Pediatric abdomen (PA erect view)

The PA erect abdominal radiograph is the standard view for assessing air-fluid levels and free air in the pediatric abdomen. This view may be taken alongside the AP supine and lateral decubitus views. As radiation protection is an essential consideration in pediatrics, some departmental protocols may only perform one view (either the PA erect or AP supine view) depending on the clinical indications ¹. 

Indications

This view is often performed supplementary to the supine radiograph. It demonstrates air-fluid levels in pathologies such as bowel obstruction or pneumoperitoneum.

Patient position

• patient is standing facing the upright bucky with no rotation of the shoulders and hips

• remove any radiopaque items (e.g. ECG dots, diaper, shiny decorative clothing)

• take the x-ray in full inspiration

• hands are placed by the patients side and away from the abdomen

Technical factors

• posteroanterior projection

• centering point

  • approximately 2 cm above the iliac crests at the midsagittal plane

• 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 ²

• orientation

  • portrait

• detector size

  • will vary depending on the child's body habitus

• exposure ³

  • 60-75 kVp

  • 2-10 mAs

• SID

  • 100 cm

• grid

  • ​if patient thickness is above 10 cm, use of a grid is advisable ³

Image technical evaluation

• 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:

  • ribs (superior)

  • iliac crests (middle)

  • obturator foramen (inferior)

• no blurring of the bowel gas due to respiratory motion

Practical points

• sometimes to reduce the child's anxiety, it may be necessary to perform this view anteroposterior; children may feel more comfortable being able to see their parent (instead of facing the bucky)

• 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!'

Immobilization techniques

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