Pediatric abdomen (lateral decubitus view)

The lateral decubitus radiograph is an additional projection for assessing the pediatric abdomen. This view is ideal for displaying free air in the abdomen and/or if the patient is unable to lie supine 1. As radiation dose is an important consideration for pediatric imaging, the lateral decubitus view is not often performed; although this will vary based on the department. 

  • patient is in a left lateral decubitus position with both knees bent up
  • ensure no rotation of hips and shoulders
  • remove any radiopaque items (e.g. ECG dots, diaper, shiny decorative clothing)
  • take the x-ray in full inspiration
  • posteroanterior projection
    • ​in order to reduce the radiation dose to radiosensitive organs 1
  • centring point
    • the midsagittal plane (xiphisternum) at the level of the iliac crest
  • collimation
    • laterally to the lateral abdominal wall
    • superior to the diaphragm
    • inferior to the inferior pubic rami
    • it is not advised to collimate too tightly laterally in case of missing bowel loops and/or organs 1
  • orientation
    • portrait
  • detector size
    • will vary depending on the child's body habitus
  • exposure 2
    • 60-75 kVp
    • 2-10 mAs
  • SID
    • 100 cm
  • grid
    • ​if patient thickness is above 10 cm, use of a grid is advisable 2
  • include the
    • lateral abdominal wall
    • inferior pubic rami inferiorly
  • must include the diaphragm superiorly
  • the abdomen should be free from rotation with symmetry of the:
  • no blurring of the bowel gas due to respiratory motion
  • It may be useful to position the patient so that they can see their parents in order to reduce anxiety
  • pediatric patients may feel uncomfortable when bony landmarks are felt for, therefore an appropriate explanation to the patient beforehand is ideal for improving patient comfort
  • to achieve sufficient inspiration, using child-appropriate language will be useful
    • e.g. 'breathe in as if you are about to go diving underwater!', 'breathe in as if you are about to blow out a birthday candle!'

It is important for the image to be free from movement artefact and rotation to avoid repeated x-rays.

  • it may be necessary for the parent or radiographer to stand with the patient or hold them in position
  • sometimes it is only necessary to keep the child's arms away from the abdominal area; in these cases, asking the child to hold onto something to their side (e.g. toy, mother's hand, pole) may be useful. 
  • techniques will vary based on the department
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Article information

rID: 68969
System: Paediatrics
Section: Radiography
Synonyms or Alternate Spellings:
  • Abdo x-ray lateral decubitus
  • lateral decubitus abdomen radiograph
  • Pediatric abdomen (lateral decubitus view)

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