Transcript Introduction to CXR Interpretation

Introduction to Radiographic
Interpretation
Special Emphasis on CXRs
Differential Absorption of X-rays
• Dependent upon
– Physical density
– Atomic number
– Thickness
• Determine the gray scale of the radiograph
• Absorb few x-rays = film black
many x-rays = film white
Five Radiographic Opacities
Air
Fat
least opaque
most lucent
Black
Soft tissue
to
to
to
Bone
Metal
most opaque
least lucent
White
Radiographic Opacities & Contrasts
Air
Fat
Water
Bone
Metal
Air
Mineral oil
Water
Tums
???
Five Radiographic Opacities
Five Radiographic Opacities
Standard Radiographic
Positions
Standard Radiographic
Positions
Standard Radiographic Directions
As seen when viewing
Dorsal
Proximal
Cranial
Cranial
Rostral
Dorsal
Right
Caudal
Palmar
Plantar
Left
Ventral
Distal
Caudal
Radiograph: two-dimensional image of a
three-dimensional object
So . . . What is it?
Lateral view
Cranial-caudal view
Radiograph: two-dimensional image of a
three-dimensional object
So . . . What is it?
Dorsoventral view
Interpretation Challenges
• Magnification
• Distortion
• Image of a familiar object is unfamiliar
• Loss of depth perception
• Summation
• Silhouette effect
Interpretation Challenges:
Magnification
• Enlargement of the radiographic image
of an object relative to its actual size
• Increased film-subject distance
Interpretation Challenges:
Magnification
Interpretation Challenges:
Magnification
Interpretation Challenges:
Distortion
• Distortion:Misrepresentation
of the true shape of an
object
Interpretation Challenges:
Unfamiliar image of a familiar object
Interpretation Challenges:
Depth perception
Interpretation Challenges:
Summation
• Superimposition of structures in different planes
• Resultant image = summation of opacities
Interpretation Challenges:
Summation
Interpretation Challenges:
Silhouette Effect
• Two structures of the same radiopacity in
contact – their margins cannot be identified
Interpretation Challenges:
Silhouette Effect
Interpretation Challenges:
Silhouette Effect
CXR Interpretation
Have a system!!
• Method 1:
“Outside-to-inside”
– Soft tissues
– Bony framework
– Lungs & hila
– Diaphragm & pleura
– Mediastinum & heart
• Method 2:
“Are There Many Lung
Lesions?”
– Abdomen & diaphragm
– Thorax
– Mediastinum & heart
– Lung (single)
– Lungs (both)
CXR Interpretation
Have a system!!
T
L
L
M
A
• Method 1:
“Outside-to-inside”
– Soft tissues
– Bony framework
– Lungs & hila
– Diaphragm & pleura
– Mediastinum & heart
• Method 2:
“Are There Many Lung
Lesions?”
– Abdomen & diaphragm
– Thorax
– Mediastinum & heart
– Lung (single)
– Lungs (both)
CXR Interpretation
Beware the poor-quality film!!
•
Poor inspiration
–
•
“Penetration”:
–
•
High diaphragms,
crowded lung markings
Disappearing thoracic
vertebral details through
the heart.
Rotation:
–
Note equal distances
from the vertebral spines
to the medial ends of the
clavicles.
CXR Interpretation
Beware the poor-quality film: Inspiration
CXR Interpretation
Normal structures visible
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Tracheal air column.
Carina.
First rib.
Peripheral lung fields have no markings except:
The minor fissure.
Top of the R diaphragm is usually between the
anterior 6th & 7th ribs, and overlying the
posterior 10th & 11th ribs.
Left diaphragm is lower (in 90-95%) by roughly
half an interspace.
Inferior margins of the posterior ribs.
Anterior mediastinal line.
Superior vena cava.
Azygous vein.
Right descending pulmonary artery.
Pulmonary arteries and veins.
Right atrium.
Inferior vena cava.
Aortic arch.
Left pulmonary artery.
Border of the left ventricle.
Descending aorta.
Fat density lines in the intermuscular fascial
layers
CXR Interpretation
Normal structures visible
A.
B.
C.
D.
E.
F.
G.
H.
I.
Costophrenic angle
Diaphragm
Heart
Aortic arch
Trachea
Hilum
Main carina
Stomach bubble
Ascending aorta
CXR Interpretation
Normal structures visible
A.
B.
C.
D.
E.
F.
G.
H.
I.
Costophrenic angle
Diaphragm
Heart
Aortic arch
Trachea
Hilum
Main carina
Stomach bubble
Ascending aorta
CXR Interpretation
Normal structures visible
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Tracheal air column.
Carina.
First rib.
Peripheral lung fields have no markings except:
The minor fissure.
Top of the R diaphragm is usually between the
anterior 6th & 7th ribs, and overlying the
posterior 10th & 11th ribs.
Left diaphragm is lower (in 90-95%) by roughly
half an interspace.
Inferior margins of the posterior ribs.
Anterior mediastinal line.
Superior vena cava.
Azygous vein.
Right descending pulmonary artery.
Pulmonary arteries and veins.
Right atrium.
Inferior vena cava.
Aortic arch.
Left pulmonary artery.
Border of the left ventricle.
Descending aorta.
Fat density lines in the intermuscular fascial
layers
CXR Interpretation
PA vs. AP views
CXR Interpretation
PA & Lateral views
CXR Interpretation
Hyperexpansion = “Air Trapping”
CXR Interpretation
“Big Lungs” & “Little Lungs”
CXR Interpretation
Interstitial Infiltrates
A. Generalized interstitial thickening = linear (“reticular”).
B. Discrete interstitial thickening = nodules.
C. Interstitial & alveolar filling = silhouette.
CXR Interpretation
Interstitial Infiltrates
CXR Interpretation
Interstitial Infiltrates
CXR Interpretation
Alveolar Infiltrates
Alveolar-filling, or “airspace” disease:
“Pointillist” patterns.
Air bronchograms.
CXR Interpretation
Alveolar Infiltrates