Download major fissures

Diagnostic Imaging
Normal chest
Anatomy on XR
Technique:
• Learn the difference between PA vs. AP CXR
• Learn the utility of a lateral (decubitus) CXR
• Understand the terms inspiration, penetration, and
rotation as they apply to determining a technically
adequate film
II. Anatomy:
• Learn the basic anatomy of the fissures of the lungs,
heart borders, bronchi, and vasculature that can be
seen on a chest x-ray
III. Interpretation:
• Develop a consistent and thorough technique for reading
images
• Learn how the silhouette sign can help localize pathology
IV. Pathology:
• Learn the concept of atelectasis and the ability to
recognize it on a chest x-ray
• Appreciate the appearance of pulmonary edema and the
differences between cardiogenic and noncardiogenic
causes
• Appreciate the difference findings of atelectasis and
pneumonia
• Recognize pleural effusions and pneumothorax appear on
CXR
• Recognize the signs of COPD
• Recognize the signs of a benign pulmonary nodule
• Learn what makes lung cancer unresectable
The plain CXR is the most commonly performed imaging exam because:
• Cardio-pulmonary disease is common
• The exam is quick, easy to do, cheap, with low radiation exposure (a
PA CXR gives only about 3-days-worth of radiation exposure we get
anyway from natural sources)
• Most importantly the contrast elements involved allow us to see the
common pathologies we’re looking for
It’s all about the contrast: For any imaging exam to be useful, there must
be contrast (signal difference) between lesion and surrounding tissue
There are 4 tissues that have densities that can be distinguished from
each other (have contrast) on plain X-ray:
• Calcium (bone)
• Soft tissue and fluid (not distinguishable on plain X-rays)
• Fat
• Gas/air
The natural contrast agent of air in the lungs allows us to see the common
soft tissue/fluid pathologies (pneumonia, lung CA, pleural effusion, Kerley
lines, etc.)
Indications for chest X ray:
• Chest pain
• Investigation of repeated and persistent chest
infection
• Chest trauma
• Localization of biopsy
• Evidence of a tumor and metastatic lesion
• Inhalation of foreign body
There are several projections of chest radiography:
Standard views
Additional views
VIEWS:
• STANDARD VIEWS
 Erect PA
 LATERAL
• INDICATIONS:
 For fit and able bodied
persons
 To diagnose any
pathology
 To visualize pleural
effusion
 To localize opacity
Posterioranterior and Lateral
The standard chest examination consists of a PA (posterioranterior) and lateral chest x-ray.
The films are read together. The PA exam is viewed as if the patient is standing in front of you with their right side
on your left. The patient is facing towards the left on the lateral view. Comparison films can be invaluable - Old
Gold! If you have comparison films, the old PA film is displayed adjacent to the new PA film and the old lateral is
displayed adjacent to the new lateral.
On the left is a simulated patient in position for a standard PA (posterioranterior) chest x-ray. On the right is a normal PA film.
PA VIEW
normal
AP VIEW
magnified
DIFFERENCE FROM PA:
Magnification of heart occur.
Scapula overlies on lungs
Clavicles above apex
CENTERAL RAY:
At the level of T6
1)A simulated patient in position
for a lateral chest x-ray
2)a normal lateral film.
Note that the receptor or
film is against the left chest.
The lateral view is obtained with the left
chest against the cassette. This
diminishes the effect of magnification on
the heart. Looking carefully at the
posterior aspect of the chest on the
lateral view, which ribs are left and
right? Which is the right/left
hemidiaphragm?
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.
ADDITIONAL VIEWS
• VIEWS:
• INDICATIONS:
• Supine AP
• For ill patients and those
with multiple injuries
• Lateral decubitus view
• Expiratory view
• Penetrated PA view
• To visualize small effusion
• To visualize pneumothorax
• Useful for cardiac chamber
visualization and left
lower lobe visualization
HOW TO CHECK QUALITY OF FILM?
• There are following factors by which we check quality
of film:
 FACTORS:
• Inclusion
• Projection
• Rotation
• Inspiration
• Penetration
INCLUSION:
• Chest x-ray should
include entire thoracic
cage.
•
•
•
•
First rib
Clavicle
Lateral edges of ribs
Costophrenic angles
ROTATION:
• Chest x-ray should not be taken with patient rotated
• Spinous process of thoracic vertebrae should lie in the
midline.
• They should form a vertical line that lies equidistant
from the medial ends of the clavicles
• EFFECTS OF ROTATION ON RADIOGRAPH:
• Become difficult to comment accurately on heart size.
• Changes in lung density due to asymmetry of
overlying lung tissue
More on
rotated side
INSPIRATION:
• Chest x-ray should be taken in second full inspiratory
phase.
• HOW TO ACESS INSPIRATION:
• Anteriorly 6th rib intersect the diaphragm at the mid
clavicular line should be included.
• 9 to 10 posterior ribs should be present.
• INSPIRATION VIEW
• EXPIRATION VIEW
PENETRATION
• Penetration is the degree
to which x-ray pass
through the body.
 CRITERIA OF WELL
PENETRATED CHEST
XRAY:
• A well penetrated x-ray is
one where the thoracic
vertebrae are just visible
through the heart shadow
but bony detail of spine are
not usually seen
CHEST X RAY ANATOMY
Lateral view
Heart contours
LUNGS
Two lungs are soft, spongy and elastic each lung is covered by the visceral
pleura and suspended in its own pleural cavity
Two lungs are separated from each other by the heart and great vessels
and other structures in the mediastinum
Attached to the mediastinum only by its root
Lungs have 2 major fissure and 1 minor fissure:
MAJOR FISSURES:
Oblique fissure
MINOR FISSURE:
Horizontal fissure
LOBES:
Right lung has three lobes divided by the oblique and horizontal
fissure
Left lung has two lobes divided by the oblique fissure only there is no
horizontal fissure
On the PA chest xray, the minor
fissure divides the right middle
lobe from the right upper lobe
(A) and is sometimes not well
seen. There is no minor fissure
on the left. The major fissures
are usually not well seen on the
PA view because you are
looking through them obliquely.
If there is fluid in the fissure, it is
occasionally manifested as a
density at the lower lateral
margin.
The left image shows the right minor
fissure (A) and the inferior borders (B) of
the major fissures bilaterally. The right
image shows the superior border of the
major fissures (B) bilaterally.
On the lateral view, both lungs are
superimposed.
Think about them separately, the left lung
has only a major fissure as shown.
The right lung will have both the major
and minor fissure.
The patient above has a pleural effusion extending into the fissure.
Which fissure is which?
What is the bright loop near the center of the films?
The patient above has a pleural effusion extending into the fissure.
Which fissure is which?
What is the bright loop near the center of the films?
The right heart border is silhouetted out.
This is caused by a pneumonia,
can you determine which lobe the pneumonia affects?
• Hilum is the wedge shaped
area on the central portion of
each lung where the
 Bronchi
 Pulmonary
• Arteries
• Veins and nerves
leave the lung
IMP POINT:
• Left hilar point is usually
higher
than right
• On chest x-ray we consider
zones of lungs.
 UPPER ZONE:
• Is present up to 2nd
intercostal space
approximately
 MIDDLE ZONE:
• From 2nd intercostal space5th intercostal space
 LOWER ZONE:
• From 5th intercostals space
to onward
TRACHEA AND MAJOR BRONCHI
• Trachea is a cylindrical tube that extend from the
level of cricoid cartilage C6 to T5(carina).
• Length 10-15 cm.
• Internal dia 10-18mm.
• 18-20 cartilaginous rings
• Divides at carina into bronchi
• Passes to the right of aorta
Pleural Effusion
Pneumothorax
Combining all the structures together
Trachea
sternum
Vertebral
body
Rt
ventricle
Lft atrium
Lft ventricle
right
hemidiaphragm
ribs