Chest x-ray review (basic)
- this is a basic article for medical students and non-radiologists
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Chest radiographs are frequently performed and a fantastic tool for making diagnoses of acute and chronic conditions, as well as acting as a tool for follow up.
There are many systematic ways to review a chest x-ray. The important thing is to get into the habit of having a systematic approach. If you do the same thing every time you look at a chest x-ray, you will be much less likely to make a mistake.
Start off the same way each time you look at a film. Every time you look at an x-ray or other scan, think about:
- who, what, why, where and when
When looking at chest x-rays, also think about:
- lines and tubes
A, B, C, D, E
One of the easiest systems for reviewing a chest x-ray is A, B, C, D, E (using the same headings as ALS (advanced life support):
- A: airway
- B: breathing (lungs and pleural spaces)
- C: circulation (cardiomediastinum)
- D: disability (fractures and dislocations)
- E: exposure (everything else)
The airways are often overlooked
- start at the top and follow the trachea down in the midline to the carina
- trace the right and left main stem bronchi
- the angle between the left and right mainstem bronchi shouldn't be much more than 90 degrees
Breathing (lungs and pleural spaces)
- compare each size in all 4 zones looking for altered density or focal mass lesions
- check around the lungs starting laterally, from the apex down to the costophrenic angle
- does the lung extend to the chest wall
- is there a pneumothorax?
- check both costophrenic angles
- is there an effusion?
- ensure you can trace the hemidiaphragms to the spine
- check the cardiac borders up to the hilar structures
Assessment of the mediastinum is predominantly about looking at the heart, but it is imperative to remember the other structures in the mediastinum.
Assess the size of the heart, review the aortic knuckle and the upper mediastinal contour. After that, check the pulmonary vessels and the hilar structures. The left hilum is usually higher than the right.
The final thing to look for is a hiatus hernia with a retrocardiac fluid-fluid level.
Check the bony thorax, especially the ribs for any evidence of fracture. If the shoulders have been includes on the film, check the glenohumeral joints and the clavicles.
Exposure (everything else)
At the end of the review, you need to remember to check for other things that don't fall into the A-D categories. This includes free gas within the abdomen (pneumoperitoneum), abnormalities in the soft tissues of the thorax including absent breast shadows.
Double-check the apices (masses, pneumothorax), hila (masses, lymphadenopathy), retrocardiac zone (lobar collapse, hiatus hernia) and below the diaphragm (tubes and free air).
Finally, always compare to old films.
- most common cause of death due to infectious diseases
- higher incidence at the extremes of age
- streptococcus pneumoniae - most common organism
- homogenous opacification in lobar pattern
- characteristic air bronchograms and volume loss
- more: lobar pneumonia
- due to obstruction; luminal (aspiration, mucous plugging), mural (cancer) or extrinsic (mass compression)
- RUL: right upper medial opacification, elevated horizontal fissure and right hilum
- LUL: left hemithorax ‘veil-like’ opacity, elevated left hilum
- RML: horizontal fissure not visible, ill-defined right heart border
- RLL: right medial basal triangular opacification, depressed right hilum
- LLL: left retrocardiac triangular opacification, double cardiac contour, depressed left hilum, loss of descending aortic and left medial hemidiaphragmatic outline
- secondary signs: elevated hemidiaphragm, crowding of ribs and mediastinal shift towards affected side
- more: lobar collapse
- air in pleural space
- categorized as primary spontaneous, secondary spontaneous (underlying lung disease) or iatrogenic/traumatic
- simple: clearly defined visceral pleural edge paralleling chest wall, peripheral lucency with absent lung markings
- tension: overexpanded hemithorax, depressed hemidiaphragm, contralateral mediastinal shift
- more: pneumothorax
Congestive cardiac failure
- commonly due to left ventricular failure
- stage 1: redistribution (upper lobe diversion, cardiomegaly)
- stage 2: interstitial edema (Kerley B lines, peribronchial cuffing, hazy hilar vessels)
- stage 3: alveolar edema (consolidation, air bronchogram, cottonwool appearance, pleural effusion)
- more: congestive cardiac failure
- collection of fluid within pleural cavity
- most commonly due to cardiac failure (transudate) or malignancy (exudate)
- >200ml fluid required for meniscus at costophrenic angle on erect CXR
- opaque hemithorax and contralateral mediastinal shift in large volume effusions
- hydropneumothorax - no meniscus visible
- more: pleural effusion
- leading cause of cancer mortality worldwide
- divided into non-small cell and small cell carcinomas
- adenocarcinoma most common histological subtype
- may present as a peripheral rounded or spiculated mass, hilar/perihilar mass, mediastinal widening, lobar collapse or pleural effusion
- more: lung carcinoma
- metastatic spread to lungs via blood or lymphatics
- most common primaries include breast cancer, colorectal cancer and renal cell cancer
- peripheral, rounded nodules scattered throughout lungs
- more: pulmonary metastases