Flashcards in Chest Radiography II Deck (93):
What is the silhouette sign?
An intrathoracic lesion touching the border of the heart, aorta, or diaphragm will obliterate that border on an x-ray
Why is the term airspace disease more appropriate than pneumonia when looking at a CXR?
opacity may not be pneumonia; could be hemorrhage for example.
A radiopacity which overlaps but does not obliterate the heart border is where in the thoracic cavity?
What is the air bronchogram sign?
The phenomenon of air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white)
True or false: intrapulmonary bronchi are not usually visualized on CXR. Why or why not?
True--since they are filled with air, and are surrounded by alveolar air
When are air bronchograms usually seen?
Bronchoalveolar cell CA
An air bronchogram indicates that the pathology is where?
It indicates that the lesion in within the lung parenchyma, rather than in the pleura or mediastinum
What are the five things that can fill the alveoli to cause the bronchogram sign?
What does an air bronchogram sign indicate?
It indicates that the airway is open--unlikely that the lung disease is due to an obstructive tumor
What are the three scenarios in which the air bronchogram sign may not be present?
-bronchi are full of secretions
-Bronchus is obstructed by a FB or tumor
-Incomplete lung consolidation
What are the five mechanisms that cause lung volume loss?
-resorption of air as a result of obstruction of a bronchus
-relaxation of the lung as a result of air or fluid in the pleural space
-Scarring causing lung contraction
What is atelectasis?
Less severe changes of volume loss than complete collapse
What are the direct signs of lobar collapse? (3)
-Displacement of the interlobar fissure
-Loss of aeration of the involved lobe
-Crowding of the bronchovascular markings
What are the two things on CXR that produce straight lines?
Fissures and air fluid levels
Triangular shaped area behind the lung = ?
Left lower lobe collapse
What are the indirect signs of lobar collapse? (5)
-Elevation of the ipsilateral diaphragm
-Deviation of the trachea to the side of collapse
-Cardiac displacement toward side of collapse
-Narrowing of the rib cage on the side of collapse
-Compensatory overaeration of the adjacent normal lung
What happens to the hemidiaphragm with lobar collapse?
Elevation of the ipsilateral diaphragm
What happens to the hilum with lobe collapse?
If higher lobe, then elevation
If lower lobe, then depression
What happens to the trachea with lobe collapse?
Deviate toward affected side
What happens to the heart with lobar collapse?
Displacement toward the side of the collapse
What happens to the rib cage with lobar collapse?
Narrowing on the side of collapse
What happens to the adjacent, normal lung with lobar collapse?
What happens to the minor fissure with RUL collapse?
Horizontal fissure goes superiorly
What are the radiographic findings of a RML collapse (PA and lateral)?
Ill defined shadowing obscuring the right heart border on PA film.
Lateral film shows thin wedge between the major and minor fissures
What are the radiological findings with a RLL collapse (PA and lateral views)?
PA = obliteration of the right hemidiaphragm, but normal heart border
Lat = Abnormally increased density over the lower thoracic spine d/t the triangular shaped density of the collapsed lobe. The major fissure is displaced downward
What are the radiological findings with LUL collapse (PA and lateral views)?
PA = LUL collapses forward and thus presents no sharp margins
Lat = The collapsed lobe is visible as a band of soft tissue retrosternally
What happens to the major fissure with LUL collapse?
Major fissure is pulled anteriorly
What are the radiological findings with LLL collapse (PA and lateral views)?
PA = triangular retrocardiac opacity with major fissure pulled medially
Lat = Increased opacity over the lower thoracic spine
What is the most common cause of a central airway obstruction in children?
Mucous plug or aspirated foreign body
What is the most common cause of a central airway obstruction in adults younger than 40?
What is the most common cause of a central airway obstruction in adults over 40?
Why is lobar collapse common with ventilator use?
Increased mucus secretion
What are the two major structures of the lungs?
Multiple alveoli form what? Several of these form what?
Secondary pulmonary lobule
What are the two major ways that the lung can respond to disease?
Thicken or thin
Most interstitial lung disease is acute or chronic? What about airspace disease?
Interstitial = Chronic
Airspace = acute
What are the four variables of lung disease?
Why do the pulmonary vessels disappear on CXR are you move peripherally? What happens if there is thickening?
They are beyond the resolution of the x-ray
Thickening will increase the distance at which you are able to see them
What are the three generalized patterns of lung disease?
How do you differentiate between acute and chronic patterns of lung disease?
Acute = interstitial markings are ill defined and not distorted
Chronic = sharp and distorted markings
What is the most reliable way to differentiate between acute vs chronic pattern of lung disease?
Compare to old films
Most diffuse interstitial lung disease is chronic, and usually caused by what?
Acute interstitial lung disease is usually due to what?
Pulmonary edema or viral/mycoplasma pneumonia
What is alveolar disease?
airspace consolidation d/t fluid, pus etc
How does a lung with alveolar disease look on CXR?
True or false: most airspace disease is acute
With airspace disease, a bronchogram sign may be present depending on what?
Depending on whether the associated bronchus is patent or occluded
What is the difference between a mass and a nodule in a lung?
Nodule is less than 3 cm, mass is greater
What are the general causes of focal alveolar consolidation?
Pulmonary mass or nodule
What is the most frequent cause of acute diffuse alveolar disease?
Bacterial pneumonia and pulmonary edema
In young patients, what are nodules/mass usually due to? What about patients over 40?
Young = indolent infx or inflammation
Old = CA
Which has sensory innervation: the visceral or parietal pleura?
Which pleura has lymphatic: visceral or parietal? What are the openings to these vessels called?
The pleural space extends to which rib posteriorly? Laterally?
12th rib poasteriorly
10th rib laterally
What is the costophranic sulcus (angle)?
The deep gutter around the dome of each hemidiaphragm
What view of the chest can you see the posterior costophrenic sulcus? Lateral costophrenic?
Posterior sulcus = lateral view
Lateral sulcus = PA view
What is the meniscus sign?
Rounding of the costophrenic angle d/t accumulation of fluid
Which view is more sensitive for detecting pleural effusions? Why?
Lateral, since you can see the posterior costophrenic sulcus better, and that is the lowest area of the diaphragm
If a hemithorax is totally opaque, it is usually due to what?
Consolidation and/or atelectasis or a large pleural effusion
If an opaque hemithorax is due to atelectasis, which way will the mediastinum shift?
Toward the involved hemithorax
If an opaque hemithorax is due to a large pleural effusion, which way will the mediastinum shift?
Shift away from the involved hemithorax
If there is an opaque hemithorax without shifting of the mediastinum, then what is it likely due to?
Both atelectasis and pleural fluid or a tumor
How much fluid does it take to visualize on a PA CXR?
More than 175 mL
How much fluid does it take to visualize on a lateral upright CXR?
More than 75 mL
How much fluid does it take to visualize on a decubitus CXR?
Greater than 5 mL
How much fluid does it take to visualize on a supine CXR?
Several hundred mL
Where are most pneumothoraces most commonly seen?
Apex of the lung
What is a tension pneumothorax?
When air enters the pleural space with each breath, but cannot escape, thus increasing the intrapleural pressure
What are the CXR findings with a tension pneumothorax?
Mediastinal shift away from the pneumothorax
Review the labeled lateral CXR. What is A?
Review the labeled lateral CXR. What is B?
Review the labeled lateral CXR. What is C?
Review the labeled lateral CXR. What is D?
right heart border
Review the labeled lateral CXR. What is E?
left heart border
Review the labeled lateral CXR. What is F?
right pulmonary artery
Review the labeled lateral CXR. What is G?
left pulmonary artery
Review the labeled lateral CXR. What is H?
Retrosternal clear space
Masses in the mediastinum cause what kind of widening?
Hemorrhage/fat or infiltrating diseases in the mediastinum cause what kind of widening?
What are the radiological findings of LV enlargement on a PA CXR?
Left heart border moves laterally, and the cardiac apex moves anterolaterally
What are the radiological findings of LV enlargement on a lateral CXR?
The left heart border moves inferoposteriorly
In a normal, erect state, how do the upper and lower lobe pulmonary arteries compare? What happens in CHF?
Upper are thinner and more delicate
Lower and thicker
CHF will cause equalization between the two in the erect state
What is the most frequent cause of pulmonary redistribution (cephalization)?
Left heart failure and mitral valve stenosis
Pulmonary redistribution without pulmonary edema = ?
What are Kerly B lines, and what causes them?
Fluid in the interlobular septa d/t increased LA pressure increases interstitial edema, causing the vessel margins to become less distinct, and peripheral interstitial markings to becomes more prominent.
Which is worse: interstitial edema, or alveolar edema?
What are the radiological findings of alveolar edema?
Diffuse, patchy infiltrate
The sensitivity for a first or second order pulmonary embolus is close to 100%, but drops markedly for further branching. How clinically significant is this? Why?
Not very, since low incidence of complications from these
What is a V/Q scan?
Compare V with Xe gas, and Q with Tc
How do you grade V/Q scans?
Based on pretest probability and results
What are the three outcomes of a V/Q scan?
What are the indications for a V/Q scan over a pulmonary angiography?
-pt with renal failure
-allergy to contrast
-Young women (?)