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
Utility of lateral decubitus film
- Volume of pleural effusion
- Mobile or loculated.
- Pneumothorax assessment: Look at the nondependent hemithorax to confirm a pneumothorax in patient who cannot be erect.
- Atelectasis: Dependant lung should increase in density due to atelectasis from the weight of the mediastinum putting pressure on it.
The diaphragm should be found at about the level of the _ to _ th posterior rib or _th - _th anterior rib on good inspiration.
The diaphragm should be found at about the level of the 8th - 10th posterior rib or 5th - 6th anterior rib on good inspiration.
What accounts for loss of cardiac silhoutte in the two films of the same patient, at the same time?
Poor inspiration
On the first film, the loss of the right heart border silhouette suggests pneumonia. However, the patient had taken a poor inspiration. With improved inspiration (second film), the right heart border is normal.
Adequacy of penetration PA view
- Thoracic spine disc spaces: barely visible through the heart
- Bony details of the spine: not visible.
- Bronchovascular structures: visible through the heart
Adequacy of penetration lateral view
- Lower spine should be darker than upper spine.
- The sternum should be seen edge on
- Posteriorly: Two sets of ribs should be visible
Why does the spine appear to be darken as you move caudally?
More air in lung in the lower lobes and less chest wall
Patient rotation
Clavicular heads should be equidistant from spinous processes
Explanation: If there is rotation of the patient, the mediastinum may look very unusual. Observe the clavicular heads and determe whether they are equal distance from the spinous process of the thoracic vertebral bodies.
What does the position of the clavicular heads tell us?
Correctly positioned patient
Magnification of clavicular head and spinous process alignment demonstrating a straight film.
What is wrong with this film?
In this rotated film skin folds can be mistaken for a tension pneumothorax (blue arrows).
Notice the skewed positioning of the heads of the clavicles (red arrows) and the spinous processes.
Why is the opacity on the left upper lobe described as a mass?
Left: well defined therefore mass.
In each of the cases above, there is an abnormal opacity in the left upper lobe. In the case on the left, the opacity would best be described as a mass because it is well-defined. The case on the right has an opacity that is poorly defined. This is airspace disease such as pneumonia.
By reference to parenchyma and pleura
A = intraparenchymal B = pleural C = extrapleural
Describe
Bone destruction indicative of an extrapleural mass.
Why is the major fissure not well visualized on a PA film?
Because it is at an oblique angle to the view.
The patient above has a pleural effusion extending into the fissure. Which fissure is which?
What is the bright loop near the center of the films?
Right minor fissure
Mitral valve ring
What structure is being shown?
Major fissure
- Area of paucity of vessels in the region of the capillaries near the fissure.
- If a very thin slice is taken, the pleura can actually be seen as a line (arrows).
The left pulmonary artery arches over the left _ _ _ and the right pulmonary artery passes posterior to the _ aorta to divide into the truncus anterior and the descending RPA.
Except in the right upper lobe, the pulmonary veins are generally _ to the pulmonary arteries.
The left pulmonary artery arches over the left upper lobe bronchus and the right pulmonary artery passes posterior to the ascending aorta to divide into the truncus anterior and the descending RPA.
Except in the right upper lobe, the pulmonary veins are generally anterior to the pulmonary arteries.
Name the structures
A = Apical segmental bronchus B = Posterior segmental bronchus C = Anterior segmental bronchus D = Bronchus intermedius E = Truncus anterior F = Carina G = Right main pulmonary artery H = Left main pulmonary artery I = Right inferior pulmonary artery J = Right superior pulmonary vein K = Right middle lobe bronchus L = Right lower lobe bronchus M = Right inferior pulmonary vein N = Left Atrium O = Left superior pulmonary vein P = Apicoposterior segmental bronchus Q = Left upper lobe bronchus R = Lingular bronchus S = Left inferior pulmonary artery T = Left inferior pulmonary vein
Silhouette sign
Loss of normal borders between thoracic structures usually caused by a radiopaque mass that touches the border of the heart or aorta.
Loss of lung/soft tissue interface caused by a mass or fluid in the normally air filled lung. If an intrathoracic opacity is in anatomic contact with, for example, the heart border, then the opacity will obscure the border.
The sign is commonly applied to the heart, aorta, chest wall, and diaphragm.
What feature is seen in the PA film?
Indistinct right heart border
ght middle lobe atelectasis can be difficult to detect in the AP film. The right heart border is indistinct on the AP film. The lateral shows a marked decrease in the distance between the horizontal and oblique fissures.
Why is this RLL atelectasis?
Persistence of the R heart border
Silhouetting of the right hemidiaphragm and a triangular density posteromedially are common signs of right lower lobe atelectasis. Right lower lobe atelectasis can be distinguished from right middle lobe atelectasis by the persistence of the right heart border.
Signs of RLL atelectasis
- Silhouetting of the right hemidiaphragm
- triangular density posteromedially
- Right lower lobe atelectasis can be distinguished from right middle lobe atelectasis by the persistance of the right heart border.
Horizontal lines less than 2cm long, commonly found in the lower zone periphery.
Kerley B lines
Kerley B lines
Thickened, edematous interlobular septa.
Locate the pneumonia: Why?
Right upper lobe
Above the major fissure
Recognition features
right sided lucency and leftward mediastinal shift
Right sided tension pneumothorax with right sided lucency and leftward mediastinal shift.
Unilateral upper lobe infiltrates: Cx
Infections
- Tuberculosis
- Histoplasmosis
- Coccidioidomycosis
- Klebsiella pneumonia
Primary lung neoplasms
Typical location
Right middle and lower lung lobes
Right upper lobe is a common area of consolidation in alcoholics who aspirate in the prone position.
Why are the RML and RLL typical sites of aspiration?
due to the larger caliber and more vertical orientation of the right mainstem bronchus.
Hamman-Rich syndrome
Acute interstitial pneumonitis: a rare, severe lung disease that usually affects otherwise healthy individuals. There is no known cause or cure.
Acute interstitial pneumonitis is often categorized as both an interstitial lung disease and a form of ARDS.
Right sided effusion: Cx other than standard causes
- Hepatic hydrothorax
- Meigs syndrome
Pleural effusion appearance parameters
Laterality, Size
Bilateral pleural effusion with a normally sized heart
- Tumor
- Connective tissue disease
- Viral infection
- CHF (less common)
Massive pleural effusion: Cx
Massive effusion: more than half of hemithorax
- Malignancy (55%)
- Parapneumonic or empyema (22%),
- Tuberculosis (TB) (12%).
If massive effusions are without contralateral displacement of mediastinal structures, the endobronchial obstructions by lung cancer or mediastinum fixation by mesothelioma should be considered
sarcoidosis with the triad of hilar adenopathy, acute arthritis, and erythema nodosum
Löfgren syndrome
A 50-year-old man has a history of several severe episodes of pneumonia as a child, and the subsequent development of recurrent purulent sputum production. He once again presents with the latter, and a chest x-ray reveals increased bilateral lower lung field markings suggestive of “tram tracks.” The most likely diagnosis is
Asbestosis
Aspiration pneumonia
Bronchiectasis
Dermatomyositis, with Jo-1–associated lung disease
Sarcoidosis
Bronchiectasis
