Chest X-ray
From Wikipedia, the free encyclopedia
| Intervention: Chest X-ray | ||
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| ICD-10 code: | ||
| ICD-9 code: | 87.3-87.4 | |
| Other codes: | ||
A chest X-ray, commonly abbreviated CXR, is a projection radiograph (X-ray), taken by a radiographer, of the thorax which is used to diagnose problems with that area.
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[edit] Problems identified through chest x-rays
Examples of such problems include but are not limited to:
- Pneumothorax, sometimes tension pneumothorax (though this is usually diagnosed clinically because of its acute nature)
- Rib fracture
- Air space disease/consolidation (e.g. pneumonia)
- Interstitial lung disease (e.g. idiopathic pulmonary fibrosis (IPF), lung cancer, active tuberculosis)
- Cardiac silhouette enlargement - congestive heart failure, pericardial effusion, hypertrophic cardiomyopathies
- Pleural effusion
- Peritonitis
- Hiatal hernia
- Emphysema
- Pulmonary embolism (rarely) - usually CXR is normal
- Dissecting aortic aneurysm (due to trauma, advanced/untreated syphilis, connective tissue disorders)
Chest X-Rays are among the most common films taken, being diagnostic of so many important problems.
[edit] Features that are typically examined on a chest X-ray
A commonly used mnemonic for what to look for on a chest X-ray is: It May Prove Quite Right (but) Stop And Be Certain How Lungs Appear:
- I = Identification (name, age, sex, indication for X-ray)
- M = Markers (differentiate left from right - diagnose dextrocardia)
- P = Position - the spinous process of T4 should be between the heads of the clavicle (if it isn't the body is rotated)
- Q = Quality - is the film penetrated properly. In a properly penetrated film the vertebral interspaces should be visible behind the central (cardiac) shadow
- R = Respiration - chest X-rays are typically done with full inspiration
- (but)
- S = Soft tissue - look for subcutaneous emphysema (suggestive of trauma), soft tissue swelling
- A = Abdomen - look for free abdominal air (suggests penetrating trauma, peritonitis, or recent surgery)
- B = Bone - look for fractures (these tend to be at the lateral aspects because of the mechanics - bending moment largest at lateral aspect)
- C = Central shadow (cardiac silhouette) - greater than 50% of lateral distance in frontal view at the diaphragm suggests cardiac enlargement (usually secondary to heart failure) or a pericardial effusion). A widened mediastinum may suggest aortic dissection.
- H = Hila (of the lungs) - can be affected in lung disease, malignant processes and infection (hilar lymphadenopathy).
- L = Lungs - for consolidation, interstitial lung disease (reticular, nodular or reticulonodular), honeycombing, miliary pattern, granulomas, lung masses
- A = Absent structures/Apices of the lung (for pneumothorax)
[edit] Views
[edit] Typical views
- Frontal (view)
- PA (posterior-anterior)
- AP (anterior-posterior) - these are typically done in the ICU
- Lateral (view)
The most common view is the PA (posterior-anterior) and is frequently done with a left lateral view (so one can identify the location of abnormalities in 3-D space). PA views are generally preferred to AP views (which are often done with mobile/portable X-ray equipment), but much less convenient in the ICU setting or when a patient cannot otherwise leave their bed. PA views are preferred because the central shadow is better defined and less of the lungs obscured by the heart/pericardial sac.
[edit] Additional views
- Decubitus - useful for differentiating pleural effusions from consolidation (e.g. pneumonia). In effusions, the fluid layers out (by comparison to an up-right view, when it often accumulates in the costophrenic angles).
- Lordotic view - used to visualize the apex of the lung, to pick-up abnormalities such as a Pancoast tumour.
- Expiratory view - helpful for the diagnosis of pneumothorax
[edit] Limitations
It must be remembered that while the chest X-ray is a cheap and safe method of investigating diseases of the chest, there are a number of serious chest conditions that may be associated with a normal chest X-ray and other means of assessment may be necessary to make the diagnosis:
- Asthma
- Chronic obstructive pulmonary disease
- Pneumocystis jiroveci pneumonia (PCP)
- Pulmonary embolism
- Smoke inhalation
- Foreign body inhalation
