Chest Radiology Flashcards
What are the four main radiographic densities?
Soft tissue (water)
Fat
Air
Bone
Dense object appear what color on x-ray? Why?
White d/t absorption of more photons
Object that are not dense appear what color on x-ray? Why?
Black
lower absorption of photons
Should CXR be performed with full inspiration or expiration?
Inspiration
The midpoint of the hemidiaphragm should be at what posterior rib level?
9th or 10th
True or false: on a PA view of the chest, the thoracic spine should be visible through the heart, with bony details well seen
False-should be visible, but fine detail is not usually seen
How do you determine if there is adequate x-ray penetration with a lateral CXR?
- The spine should darken as you move caudally
- the sternum should be on edge
- posteriorly should be 2 sets of ribs
true or false: on a normal lateral CXR, the ribs should align
false–rarely do they align
what identifies an under penetrated film?
inability to make out any of the vertebral bodies
What identifies an over-penetrated CXR?
Clear vertebrae, but inability to make out lung structures
What should happen to the spine on a lateral CXR as you move inferiorly?
Should get darker
How do you determine rotation for a CXR?
Assess the clavicular heads–should be equidistant from the spinous processes of the vertebral bodies
What are the three major determinants of an adequate CXR?
Good inspiration
Adequate penetration
No rotation
How do you differentiate the anterior and posterior ribs on a CXR?
Posterior = horizontally oriented Anterior = vertically oriented
What is the right paratracheal stripe?
Border of the right bronchus on CXR
What is the normal size of the right paratracheal stripe?
No more than 5 mm in diameter
The right heart border is formed by which structure of the heart?
Right atrium
The left heart border is formed by which structure of the heart?
Left ventricle
Where is the ascending aorta seen on a CXR?
Right side of the chest, (second bump after the RA bump)
Where is the SVC seen on a CXR?
just above the ascending aorta
Where is the right brachiocephalic vein seen on a CXR?
Just above the SVC
What is the order of vascular structures on the left side of a CXR going from superior to inferior?
Left brachicephalic Aortic arch AP window Descending thoracic aorta LV
What is the AP window on a CXR?
Space between the undersurface of the aortic arch and the superior surface of the left pulmonary artery
What is responsible for the delineation of the vascular structures of the chest?
Difference in density of the lungs vs the vascular structures
True or false: in order to see a structure on CXR, the XR beam must pass parallel or tangential to the structure
True (cannot by perpendicular)
Where does the left brachiocephalic vein lay in relation to the right brachiocephalic artery?
Anterior to the artery
What is the vascular structure that sits to the right of the ascending aortic arch on a transverse section of a CT?
SVC
What structures bound the LV?
lingula and the LLL
What structures bound the right atrium?
RLL
RML
What structures bound the SVC?
RUL
What structures bound the aortic arch?
LUL
What are the lung fissures, generally?
The space between the lobes where the visceral pleural surfaces touch
What are the two fissures of the right lung?
horizontal and oblique
What is the fissure that divides the left lung?
Oblique fissure
What is the pleural space?
Potential space between the visceral and parietal pleura
Which sits anterior: the right middle lobe or the right lower lobe?
Right middle lobe
The lung fissure are only visible when the x-rays are in what relation to the fissures?
Only if they are parallel–cannot be perpendicular or oblique
The major fissures will be best seen on which views? Minor fissures?
Major = lateral view Minor = PA or lateral
On a lateral CXR, how does the major fissure of the left lung relate to the right lung?
Left is posterior to the right
How does the right upper lobe bronchus appear on a lateral CXR?
Area of radiolucency in the trachea
Radiolucent areas in the bronchi on a lateral CXR mean are what?
branching bronchi
True or false: you cannot really appreciate much of the aorta on a lateral CXR unless the pt has COPD
True
How does the left pulmonary artery appear on a lateral CXR?
Comma shaped opacity that sits over the continuum of the left bronchus
What is the radiodense structure that sits anterior to the pulmonary bronchus on a lateral CXR?
Right pulmonary artery and the right superior pulmonary vein
What obscures the superior margin of the aortic arch on CXR?
Great vessels or axillary folds
What is contained within the aortic-pulmonic window?
Lymph nodes
Left recurrent laryngeal nerve
Fat
How do you identify the aortic-pulmonic window on CXR?
It is the crescent shaped lucency between the inferior border of the aortic arch, and the superior border of the left pulmonary artery
Why are the right ribs magnified with a lateral CXR?
Because the left side is adjacent to the detector
The left hemidiaphragm is obscured by what structure anteriorly?
the heart
How do you identify the right hemidiaphragm from the left?
Left should go to non magnified ribs, and never goes to the anterior chest
Right should follow magnified ribs
What are the two structures of the heart the comprise the posterior wall of the heart?
LA
LV
Where is the pulmonary outflow tract on a lateral CXR?
anterior-superior part of the heart
Where is the posterior border of the IVC on a lateral CXR?
Just below the left ventricle
What are the three clear spaces seen on a CXR?
Retrosternal
Retrotracheal
Retrocardial
What does a retrosternal clear space indicate? (5 T’s)
Terrible lymphoma Thymoma Teratoma Thyroid Thoracic AA
What are the pathologies that correlate to a retrotracheal clear space? (3)
Vascular abnormalities
Esophageal disease
Lung CA
What are the diseases that can present in the retrocardiac clear space? (4)
Hiatal hernias
Esophageal disease
LV enlargement
Pneumonia
On a lateral CXR, what are the black spaces between the vertebrae?
Neural foramen
Which are magnified on a lateral CXR, the right or left ribs?
Right
What are the four major structures that reside in the anterior mediastinal space?
Thymus
Lymph nodes
Fat
Internal mammary vessels
True or false: if something crosses the midline of the chest, it is likely a lung pathology
False– lungs do not communicate with one another, so not likely
How can you differentiate anterior vs posterior masses in the chest?
Anterior ones will still show the descending aorta well since it is still bounded by air
What is contained within the middle mediastinum?
Heart/pericardium
Ascending aorta and arch
SVC/IVC
Which part of the mediastinum houses the AP window?
Middle
How do you identify the AP window on a chest x-ray?
Concavity on the left side beneath the aorta and above the pulmonary artery
What is the right paratracheal stripe? What is the normal thickness of this?
The interface between the right lateral wall of the trachea and the RUL
Normal thickness is less than 5 mm
What are the 4 major structures in the posterior mediastinum?
Esophagus
Descending aorta
Azygous and hemiazygous veins
Thoracic duct
What is the normal cardio:thoracic ratio?
Less than 0.5
When is the cardiothoracic ratio only valid?
If the CXR is a PA
What is the spatial relationship between the left hilar structures compared to the right?
Left are usually higher (97% of cases, other 3% same level)
What is the spatial relationship between the left hemidiaphragm compared to the right?
The right hemidiaphragm is normally slightly higher than the left d/t liver
What is the very first step in evaluating a CXR?
“administrative work” (pt, time, type)
What is the second step in evaluating a CXR?
Ensure adequate penetration, rotation, inspiration vs expiration
True or false: by definition, you cannot do a supine PA chest
True
A ring in the heart = ?
Prosthetic valve
Line that enters the heart = ?
Swan-Ganz catheter
Air beneath the right hemidiaphragm = ?
Pneumoperitoneum
Curving of the costophrenic angle = ?
Pleural effusion
