Intro to Chest imaging
Matthew Bentz, MD
OHSU Diagnostic Radiology
Assistant Professor
2015
Objectives
• Remember your search pattern and use it on
every CXR
• Learn appropriate positioning of ET tubes
and central lines
• List the six commonly encountered
radiographic patterns on CXR
Concepts
1) Density differences form the image
2) Pattern and distribution are key
3) Diffuse versus focal reflects systemic versus local
4) Wide mediastinum
Concept #1
• Organ boundaries are seen only when the
densities are different between the tissues
– Pulmonary vessels are sharply seen in normal
lungs (Soft tissue – air interface)
– Airways are not seen in normal lung (Air – Air
interface)
Tissue Appearance on Radiographs
The Contrast in Densities is Essential
Air
Fat
Densities
Water/tissue
Bone
Metal
Density – the key to x ray films
Normal chest X ray
Bacterial and Aspiration Pneumonia
More airways are visible due to the
increased density of the pneumonia
ETT Position
• Ideal is 3-4 cm above carina
– Carina located ~ T6
• Position ETT between T4 and T6
• ETT Tube follows the chin (up / down)
– “The Hose goes with the Nose”
T1
T2
T3
T4
Carina
Tip of ETT
Practice
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
Bonus –
Look at the
ET tube
balloon
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
A. High
B. Low
C. Just Right
D. Not in the
trachea
E. They aren’t
intubated
Central lines
• Our perspective on most central lines
– Is it central? Yes = good
– Is it flopping around hitting the AV Valve? Yes = bad
– Close to the CavoAtrial Junction (CAJ) is fine
– CAJ landmarks
• About 2 cm below the bulge of the right atrial appendage
• About 2 vertebral bodies below the carina (better for peds)
Appropriately placed IJ line?
Subclavian artery vs vein
• The subclavian vein is below the clavicle
• The subclavian artery may extend above the
clavicle
• So if a subclavian line goes above the clavicle
(on a technically good CXR), you must have a
high suspicion that it is arterial
Which side is arterial, which is venous?
PICC lines
• Goal for the tip is the same, i.e. central
• Make sure it doesn’t take a wrong turn!
– Make sure to look at the arms and neck
Finding the tip can often feel like this
If you truly can’t see the tip, repeat
the film in a different position
Do not assume it’s ok if you don’t see it
Arterial PICC
PICC Line Radiograph: Appropriate
position or not?
Feeding tubes
• Make sure they travel downward along the
midline
• Should terminate below the diaphragm
• Make sure to locate the proximal sidehole
• Look at the carina!
Look at the carina