3. Chest Radiography Interpretation Flashcards
What is the most frequently requested radiological examination?
chest radiography
What is the role of chest radiography?
to exclude or confirm lung pathology
- visualize inserted lines/tubes (deep venous lines, tracheal tube, gastric tube)
- visualize the heart and its vessels
- examine the mediastinum (ie. lymphadenopathy)
- diagnose pathologies related to ribs/vertbrae and soft tissues (subcutaneous emphysema)
What are the types of chest radiography?
- conventional two-view radiograph: postero-anterior (PA) + lateral views
- portable antero-posterior radiograph: AP view
When is AP chest radiograph used?
when the patient cannot be safely mobilized, so the film is placed under their back (in supine position) with the X-ray source coming from above
Which is the preferred type of chest radiography and why?
- PA view is preferred because there is less magnification and distortion, since the chest is closer to the film
- AP view should only be used in ICU, because it magnifies the heart and widens the mediastinum
Why is the lateral view useful in chest radiography?
- fluid levels equal to or above 50-100mL can be visible on lateral view
- whereas, on PA view, fluid levels need to reach 200-300mL to be visible
What is the use of lateral decubitus view?
- lateral decubitus view is when the patient is laying on their side, the film is in front of the chest and the X-ray source comes from behind
- it is helpful to visualize pleural effusion
- differentiate between mobile or loculated pleural effusion
How to check for technical adequacy in chest radiography?
- the thoracic spine should be visible through the heart shadow, suggesting good penetration
- patient should be examined in full inspiration (except PTX)
- diaphragm at the level of 10th-11th rib suggests excellent inspiration
- symmetrical clavicles suggest no rotation
- no angulation of X-ray (the clavicles shouldn’t project at or above the first rib)
How to analyze a chest X-ray?
- check age, sex, anamnesis, and older films
- use a spiral method: outside to center (extrathoracic structures, diaphragm, sinuses, lung parenchyma, hilus, mediastinum)
Which areas need special attention of chest radiography?
areas in which the pathology can be easily overlooked
- apical zones
- hilar zones
- retrocardial zone
- zone below the diaphragmatic dome
What is the cardiothoracic index?
ratio of the maximal horizontal cardiac diameter to maximal horizontal thoracic diameter
- ratio greater than 50% suggest cardiomegaly
- should NOT be measured in AP view!!
What is the meniscus sign on chest radiograph?
- costodiaphragmatic angle cannot be seen
- pleural fluid (at least 200-300mL) results in radio-opacity of the lung
- fluid filling is in the shape of a meniscus
How are small amounts of pleural fluid detected?
- CT and US
- US is useful in guiding the removal of pleural fluid
- CT is useful to evaluate underlying disease
What is a white lung on chest radiograph?
- white lung can be atelectasis (collapse or incomplete filling of lung) or pulmonectomy
- there is a pulling of the mediastinum, so it is no longer on the midline
- large effusion can push the mediastinum away
- in case of pneumonia, there is no mediastinal shift
What are the signs of pneumothorax?
- on chest X-ray the visceral pleura is visible (separates from the parietal pleura)
- small pneumothorax can only be diagnosed by CT but lung windowing is necessary for air detection
Signs of lobar pneumonia
- consolidation
- aerobronchogram
- visible fissure
if no resolution after antibiotics, there is suspicion of bronchoalveolar carcinoma
What is the basket sign in chest x-ray?
- classic sign of lung abscess in radiography
- pyogenic abscesses can be caused by staphylococcus/klebsiella infection
- cavitating mass can also be due to tuberculosis, fungal infection, squamous cell carcinoma
Chest radiography in case of interstitial pulmonary disease/edema
- causes: viral pneumonia, sarcoidosis, fibrosis, pneumoconiosis
- “batwing” or “butterfly” sign: bilateral perihilar opacities due to lung edema
- in case of worsening conditions, there is perihilar consolidations
- cephalization: pulmonary veins in the superior zone are dilated
Chest radiography of severe (alveolar) lung edema
- causes: bacterial pneumonia, ARDS (acute resp. distress syndrome), IRDS (infant resp. distress syndrome), bronchioalveolar carcinoma, pulmonary hemorrhage
- aerobronchogram: air filled bronchi with opacified alveoli (collapsed alveoli)
- pathological airspace: something other than air fills the alveoli
What are the stages of pulmonary edema?
- cephalization
- pulmonary interstitial edema
- pulmonary alveolar edema
What are the radiological signs of heart failure?
- fluid in lung fissures
- Kerley B lines
- prominent upper lobe arteries
- fluid in the lung interstitium
- pleural effusion
What are the types of diseases affecting lung parenchyma?
- airspace (alveolar) disease
- interstitial (infiltrative) disease
What causes pathological airspaces?
something other than air filling the alveoli, appearing as fluffy, hazy, cloudlike/poorly marginated airbronchogram
- transudate: alveolar pulmonary edema
- blood: pulmonary hemorrhage
- gastric juice: aspiration
- inflammatory exudate: pneumonia
- water: near-drowning
What are examples of interstitial lung diseases?
can be focal or diffuse, appearing with sharp/discrete margins and no airbronchogram
- interstitial pulmonary edema
- interstitial pneumonia
- lymphangitic carcinoma
- fibrosis
- pneumoconiosis
