Pediatric chest (horizontal beam lateral view)

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The horizontal beam (cross-table) pediatric lateral chest view is a modified lateral projection often utilized in populations under the age of 6 months old due to the inability of that patient to independently hold up their head.

Indications

A lateral radiograph helps confirm the presence of an anterior pneumothorax that is suspected but not definite based on a frontal radiograph . A lateral decubitus view would be an alterative for this indication.

There is a body of research that suggest the lateral projection is not required for the detection of pneumonia in the paediatic patient . The appropriateness of a lateral chest x-ray in the paediatic patient will differ from institution to institution.

Patient position

  • the patient is supine, placed on a radiolucent sponge to ensure the entirety of the chest is imaged
  • arms are held above the patients by either a carer, nurse or external velcro straps. Legs are kept still by either a carer, nurse or external velcro strap
  • left side of the thorax adjacent to the image receptor
  • chin raised out of the image field
  • midsagittal plane must be perpendicular to the divergent beam
  • patient is placed close to the image receptor to ensure little to no magnification and ultimately a safe examination

Technical factors

  • lateral projection
  • suspended inspiration (on observation)  
  • centering point
    • the midcoronal plane of the level of the 7th thoracic vertebra, approximately the inferior angle of the scapulae  
  • collimation
    • superiorly 5 cm above the shoulder joint to allow proper visualization of the upper airways 
    • inferior to the inferior border of the 12th rib 
    • anteroposterior to the level of the acromioclavicular joints
  • orientation  
    • landscape
  • detector size
    • fit to childs chest 
  • exposure 3
    • 70 kVp
    • 1.6 mAs
  • SID
    • 180 cm
  • grid
    • grid is often not used

Image technical evaluation 

The entire lung fields should be visible superior from the apices inferior to the posterior costophrenic angle

  • the chin should not be superimposing any structures 
  • there is superimposition of the anterior ribs
  • the sternum is seen in profile
  • superimposition of the posterior costophrenic recess
  • a minimum of ten posterior ribs are visualized above the diaphragm
  • the ribs and thoracic cage are seen only faintly over the heart
  • clear vascular markings of the lungs should be visible

Practical Points

In order to streamline workflow, preparing the room beforehand (set up the detector and prepare lead gowns) will be extremely useful in pediatric chest imaging.

Immobilization

Children under the age of 6 months will seldom maintain a position, and to leave them on an examination table unattended is irresponsible. Departments will either have specialized equipment or utilize the carer/parent, radiographer, or nurse to maintain the child's position.

Specialized equipment

Specialized pediatric departments will often have immobilization devices that possess multiple velcro attachment points to ensure the patient is not moving during the examination. The appropriateness in using these devices will vary greatly from region to region.

Personnel immobilizing the patient

When specialized equipment is not available, yet a lateral cross table projection is required, the radiographer may nominate themselves, a carer/parent or the nurse to maintain a correct patient position. The patient should be placed on a radiolucent sponge to ensure no artifact from the table/bed is present, arms will be placed above head (placing them behind the head restricts movement and is most effective) and the legs kept still to avoid movement.