Pediatric chest (AP erect view)

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The anteroposterior erect chest view is ideal in younger cooperative pediatric patients (approximately 3-7 years old; this age range is only a guide). This chest view examines the lungs, bony thoracic cavity, mediastinum and great vessels.

The AP erect view is often chosen over the PA erect view for younger children as this view allows for observing the child’s breathing and decreased patient stress (due to the child being able to observe what is happening in the room). However, the AP view will result in an increased radiation dose to radiosensitive organs and magnify the heart and mediastinum . The choice to perform a PA erect or AP erect chest view will depend on the radiographer’s judgment of the patient’s cooperative and understanding ability.

Patient position

  • patient is sitting or standing erect
    • if patient is seated, ensure that the lower limbs are not on the same level as the buttocks (i.e. full extension) as this creates lordosis. Ideally, have the child sit on a box or sponge so the legs are below the buttocks
  • head is straight and chin raised out of the field of view
  • have the patient's arms raised above their head

Technical factors

  • anteroposterior projection
  • suspended inspiration
    • observe breathing by watching the patient’s stomach
  • centering point
  • collimation
    • superior to the 3rd cervical vertebrae
    • inferior to the thoracolumbar junction
    • lateral to the skin margins
    • it is advised not to collimate too tightly at the apices as breathing may cause the apices to move superiorly
  • orientation
    • portrait
  • detector size
    • 24 cm x 30 cm or 35 cm x 43 cm depending on the patient’s size
  • exposure
    • 73-81 kVp
    • 1-2 mAs
  • SID
    • 110 cm
  • grid
    • no

Image technical evaluation

  • entire lung fields should be visible; post-processing collimation is not advisable in pediatric imaging (if it is exposed it should be examined). This is particularly important if the clinical indications query a foreign body as demonstrating the abdomen will also be useful in diagnosis
  • full inspiratory effort
    • ensure 8 visible posterior ribs in children aged 0-3 years old
    • ensure 9 posterior ribs in children aged 3-7 years old
    • ensure 10 posterior ribs in children aged 7 years old and above
  • lung fields are symmetrical in size, 
Rotation
  • the clavicles lie on the same horizontal plane and anterior ribs are of equal length
    • due to ossification centers in children, the medial ends of clavicles are difficult to visualize; therefore measuring the medial ends of the clavicle to the spinous process is not advised
  • the head of clavicles to lie at the level between T2 and T4

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.

Ensuring appropriate inspiration and no motion may also require specialized communication techniques to gain cooperation from the child. Examples include:

  • “you have to breathe in like you are about to blow out a birthday candle!”
  • “take a big sniff now”
  • “lets play dead fish!”
  • “freeze!”
Immobilization

The AP erect chest view is often associated with using the parent or a staff member to hold the child’s arms above their head. However, research regarding the most effective method of immobilization is lacking. It is suggested to try explanations and distraction before automatically assuming the patient requires physical holding .

Specialized equipment

Specialized pediatric departments will have 'chairs' appropriate to hold children during examination , these chairs often contain multiple Velcro strap points, are counterweighted for stability and have a radiolucent backing such as perspex. It is important when using this equipment that the children is safely fastened with no risk of falling. In extreme cases, the parent may stand in front of the patient ensuring they feel safe.