Chest radiograph

The chest radiograph (also known as the chest x-ray or CXR) is the most ubiquitous radiological investigation.

For paediatric chest radiograph see: Chest radiograph (pediatric(paediatric)

Indications

The chest radiograph is performed for a broad content of indications, including but not limited to ^1-4:

• respiratory disease
• cardiac disease
• haemoptysis  
• suspected pulmonary embolism
• investigation of tuberculosis  
• pneumonia
• pneumothorax 
• suspected metastasis 
• follow up of known disease to assess progress
• chronic dyspnoea
• trauma 
• evaluation of symptoms that could relate to cardiovascular and gastrointestinal systems
• thoracic disease processes 
• monitoring of patients in intensive care units 
• post-operative imaging
• immigration screening
• check position of nasogastric tubes, endotracheal tubes, PICCs etc.

Projections

Standard projections

• PA view
  • is performed standing and in full inspiration
  • it examines the lungs, bony thoracic cavity, mediastinum and great vessels
  • disadvantages: must be able to stand erect
  • advantages: better visualisation of the mediastinum and lungs
• lateral view
  • performed erect left lateral, labelled with the side closest to the cassette
  • ideal for localisation of suspected lung lesions when taken in conjunction with the PA view
  • examines the retrosternal and retrocardiac spaces
  • used to confirm the presence & location of opacities on frontal X-rays
  • salient points
    • gastric bubble is under the left hemidiaphragm; left hemidiaphragm is less distinct due to the cardiac silhouette
    • right hemidiaphragm appears higher and more complete (as the right is closer to the beam)

Additional projections

Other forms of the chest radiographs are performed in a variety of clinical scenarios, usually if the patient is unable to tolerate a standing PA radiograph:

• AP erect
  • sitting up on the bed; can be performed outside the radiology department, by a mobile x-ray unit
  • disadvantages: mediastinal structures may appear magnified, poorly inspired, rotated; poor inspiration causes crowding of the vessels
  • advantages: better for intubated, sick patients
• supine
  •  usually for trauma and critical care patients
• lateral decubitus
  • the patient is laying either left lateral or right lateral on a trolley on top of a radiolucent sponge.
  • the detector is placed landscape posterior to the patient running parallel with the long axis of the thorax.
  • the patient’s hands should be raised to avoid superimposing on the region of interest, legs may be flexed for balance.
  • problem-solving film, used to differentiate pneumothorax vs. pleural effusion; pneumothorax vs. pneumomediastinum.
  • air trapping due to inhaled foreign bodies, and showing and quantifying pleural effusions
• expiration view
  •  for pneumothorax and air trapping due to inhaled foreign bodies
• lordotic view
  • demonstrates areas of the lung apices that appear obscured on thePA/AP chest radiographic views
• right anterior oblique (RAO)/left anterior oblique (LAO) view
  •  for rib fractures and intrathoracic lesions (RAO also used routinely used in barium oesophagography)
• ribs AP view
  • for suspected posterior rib fractures 
• ribs PA view
  • for suspected anterior rib fractures 
• sternum lateral view 
  • a lateral projection often used to query fractures or infection
• sternum oblique view 
  • an RAO projection that is orthogonal to the lateral sternum view 

Patient preparation

The patient should be asked to remove all clothing and jewellery from the waist up and dress in a hospital gown. Long hair should be worn up.