Pulmonary Radiographic Pathology

Question 1

What is the Silouette Sign?

Answer 1

When there is more tissue/fluid in an area than normal, you will lose the border of another soft tissue area adjacent to it.

Question 2

What is the Air Bronchogram sign?

Answer 2

Shows that airways are open but filled with another substance than air.

Question 3

What are the 5 basic mechanisms that cause volume loss in the lung?

Answer 3

1) Resorption of air as a result of obstruction of bronchus
2) Relaxation of the lung as a result of air or fluid in pleural space
3) Scarring causing lung contraction
4) Decreased Surfactant reducing lung distensibility
5) Hypoventilation as a result of CNS depression or pain

Question 4

What will give you a straight line on a Chest CT?

Answer 4

Fluid Levels and Lung fissures

Question 5

What are the direct signs of Lung collapse?

Answer 5

Displacement of the interlobar septa (most reliable sign)
Loss of aeration of the involved lobe
Crowding of the bronchovascular markings in the affected lobe

Question 6

What are the indirect signs of lung collapse?

Answer 6

Elevation of Ips Hemidiaphragm (normally right > left)
Hilar Displacement
(norm left> rt)
Dev of Trachea toward collapse
Cardiac Disp toward collapse
Narrowing rib cage (collapse)
Overaeration of adjacent normal lung

Question 7

What are the most common causes of obstruction in Children, young adults and older adults?

Answer 7

Child: Mucus Plug or aspiration
YA: Muc Plug, Foreign body, endobronchial tumor
OA: Bronchogenic CA

Question 8

What are the different reactions of the lung to disease?

Answer 8

Interstitium can thicken or thin
Alveoli can have fluid or air
Changes can be focal or diffuse
Changes can be acute or chronic

Question 9

What are the different substanes that can fill the lung?

Answer 9

Water, pus, blood, proteinaceous fluid and tumor

Question 10

What are the different forms of Interstitial pattern changes in the lung?

Answer 10

Generalized-Linear = Reticular
Discrete - Multiple small nodules
Combo- linear and multiple small nodules- Reticulonodular

Question 11

What is the difference in appearance between Acute and Chronic Lung disease on CT?

Answer 11

Acute: Interstitial markings are ill defined and not distorted (normal branching pattern)
Chronic: Interstitial markings are sharp and distorted (angular, irregular or bowed)

Question 12

What is the most relaible method for distinguishing acute from chronic changes in the lung?

Answer 12

Review old Films!

Question 13

What are the most common causes of Acute vs Chronic Lung disease?

Answer 13

Acute: Bacterial Pneumonia

Chronic: Indolent infection or inflammatory lung disease
>40yo cancer is a greater concern

Question 14

What is the name of the posterior space behind the lung?

Answer 14

Costophrenic Sulcus

Question 15

What is the Meniscus sign?

Answer 15

Left pleural effusion causing rounding of costophrenic angle.

Question 16

What will cause a complete shift of structure and mediastinum with collapse of lung? Collapse with no shift?

Answer 16

Large Pleural effusion = SHIFT

Combination of pleural effusion with lung collapse = NO SHIFT

Question 17

What causes a tension Pneumothorax?

Answer 17

Air can enter the pleural space with each breath but cannot escape. Inc intrapleural pressure.

Question 18

What will be seen in the pulmonary vessels in Congestive heart failure?

Answer 18

Vessels in the lower lobe are smaller than those in upper lobe. Opposite of normal anatomy.

Question 19

What are Kerly B lines?

Answer 19

Fluid that builds up in the interlobular septa causing short lines perpendcular to the pleural surface.

Question 20

Why would you not do a V/Q scan?

Answer 20

If the Pretest probability is close to 50, the VQ scan will probably be too ambiguous.

Question 21

When is VQ scan used?

Answer 21

Pt with renal failue who cannot recieve IV contrast
Pt allergic to IV contrast
VQ Scans give less radiation to the breasts than Angiogram.