LungRadiology Flashcards
Differentiate: nodule vs mass
Nodule < 3 cm Mass > 3 cm
Lesions greater than 3 cm in diameter have a greater than _% probability of being malignant.
75
Why are smaller lesions on CXR likely to be benign?
To be visible on a CXR, they must be highly dense: a property usually associated with calcification.
_ calcification on CXR, although usually benign, may represent malignancy.
_ calcification on CXR, although usually benign, may represent malignancy
Ddx nodules
Infection Primary or lung metastasis Granulomata Rheumatoid nodules Wegener granulomatosis Vascular malformations Bronchogenic cysts Hamartoma
DDx lung masses
Ddx lung nodules + sarcomas, fibromas, and progressive massive fibrosis (
DDx anterior mediastinal masses
Teratoma Thymus derived masses: cyst, lipoma, cancer Thoracic thyroid Lymphoma
The _ _ is that portion of the mediastinum anterior to the pericardium and below the thoracic plane.
anterior mediastinum
Opacification of air spaces, caused by the filling of alveoli with blood, pus, or fluid.
Seen on the CXR as patchy areas of increased density, often surrounding air bronchograms.
alveolar infiltrate
marked by their homogeneity, their irregular and often fluffy appearance, and the presence of air bronchograms
Alveolar infiltrate
Differentiate alveolar from interstitial infiltrates
(Hard in practice, patterns are different)
Alveolar Interstitial pattern
Fluffy Small nodules
Ill-defined margins Linear/reticular
Coalescing septal lines
Segmental/lobar Reticulo-nodular
Alveolar infiltrate contents
- Water
- Blood
- Pus
- Protein
- Calcium: rare
Interstitial infiltrates: type basis
Morphology
- Reticular
- Nodular
- Reticulo-nodular
- Honeycombing
- Ground glass
Alveolar infiltrates with pus
Pneumonia
Alveolar infiltrate with blood
- Goodpasture syndrome
- Idiopathic pulmonary hemosiderosis
- Systemic lupus erythematosus (SLE)
_ infiltrate —implies scarring and end-stage disease and is usually seen with idiopathic pulmonary fibrosis (IPF)
Honeycomb
Causes of
- Consolidation,
- Edema
- Atelectasis
- Severe interstitial disease
- Neoplasm
- Normal expiration.
Tubular outline of an airway made visible by filling of the surrounding alveoli by fluid or inflammatory exudates
Air bronchogram
Differentiate between right and left ribs on lateral CXR
Size: right ribs (red arrows below) are larger due to magnification
Position: posterior to the left ribs if the patient was examined in a true lateral position.
This can be very helpful if there is a unilateral pleural effusion seen only on the lateral view.
https://www.med-ed.virginia.edu/courses/rad/cxr/technique2chest.html
Differentiate right from left hemidiaphragm on lateral CXR
- Lower: left
- Visibility: anterior part of right hemidiaphragm remains visible.
Why does the anterior part of the left hemidiaphragm disappear?
Since the heart lies predominantly on the left hemidiaphragm the result on a lateral film is silouhetting out of the anterior portion of the hemidiaphragm, whereas the anterior right hemidiaphragm remains visible.
Why is the X-ray tube 6 feet away for a PA film?
Diminishes the effect of magnification of structures closer to the x-ray tube.
Why does the heart look larger on AP views?
- In the supine AP the x-ray tube is 40 inches from the patient vs 72 inches for PA view causing magnification of closer structures.
- The heart is anterior: therefore closer.
AP vs PA
Left: PA Right: AP supine film
Explanation: AP shows magnification of the heart and widening of the mediastinum. Whenever possible the patient should be imaged in an upright PA position. AP views are less useful and should be reserved for very ill patients who cannot stand erect.
https://www.med-ed.virginia.edu/courses/rad/cxr/technique3chest.html