Pulmonary Radiographic Pathology Flashcards
What is the Silouette Sign?
When there is more tissue/fluid in an area than normal, you will lose the border of another soft tissue area adjacent to it.
What is the Air Bronchogram sign?
Shows that airways are open but filled with another substance than air.
What are the 5 basic mechanisms that cause volume loss in the lung?
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
What will give you a straight line on a Chest CT?
Fluid Levels and Lung fissures
What are the direct signs of Lung collapse?
Displacement of the interlobar septa (most reliable sign)
Loss of aeration of the involved lobe
Crowding of the bronchovascular markings in the affected lobe
What are the indirect signs of lung collapse?
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
What are the most common causes of obstruction in Children, young adults and older adults?
Child: Mucus Plug or aspiration
YA: Muc Plug, Foreign body, endobronchial tumor
OA: Bronchogenic CA
What are the different reactions of the lung to disease?
Interstitium can thicken or thin
Alveoli can have fluid or air
Changes can be focal or diffuse
Changes can be acute or chronic
What are the different substanes that can fill the lung?
Water, pus, blood, proteinaceous fluid and tumor
What are the different forms of Interstitial pattern changes in the lung?
Generalized-Linear = Reticular
Discrete - Multiple small nodules
Combo- linear and multiple small nodules- Reticulonodular
What is the difference in appearance between Acute and Chronic Lung disease on CT?
Acute: Interstitial markings are ill defined and not distorted (normal branching pattern)
Chronic: Interstitial markings are sharp and distorted (angular, irregular or bowed)
What is the most relaible method for distinguishing acute from chronic changes in the lung?
Review old Films!
What are the most common causes of Acute vs Chronic Lung disease?
Acute: Bacterial Pneumonia
Chronic: Indolent infection or inflammatory lung disease
>40yo cancer is a greater concern
What is the name of the posterior space behind the lung?
Costophrenic Sulcus
What is the Meniscus sign?
Left pleural effusion causing rounding of costophrenic angle.
What will cause a complete shift of structure and mediastinum with collapse of lung? Collapse with no shift?
Large Pleural effusion = SHIFT
Combination of pleural effusion with lung collapse = NO SHIFT
What causes a tension Pneumothorax?
Air can enter the pleural space with each breath but cannot escape. Inc intrapleural pressure.
What will be seen in the pulmonary vessels in Congestive heart failure?
Vessels in the lower lobe are smaller than those in upper lobe. Opposite of normal anatomy.
What are Kerly B lines?
Fluid that builds up in the interlobular septa causing short lines perpendcular to the pleural surface.
Why would you not do a V/Q scan?
If the Pretest probability is close to 50, the VQ scan will probably be too ambiguous.
When is VQ scan used?
Pt with renal failue who cannot recieve IV contrast
Pt allergic to IV contrast
VQ Scans give less radiation to the breasts than Angiogram.
