CXR

Question 1

How does air look on an xray?

Answer 1

Black

Question 2

How does fat look on an xray?

Answer 2

Grey

Question 3

How does bone look on an xray?

Answer 3

White (more white than soft tissue)

Question 4

How does soft tissue look on an xray?

Answer 4

White

Question 5

What accounts for the different colors on an xray?

Answer 5

1. The less dense the area, the more photons pass through and the blacker the resulting image
2. Least dense to most dense: air, fat, soft tissue, bone

Question 6

What density are most tumors?

Answer 6

soft tissue density (white)

Question 7

What color are abnormal air pockets?

Answer 7

Still black

Question 8

When a lung is too back or too white, what abnormalities are suspected?

Answer 8

1. Too black: abnormal gas collection

2. Too white: tumor or infection

Question 9

What color are healthy lungs?

Answer 9

The lungs are dark grey. They are not completely black bc they contain some soft tissue elements like blood vessels

Question 10

Define contrast resolution

Answer 10

Refers to our ability to see different structures bc they differ in density

Question 11

Where can tumors hide in the chest so they are undetectable on xray due to poor contrast resolution?

Answer 11

Mediastinum

Question 12

Define silhouette sign

Answer 12

Loss of the normal interface between the lungs and adjacent soft tissue

Question 13

What does the presence of the silhouette sign mean?

Answer 13

1. An abnormality is present

2. Helps localize the abnormality

Question 14

If the interface at the right atrium is lost, where is the abnormality located?

Answer 14

Right middle lobe

Question 15

If the interface at the left ventricle is lost, where is the abnormality located?

Answer 15

Lingula of left lung

Question 16

If the interface at the left lung and diapraghm is lost, where is the abnormality located?

Answer 16

Left lower lobe

Question 17

What can cause increased lung density?

Answer 17

1. Consolidation
2. atelectasis
3. nodules/masses
4. effusion

Question 18

What is consolidation? How does it affect lung density and volume?

Answer 18

1. consolidation occurs when air is replaced with soft tissue and the lung turns white
2. Lung volume remains the same

Question 19

What processes replace lung with soft tissue?

Answer 19

1. pneumonia
2. bleeding
3. PE from heart failure
4. Cancer

Question 20

Define atelectasis. How does it affect lung density and volume?

Answer 20

1. The air has been removed form the lung, leaving only the soft tissue elements like blood behind
2. Lung turns white (increased density)
3. Decreased volume

Question 21

What are bronchograms? What condition are bronchograms found in?

Answer 21

1. Normally the bronchi are poorly visible on xray bc they are too thin. If they are filled with fluid, the bronchi are visible against the soft tissue density background
2. Consolidation

Question 22

What causes atelectasis?

Answer 22

1. passive
   A. Caused by a mass or PE pushing on a lung causing decreased lung volume
2. adhesive
   A. Results from inadequate surfactant (respiratory distress of the newborn)
3. cicatrical
   A. volume loss due to scarring after infection or radiation
4. obstructive
   A. Mass like cancer obstructing a bronchus. Air distal to the obstruction is resorbed

Question 23

How is a mass differentiated from consolidation?

Answer 23

Mass has well defined borders, consolidation is diffuse

Question 24

What causes lung masses?

Answer 24

Lung cancer, congenital anomaly, pneumonia. depends on history

Question 25

What is the difference between a nodule and a mass?

Answer 25

Nodule: 3cm

Question 26

Define pleural effusion

Answer 26

A fluid collection in the potential space between the visceral and parietal pleura

Question 27

How are pleural effusions recognized?

Answer 27

Conforms to the anatomy of the pleural space. Tend to be peripheral and cause blunting of the cvangles (menisucus appearance)

Question 28

What causes pleural effusion?

Answer 28

Cancer, infection, heart failure

Question 29

What is bilateral symmetrical perihilar opacity with small bilateral effusions?

Answer 29

Almost invariably left heart failure

Question 30

What are the possible causes of a completely opacified hemithorax? How are they differentiated?

Answer 30

1. Atelectasis: mediastinum shifts toward atelectasis to compensate for the volume lost by the lung 2. massive pleural effusion: mediastinum shifts away from effusion

Question 31

What happens to the lung volume in a completely opacified hemithorax?

Answer 31

The lung is deflated

Question 32

How is obstructive atelectasis treated?

Answer 32

removal of obstruction

Question 33

How is pleural effusion treated?

Answer 33

Thoracentesis

Question 34

What causes decreased lung density?

Answer 34

1. Pneumothorax 2. Pneumomediastinum 3. Pneumopericardium 4. Pulmonary cavitation

Question 35

Where is the air located in a pneumothorax?

Answer 35

In the pleural space

Question 36

What happens to the mediastinum in a tension pneumo?

Answer 36

Pushed away from the pneuo

Question 37

How is a tension pnuemothorax treated?

Answer 37

chest tube

Question 38

Where is a pneunothorax located in a supine pt?

Answer 38

Air rises over the diapraghm in the lateral sulcus (deep sulcus)

Question 39

Define bulla

Answer 39

A thin walled, well defined area greater than 1 cm where normal lung has been destroyed and replaced by air. Roughly sphereical in shape

Question 40

How are skin folds differentiated from pleural lines?

Answer 40

Skin folds are thicker, and may extend into the opposite hemithorax

Question 41

What causes pneumothoraces?

Answer 41

1. Central line puncture 2. trauma 3. rib fracture 4. barotrauma 5. Spontaneous, tall thin adolescent males 6. Bleb rupture

Question 42

Define pneumomediastinum. How does it appear on xray?

Answer 42

1. Abnormal air collection in mediastinum | 2. Streaks of air in the mediastinal area often extending into the neck. May have continuous diaphragm sign

Question 43

What is a continuous diaphragm sign?

Answer 43

Air is entrapped between the heart and diaphragm, causing you to be able to see an uninterrupted diaphragmatic line across the chest

Question 44

What causes a pneumomediastinum?

Answer 44

1. Rupture of esophagus, trachea or tracheobronchial tree | 2. Rupture of overinflated alveoli (most common) in asthmatics, vomiting, or vigorous valsalva maneuver

Question 45

Define pneumopericardium and its causes

Answer 45

1. Air in the pericardium | 2. trauma, surgery, infection with gas forming bacteria, positive pressure ventilation

Question 46

When does a pulmonary cavity occur? Etiology?

Answer 46

1. A portion of the lung is destroyed and replaced by air after erosion into a bronchi 2. cancer, infections, vasculitis

Question 47

How can a bulla and cavity be differentiated?

Answer 47

Bulla is usually smooth and thin walled, seen in emphysema | Cavities are thick walled with irregular borders, seen in TB