Chest radiology II

Question 1

what is a silhouette sign?

Answer 1

two substances of the same radiographic density cannot be differentiated from each other on an x ray

Question 2

what is the air bronchogram sign?

Answer 2

intrapulmonary bronchi are not visible on the normal CXR because they are filled with air and are surrounded y alveolar air

parenhcymal consolidation may result in visualization of these bronchi since air within the lumens will stand out in contrast to the surrounding opaque lung

Question 3

air bronchograms are often seen in what conditions?

Answer 3

pneumonia and pulmonary edema

Question 4

an air bronchogram is indicative of what process?

Answer 4

lesion is within lung parenchyma rather than in pleura or mediastinum (since airways are open)

Question 5

what are the five mechanisms that cause lung volume loss?

Answer 5

1. resporption of air
2. relaxation
3. scarring
4. decreased surfactant
5. hypoventilation

Question 6

what are the only two (natural) things that produce straight lines on CXRs?

Answer 6

fissures

fluid lines

Question 7

what are the signs of direct lung collapse?

Answer 7

1. displacement of interlobar septa (fissures) - most reliable
2. loss of aeration of involved lobe
3. crowding of the bronchovascular markings

Question 8

what are the indirect signs of lung collapse?

Answer 8

1. elevation of ipsilateral hemidiaphgram
2. hilar displacement
3. deviation of trachea to side of collapse
4. cardiac displacement
5. narrowing of rib cage on collapsed side
6. compensatory overaeration of normal lung

Question 9

what makes up acini? what makes up secondary pulmonary lobules?

Answer 9

acini - multiple alveoli

secondary pulmonary lobule - multiple acini

Question 10

what is the fundamental anatomic unit of the lung?

Answer 10

secondary pulmonary lobule

Question 11

interstitial pattern can appear in what 3 forms?

Answer 11

generalized thickening
discrete thickening
combination

Question 12

signs of acute interstitial markings

Answer 12

ill defined and are not distorted (normal branching pattern)

Question 13

signs of chronic interstitial markings

Answer 13

interstitial markings are sharp and distorted (angular, irregular, or bowed)

Question 14

what is the most reliable method for distinguishing acute from chronic interstitial changes?

Answer 14

finding an old film for comparison

Question 15

most diffuse (and chronic) interstitial lung disease is caused by what factor?

Answer 15

fibrosis

Question 16

focal alveolar consolidation = ?

Answer 16

pulmonary mass or nodule

Question 17

what are the most common causes of acute diffuse alveolar disease?

Answer 17

bacterial pneumonia

pulmonary edema

Question 18

where do the pleural spaces extend posteriorly and laterally?

Answer 18

posteriorly - 12th rib

laterally - 10th rib

Question 19

which film view is most sensitive for detection of small pleural effusions? why?

Answer 19

lateral

can see fluid tracking up major fissure

Question 20

how does air in the pleural space compare to normal lung air?

Answer 20

pleural space air is more radiolucent

also, no lung markings will be seen

Question 21

where does the mediastinum go in a tension pneumothorax?

Answer 21

shifts mediastinum away from pneumothorax

Question 22

what is the most frequent sign of mediastinal disease?

Answer 22

mediastinal widening

Question 23

what is the most common cause of a middle mediastinal mass?

Answer 23

enlarged lymph nodes

Question 24

how does LV enlargement appear on PA chest? lateral?

Answer 24

PA - left heart border moves laterally and the cardiac apex moves anterolaterally

lateral view - left heart border moves inferoposteriorly

Question 25

what is the relationship of lobe vessels in CHF?

Answer 25

upper lobe vessels are larger than lower lobe vessels

Question 26

what are the most common causes of redistribution or cephalization on CXR?

Answer 26

left heart failure and mitral valve stenosis

Question 27

what is the downside of CT pulmonary angiogram?

Answer 27

ionizing radiation - significant increase in cancer risk especially in young women (breast cancer)