EXAM #1: INTRO TO CHEST RADIOLOGY Flashcards
What are the four different densities on a CXR?
1) Soft tissue (water)
2) Fat
3) Air
4) Bone (calcium)
How do high density objects appear on CXR?
White
*Note that these are absorbing more photons
How do low density objects appear on CXR?
Black
*Note that these are absorbing fewer photons
What are the three things to look for to determine of a CXR is adequate for interpretation?
1) Full inspiration
2) Apex of the right hemidiaphragm should be at the level of the posterior 9th or 10th ribs
3) Non-rotated film
How much “penetration” should there be on a PA CXR?
T-spine should be just visible, but no detail
How much “penetration” should there be on a lateral CXR?
Spine should darken as you move caudally
Where do you look for rotation on a CXR?
Clavicles–should be equal distance from the spinous process of the vertebral body
How do you tell the difference between a posterior and anterior rib?
Posterior= horizontal Anterior= vertical
What is the significance of the right paratracheal stripe?
Should be less than 5mm
*Enlargement can be lymphadenopathy most commonly associated with lung cancer
What forms the right heart border?
Right atrium
What is the AP window?
Space between the aorta and the pulmonary artery
What do you need to have to visualize structures on a CXR?
Different densities
What forms the left heart border?
Left ventricle
What is a fissure?
Adjacent viseral pleura
What is the difference between the fissures in the right and left lung?
Right= 2x
- Horizontal= superior
- Oblique= inferior
Left= 1x major fissure
What fissure separates the upper and lower lobes of the lungs?
Oblique/major fissure
What does the horizontal fissure separate?
Right upper lobe from right middle lobe
On the lateral CXR, what do you need to look for to tell the difference between the right and left hemi-diaphragms?
Which ribs the hemi-diaphragm abuts:
- Left= smaller/ non-magnified
- Right= larger/magnified
What structure prevents the anterior left hemi-diaphragm from touching the anterior thorax?
Heart
What is the retrosternal clear space?
Space between the chest wall and heart i.e. anterior mediastinum
What are the 5 T’s that can fill the retrosternal space?
1) Terrible lymphoma
2) Thymoma
3) Teratoma
4) Thyroid
5) Throacic aortic aneurysm
What is the retrotracheal clear space?
Space between the trachea and the T-spine
What diseases can fill the retrotracheal clear space?
1) Vascular abnormalities
2) Esophageal disease
3) Lung cancer
What is the retrocardiac space?
This is the normal clear “space” that is posterior to the heart on lateral CXR
What diseases can fill the retrocardiac space?
1) Hiatal hernia
2) Esophageal disease
3) LV enlargement
4) Pneumonia
What are the contents of the anterior mediastinum?
- Thymus
- Lymph nodes
- Fat
- Inframammary vessels
What should you remember about a mass that crosses the midline on a CXR?
Likely NOT part of the lung b/c the lungs don’t communicate
What shape should the AP window be on PA CXR?
Concave
What is the cardiothoracic ratio?
Max diameter of heart vs. thorax
Should be less than 0.5 on PA CXR
What should the relationship between the right and left hilar structures be?
Left is typically higher than right
What should the relationship between the hemidiaphragms be?
Right is higher than left (b/c of liver)
What is the sequence for reviewing a CXR?
1) Admin
2) Quality
3) Initial survey
4) Soft tissue
5) Bones
6) Mediastinum
7) Pleura spaces
8) Lungs
