is benign. Nodules with
irregular calcifications or those that are off center
should be considered suspicious, and need to be
worked up further with a PET scan or biopsy.
Multiple Pulmonary Nodules ???
Atelectasis ???
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Atelectasis is almost always associated with a
linear increased density on chest x-ray.
The apex tends to be at the hilum.
The density is associated with volume loss.
Some indirect signs of volume loss include
vascular crowding or fissural, tracheal, or
mediastinal shift, towards the collapse. There
may be compensatory hyperinflation of
adjacent lobes, or hilar elevation (upper lobe
collapse) or depression (lower lobe collapse).
Pneumonia ???
airspace opacity, lobar consolidation with ill-defined borders, or interstitial
opacities
Opacity ???
?
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Pulmonary Embolism ???
Roughly ten percent of pulmonary embolisms result in pulmonary
infarction
In the case of pulmonary infarctions, the main radiographic feature is
multifocal consolidation at the pleural base in the lower lungs
Pleural Effusion ???
Pneumothorax ???
CASES