Chest radiograph
The chest radiograph (also known as the chest x-ray or CXR) is anecdotally thought to be the most frequently-performed radiological investigation globally although no published data is known to corroborate this. UK government statistical data from the NHS in England and Wales shows that the chest radiograph remains consistently the most frequently requested imaging test by GPs (2019 dataset) 5.
For pediatric chest radiograph see: chest radiograph (pediatric)
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Indications
The chest radiograph is performed for a broad content of indications, including but not limited to 1-4:
- respiratory disease
- cardiac disease
- hemoptysis
- suspected pulmonary embolism
- investigation of tuberculosis
- pneumonia
- pneumothorax
- suspected metastasis
- follow up of known disease to assess progress
- chronic dyspnea
- trauma
- pneumoperitoneum
- evaluation of symptoms that could relate to abdominopelvic pathology
- thoracic disease processes
- monitoring of patients in intensive care units
- post-operative imaging
- pre-employment medical fitness
- immigration screening
- check position of nasogastric tubes, endotracheal tubes, PICCs etc.
- exclude radiopaque foreign bodies (accidental aspiration, MRI safety screen)
Projections
PA projection
- the posteroanterior (PA) view is the standard frontal chest projection
- the x-ray beam traverses the patient from posterior to anterior
- it is performed standing and in full inspiration with the patient hugging the detector to pull the scapulae laterally
- it is the best general radiographic technique to examine the lungs, bony thoracic cavity, mediastinum and great vessels
- advantages: technically excellent visualization of the mediastinum and lungs, with accurate assessment of heart size
- disadvantages: patient must be able to stand erect
AP projection
- the anteroposterior (AP) erect view is an alternative frontal projection to the PA projection with the beam traversing the patient from anterior to posterior
- it can be performed with the patient sitting up on the bed and even performed outside the radiology department using a mobile x-ray unit
- advantages: more convenient for intubated and sick patients who will not be able to stand for a PA projection
- disadvantages: mediastinal structures may appear magnified as the heart is further away from the detector, often poorly inspired, more likely to be rotated and to create skin folds, scapulae often cover some of the lungs
- a AP supine view is a further alternative frontal projection technique often used in trauma patients, or patients who can't sit up
- the supine position results in physiological widening of the cardiomediastinal outline including superior mediastinum, as well as congestion of the pulmonary veins with upper lobe venous diversion
Lateral projection
- the lateral view of the chest is performed erect left lateral and labeled with the side closest to the cassette
- a paravertebral gutter technique involves rotating the right side 5-10° anterior (RAO) to align the posterior ribs along the divergent beam
- it allows for localization of suspected chest pathology when assessed in conjunction with a PA view
- examines the retrosternal and retrocardiac spaces
- it allows assessment of the posterior costophrenic recesses
- salient points
- gastric bubble is under the left hemidiaphragm; left hemidiaphragm is less distinct anteriorly due to the cardiac silhouette
- right hemidiaphragm appears higher and more complete (as the right is closer to the beam)
- the radiation dose from a lateral chest radiograph is substantially higher than that of a PA projection and should probably not be routinely performed for this reason
Additional projections
Other forms of the chest radiographs are performed in a variety of clinical scenarios:
-
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
-
right anterior oblique (RAO)/left anterior oblique (LAO) view
- for rib fractures and intrathoracic lesions (RAO also used routinely used in barium esophagography)
-
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
Pitfalls
- rotation of the frontal projection can markedly affect the appearance of the CXR
- apparent mediastinal widening
- tracheal deviation
- apparent increased thickness of the paratracheal stripes
- asymmetric lung density
- supine positioning of the patient will alter the appearance of the CXR
- enlarge the heart (cardiothoracic ratio)
- alter the appearance of fluid or gas in the pleural space
- pneumothorax
- pleural effusion
- alter the appearance of fluid in the lung air spaces
- upper lobe vascular redistribution
- alveolar fluid distribution
- skin folds on AP projections may mimic visceral pleural sign of pneumothorax
- think twice before labeling dextrocardia as there exist processing errors; correlate with stomach bubble
Patient preparation
The patient should be asked to remove all clothing and jewelry from the waist up and dress in a hospital gown. Long hair should be worn up.
Tubings and lines must be removed from field of view in ward radiography.
Related Radiopaedia articles
Chest
- imaging techniques
-
chest x-ray
-
approach
- adult
- pediatric
- neonatal
-
airspace opacification
- differential diagnoses of airspace opacification
- lobar consolidation
-
atelectasis
- mechanism-based
- morphology-based
- lobar lung collapse
- chest x-ray in the exam setting
- cardiomediastinal contour
- chest radiograph zones
- tracheal air column
- fissures
- normal chest x-ray appearance of the diaphragm
- nipple shadow
-
lines and stripes
- anterior junction line
- posterior junction line
- right paratracheal stripe
- left paratracheal stripe
- posterior tracheal stripe/tracheo-esophageal stripe
- posterior wall of bronchus intermedius
- right paraspinal line
- left paraspinal line
- aortic-pulmonary stripe
- aortopulmonary window
- azygo-esophageal recess
- spaces
- signs
- air bronchogram
- big rib sign
- Chang sign
- Chen sign
- coin lesion
- continuous diaphragm sign
- dense hilum sign
- double contour sign
- egg-on-a-string sign
- extrapleural sign
- finger in glove sign
- flat waist sign
- Fleischner sign
- ginkgo leaf sign
- Golden S sign
- Hampton hump
- haystack sign
- hilum convergence sign
- hilum overlay sign
- Hoffman-Rigler sign
- holly leaf sign
- incomplete border sign
- juxtaphrenic peak sign
- Kirklin sign
- medial stripe sign
- melting ice cube sign
- more black sign
- Naclerio V sign
- Palla sign
- pericardial fat tag sign
- Shmoo sign
- silhouette sign
- snowman sign
- spinnaker sign
- steeple sign
- straight left heart border sign
- third mogul sign
- tram-track sign
- walking man sign
- water bottle sign
- wave sign
- Westermark sign
-
approach
- HRCT
-
chest x-ray
- airways
- bronchitis
- small airways disease
-
bronchiectasis
- broncho-arterial ratio
- related conditions
- differentials by distribution
- narrowing
-
tracheal stenosis
- diffuse tracheal narrowing (differential)
-
bronchial stenosis
- diffuse airway narrowing (differential)
-
tracheal stenosis
- diverticula
- pulmonary edema
-
interstitial lung disease (ILD)
- drug-induced interstitial lung disease
-
hypersensitivity pneumonitis
- acute hypersensitivity pneumonitis
- subacute hypersensitivity pneumonitis
- chronic hypersensitivity pneumonitis
- etiology
- bird fancier's lung: pigeon fancier's lung
- farmer's lung
- cheese workers' lung
- bagassosis
- mushroom worker’s lung
- malt worker’s lung
- maple bark disease
- hot tub lung
- wine maker’s lung
- woodsman’s disease
- thatched roof lung
- tobacco grower’s lung
- potato riddler’s lung
- summer-type pneumonitis
- dry rot lung
- machine operator’s lung
- humidifier lung
- shower curtain disease
- furrier’s lung
- miller’s lung
- lycoperdonosis
- saxophone lung
-
idiopathic interstitial pneumonia (mnemonic)
- acute interstitial pneumonia (AIP)
- cryptogenic organizing pneumonia (COP)
- desquamative interstitial pneumonia (DIP)
- non-specific interstitial pneumonia (NSIP)
- idiopathic pleuroparenchymal fibroelastosis
- lymphoid interstitial pneumonia (LIP)
- respiratory bronchiolitis–associated interstitial lung disease (RB-ILD)
- usual interstitial pneumonia / idiopathic pulmonary fibrosis (UIP/IPF)
-
pneumoconioses
- fibrotic
- non-fibrotic
-
lung cancer
-
non-small-cell lung cancer
-
adenocarcinoma
- pre-invasive tumors
- minimally invasive tumors
- invasive tumors
- variants of invasive carcinoma
- described imaging features
- adenosquamous carcinoma
- large cell carcinoma
- primary sarcomatoid carcinoma of the lung
- squamous cell carcinoma
- salivary gland-type tumors
-
adenocarcinoma
- pulmonary neuroendocrine tumors
- preinvasive lesions
-
lung cancer invasion patterns
- tumor spread through air spaces (STAS)
- presence of non-lepidic patterns such as acinar, papillary, solid, or micropapillary
- myofibroblastic stroma associated with invasive tumor cells
- pleural invasion
- vascular invasion
- tumors by location
- benign neoplasms
- pulmonary metastases
- lung cancer screening
- lung cancer staging
-
non-small-cell lung cancer
Radiographic views
- imaging in practice
- paediatric radiography
- general radiography (adult)
- shunt series
- chest radiography
- abdominal radiography
-
upper limb radiography
-
shoulder girdle radiography
- scapula series
-
shoulder series
- AP view
- internal rotation view
- external rotation view
- superoinferior axial view
- inferosuperior axial view
- modified trauma axial
- supine lateral
- modified supine lateral
- Y lateral view
- AP glenoid view (Grashey view)
- apical oblique view (Garth view)
- humerus (neck) AP view
- humerus axial (bicipital groove) view (Fisk view)
- outlet view (Neer view)
- Stryker notch view
- acromioclavicular joint series
- clavicle series
- sternoclavicular joint series
- arm and forearm radiography
- wrist and hand radiography
-
shoulder girdle radiography
-
lower limb radiography
- pelvic girdle radiography
- thigh and leg radiography
- ankle and foot radiography
- skull radiography
-
paranasal sinuses and facial bones radiography
- facial bones
- Caldwell view (angled skull PA view)
- nasal bones
- zygomatic arches
- orbits
- paranasal sinuses
- temporal bones
- dental radiography
- orthopantomography (OPG)
- mandible
- temporomandibular joints
- spine radiography