From the Guidelines
To read a pediatric chest X-ray, follow a systematic approach starting with proper positioning and technical adequacy assessment, and consider using point-of-care ultrasound (POCUS) as an adjunct tool for detecting pneumonia, pneumothorax, and pleural effusions, as it has been shown to have higher diagnostic accuracy compared to chest X-rays in certain cases 1. When evaluating a pediatric chest X-ray, it is essential to consider the child's age and anatomical differences compared to adults. Children have a more horizontal rib orientation, and their hearts appear proportionally larger 1. The thymus may appear as a sail-shaped opacity in the upper mediastinum, which is normal until age 3-4.
Systematic Approach to Reading Pediatric Chest X-ray
- Check the child's positioning and technical adequacy of the X-ray
- Evaluate the airway, noting the position and patency of the trachea
- Examine the lungs for proper inflation, abnormal opacities, or air trapping
- Assess the heart size, which should be less than 50-55% of the thoracic width on an AP view
- Look at the diaphragm for proper contour and position, and examine the pleural spaces for effusions
- Check the bones and soft tissues for abnormalities or asymmetry
Use of POCUS in Pediatric Chest X-ray Interpretation
- POCUS can be used to detect pneumonia, pneumothorax, and pleural effusions with high diagnostic accuracy 1
- LUS signs of pneumonia include consolidations, dynamic air bronchograms, B-lines, and pleural effusion
- POCUS can also be used to guide thoracentesis and evaluate lung aeration in acute respiratory distress syndrome (ARDS) 1
Clinical Context and Comparison with Previous Images
- Always consider the clinical context when interpreting pediatric chest X-ray findings
- Compare with previous images when available to assess for changes or improvements in the child's condition
- Use the systematic approach and consider the use of POCUS as an adjunct tool to improve diagnostic accuracy and patient outcomes 1
From the Research
Understanding Pediatric Chest X-Rays
To read a pediatric chest X-ray, it is essential to understand the fundamental principles of obtaining and interpreting the images 2. The radiographic technique for pediatric chest X-rays differs substantially from that in adults, with anteroposterior (AP) and posteroanterior (PA) X-rays being sufficient in most cases, and lateral radiographs rarely needed 3.
Key Structures to Identify
When interpreting a pediatric chest X-ray, it is crucial to identify key anatomical structures, including:
- The trachea with the bifurcation and the main bronchi with the adjacent great vessels
- The thymus, which may overshadow the heart, great vessels, and lung hila in the first years of life
- The lungs and mediastinum, for which knowledge of anatomy in childhood and malformations is essential
Common Abnormalities
Some common radiological abnormalities seen in children include:
- Pulmonary edema, which can be caused by various mechanisms, including hydrostatic pressure edema, permeability edema, and mixed edema 4
- Pneumonia, pneumothorax, and foreign body aspiration or ingestion, for which chest X-rays are commonly requested 2
Structured Approach to Interpretation
A structured and logical approach to X-ray interpretation is recommended, drawing attention to abnormal signs that should be sought 5. This approach can help clinicians arrive at the correct diagnosis in many cases. Additionally, knowledge of the underlying mechanism and rationale for requesting X-rays can aid in communicating the relevance of the procedure to other team members 2.
Diagnostic Workflow
In complex cases, optimized computed tomography (CT) and/or magnetic resonance imaging (MRI) may be crucial in the diagnostic workflow, particularly for congenital heart diseases, lung and airway malformations, and pulmonary complications in cystic fibrosis 3. Ultrasound should always be used to investigate diseases of the pleura and chest wall 3.